The Neoichnology of Juliform Millipedes and Upper Monongahela to Lower Dunkard

Group Paleosols: A Multi-Proxy Approach to Paleolandscape Variability

A thesis presented to

the faculty of

the College of Arts and Sciences of Ohio University

In partial fulfillment

of the requirements for the degree

Master of Science

Jared J. Bowen

December 2013

This thesis titled

The Neoichnology of Juliform Millipedes and Upper Monongahela to Lower Dunkard

Group Paleosols: A Multi-Proxy Approach to Paleolandscape Variability

JARED J. BOWEN

has been approved for

the Department of Geological Sciences

and the College of Arts and Sciences by

Daniel I. Hembree

Associate Professor of Geological Sciences

Robert Frank

Dean, College of Arts and Sciences 3

ABSTRACT

BOWEN, JARED J., M.S., December 2013, Geological Sciences

The Neoichnology of Juliform Millipedes and Upper Monongahela to Lower Dunkard

Group Paleosols: A Multi-Proxy Approach to Paleolandscape Variability

Director of Thesis: Daniel I. Hembree

Ichnology and paleopedology are becoming increasingly important to understanding the complexities of continental paleoclimatic, paleoenvironmental, and paleoecological conditions. Forming and behaving in direct response to external conditions, studies of paleosols and the organisms that were interacting with these ancient soils are imperative to making accurate interpretations. In order to further facilitate the understanding of how soils, organisms, and external factors are related, two separate studies were conducted.

The first study consisted of an investigation into the morphology of traces produced by two species of extant burrowing millipedes; Narceus americanus and Floridobolus penneri. Biogenic structures produced included vertical, subvertical, helical, O- and J- shaped burrows. By comparing these structures to those of two other juliform millipedes,

Orthoporus ornatus and Archispirostreptus gigas, using statistical analyses differences in burrow morphology were attributed to the function of the burrow rather than environmental conditions. The second study consisted of a paleopedologic, ichnologic, and paleontologic investigation into the upper Monongahela and lower Dunkard group paleosols in southeastern Athens County, Ohio. Eight distinct pedotypes were identified based on micro- and macro-morphological features and were interpreted as variations of

Vertisols, Inceptisols, Entisols, and a Histosol in a mostly fluvial-dominated, 4 aggradational floodplain. Large lateral and vertical variations in the studied sections were attributed to changes in climatic, topographic, and depositional settings. The results of these studies can be directly applied to understanding ancient continental settings and stresses the importance of combining all available information in order to make educated, accurate, paleoclimatic, paleoenvironmental, and paleoecological interpretations. 5

ACKNOWLEDGMENTS

I would like to thank my advisor, Dr. Daniel Hembree for taking me on as his

student and teaching me things about paleosols and ichnofossils that I would never have known otherwise, as well as his patience with me while working on this project. I would also like to thank my committee members, Dr. Alycia Stigall and Dr. Gregory Nadon for their suggestions and advise in their areas of expertise.

I would like to thank Allison Durkee for her hard work in the field and in the

Continental Ichnology Laboratory that made completion of this work possible. I thank the other paleontology graduate students, Hannah Brame and Mike Hils for their advice, discussions, and lending an ear as the scope of this project increased. Additionally, I would like to thank the other graduate students in the department for providing much needed stress relieving activities and support.

Finally, I would like to thank my family for their endless support in my desire for higher education and their understanding of my busy schedule.

This work would not have been possible without funding from the National Science

Foundation (EAR-0844256), the Ohio University Department of Geological Sciences

Alumni Graduate Research Grant, and the SEPM Ed Picou Fellowship Grant for

Graduate Studies in the Earth Sciences.

TABLE OF CONTENTS

Page

Abstract ...... 3 Acknowledgments...... 5 List of Tables ...... 9 List of Figures ...... 10 1 Introduction ...... 22 1.1 References ...... 25 2 The Neoichnology of Juliform Millipedes: Burrows of Soil Macrodetritivores ...... 29 2.1 Abstract ...... 29 2.2 Introduction ...... 30 2.3 Millipede Ecology and Behavior ...... 33 2.4 Materials and Methods ...... 37 2.5 Experimental Results ...... 45 2.5.1 Behavior ...... 45 2.5.2 Surface Trace Morphology ...... 58 2.5.3 Burrow Morphology ...... 60 2.5.4 Environmental Effects ...... 77 2.6 Analysis of Burrow Architecture ...... 78 2.6.1 Burrows of N. americanus ...... 78 2.6.2 Burrows of F. penneri ...... 82 2.6.3 Narceus americanus and F. penneri Burrows ...... 83 2.6.4 Spirobolid and Spirostreptid Burrows ...... 85 2.6.5 Environmental Conditions and Burrow Morphology ...... 87 2.7 Discussion ...... 93 2.7.1 Organism and Burrow Morphology ...... 93 2.7.2 Burrow Morphology and Behavior ...... 97 2.7.3 Burrow Morphology and Sediment Properties ...... 101 2.7.4 Millipede Burrows: Function and Similarity ...... 102 2.8 Significance ...... 104 7

2.8.1 Recognition of Juliform Millipede Burrows in the Fossil Record ...... 104 2.8.2 Paleontologic and Paleoecologic Significance ...... 106 2.8.3 Paleopedologic and Paleoenvironmental Significance ...... 109 2.9 Conclusions ...... 112 2.10 References ...... 115 3 A Multi-Proxy Approach to Complex Variability in Ancient Terrestrial Landscapes ...... 124 3.1 Abstract ...... 124 3.2 Introduction ...... 125 3.3 Geologic Setting ...... 129 3.4 Methodology ...... 136 3.5 Stratigraphy and Sedimentology ...... 139 3.5.1 Upper Monongahela Group ...... 140 3.5.2 Lower Dunkard Group ...... 143 3.6 Continental Ichnology of the Uppermost Monongahela and Lower Dunkard Groups ...... 145 3.6.1 Rhizoliths ...... 148 3.6.2 Animal-Soil Interactions ...... 158 3.6.3 Coprolites ...... 173 3.6.4 Plant-Animal Interactions ...... 176 3.7 Body Fossils ...... 179 3.7.1 Flora ...... 179 3.7.2 Fauna ...... 185 3.8 Paleosols of the Upper Monongahela and Lower Dunkard Groups ...... 186 3.8.1 Monongahela Group Paleosols ...... 188 3.8.2 Monongahela and Dunkard Group Paleosols ...... 204 3.8.3 Dunkard Group Paleosols ...... 213 3.9 Discussion ...... 246 3.9.1 Late Pennsylvanian-Early Permian Soil Ecosystems ...... 247 3.9.2 Monongahela and Dunkard Group Landscape Evolution ...... 256 3.9.3 Sedimentation Rates and Time of Exposure ...... 257 3.9.4 Local Hydrology and Topography ...... 258 8

3.9.5 Paleoclimate and Monongahela and Dunkard Group Paleosols ...... 264 3.10 Conclusion ...... 271 3.11 References ...... 276 4 Conclusions ...... 295 4.1 References ...... 297 Appendix 1: Bray Curtis Similarity Matrix of all Burrows Used ...... 299 Appendix 2: Spearman’s Rank Analysis For N. americanus ...... 300 Appendix 3: Spearman’s Rank Analysis for N. americanus ...... 301 Appendix 4: Spearman’s Rank Analysis for F. penneri ...... 302 Appendix 5: Spearman’s Rank Analysis for F. penneri ...... 303 Appendix 6: Detailed Stratigraphic Columns ...... 304

LIST OF TABLES

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Table 2.1: Experimental parameters and burrow architectures produced. Tank sizes are in gallons. In the sediment column, F= Coconut fiber (organic), and Sa= Fine- to medium-grained carbonate sand. Depth is the total depth of the sediment in the tank and is measured in centimeters. % Moisture is the average moisture content of the sediment. Duration is split into two categories; expected time to completion of trial and the actual trial duration in parentheses. Key to burrow architectures and modifications: V=Vertical shaft, Sub V=Subvertical burrow, H=Helical burrow, J=J-shaped burrow, O=O-shaped burrow (T1=Type 1, T2=Type 2), C=Chamber present, B=Branch present (# present in parentheses), DE=Two entrances...... 41

Table 2.2: Quantitative measurements of burrow casts of subvertical burrows (Sub V) produced by N. americanus...... 46

Table 2.3:Quantitative measurements of burrow casts of vertical shafts (V) and helical burrows (H) produced by N. americanus...... 47

Table 2.4: Quantitative measurements of burrow casts of O-shaped burrows (O) produced by N. americanus...... 48

Table 2.5: Quantitative measurements of burrow casts of subvertical burrows (Sub V) produced by F. penneri ...... 49

Table 2.6: Quantitative measurements of burrow casts of subvetical burrows (Sub V) produced by F. penneri, continued from Table 5 ...... 50

Table 2.7: Quantitative measurements of burrow casts of vertical shafts (V) produced by F. penneri ...... 51

Table 2.8: Quantitative measurements of burrow casts of J-shaped (J), helical (H), and O-shaped (O) burrows produced by F. penneri ...... 52

Table 3.1: Molecular weathering ratios, chemical index of alteration (CIA-K), estimated mean annual precipitation (MAP), and bulk geochemistry data calculated from whole- rock X-ray fluorescence (XRF) of samples from upper Monongahela and lower Dunkard group paleosols. Bulk geochemical data are given as weight percents ...... 194

Table 3.2: Clay mineralogy from X-ray diffraction (XRD) of the <4 micron fraction of upper Monongahela and lower Dunkard group paleosols. R1 M-L I/S 30%S: ordered mixed-layer illite/smectite with 30% smectite. R1 M-L I/S 20%S: ordered mixed-layer illite/smectite with 20% smectite ...... 195 10

LIST OF FIGURES

Page

Figure 2.1 Millipede morphology and distribution. A) Diagram of a N. americanus specimen used in this study showing the head, first five segments behind the head, and three diplosegments. B) Distribution map of N. americanus after Shelley et al. (2006). C) (Inset) Distribution of F. penneri in central Florida ...... 35

Figure 2.2 A) Coiled N. americanus specimen used in this study. B) N. americanus with usual color characteristics from Chimney Tops trail, Great Smoky Mountains, Tennessee. C) A F. penneri specimen used in this study. Scale bars are 1 cm ...... 38

Figure 2.3 Diagrams of quantitative burrow measurements. A) Burrows were described using the average of the angle at which they entered the subsurface (a) and the angle at which they shift below the surface (a1), total length (L), branching angle (BA), maximum depth below the surface (D), shaft and chamber width (w), height (h), and circumference (c). B) The complexity of a burrow system is the sum of the number of entrances (e), segments (s), and chambers (ch). C) The tortuosity of a burrow system is the average sinuosity of all burrow segments in the system. A single segment’s tortuosity is the total length of the segment (u) divided by the straight line distance (v). Based on Meadows, 1991...... 43

Figure 2.4 Illustrations of burrow architectures and modifications produced by N. americanus and F. penneri. Percents are of the total number of burrows produced by both N. americanus and F. penneri. Complexity (C) and tortuosity (T) are given as representative values that may occur in the given illustrations. A) Dominant architectures used to classify burrows represent gross burrow morphology. B) Modifications to dominant architectures that affect the quantitative properties. Black portions represent the modifying structures while gray portions represent the dominant background architectures ...... 53

Figure 2.5 Time lapse photographs of N. americanus burrowing in 50 coconut fiber/50 soil sediment under 35% moisture conditions. The photos are taken at approximately two minute intervals shortly after burrowing commenced ...... 55

Figure 2.6 Behaviors exhibited by F. penneri. A) Photograph of a 50 coconut fiber/50 soil sediment, 49% sediment moisture experiment with five individuals in a 65 gallon terrarium. Two individuals can be seen against the glass. Inset: Large chamber with a coiled millipede; molting was later observed in this chamber. B) Molting individual at the surface of a holding tank. C, D) Specimens that were excavated from a 50 carbonate sand/50 soil, 70% sediment moisture experiment; the white line indicates the sediment surface. E) Plaster cast of a possible communal burrow produced in a 25 carbonate sand/ 75 soil, 50% sediment moisture experiment. Two individuals entered and exited this 11

burrow several times before becoming inactive. The burrow was not used in analyses due to the entrance collapsing into a chamber prior to casting ...... 57

Figure 2.7 Surface traces produced by N. americanus and F. penneri. A) Surface furrowing and a shallow burrow produced by N. americanus in 50 coconut fiber/50 soil sediment under 35% sediment moisture conditions when the individual attempted to burrow. B) Surface furrowing produced by F. penneri in 25 carbonate sand/75 soil sediment under 50% sediment moisture conditions; trace-making specimen is in the upper right corner. C) Terrarium shown in B; arrows point to trails around the edges of the enclosure. D) Trails outlined by large grains in 50 coconut fiber/50 soil sediment. E) Burrow entrance produced by F. penneri in 50 carbonate sand/50 soil sediment. F) Burrow entrance produced by N. americanus in 50 coconut fiber/50 soil sediment...... 59

Figure 2.8 Surficial features present in the casts of millipede burrows. A) Vertically oriented wedge-shaped indent at the end of OS21F. Photograph taken from below the specimen at an oblique angle. B) Vertically oriented wedge-shaped indent at the end of OS26A. Photograph taken from below the specimen at an oblique angle. C–E) Fecal pellets preserved in the walls, floors, endpoints, and chambers of three F. penneri burrows (FB7H, FB7F, FB7G). Fecal pellets were found in burrows of both N. americanus and F. penneri ...... 62

Figure 2.9 Vertical shafts produced by N. americanus. A, B) Side views of two simple, vertical shafts (OS30A and OS33A). C) Oblique view of a vertical shaft with a terminal helical structure (OS30F) ...... 65

Figure 2.10 Vertical shafts produced by F. penneri. A, B) Side views of two simple, vertical shafts (FB2A and FB2B). C) Side view of a vertical shaft with an intermediate helical modification (FB7D) ...... 66

Figure 2.11 Subvertical burrows produced by N. americanus. A) Side view of a simple, subvertical burrow (OS21C). B) Side view of a simple, subvertical burrow (OS30D). C) Front view of a subvertical burrow with a small branch near the entrance (OS21D). D) Front view of a subvertical burrow with a small intermediate chamber (OS21E). E) Side view of a subvertical burrow with a terminal chamber (OS26A). Arrow points to a vertically oriented wedge-shaped indent ...... 68

Figure 2.12 Subvertical burrows produced by F. penneri. A) Front view of a simple, slightly sinuous subvertical burrow (FB2F). B) Side view of a simple, subvertical burrow (FB2E). C) Side view of a subvertical burrow with a small branch near the entrance (FB7F). D) Side view of a subvertical burrow with a terminal chamber (FB5E). E) Side view of a subvertical burrow with a large chamber and small branch (FB7H) ...... 70

Figure 2.13 Helical burrows produced by N. americanus. A) Side view of a simple, helical burrow (OS25B). B) Side view of a helical burrow with a small branch (OS29B). 12

C) Oblique view of a helical burrow with a chamber in the midsection of the burrow (OS21F). Arrow points to a vertically oriented, wedge-shaped indent ...... 71

Figure 2.14 Helical burrows produced by F. penneri. A) Side view of a simple, helical burrow (FB4B). B) Oblique view of a helical burrow with two small branches (FB1) .71

Figure 2.15 O-shaped burrows produced by N. americanus. A) Oblique view of the underside of a horizontally oriented, Type 2, O-shaped burrow just below the surface with an additional entrance (OS31A). B) Side view of a simple, Type 2, O-shaped burrow (OS31B). C) Front oblique view of a Type 1, O-shaped burrow at the terminal end of a subvertical shaft (OS29A). D) Side view of a Type 1, O-shaped structure (OS26B) ....74

Figure 2.16 O-shaped burrows produced by F. penneri. A) Side view of a Type 1, O- shaped burrow with two small branches (FB5F). B) Front view of a Type 1, O-shaped burrow with a chamber on one side of the O-shape (FB6B). C) Oblique side view of a Type 2, O-shaped burrow with a branch (FB5G) ...... 75

Figure 2.17 J-shaped burrows produced by F. penneri. A) Front view of a simple, J- shaped burrow (FB2J). B) Front view of a simple, J-shaped burrow (FB2I). C) J-shaped burrow with a branch near the entrance (FB2H) ...... 76

Figure 2.18 Summary of Bray Curtis similarity measure results for the burrows of four millipede species. Numbers are averages of the similarity values produced when burrows of similar or different architectures are compared. Total Avg columns represent the average value of similarity when all burrows produced by one species are compared to those produced by itself or another species. Values of 1.0 indicate that there was only one burrow produced of that architecture by that species. Values of 0.9–0.8 indicate high similarity, 0.7–0.6 indicate moderate similarity, and values of 0.5 or less indicate dissimilarity...... 80

Figure 2.19 Bray Curtis similarity measure results within the same burrow architectures of N. americanus. A) Comparison matrix of subvertical burrows. B) Comparison matrix of vertical shafts. C) Comparison matrix of helical burrows. D) Comparison matrix of O- shaped burrows. OS29A and OS26B are Type 1, O-shaped burrows. OS31A and B are Type 2, O-shaped burrows. Green cells indicate identical burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows ...... 81

Figure 2.20 Bray Curtis similarity measure results within the same burrow architectures of F. penneri. A) Comparison matrix of subvertical burrows. B) Comparison matrix of vertical shafts. C) Comparison matrix of J-shaped burrows. D) Comparison matrix of O- shaped burrows. FB5F and FB6B are Type 1, O-shaped burrows. FB5G is a Type 2, O- shaped burrow. E) Comparison table of helical burrows. Green cells indicate identical 13

burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows ...... 84

Figure 2.21 Bray Curtis similarity measure results comparing burrows produced by N. americanus (prefix OS) and F. penneri (prefix FB) of the same architectures. A) Comparison matrix of subvertical burrows. B) Comparison matrix of vertical shafts. C) Comparison matrix of helical burrows. D) Comparison matrix of O-shaped burrows. Green cells indicate identical burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows ...... 86

Figure 2.22 Bray Curtis similarity matrix comparing burrows produced by N. americanus (prefix OS) to burrows produced by O. ornatus (prefix SB). Cells outlined in thick black lines in the matrix indicate comparison of burrows with the same architecture. SB1, SB7, and SB10 are subvertical burrows. SB2, SB4, SB6, SB8, and SB9 are vertical burrows. SB5 is a sinuous burrow. SB3 is a U-shaped burrow. SB11–13 are J-shaped burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows ...... 88

Figure 2.23 Bray Curtis similarity matrix comparing burrows produced by F. penneri (prefix FB) to burrows produced by O. ornatus (prefix SB). Cells outlined in thick black lines in the matrix indicate comparison of burrows with the same architecture. SB1, SB7, and SB10 are subvertical burrows. SB2, SB4, SB6, SB8, and SB9 are vertical burrows. SB5 is a sinuous burrow. SB3 is a U-shaped burrow. SB11–13 are J-shaped burrows. Green cells indicate identical burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows ...... 89

Figure 2.24 Bray Curtis similarity matrix comparing burrows produced by N. americanus (prefix OS) to burrows produced by A. gigas (prefix AB). Cells outlined in thick black lines in the matrix indicate comparison of burrows of the same architecture. AB2 and AB8 are sinuous burrows. AB1, AB3, AB4, and AB6 are helical burrows. AB7 and AB5 are U-shaped burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows ...... 90

Figure 2.25 Bray Curtis similarity matrix comparing burrows produced by F. penneri (prefix FB) to burrows produced by A. gigas (prefix AB). Cells outlined in thick black lines in the matrix indicate comparison of burrows of the same architecture. AB2 and AB8 are sinuous burrows. AB1, AB3, AB4, and AB6 are helical burrows. AB7 and AB5 are U-shaped burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows ...... 91

SB5 is a sinuous burrow. SB3 is a U-shaped burrow. SB11–13 are J-shaped burrows. AB2 and AB8 are sinuous burrows. AB1, AB3, AB4, and AB6 are helical burrows. AB7 and AB5 are U-shaped burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows ...... 92

Figure 2.27 Scatter plots of data used in Spearman’s rank correlation tests of N. americanus burrows. Rs values indicate no significant relationship between sediment clay composition and sediment moisture to any of the eight different quantitative burrow properties tested ...... 94

Figure 3.1 A) Location of the Dunkard (green) and Monongahela (orange) groups in the Appalachian basin and the study area in southeast Ohio. B) Map of Athens County in southeast Ohio and location of the road cut used in this study...... 132

Figure 3.2 General stratigraphic columns and biostratigraphic age determinations of the upper Monongahela and Dunkard groups. A) Interpreted ages of upper Monongahela and Dunkard Group deposits based on biostratigraphic evidence. B) General stratigraphic column of the upper Monongahela Group present in southeastern Ohio (modified from Hembree et al. 2011 and Sturgeon 1958) combined with a stratigraphic column of Dunkard Group deposits from northern West Virginia and southwestern Pennsylvania (modified from Fedorko and Skema 2011) highlighting known green and red mudstone units as well as identifiable marker beds. C) General stratigraphic column of Dunkard Group deposits near Marietta, Ohio (modified from Martin 1998) in the approximate position of correlative deposits highlighting known red mudstone units ...... 133

Figure 3.3 Uniontown Mudstone to Little Waynesburg Coal. A) The base of Section 2. The three black bars represent approximate vertical exposure of the Uniontown Mudstone, Waynesburg Marlstone, and Gilboy Sandstone, respectively. B) The Uniontown Marlstone and overlying Waynesburg Limestone. Arrow points to the approximate contact. C) The Waynesburg Limestone (lower arrow) and the overlying Little Waynesburg Coal (upper arrow) ...... 142

Figure 3.4 Rhizohaloes from upper Monongahela and lower Dunkard group paleosols. A) Green rhizohalo with an organic core from a PT7 paleosol (S1, P#1-Bss) (brightness and contrast modified). B) Gray rhizohalo with an organic core from a PT1 paleosol (S1, P#30-A). C) Yellow rhizohalo with a brown core from a PT7 paleosol (S2, P#1-Bk). D) Thin section of a red rimmed, gray rhizohalo with an organic core from a PT3 paleosol (S3, P#16-Bk) (normal light). E) Thin section of a green rhizohalo from PT1 paleosol (S2, P#29-A) (cross-polarized light). F) Large green rhizohalo from a PT6 paleosol (S2, 15

P#12-A). G) Thin section of a small green rhizohalo from a DPT2 paleosol (S3, P#6-B) (cross-polarized light) ...... 150

Figure 3.5 Root casts from upper Monongahela and lower Dunkard group paleosols. A) Tan, fine-grained sandstone and siltstone root cast cemented with calcite from a PT5 paleosol (S1, P#16-Bg). B) Large, green root cast in a PT4A paleosol (S2, P#14-Bc). C) Thin section of a root cast cemented with calcite from a MPT2 paleosol (S2, P#22-Bg) (cross-polarized light). D) Thin section of a root cast filled with calcareous nodules and illuviated organics from a PT1 paleosol (S2, P#27-Bk) (normal light). E) Large, horizontally oriented, fine-sandstone filled root cast that tapers to the right (foreground) in a PT5 paleosol (S1, P#16-Ag). Arrow points to a circular, calcareous, mudstone-filled structure interpreted as a stump cast. These features are approximately 20 cm above the root cast shown in (A) ...... 153

Figure 3.6 Rhizotubules from upper Monongahela and lower Dunkard group paleosols. A) Branching rhizotubule from the C horizon of a PT7 paleosol (S2, P#1-Cg). B) Thin section of a rhizotubule filled with sparry calcite from the Bki horizon of a PT3 paleosol (S1, P#20-Bki) (cross-polarized light). Lines denote the edges of the rhizotubule. C) Cross section of a branching rhizotubule from a PT7 paleosol (S2, P#1-Bss). D) Thin section of a calcite spar-filled rhizotubule in a limestone from a MPT2 paleosol (S2, P#22-C) (cross-polarized light). The black arrow points to erosional surface with mosepic plasmic microfabric. The white arrow points to clay within the limestone matrix with an undulic plasmic microfabric. E) Rhizotubule from a PT7 paleosol (S2, P#1-Bss) ...... 154

Figure 3.7 Calcareous rhizoconcretions from upper Monongahela and lower Dunkard group paleosols. A) Field photograph of stacked rhizoconcretions forming a discontinuous bench in a PT4A paleosol (S2, P#15-Bkss). B) Thin section of a rhizoconcretion from a PT3 paleosol (S1, P#21-Btg) (cross-polarized light). C) Thin section of a rhizoconcretion incorporating iron oxides from a PT4B paleosol (S3, P#15- Bc) (normal light) ...... 156

Figure 3.8 Variations of root preservation in lower Dunkard group paleosols. A) Juxtaposition of several types of root preservation: 1) Calcareous root cast from a PT5 paleosol (S1, P#16-Bg); 2) Rhizoconcretion that alternates iron and calcite in the structure from a PT4B paleosol (S2, P#18-Bc); 3) Large calcareous root cast from the Bkss horizon of a PT4A paleosol (S2, P#15-Bkss); 4) Calcareous rhizoconcretion with iron-stained calcite on the exterior from a PT4A paleosol (S3, P#12-BC). The remaining are ferruginous or manganiferous root petrifactions or rhizoconcretions primarily from PT4B paleosols. B) Ferruginous petrifaction of Stigmaria from a PT4B paleosol. Arrow points to an indentation likely where the vascular bundle attaches to the outer wall. C) Cross section of a ferruginous petrifaction of Stigmaria from a PT4B paleosol with the vascular bundle preserved with calcite. D) Horizontally oriented, ferruginous root petrifaction from a PT4B paleosol. E) Ferruginous or manganiferous root petrifaction showing a central core from a PT4B paleosol. F) Thin section of a ferruginous 16 rhizoconcretion from a DPT2 paleosol (S1, P#4-Btss) (normal light). G) Thin section of a ferruginous rhizoconcretion from a PT3 paleosol (S3, P#17-Bgkss) (normal light) .... 159

Figure 3.9 Burrows in upper Monongahela and lower Dunkard group paleosols that are highlighted by color variations. A) Thin section of a gleyed burrow in a PT1 paleosol (S2, P#25-BCg) (cross-polarized light). B) Gleyed burrow in a PT4B paleosol (S2, P#16- ABss). C) Thin section of a gleyed burrow with a dark red rim from a PT6 paleosol (S1, P#12-BC) (cross-polarized light). D) Thin section of multiple small burrows with red rims from a PT6 paleosol (S1, P#12-BC) (cross-polarized light). E) Thin section of a gleyed, looped burrow from a DPT2 paleosol (S3, P#6-B) (cross-polarized light). F) Gleyed, looped burrow from a PT3 paleosol (S2, P#19-B) (brightness and contrast adjusted). The green areas are gleyed tunnels. G) Gleyed burrow from a PT3 paleosol (S3, P#6-B). H) Thin section of a J-shaped, gleyed burrow from a PT1 paleosol (S2, P#25-BCg) (cross-polarized light). I) Red-rimmed burrow from a PT1 paleosol (S1, P#29-B) ...... 162

Figure 3.10 Actively filled burrows from upper Monongahela and lower Dunkard group paleosols. A) Vertically oriented, thickly meniscate, sandstone-filled burrow from a MPT2 paleosol (S1, P#22-Bg). B) Tightly meniscate, back-filled burrow from a PT4B paleosol (S1, P#15-Bc). C) Scanned thin section of a tightly meniscate, back-filled burrow from a PT4B paleosol (S2, P#16-ABss). Arrows point to green rhizohaloes with yellow cores. D) Thin section of a poorly meniscate, back-filled burrow from a PT1 paleosol (S2, P#28-Bc) (normal light). E) Thin section of an actively filled burrow in a DPT2 paleosol (S1, P#5-Agk) (normal light). Arrows point to possible fecal pellets. F) Thin section of actively filled burrows from a DPT2 paleosol (S1, P#5-Agk) (normal light)...... 166

Figure 3.11 Passive, homogeneous-fill burrows from upper Monongahela and lower Dunkard group paleosols. A) Thin section of a burrow lined with organics from a MPT2 paleosol (S1, P#24-Btg) (normal light). B) Thin section of a compressed clay lined burrow with a chamber from a DPT2 paleosol (S1, P#2-BC) (cross-polarized light). C) Thin section of a burrow lined by illuviated clay from a MPT2 paleosol (S2, P#22-Bg) (normal light). D) J-shaped burrow from the C horizon of a PT7 paleosol (S2, P#1-Cg). E) Thin section of a partly clay lined burrow with a tunnel and chamber that is mostly visible due to differences in grain orientation from a MPT2 paleosol (S2, P#22-Bg) (cross-polarized light). F) Thin section of an unlined burrow visible due to differences in grain orientation from a MPT2 paleosol (S1, P#24-Btg) (cross-polarized light). Arrow points to the outer wall of the burrow. G) Thin section of a burrow partially lined with illuviated clay and visible due to differences in grain orientation from a MPT2 paleosol (S1, P#25-Btg) (normal light). Arrow points to possible fecal pellet ...... 168

Figure 3.12 Passive, heterogeneous-fill burrows from upper Monongahela and lower Dunkard group paleosols. A) Thin section of a vertically oriented burrow with fill that is 17

coarser than the surrounding matrix from a MPT2 paleosol (S2, P#22-Bg) (normal light). B) Thin section of a burrow with fill that is finer than the surrounding matrix from a MPT2 paleosol (S2, P#22-C) (cross-polarized light). C) Calcite cemented, vertically oriented burrow in a non-calcareous matrix from a MPT2 paleosol (S1, P#24-Btg). D) Large burrow chamber filled with coarser-grained material (light gray) than the surrounding matrix (light purple) in a PT1 paleosol (S3, P#25). E) Thin section of a subvertically oriented burrow with fill that is coarser than the surrounding matrix from a MPT2 paleosol (S1, P#25-Btg) (normal light). F) Scanned thin section of a burrow network with coarser fill than the surrounding matrix in a MPT2 paleosol (S1, P#23-Bk). Black arrows point to large diameter (upper) and small diameter (lower) tunnels. White arrow indicates up direction ...... 171

Figure 3.13 Passive heterogeneous-fill burrows and other features consisting of calcite spar from upper Monongahela and lower Dunkard group paleosols. A) Scanned thin section of a PT3 paleosol with arrows showing the locations of features in B–G (S1, P#20-Bki). B) Thin section of a sinuous, horizontally oriented burrow with organic fill (cross-polarized light). C) Thin section of a U-shaped burrow with abundant organics (cross-polarized light). D) Thin section of a burrow network with vertically oriented tunnels leading to chambers overprinting other features (cross-polarized light). E) Thin section of a Y-shaped burrow with arrows pointing to indentations along the wall of the burrow (cross-polarized light). F) Thin section of a sinuous, horizonally oriented burrow leading to an elongate chamber (cross-polarized light). G) Thin section of a preserved seed with rootlets extending from the bottom (normal light). H) Thin section of a subhorizontally oriented burrow leading to a chamber in a MPT2 paleosol (S1, P#22-C) (cross-polarized light). I) Thin section of a horizontally oriented burrow leading to an elongate chamber in a MPT2 paleosol (S2, P#23-C) (normal light) ...... 174

Figure 3.14 Coprolites from upper Monongahela and lower Dunkard group paleosols. A) Thin section of small, oblong to circular pellets in a gleyed burrow channel from a PT1 paleosol (S3, P#25-BC) (cross-polarized light). B) Thin section of a rectangular coprolite with rounded edges from a PT1 paleosol (S2, P#30-B) (cross-polarized light). Arrow points to a horizontally oriented burrow leading to a chamber within the coprolite. C) Thin section of a small, tear drop-shaped coprolite from a PT1 paleosol (S2, P#28-Bg) (cross-polarized light). D) Thin section of an elongate tear drop-shaped coprolite from a MPT2 paleosol (S1, P#25-Btg) (normal light). E) Thin section of a rounded, tear drop- shaped coprolite with a spiraled morphology from a PT6 paleosol (S3, #10-Bss) (cross- polarized light). Arrow points to an organic fragment with gleyed outline. F) Silica- replaced coprolite with a heteropolar spiral from a PT6 paleosol ...... 177

that crosses secondary veins of Neuropteris at an acute angle from a DPT2 paleosol (S2, P#8-Bssg). F) Crescent-shaped damage (DT12) in a Neuropteris from a DPT2 paleosol (S2, P#10-Bss) ...... 180

Figure 3.16 Fossil flora in upper Monongahela and lower Dunkard group deposits. A) Macroneuropteris from a DPT2 paleosol (S2, P#8-Bssg). B) Cordaites from a MPT2 paleosol (S2, P#21-Bg). C) Asterophyllites from a siltstone capping a PT7 paleosol (S2) (brightness and contrast adjusted). D) Pecopteris from a siltstone capping a PT7 paleosol (S2). E) Pecopteris from a fine-grained sandy mudstone capping a PT7 paleosol (S3). F) Sphenophyllum (?) from a mudstone capping a PT7 paleosol (S3). G) Lepidophylloides from a MPT2 paleosol (S2, P#20-Bg). H) Danaeites emersonii from a fine-grained sandy mud in a MPT2 paleosol (S2, P#21-Bg). I) Odontopteris from a siltstone capping a PT7 paleosol (S1) ...... 182

Figure 3.17 Fossil flora in upper Monongahela and lower Dunkard group deposits. A) Autunia conferta from a DPT2 paleosol (S1, P#8-Bss). B) Trunk impression below the Little Waynesburg Coal with charcoal and coal formation (S2). C) Thin section of Stigmaria of Sigillaria showing the vascular bundle pushed to the side by sparry calcite formation from a PT3 paleosol (S1, P#18-Bg) (cross-polarized light) ...... 183

Figure 3.18 Fossil fauna in upper Monongahela and lower Dunkard group paleosols. A) Gastropod from a MPT2 paleosol (S2, P#22-C). B) Gastropod from a PT4B paleosol (S2, P#16-Cg). C) Terrestrial gastropod Anthrocopupa ohioensis (Whitfield) from a PT4A paleosol (S2, P#14-A). D) Thin section of an ostracode (?) shell fragment from a PT1 paleosol (S2, P#27-Bk) (normal light). E) Thin section of an ostracode shell fragment from a PT1 paleosol (S2, P#28-Bg) (cross-polarized light). F) Thin section of bone fragment from a PT1 paleosol (S2, P#27-Bk) (under normal light). G) Thin section of a small bone from a PT1 paleosol (S2, P#26-BCg) (cross-polarized light). H) Thin section of a tooth from a PT1 paleosol (S2, P#27-Bk) (normal light). I) Thin section of a bone fragment in a MPT2 paleosol immediately above the Gilboy Sandstone (S2, P#23-C) (normal light). J) Thin section of a fish (?) tooth in a PT1 paleosol (T2, P#26-BCg) (normal light). K–L) Sacral rib of a large tetrapod from a PT6 paleosol (S2, P#11-B) ...... 187

Figure 3.19 Stratigraphic columns of the upper Monongahela and lower Dunkard groups from the study area with labeled pedotypes and indicators of lateral shifts of where sections were measured. Dashed lines indicate approximate interpreted landscape surfaces. Sections are not corrected for regional dip. Key used for all stratigraphic columns ...... 189

calciasepic plasmic microfabric and intertextic grain microfabric (S2, P#25-BCg) (normal light). D) Thin section of a prismatic ped also showing calciasepic plasmic microfabric (S3, P#22-BCgc) (normal light). E) Thin section of a locally present ostracodal biopelmicrite (S2, P#28) (cross-polarized light). F) Large yellow rhizohalo (S1, P#32-A). G) Fracture fill (S2, P#29-A) ...... 191

Figure 3.21 Fossils from the Waynesburg Marlstone and Limestone. A) Thin section of a charophyte from an ostracodal intramicrudite (Section 1, 5.5 m) (cross-polarized light). B) Thin section of a fish scale (?) that has been partially micritized in an intraclastic ostracodal pelmicrite (Section 2, 5.75 m) (normal light). C) Thin section of an ostracode from an ostracodal intramicrudite (Section 3, 4.2 m) (normal light). D) Thin section of two microconchids from an ostracodal intramicrudite (Section 3, 4.2 m) (normal light). E) Thin section of cyanobacteria from an ostracodal algal biomicrite (Waynesburg Limestone) (Section 1, 5.8 m) (cross-polarized light). F) Xenacanth shark tooth from the Waynesburg Limestone...... 197

Figure 3.22 Representative stratigraphic columns of MPT2 and DPT2 paleosols in Section 1. DPT2 paleosols: A) Thin section showing omnisepic plasmic microfabric (S1, P#5-Agk) (cross-polarized light). B) Thin section showing an argillic plasmic microfabric and agglomeroplasmic grain microfabric (S1, P#5-B) (normal light). The dark yellow color is likely caused by the presence of amorphous iron oxy-hydroxides. C) Thin section showing an argillic plasmic microfabric and an intertextic grain microfabric with horizontally oriented organic roots (S1, P#5-C) (cross-polarized light). MPT2 paleosols: D) Thin section of a carbonate nodule with layered clay argillans in a granular microfabric showing two periods of nodule formation (S1, P#23-Bg) (cross-polarized light). E) Thin section of an angular blocky ped showing a mosepic plasmic microfabric (S1, P#25-Btg) (cross-polarized light). F) Thin section of an argillan associated with larger grains than the surrounding matrix (S1, P#25-BCn) (normal light). G) Thin section of three horizontally oriented burrows with varying fill and dendritic iron/manganese growths in argillasepic plasmic microfabric (S2, P#23-C) (normal light) ...... 206

Figure 3.23 Representative stratigraphic column of PT3 paleosols in Section 1. A) Finely laminated organics and claystone from (S3, P#16-O). B) Thin section of finely laminated organics and claystone (S3, P#17-A) (cross-polarized light). C) Thin section of a carbonate nodule (S1, P#18-Bg) (normal light). The left side of the photograph is gleyed and the right side is primarily oxidized. Arrow points to a preserved rhizolith within the nodule. D) Thin section of isotic, calciasepic plasmic microfabrics and porphyroskelic grain fabric containing a calcite spar-filled burrow (black arrow) that avoids a grain that has shifted in the subsurface (white arrow) (S1, P#20-Bki) (cross-polarized light). E) Thin section of iron nodules accumulating around and replacing a dark brown fragment (S3, P#17-Bgkss) (cross-polarized light). F) Thin section showing calcareous rhizolith preservation in a carbonate nodule (S1, P#21-Btg) (normal light). G) Thin section of the side of a coarser-grain heterogeneous-fill burrow (S1, P#21-BCgn) (cross-polarized 20 light). The matrix is to the bottom left and the inside of the burrow is to the upper right ...... 215

Figure 3.24 Representative stratigraphic column of PT4A and PT4B paleosols in Section 2. PT4A: A) Thin section of a pedogenic mud aggregate (S2, P#14-Bkss) (cross-polarized light). PT4B: B) Dense arrangement of yellow-cored green rhizohaloes that originate near the top of the sample (S1, P#15-Bc). C) Thin section of alternating claystone and organics (S2, P#16-ABss) (cross-polarized light). D) Cut sample of calcareous sandstone with climbing ripples (S2, P#16-C). E) Thin section showing an argillasepic plasmic microfabric (S3, P#15-Bc) (normal light). Red color is attributed to abundant, dispersed iron oxides. F) Cross section of an iron-rich concretion showing the concentric layering of iron-oxides, iron-oxyhydroxides, and calcite as well as the occurrence of several nucleation points. G) In situ ferruginous rhizoconcretions (black arrows) and a large iron- rich concretion (lower left) (S3, P#15-Bc) ...... 224

Figure 3.25 Stratigraphic column of PT5 in Section 1. A) The complete PT5 profile. Top arrow points to the location of a large horizontal root cast and stump cast. Lower arrow points to a vertically oriented root cast. B) Thin section of material filling the stump cast (S1, P#16-Ag) (normal light). C) Thin section showing a laminated argillasepic plasmic fabric (S1, P#16-Ag) (cross-polarized light). D) Thin section showing clay argillans in an insepic plasmic microfabric (S1, P#16-Cg) (cross-polarized light) ...... 232

Figure 3.26 Representative stratigraphic column of PT6 paleosols in Section 1. A) Thin section showing a large fragment (lower half of photograph) of material similar to the matrix observed in lower horizons (S3, P#10-Bss) (normal light). The upper half of the photograph is the matrix with a granular to agglomeroplasmic grain microfabric and silasepic plasmic microfabric. B) Thin section showing contrast between an all claystone clast and the surrounding undulic plasmic microfabric and intertextic grain microfabric of the matrix (S1, P#12-BC) (cross-polarized light). C) Thin section showing a gleyed rhizohalo with root hairs, a gleyed, horizontally oriented burrow, and abundant, smaller gleyed burrows in a claystone matrix (S1, P#12-BC) (normal light). D) Thin section of a yellow rhizohalo from the same thin section as C (normal light) ...... 237

Figure 3.27 Representative stratigraphic column of PT7 paleosols in Section 1. A) Thin section showing a calciasepic to crystic plasmic microfabric with a porphyroskelic grain microfabric (S1, P#1-Bss) (normal light). B) Thin section showing a wedge-shaped ped in an argillasepic to inundulic plasmic microfabric with abundant pedogenic mud aggregates (S1, P#1-Bss) (normal light). C) Large slickenside surface (S3, P#1-Bss). D) Thin section showing a blocky ped in an argillasepic to inundulic plasmic microfabric and porphyroskelic grain microfabric (S1, P#1-Bss) (normal light). E) Thin section showing an argillan in silasepic plasmic microfabric and granular grain fabric (S1, P#1- Cg) (cross-polarized light) ...... 242

Figure 3.28 Simplified stratigraphic columns with interpretations of the environment of formation for upper Monongahela and lower Dunkard group deposits. Thick black lines indicate interpreted contemporaneous landscape surfaces. The fluvial color code (yellow) refers to any fluvial-related deposit that has undergone little, if any, pedogenesis and includes channel, crevasse splay, and possibly point bar deposits ...... 261

Figure 3.29 Paleoclimatic interpretations and soil drainage conditions of upper Monongahela and lower Dunkard group paleosols based on bulk geochemistry (circles), clay mineralogy (triangles), and depth to Bk horizons (white nodules). Paleoprecipitation estimates based on clay mineralogy are given error bars of ±250 mm and are based on majority clay mineral composition. Paleoprecipitation estimates based on depth to Bk horizon are given error bars of ±147 mm (Retallack, 2005). The paleoprecipitation curve is based on CIA-K from bulk geochemical analyses. Dashed lines indicate paleosols with no bulk geochemical data ...... 267

1 INTRODUCTION

The purpose of this thesis is: 1) to present data on the variations of traces produced

by extant soil-dwelling organisms in order to recognize their presence in the fossil record,

and 2) to demonstrate the effectiveness of such studies in aiding the interpretation of

variations in ancient, terrestrial paleoclimate, paleoenvironment, and paleoecology. The

reconstruction of ancient conditions is based on the establishment, understanding, and

application of modern analogs (Retallack, 2001). In the terrestrial realm this involves the

study of terrestrial deposits, organism behaviors, and the modern organisms (plants and

animals) themselves, then relating them to paleosols, ichnofossils, and body fossils in the

rock record.

Ichnofossils are preserved biogenic structures that result from the life activities of an

organism within or on a medium (Bromley, 1996). Unlike body fossils, ichnofossils are

not likely to survive transport and, therefore, preserve the in situ behavioral response of

an organism to external conditions (Bromley, 1996). Additionally, ichnofossils provide

useful terrestrial paleoenvironmental and paleoecological data and are often preserved in

settings where body fossils may be rare suggesting a more ecologically diverse

environment than body fossils alone would suggest (Hasiotis and Dubiel, 1993;

Retallack, 2001; Melchor et al., 2002; Hembree, et al., 2004; Hembree and Hasiotis,

2007; MacEachern et al., 2007; Smith and Hasiotis, 2008; Hembree and Hasiotis, 2008;

Smith et al., 2008; Genise et al., 2009; Hamer and Sheldon, 2010; Hembree et al., 2011).

Soil formation results in a taphonomic bias against body fossil preservation due to the abundance of bacteria, fungi, and other decomposers (Retallack, 2001) and therefore 23

ichnofossil recognition is particularly important in reconstructing organism diversity and

abundance in ancient soil ecosystems. Establishing modern analogues of ichnofossils

requires neoichnology in which extant organisms are observed in the field or in

controlled laboratory settings while interacting with a medium under varying

environmental conditions.

A paleosol is the buried and preserved soil of an ancient landscape (Retallack, 2001)

and its formation, like modern soils, is affected by time, topography, parent material,

climate, and biota (Jenny, 1994). Paleosols and their constituents have been used

increasingly to solve a wide array of geologic problems including, but not limited to,

paleoclimate, sequence stratigraphy, ichnology, topography, and paleoenvironmental

reconstructions (McCarthy and Plint, 1998; Kraus, 1999; Retallack, 2001, 2005; Driese et

al., 2005; Hembree and Hasiotis, 2007; Sheldon and Tabor, 2009; Mack et al., 2010;

Hembree and Nadon, 2011; Catena and Hembree, 2012; Dzenowski and Hembree, 2012).

Modern soils are well studied and environmental conditions where specific soils form are

well documented (Retallack, 2001; Buol et al., 2003; Schaetzl and Anderson, 2009).

Factors of these modern soil-forming environments can be applied to paleosols in order

to interpret ancient environments.

Chapter 2 presents the results of a neoichnological study investigating the

morphology of the biogenic structures produced by two millipede species of the

superorder Juliformia, in a laboratory setting under varying environmental conditions and

compares the results to burrows produced by two other juliform millipede species from a previous study (Hembree, 2009). Millipede body fossils occur in Silurian strata (Wilson 24 and Anderson, 2004) and trackways attributed to millipedes are from Late Ordovician strata (Johnson et al., 1994). Despite their long evolutionary history, high diversity, and widespread distribution, few fossil burrows attributed to millipedes have been described

(e.g. Retallack and Feakes, 1987; Retallack, 2001; Hembree, 2009). This study compares the burrows of N. americanus, a temperate to subtropical species, F. penneri, a xeric species, O. ornatus, a desert species, and A. gigas a large, African desert species in order to evaluate the hypothesis that millipedes create a specific and diagnostic burrow morphology.

Chapter 3 presents a thorough, small-scale investigation of paleosols of the

Pennsylvanian to Permian, upper Monongahela and lower Dunkard groups from a locality in southeastern Athens County, Ohio. Detailed stratigraphic sections, bulk geochemical, clay mineralogical, and petrographic analyses are presented. The ichnofossils and paleosols present in the study area are described and used to interpret paleoclimatic, paleoenvironmental, and paleoecologic conditions. Upper Monongahela and lower Dunkard group rocks were originally deposited during the Allegheny orogeny when the study area was located near the tropics (Martin, 1998; Becker et al., 2006;

Tabor and Poulsen 2008). Two modern, low-gradient alluvial fan complexes and the

Florida Everglades have been proposed as modern analogues (Cecil et al., 2011). The paleosols of the upper Monongahela and lower Dunkard groups preserve high levels of lateral and vertical variability that would be present in these modern analogues during changing environmental conditions. 25

Combining the information available from studying the ichnofossils, paleosols, and body fossils of terrestrial deposits allows more accurate paleoclimatic, paleoenvironmental, and paleoecological reconstructions. This study illustrates how the inclusion of the ichnofossil and paleosol data allows the recognition of subtle changes in environmental conditions not possible using only grain size data.

1.1 References

Becker, T.P., Thomas, W.A., Gehrels, G.E., 2006. Linking Late Paleozoic sedimentary provenance in the Appalachian Basin to the history of Alleghanian deformation. American Journal of Science 306. 777–798.

Buol, S.W., Southard, R.J., Graham, R.C., McDaniel, P.A., 2003. Soil Genesis and Classification, fifth ed. Blackwell Publishing, Ames.

Bromley, R. G. 1996. Trace Fossils; Biology, Taphonomy and Applications, 2nd edition. Chapman & Hall, London.

Catena, A., Hembree, D., 2012. Recognizing vertical and lateral variability in terrestrial landscapes: A case study from the paleosols of the Late Pennsylvanian Casselman Formation (Conemaugh Group) southeast Ohio, USA. Geosciences 2, 178–202.

Cecil, C.B., DiMichele, W., Fedorko, N., Skema, V., 2011. Autocyclic and allocyclic controls on the origin of the Dunkard Group, in: Harper, J.A. (Ed.), Geology of the Pennsylvanian-Permian in the Dunkard Basin. Guidebook, 76th Annual Field Conference of Pennsylvania Geologists. Field Conference of Pennsylvania Geologists, Inc., Pennsylvania, pp. 26–45.

Dzenowski, N.D., Hembree, D.I., 2012. Examining local climate variability in the Late Pennsylvanian through paleosols: An example from the Lower Conemaugh Group of southeastern Ohio, USA. Geosciences 2, 260–276.

Driese, S.G., Nordt, L.E., Lynn, W.C., Stiles, C.A., Mora, C.I., Wilding, L.P., 2005. Distinguishing climate in the soil record using chemical trends in a Vertisol climosequence from the Texas coast prairie, and application to interpreting Paleozoic paleosols in the Appalachian Basin, U.S.A.. Journal of Sedimentary Research 75, 339–349. 26

Genise, J. F., Melchor, R. N., Archangelsky, M., Bala, L. O., Straneck, R., Valais, S. 2009. Application of neoichnological studies to behavioural and taphonomic interpretation of fossil bird-like tracks from lacustrine settings: The Late Triassic– Early Jurassic? Santo Domingo Formation, Argentina. Palaeogeography, Palaeoclimatology, Palaeoecology 272, 143–161.

Hamer, J.M.M., Sheldon, N.D. 2010. Neoichnology at lake margins: Implications for paleo-lake systems. Sedimentary Geology 228, 319–327.

Hasiotis, S.T., Dubiel, R.F. 1993. Crayfish burrows and their paleohydrologic significance – Upper Triassic Chinle Formation, Fort Wingate, New Mexico, in: Lucas, S.G., Morales, M. (Eds.), The Nonmarine Triassic, New Mexico Museum of Natural History & Science Bulletin No. 3, 24–26.

Hembree, D.I. 2009. Neoichnology of burrowing millipedes: Linking modern burrow morphology, organism behavior, and sediment properties to interpret continental ichnofossils. Palaios 24, 425–439.

Hembree, D.I., Hasiotis, S.T. 2007. Paleosols and ichnofossils of the White River Formation of Colorado: Insight into soil ecosystems of the North American Midcontinent during the Eocene-Oligocene transition. Palaios 22, 123–142.

Hembree, D.I., Hasiotis, S.T. 2008. Miocene vertebrate and invertebrate burrows defining compound paleosols in the Pawnee Creek Formation, Colorado, U.S.A. Palaeogeography, Palaeoclimatology, Palaeoecology 270, 349–365.

Hembree, D.I., Martin, L.D., Hasiotis, S.T. 2004. Amphibian burrows and ephemeral ponds of the Lower Permian Speiser Shale, Kansas: evidence for seasonality in the midcontinent. Palaeogeography, Palaeoclimatology, Palaeoecology 203, 127–152.

Hembree, D.I., Nadon, G.C., King, M.R. 2011. Large, complex burrow systems from freshwater deposits of the Monongahela Group (Virgilian), Southeast Ohio, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 300, 128–137. Jenny, H., 1994. Factors of Soil Formation; A System of Quantitative Pedology. Dover Publications, New York.

Johnson, E.W., Briggs, D.E.G., Suthren, R.J., Wright, J.L., Tunnicliff, W.P. 1994. Non- maine arthropod traces from the subaerial Ordovician Borrowdale Volcanic Group, English Lake District. Geological Magazine 131, 395–406. Kraus, M.J., 1999. Paleosols in clastic sedimentary rocks; their geologic applications. Earth Science Reviews 47, 41–70.

MacEachern, J.A., Bann, K.L., Pemberton, S.G., Gingras, M.K., 2007. The ichnofacies paradigm: High-resolution paleoenvironmental interpretation of the rock record, in: MacEachern, J.A., Bann, K.L., Gingras, M.K., Pemberton, S.G. (Eds.), Applied Ichnology, SEPM Short Course Notes 52. Society for Sedimentary Gology, pp. 27– 64.

Mack, G.H., Tabor, N.J., Zollinger, H.J., 2010. Palaeosols and sequence stratigraphy of the Lower Permian Abo Member, south-cenral New Mexico, USA. Sedimentology 57, 1566–1583.

Martin, W.D., 1998. Geology of the Dunkard Group (Upper Pennsylvanian-Lower Permian) in Ohio, West Virginia, and Pennsylvania. Ohio Division of Geological Survey 73. McCarthy, P.J., Plint, A.G., 1998. Recognition of interfluves sequence boundaries: Integrating paleopedology and sequence stratigraphy. Geology 26, 387–390.

Melchor, R.N., Genise, J.F., Miquel, S.E. 2002. Ichnology, sedimentology and paleontology of Eocene calcareous paleosols from a palustrine sequence, Argentina. Palaios 17, 16–35.

Retallack, G.J., 2001. Soils of the Past, second ed. Blackwell Science, Oxford.

Retallack, G.J., 2005. Pedogenic carbonate proxies for amount and seasonality of precipitation in paleosols. Geology 33, 333–336.

Retallack, G.J., Feakes, C.R. 1987. Trace fossil evidence for Late Ordovician animals on land. Science 235, 61–63.

Schaetzl, R., Anderson, S., 2009. Soils: Genesis and Geomorphology. Cambridge University Press, Cambridge.

Sheldon, N.D., Tabor, N.J., 2009. Quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols. Earth Science Reviews 95, 1–52.

Smith, J.J., Hasiotis, S.T. 2008. Traces and burrowing behaviors of the cicada nymph Cicadetta calliope: Neoichnology and paleoecological significance of extant soil- dwelling insects. Palaios 23, 503–513.

Smith, J.J., Hasiotis, S.T., Kraus, M.J., Woody, D.T. 2008. Relationship of floodplain ichnocoenoses to paleopedology, paleohydrology, and paleoclimate in the Willwood Formation, Wyoming, during the Paleocene-Eocene thermal maximum. Palaios 23, 683–699.

Tabor, N.J., Poulson, C.J., 2008. Palaeoclimate across the Late Pennsylvanian–Early Permian tropical palaeolatitudes: A review of climate indicators, their distribution, and relation to palaeophysiographic climate factors. Palaeogeography, Palaeoclimatology, Palaeoecology 268, 293–310.

Wilson, H.M., Anderson, L.I. 2004. Morphology and taxonomy of Paleozoic millipedes (Diplopoda: Chilognatha: Archipolypoda) from Scotland. Journal of Paleontology 78, 169–184.

2 THE NEOICHNOLOGY OF JULIFORM MILLIPEDES: BURROWS OF SOIL

MACRODETRITIVORES

2.1 Abstract

Burrowing detritivores such as millipedes play an important role in soil formation. In

order to improve the recognition of millipede burrows and, therefore, the presence of

millipede macrodetritivores in the fossil record, this study describes the burrowing

behavior and resulting burrow morphologies of two species of spirobolid millipedes of

the superorder Juliformia: Narceus americanus and Floridobolus penneri. Specimens

were placed in terrariums filled with sediment of varied compositions and controlled

moisture contents for 7–94 days. Open burrows were cast with plaster, excavated, and

described both qualitatively and quantitatively. Both N. americanus and F. penneri

produced vertical, subvertical, helical, and O-shaped burrows. Floridobolus penneri also

produced J-shaped burrows. The burrow casts were compared to each other using the

Bray Curtis similarity measure and to environmental conditions using Spearman’s rank

correlation. Burrows of two other millipede species of the Order Spirostreptida,

Orthoporus ornatus and Archispirostreptus gigas, were also included in the Bray Curtis comparisons. Burrows of both species were statistically similar and their morphology was unaffected by sediment properties. Burrows produced by A. gigas, the largest species, were the least similar to other species even after removing size-dependent properties from the analysis. Differences and similarities in burrow morphology were instead attributed to the function of the burrow, refuge or feeding. Despite some fundamental differences, all 30 millipede burrow shafts and tunnels had an average width-to-height ratio of 1.0–1.14.

These results show that juliform millipedes produce burrows with unique morphologies that may be used to differentiate their burrows from those produced by other soil organisms.

2.2 Introduction

The purpose of this paper is to characterize biogenic structures produced by two extant spirobolidan millipedes (Myriapoda: Diplopoda) under controlled laboratory conditions. Both species, Narceus americanus (Family: Spirobolidae) and Floridobolus penneri (Family: Floridobolidae), are members of the superorder Juliformia and are known to burrow, but live in different habitats. Surface and subsurface biogenic structures produced by Floridobolus penneri and Narceus americanus are thoroughly described along with the associated burrowing techniques and behaviors. Sediment composition, moisture, available space, and duration of experiment were varied to determine the effect of these variables on trace morphology. By describing the biogenic structures produced by common extant soil detritivores under varying environmental conditions, similar ichnofossils may be used to aid in the interpretation of paleoenvironmental, paleoecologic, and paleoclimatic conditions of continental deposits.

Ichnofossils are preserved biogenic structures that result from the life activities of an organism within or on a medium (Bromley, 1996). These structures include tracks, trails, burrows, and borings. Due to the nature of ichnofossils, unlike body fossils, they are not likely to be transported beyond the location where they were produced. Remaining in 31

situ, these structures represent the direct response of the organism to its environment

(Bromley, 1996). As such, an understanding of ichnofossils and the potential tracemaker

is invaluable to paleoenvironmental, paleoecological and paleoclimatic reconstructions.

As environmental conditions (substrate, moisture, temperature, etc.) change, the behavior

of the organism and thus the trace may also change (Davis et al., 2007; Hasiotis, 2007;

Genise et al., 2009; Hembree, 2009; Hamer and Sheldon, 2010; Dashtgard, 2011;

Hembree et al., 2012, Smilek and Hembree, 2012). Whereas ichnofossils are most

commonly used in the interpretation of marine environments, recent work has shown that

robust paleoenvironmental and paleoecological data can be acquired from continental

ichnofossils as well, often in the absence of body fossils (Hasiotis and Dubiel, 1993;

Melchor et al., 2002; Hembree, et al., 2004; Hembree and Hasiotis, 2007; Smith and

Hasiotis, 2007; Hembree and Hasiotis, 2008; Smith et al., 2008; Genise et al., 2009;

Hamer and Sheldon, 2010; Hembree et al., 2011) An understanding of the significance of

ichnofossils comes from experimental neoichnology. These studies involve the

observation of extant organisms in the field or controlled laboratory settings while they

are interacting with a medium. Careful observations of organism behaviors and reactions

to changing conditions, as well as careful documentation of the traces produced, allow

these structures to serve as analogues for trace fossils to interpret how similar organisms may have responded to past conditions.

With over 12,000 species described, the class Diplopoda (millipedes) is among the most diverse groups of extant terrestrial organisms (Sierwald and Bond, 2007). Although these animals are common their trace-making abilities are poorly understood (Hembree, 32

2009). It is well documented that arthropods, specifically diplopods, were among the first macrofauna to colonize land (Almond, 1985; Rolfe, 1985; Jeram et al., 1990; Pisani et al.,

2004; Ward et al., 2006; Schaefer et al., 2010). Fossil millipedes have been found in deposits as old as the Silurian (Wilson and Anderson, 2004). Relatively few fossil millipedes have been described, however, likely due to the rapid decay of organic matter that is common in their terrestrial habitats as well as their tendency to consume their molts (Shear and Edgecombe, 2009). The primary exceptions to this taphonomic bias occur in the Mississippian and Pennsylvanian with some exceptionally well-preserved fossils (Hoffman, 1963; Wilson, 2005a, 2005b, 2006a). The taphonomic bias is very evident in the Permian which lacks any well-described specimens (Shear and

Edgecombe, 2009).

Fossil trackways attributed to millipedes occur as early as the Late Ordovician

(Johnson et al., 1994) and coprolites attributed to millipedes have been described from the Early Devonian (Edwards et al., 2012). Millipede body fossils with a fully fused, ring-form body known to be well adapted to burrowing in extant members of the

Juliformia appear in the Early Devonian (Wilson, 2006b; Cong et al., 2009). Undisputed

millipede burrows of that age, however, have yet to be described; although burrows in the

Ordovician Juniata Formation have been suggested to have been produced by millipedes

(Retallack and Feakes, 1987; Retallack, 2001a). Given the presence of burrowing

adaptations, fossil burrows may be an effective proxy for the presence of millipedes if

they could be distinguished from those of other burrowing animals. With the higher 33 preservation potential of trace fossils, the recognition of fossil millipede burrows could also assist in refining the date for the colonization of land by arthropods.

Millipedes are very widespread but are only able to tolerate small environmental changes (Golovatch and Kime, 2009). Many studies of extant millipedes have illustrated their sensitivity to precise levels of light, temperature, moisture, food resources, calcium, nitrogen, and specific landscapes; all factors that would greatly assist in paleoenvironmental reconstructions if the presence of millipedes could be identified in the fossil record (Crozier, 1924; O’Neill, 1967, 1968a, 1968b, 1969; Toye, 1966;

Banerjee, 1967; Davis, 1978 (thesis); Moeed and Meads, 1985; Crawford, 1992; Bailey and Kovaliski, 1993; Dangerfield and Chipfunde, 1995; Cárcamo et al., 2000; Greyling et al., 2001; Kalisz and Powell, 2003; Tuf et al., 2006; Farfan, 2008 (thesis); Stašiov, 2009;

Stašiov et al., 2012; Fujimaki et al., 2010; Kime and Golovatch, 2000; Galanes and

Thomlinson, 2011).

2.3 Millipede Ecology and Behavior

The Class Diplopoda is divided into 16 extant orders and 8 extinct orders distributed over every continent except for Antarctica (Golovatch and Kime, 2009). Millipedes are present in most terrestrial habitats living primarily at or near the leaf litter/soil interface

(Sierwald and Bond, 2007). The typical environments for millipedes are temperate to tropical, humid deciduous forests and milder climates; however, they have been known to thrive in more extreme areas including at high altitudes, in caves, and in deserts

(Golovatch and Kime, 2009). Millipedes can be identified by their elongate body form 34 consisting of multiple fused segments (diplosegments), with two pairs of legs and two pairs of tracheae on all but the head and first several segments (Fig. 2.1A) (Sierwald and

Bond, 2007). All but one group of millipedes have a chitinous exoskeleton that incorporates calcite into the structure providing physical defense and protection against desiccation (O’Neill, 1969; Thorez et al., 1992 Eisner et al., 1998; Shear and Edgecombe,

2009). Additionally, the diplosegment condition increases pushing force capability while the calcite reinforced cuticle protects the animal as it pushes itself into sediment using the collum as the primary force point (Manton, 1953, 1958, 1961; Borrell, 2004). The requirement of calcium in the cuticle of most millipedes may be related to a preference in some millipedes toward calcium-rich environments (Kime and Golovatch, 2000).

Many extant millipedes are morphologically adapted to using different, but similar, burrowing techniques. Among millipedes, the orders Polydesmida, Spirostreptida,

Spirobolida, and Julida are the best adapted to burrowing and feeding in soils; these have been labeled the “ring-forming group” (Enghoff et al., 1993; Cong et al., 2009). Three specific morphotypes of burrowing millipedes have been described: (1) juloid, or ramming-type body forms, that use a compressive burrowing technique that results in a compacted lining (Hembree, 2009) and are chiefly composed of members of the superorder Juliformia; (2) Polydesmoid, or wedge-type body forms, that force their way into cracks or crevices and then lift their bodies to create wider openings; and (3)

Platydesmoid, or borer-type body forms, with flat backs and tapered anterior ends that are pushed into the sediment (Kime and Golovatch, 2000). Millipedes are known to increase 35

their energy output in response to stressed conditions and will burrow in order to avoid

desiccation (O’Neill, 1967, 1968; Dangerfield and Chipfunde, 1995, Villani et al., 1999).

As burrowers, millipedes create open structures which could then be used as elite

structures that allow other soil-dwelling organisms to take advantage of deeper soil

environments (Hembree, 2009).

As primary detritivores and one of the first macrodetritivores, most millipedes play

an important role in the initial breakdown of plant material including wood (Ausmus,

1977; Crawford, 1992). In temperate forests they are estimated to consume up to 15% of

annual leaf fall and up to 36% of the annual litter in coniferous forests (Golovatch and

Kime, 2009). In addition to the initial physical breakdown of plant material,

decomposition of litter by millipedes can increase the overall rate of nitrogen

mineralization and influence the microbial activity of soils (Cárcamo et al., 2000). It is

clear that millipedes presently play an important part in the formation of soils in many

ecosystems and may have played an even larger role in the past since the evidence of

terrestrial millipedes predates the appearance of other macrodetritivores by at least 27

million years (Crawford, 1992).

Narceus americanus is a large North American millipede that can reach up to 10 cm in length as an adult and can be found in the eastern half of the United States and in small portions of southeastern Canada (Fig. 2.1B) (Shelley et al., 2006). Narceus americanus

can be found at all elevations and is primarily found on temperate to subtropical forest

floors in leaf litter or dead logs (O’Neill, 1968; Ausmus, 1977; Shelley et al., 2006). In

addition to humid environments, N. americanus has shown a relatively high tolerance for 37 dry conditions and appears to be well adapted to preventing desiccation, undoubtedly assisting in its widespread distribution (O’Neill, 1969; Shelley et al., 2006; Walker et al.,

2009). During the winter and daylight hours N. americanus will burrow into the subsurface to avoid frigid temperatures and desiccating conditions respectively and is primarily active in the spring (Walker et al., 2009).

Floridobolus penneri, also known as the Florida scrub millipede, is a large North

American millipede reaching 9 cm in adult length that is restricted to xeric, infertile, sandy scrub in south central Florida (Fig. 2.1C) (Carrel and Britt, 2009). Although little has been published regarding the ecology of F. penneri, it does spend a majority of the time in its burrows and is mostly surface active in the mid-summer (Carrel and Britt,

2009). Its food preference, once thought to be mostly Florida rosemary, is still not well known (Sattman, 2006; Carrel and Britt, 2009).

2.4 Materials and Methods

Nineteen specimens of N. americanus and twenty-one specimens of F. penneri were acquired from a commercial source. The average length and width of all N. americanus involved in this study was 49 mm (27–75 mm, SD=15.7) and 4.4 mm (2.5–7.0 mm,

SD=1.48) respectively. Specimens of N. americanus received were a light tan color (Fig.

2.2A) rather than the normal red/gray (Fig. 2.2B). It is likely that these specimens were an albino variety (Shelley, Personal communication). The average length and width of all

F. penneri used in this study were 68 mm (63–74 mm, SD=3.66) and 7 mm (6–9 mm,

SD=0.92) respectively (Fig. 2.2C). Specimens of N. americanus were kept in the 38

laboratory for several months prior to the start of the experiments to acclimate to lab

conditions. Specimens of F. penneri were given one week to acclimate. During these

acclimation periods and in between experiments, individuals and groups of up to five

specimens were placed in small holding tanks with 5–10 cm of organic (coconut fiber)

substrate. The laboratory was kept at 26°C and 20% humidity with the lights set on a 12-

hour light-dark cycle. In order to maintain moisture within the sediment, the surface was

sprayed with water five days per week and small water dishes were placed inside the

tanks. Millipedes were fed a diet of apples placed on the sediment surface.

Twenty-three experimental trials were set up using either groups of 4 or 5 individuals or single specimens of both species (Table 1). These trials were designed to address the

39 hypotheses that: 1) N. americanus and F. penneri each produce distinct suites of biogenic structures; 2) the burrowing behaviors and resulting biogenic structures of N. americanus and F. penneri vary significantly with changes in sediment composition and moisture content; and 3) biogenic structures produced by N. americanus and F. penneri are distinguishable from those produced by other millipedes using a specific set of quantitative morphologic characteristics.

Groups of 4–5 specimens as well as single individuals were used in the experiments in order to investigate the animal’s known aggregation behavior and to determine if this aggregation affected burrow morphology in the form of communal burrows. In order to evaluate the effect of space limitation on the behavior of the millipedes, two different sizes of terrariums were used in the trials: 30 gallon (91L x 45W x 33H cm) and 65 gallon (91L x 45W x 62H cm). Each tank was filled with 16–20 and 39–50 cm of sediment respectively. Each trial subjected the millipede to a stress that was related to sediment composition or sediment moisture content. Sediment compositions consisted of

100% potting soil, 50% organic matter (coconut fiber) and 50% soil, 50% carbonate sand

(fine- to medium-grained) and 50% soil, and 25% carbonate sand (fine- to medium- grained) and 75% soil. The soil was passed through a 4 mm sieve prior to use in order to achieve better particle sorting. Initial sediment moisture was obtained by mixing the sediment with water and measuring the moisture content with an Aquaterr EC-300

Salinity Multimeter every 10 cm until the average moisture throughout a terrarium reached the desired levels of 35%, 50% and 60–70%. Once the terrariums reached experimental parameters, the millipede(s) were placed on the sediment surface. 40

All experiments were started with the laboratory lights on until initial observations

were made. The tanks were monitored for up to one hour or until all individuals burrowed under the surface. Observations recorded included the time it took individuals to begin burrowing, the techniques used to burrow, and any surface structures that were produced by movement of the animal. After these initial observations, the terrariums were monitored several times daily for the appearance of new burrow openings, closed burrow openings, and behaviors associated with surface traces and burrows. After a predetermined amount of time (7–14 days) individuals on the surface of the tanks were removed and the tanks were continually checked until the remaining individuals surfaced or were excavated (up to 94 days). If no burrow openings were present at the end of the predetermined time, the experiment was ended and this result was recorded. Any open burrows were cast with Drystone® plaster. After a minimum drying period of three hours, the casts were excavated and described.

Burrow casts were described using qualitative descriptions of their general morphology and surficial markings as well as ten quantitative measurements (Fig. 2.3).

The quantitative measurements consisted of eight direct measurements (Fig. 2.3A): 1)

Table 2.1 Experimental parameters and burrow architectures produced. Tank sizes are in gallons. In the sediment column, F= Coconut fiber (organic), and Sa= Fine- to medium- grained carbonate sand. Depth is the total depth of the sediment in the tank and is measured in centimeters. % Moisture is the average moisture content of the sediment. Duration is split into two categories; expected time to completion of trial and the actual trial duration in parentheses. Key to burrow architectures and modifications: V=Vertical shaft, Sub V=Subvertical burrow, H=Helical burrow, J=J-shaped burrow, O=O-shaped burrow (T1=Type 1, T2=Type 2),C=Chamber present, B=Branch present (# present in parentheses), DE=Two entrances.

Table 2.1 (continued) Experiment 1: Basic Morphology Species Specimens Tank Size Sediment Depth % Mois ture Duration Burrow #s Burrow Architectures N. americanus 5 30 50/50 (F/Soil) 20 37% 7 (12) OS 26 A-B S ub V, O (T1 ) N. americanus 5 65 50/50 (F/Soil) 45 32% 7 (12) OS 23 S ub V N. americanus 1 30 50/50 (F/Soil) 20 35% 7(8) No Burrow None N. americanus 1 30 50/50 (F/Soil) 20 30% 7(8) OS 24 S ub VC N. americanus 1 65 50/50 (F/Soil) 45 40% 7(7) OS 28 V N. americanus 5 30 50/50 (F/Soil) 20 35% 14(21) OS 25 A-B S ub V, H N. americanus 5 65 50/50 (F/Soil) 43 37% 14(14) OS 21 A-F Sub V, Sub VB, Sub VC, HC N. americanus 1 30 50/50 (F/Soil) 20 35% 14(14) OS 1 H N. americanus 1 65 50/50 (F/Soil) 45 35% 14(19) No Burrow None Experiment 2: Substrate Composition Species Specimens Tank Size Sediment Depth % Mois ture Duration Burrow #s Burrow Architectures F. penneri 5 30 50/50 (Sa/Soil) 16 50% 14(94) FB 6 A-E Sub V, OC (T1) F. penneri 5 65 100% Soil 39 54% 7(8) FB 7 A-H V, VH, Sub V,Sub VB, J, Sub VCB F. penneri 4 30 50/50 (Sa/Soil) 19 70% 14(54) No Burrow None F. penneri 5 30 25/75 (Sa/Soil) 20 50% 14(14) FB 5 A-G V, Sub V, Sub VC, OB(2) (T1), OB (T2) F. penneri 1 30 50/50 (Sa/Soil) 19 58% 14(19) FB 4 A-B V, H F. penneri 1 30 25/75 (Sa/Soil) 20 52% 14(41) No Burrow None N. americanus 5 30 25/75 (Sa/Soil) 20 51% 14(23) OS 32 S ub V N. americanus 1 30 25/75 (Sa/Soil) 20 60% 14(14) OS 31 A-B ODE (T2), O (T2) N. americanus 1 65 100% Soil 39 60% 14(51) OS 33 A-C V, H Experiment 3: Substrate Moisture Species Specimens Tank Size Sediment Depth % Mois ture Duration Burrow #s Burrow Architectures F. penneri 5 65 50/50 (F/Soil) 45 49% 14(63) FB 2 A-M Sub V, V, J, JB F. penneri 1 65 50/50 (F/Soil) 45 50% 14(13) FB 3 A-I S ub V, V F. penneri 1 65 50/50 (F/Soil) 45 50% 14(14) FB 1 HB N. americanus 5 65 50/50 (F/Soil) 48 50% 14(22) OS 29 A-C V, O (T1), H N. americanus 1 65 50/50 (F/Soil) 50 50% 14(21) OS 30 A-F V, VH, Sub V, Sub VC 23 Total Experiments 14 N. americanus 9 F. penneri

number of surface openings (e), 2) maximum depth (D), 3) total length of the burrow (L),

4) width (w), 5) height (h), 6) width to height ratio (w/h), 7) circumference (c), and 8) the

angle of the slope of the burrow as it enters the subsurface (a) and shifts below it

(a1,a2…) in relation to the horizontal. There were also two derived measurements of the

burrow systems: 9) complexity (Fig. 2.3B) and 10) tortuosity (Fig. 2.3C). The width, height, width-to-height ratio, and circumference of the shafts, tunnels and chambers were

measured every one centimeter starting from the surface opening. The average width,

height, width-to-height ratio, and circumference of the burrow system were calculated to

obtain representative measurements for each property. The average slope of the burrow

system was calculated from the slopes of the burrow as it entered the subsurface and each

shift under the surface measured in relation to horizontal. Branching angles were not

included in the burrow systems average slope, but were recorded. The maximum depth

was measured perpendicular to the surface from the burrow entrance to the deepest

portion of the burrow. The total length of the burrow consisted of the sum of the lengths

of all the shafts, tunnels, and chambers in the burrow system.

Complexity and tortuosity are two scale independent means of comparing burrows

(Meadows, 1991; Hembree and Hasiotis, 2006). Complexity (C) is an index measurement

that is calculated by taking the sum of the number of surface openings (e), segments (s), and chambers (ch) and, therefore, represents the entire burrow system. Tortuosity (T) is a measure of the deviation of a burrow segment from a straight line. It is calculated by dividing the total length of the burrow segment (u) by the shortest distance between the endpoints (v). Tortuosity was calculated for each segment of a burrow system, and then 43

the average of these was calculated to represent the tortuosity of the entire burrow

system. When a burrow connected back onto itself, the shortest distance between endpoints (v) was set to 0.1 cm in order to avoid dividing by 0.The ten quantitative properties were used to compare the burrows of N. americanus and F. penneri both

within and between each species. In addition, the burrows of these species were

compared to those of two spirostreptid millipedes, Orthoporus ornatus and

Archispirostreptus gigas from southwestern United States and western Africa respectively, produced using similar experimental methods (Hembree, 2009). The burrow

casts were compared using the non-parametric Bray Curtis similarity measure. This statistical test allows each burrow to be compared using all ten quantitative variables at once to determine the level of similarity between each specimen (Hammer and Harper,

2006; Hembree et al., 2012). The output of this analysis is a similarity value that is given from 0–1, with 0 indicating completely different structures and 1 indicating identical structures. This study follows designations made in Hembree et al. (2012) that interpret values from 0.9–0.8 as indicating a high level of similarity, 0.7–0.6 as indicating a moderate level of similarity, and any value from 0.5 to 0 as indicating dissimilarity.

In order to evaluate the effect of differences in environmental conditions on burrow morphology, Spearman’s rank correlation was used to compare sediment properties and burrow properties. This nonparametric analysis is used to determine if two variables are covariant (Hammer and Harper, 2006). In this test, two variables are converted to ranks and then a correlation analysis is run using the ranked data. Sediment composition and sediment moisture content were treated as independent variables while the quantitative measures of complexity, tortuosity, average circumference, total length, average width, average height, maximum depth and average slope were treated as dependent variables. All statistical

analyses were carried out with Paleontological Statistics (PAST Ver. 2.13) (Hammer et

al., 2001). 45

2.5 Experimental Results

Both N. americanus and F. penneri produced temporarily and permanently open structures along with surficial traces in all sediment compositions and moisture conditions. A total of 29 and 42 burrow casts of were made from burrows produced by N. americanus and F. penneri respectively (Tables 2–8). Overall, five basic architectures

were created with four modifying features (Fig. 2.4). Not all burrow casts represented the complete structures. In particular, individuals were observed burrowing to much greater depths than any successful cast. This was likely due to subsurface collapse of tunnels, the construction of burrow plugs or backfill by the millipedes, or accumulation of sediment by the plaster as it flowed into the open burrow causing a plug to form. When burrowing against the side of the tank or when individuals were extracted from their burrows, observations on depth and orientation of the individual were noted.

2.5.1 Behavior

2.5.1.1 Narceus americanus

Specimens began burrowing shortly after being placed into the terrariums. Often, specimens would first travel around the edges of the tank and only rarely cross into the middle. After 0–15 minutes the animals would begin burrowing, typically at the corners or along the sides of the enclosure. In many instances these initial burrows were abandoned and the individual would resume traveling around the tank. Most individuals burrowed completely into the sediment within one hour. The only exception occurred in a

Table 2.2 Quantitative measurements of burrow casts of subvertical burrows (Sub V) produced by N. americanus.

OS25 OS21 OS21 OS21 OS30 OS30 OS21 OS21 OS26 OS30 OS32 OS23 A A B C B D D OS24 E A E Sub Sub Sub Sub Sub Sub Sub Sub Sub Sub Sub Sub Sub Architecture V V V V V V V V VB VC VC VC VC Surface Openings 1 1 1 1 1 1 1 1 1 1 1 1 1 Maximum Depth (cm) 4.1 6.7 3.0 1.9 4.0 7.1 2.6 5.9 11.9 4.0 13.4 5.8 6.6 Total Length (cm) 4.3 8.2 9.4 2.3 4.3 8.0 3.1 6.8 13.8 7.2 15.7 6.8 7.5 Maximum Width (mm) 9.3 16.9 11.7 13.0 14.5 11. 5 9.6 10.8 11.7 17.6 16.8 26.2 16.5 Minimum Width (mm) 8.5 8.0 7.8 10.5 11.0 8.8 9.5 7.5 8.6 7.1 7.2 11.2 6.0 Average Width (mm) 8.8 10.4 10.2 11.8 12.4 9.3 9.6 9.3 10.2 10.9 10.5 15.6 11.4 Maximum Height (mm) 9.8 9.5 10.1 12.5 12.3 8.8 9.8 10.9 11.6 9.7 10.4 16.4 10.0 Minimum Height (mm) 8.6 7.3 5.7 11.8 10.5 7.4 8.2 8.1 6.3 6.0 5.8 8.9 7.0 Average Height (mm) 9.2 8.3 7.9 12.2 11.4 8.1 9.0 9.4 9.3 8.0 9.1 11.6 8.4 Average W/H Ratio 1.0 1.3 1.3 1.0 1.1 1.1 1.1 1.0 1.1 1.3 1.2 1.4 1.3 Maximum Circumference (cm) 3 4.1 3.7 4.2 4.3 3.1 2.9 3.5 3.6 4.6 4.3 8.4 4.7 Minimum Circumference (cm) 2.7 2.7 2.5 3.5 3.3 2.2 2.8 2.7 2.6 2.5 2.3 3.3 2.5 Average Circumference (cm) 2.8 3.1 3.1 3.9 3.7 2.7 2.9 3.1 3.1 3.3 3.2 4.9 3.5

Maximum Slope (Degrees) 70 65 45 33 73 90 70 80 90 67 81 55 90 Minimum Slope (Degrees) 70 50 25 33 70 25 70 60 40 20 55 55 65 Average Slope (Degrees) 70 38 35 33 72 57 70 70 63 44 64 55 78 Branching Angle (Degrees) n/a n/a n/a n/a n/a n/a n/a n/a 60 n/a n/a n/a n/a Complexity 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 4.0 3.0 4.0 3.0 4.0 Tortuosity 1.0 1.2 1.7 1.0 1.1 1.1 1.2 1.2 1.1 1.5 1.1 1.1 1.1

Table 2.3 Quantitative measurements of burrow casts of vertical shafts (V) and helical burrows (H) produced by N. americanus.

OS28 OS29C OS30A OS30C OS33A OS33B OS30F OS1 OS25B OS33C OS29B OS21F Architecture V V V V V V VH H H H HB HC

Surface Openings 1 1 1 1 1 1 1 1 1 1 1 1

Maximum Depth (cm) 2.4 1.9 2.5 2.3 3.1 2.2 5.9 2.8 2.5 3.0 3.4 2.9

Total Length (cm) 3.0 1.9 2.5 2.6 3.1 3.0 11.8 7.0 8.4 6.8 10.7 10.0

Maximum Width (mm) 14.0 11.7 9.3 10.4 12.0 13.8 10.4 10.2 11.0 11.8 10 .6 16.5 Minimum Width (mm) 14.0 11.7 7.0 9.3 10.4 13.0 7.2 7.4 9.0 7.0 7.4 6.8 Average Width (mm) 14.0 11.7 8.2 9.9 11.2 13.4 9.1 8.9 10.1 9.6 8.4 11.6

Maximum Height (mm) 13.8 9.0 8.8 9.3 14.7 14.1 9.6 9.8 9.1 11.7 9.2 11.5 Minimum Height (mm) 9.5 9.0 7.7 8.0 11.1 10.6 6.7 6.3 5.8 8.5 6.1 8.0 Average Height (mm) 11.7 9.0 8.3 8.7 12.9 12.4 8.3 8.3 8.0 9.8 7.8 9.7

Average W/H Ratio 1.2 1.3 1.0 1.1 0.9 1.1 1.1 1.1 1.3 1.0 1.1 1.2

Maximum Circumference (cm) 5 3.5 2.8 3.1 4.3 4.4 3.2 3.2 3.3 4.3 3 4.3 Minimum Circumference (cm) 3.7 3.5 2.4 2.8 3.5 3.9 2.1 2.2 3 2.3 2.5 2.3 Average Circumference (cm) 4.4 3.5 2.6 3.0 3.9 4.2 2.8 2.8 3.2 3.1 2.7 3.4

Maximum Slope (Degrees) 85 80 90 80 90 90 90 60 50 80 60 55 Minimum Slope (Degrees) 85 80 90 80 90 90 0 15 0 50 60 0 Average Slope (Degrees) 85 80 90 80 90 90 45 45 25 65 75 25

B ranching Angle (Degrees) n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a 90 n/a

Comple xity 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 4.0 4.0

Tortuosity 1.3 1.0 1.0 1.1 1.0 1.0 2.0 3.5 5.6 2.3 1.5 1.2

Table 2.4 Quantitative measurements of burrow casts of O-shaped burrows (O) produced by N. americanus.

OS29A OS26B OS31A OS31B Average of All Burrows Architecture O Type 1 O Type 1 O Type 2 O Type 2

Surface Openings 1 1 2 1 1

Maximum Depth (cm) 3.4 6.9 2.5 1.9 4.4

Total Length (cm) 10.6 12.5 12.3 10.0 7.4

Maximum Width (mm) 12.9 18.0 13.4 10.9 13.2 Minimum Width (mm) 8.3 7.4 8.7 9.1 8.8 Average Width (mm) 10.5 10.9 10.4 10.1 10.6

Maximum Height (mm) 9.6 11.3 12.7 11.7 11.0 Minimum Height (mm) 6.0 6.7 9.3 8.9 7.9 Average Height (mm) 8.2 9.3 10.4 9.9 9.5

Aver age W/H Ratio 1.3 1.2 1.0 1.0 1.1

Maximum Circumference (cm) 3.5 4.8 3.9 3.6 4.0 Minimum Circumference (cm) 2.7 2.3 2.9 3.1 2.8 Average Circumference (cm) 3.1 3.4 3.5 3.3 3.3

Maximum Slope (Degrees) 60 60 90 20 71 Minimum Slope (Degrees) 15 60 0 20 47 Average Slope (Degrees) 38 60 43 20 59 Branching Angle (Degrees) n/a n/a n/a n/a 75

Complexity 3.0 3.0 6.0 2.0 2.6

Tortuosity 43.0 39.0 1.8 99.0 7.6

Table 2.5 Quantitative measurements of burrow casts of subvertical burrows (Sub V) produced by F. penneri.

FB2C FB3C FB3D FB3E FB3F FB3G FB3H FB3I FB2E FB2F FB2G FB6A FB3A FB5B Architecture Sub V Sub V Sub V Sub V Sub V Sub V Sub V Sub V Sub V Sub V Sub V Sub V Sub V Sub V Surface Openings 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Maximum Depth (cm) 3.5 1.7 3.3 3.3 3.6 6.8 6.5 8.2 7.9 6.9 4.4 1.8 1.5 2.8 Total Length (cm) 4.0 1.7 4.2 3.3 4.2 7.4 6.8 8.6 9.6 9.5 10.0 4.3 3.3 3.4 Maximum Width (mm) 13.1 9.4 14.0 14.1 14.2 10.8 12.8 12.8 12.5 12.2 6.5 17.0 8.2 15.9 Minimum Width (mm) 11.0 9.4 9.6 13.2 12.4 8.8 10.2 10.3 9.2 9.7 0.9 10.0 7.3 14.5 Average Width (mm) 12.1 9.4 11.1 13.7 13.2 10.1 11.4 11.4 11.0 10.8 4.0 13.7 7.8 15.2 Maximum Height (mm) 14.3 10.6 11.6 12.0 11.1 12.0 12.4 12.5 13.3 11.4 7.8 10.7 8.5 19.6 Minimum Height (mm) 10.0 10.6 8.6 8.3 9.2 8.7 10.8 8.5 8.1 8.7 3.4 10.0 7.6 13.3 Average Height (mm) 12.8 10.6 10.0 10.2 10.4 10.5 11.5 10.5 10.9 10.1 5.8 10.3 8.1 16.5 Average W/H Ratio 1.0 0.9 1.1 1.4 1.3 1.0 1.0 1.1 1.0 1.1 0.7 1.3 1.0 1.0 Maximum Circumference (cm) 4.4 3.2 4 4.4 4 3.7 4 4.1 3.9 3.7 3.7 4.5 2.7 5.7 Minimum Circumference (cm) 3.4 3.2 3.1 3.7 3.8 2.9 3.1 3.2 3.2 2.9 2.4 2.8 2.6 4.6 Average Circumference (cm) 4.0 3.2 3.4 4.1 3.9 3.3 3.6 3.6 3.6 3.4 3.2 3.7 2.7 5.2

Maximum Slope (Degrees) 65 75 68 65 75 78 70 65 65 55 78 20 45 45 Minimum Slope (Degrees) 65 75 68 65 75 78 70 65 65 55 78 20 45 45 Average Slope (Degrees) 65 75 68 65 75 78 70 65 65 55 78 20 45 45

Branching Angle (Degrees) n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a

Complexity 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 4.0 2.0 2.0 2.0

Tortuos ity 1.0 1.0 1.2 1.0 1.2 1.1 1.0 1.1 1.1 1.2 1.1 1.4 1.6 1.1

Table 2.6 Quantitative measurements of burrow casts of subvetical burrows (Sub V) produced by F. penneri, continued from Table 5.

FB5C FB5D FB7A FB7C FB7E FB7F FB7H FB5E Architecture Sub V Sub V Sub V Sub V Sub V Sub VB Sub VCB Sub VC

Surface Openings 1 1 1 1 1 1 1 1

Maximum Depth (cm) 4.2 5.7 2.1 4.1 8.7 8.0 7.4 5.2

Total Length (cm) 4.9 7.7 2.4 5.5 9.2 12.4 18.6 6.8

Maximum Width (mm) 12.9 16.3 11. 3 16.0 15.0 18.3 30.1 16.4 Minimum Width (mm) 8.0 12.7 10.3 9.1 9.0 10.1 8.7 10.4 Average Width (mm) 11.0 13.9 10.8 12.8 12.3 13.6 16.8 12.7

Maximum Height (mm) 11.8 16.3 12.0 14.0 na 12.8 19.0 24.7 Minimum Height (mm) 10.9 11.8 10.8 10.7 na 10.3 8.7 11.5 Average Height (mm) 11.5 13.9 11.4 12.7 10.0 11.3 13.4 15.6

Average W/H Ratio 1.0 1.0 0.9 0.9 1.2 1.2 1.3 0.9

Maximum Circumference (cm) 4.1 5.2 3.6 4.5 3.9 4.5 8.1 6.2 Minimum Circumference (cm) 3.2 3.3 3.1 3 2.9 3.1 2.6 3.3 Average Circumference (cm) 3.7 4.5 3.4 3.9 3.6 4.0 5.0 4.7

Maximum Slope (Degrees) 70 55 75 75 90 90 90 65 Minimum Slope (Degrees) 70 55 75 50 65 50 20 45 Average Slope (Degrees) 70 55 75 62 78 70 50 55

Branching Angle (Degrees) n/a n/a n/a n/a n/a 20 55 n/a

Complexity 2.0 2.0 2.0 2.0 2.0 3.0 4.0 3.0

Tortuosity 1.1 1.2 1.1 1.3 1.1 1.1 1.5 1.3

Table 2.7 Quantitative measurements of burrow casts of vertical shafts (V) produced by F. penneri.

FB3B FB2A FB2B FB2D FB4A FB5A FB7B FB2M FB7D Architecture V V V V V V V V VH Surface Openings 1 1 1 1 1 1 1 1 1 Maximum Depth (cm) 2.2 4.1 3.1 6.0 3.3 2.1 3.6 3.6 6.9 Total Length (cm) 2.2 4.1 3.1 6.7 3.6 2.1 4.7 3.6 8.4 Maximum Width (mm) 12.6 10.6 15.0 15.6 16.5 16.9 14.5 23.3 14.4 Minimum Width (mm) 9.8 9.2 13.6 8.6 12.3 10.3 7.6 12.1 10.3 Average Width (mm) 11.2 9.9 14.3 13.2 14.7 13.6 12.0 16.6 12.1 Maximum Height (mm) 9.7 11.9 15.8 13.3 13.4 15.4 13 .7 23.0 11.3 Minimum Height (mm) 9.1 10.0 14.0 9.6 10.5 12.0 11.6 12.7 9.8 Average Height (mm) 9.4 11.1 14.9 11.5 12.2 13.7 12.7 16.7 11.0 Average W/H Ratio 1.2 0.9 1.0 1.1 1.2 1.0 0.7 1.0 1.1 Maximum Circumference (cm) 3.6 3.8 5. 2 5.6 5.5 4.6 4 6.5 3.8 Minimum Circumference (cm) 3 3.4 4.6 2.6 3.5 3.4 3.2 3.8 3.3 Average Circumference (cm) 3.3 3.6 4.9 4.4 4.6 4.0 3.6 5.2 3.6 Maximum Slope (Degrees) 90 85 90 85 90 90 90 90 90 Minimum Slope (Degrees) 90 85 90 60 90 90 40 90 55 Average Slope (Degrees) 90 85 90 73 90 90 65 90 73 Branching Angle (Degrees) n/a n/a n/a n/a n/a n/a n/a n/a n/a Complexity 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Tortuosity 1.0 1.0 1.0 1.1 1.1 1.0 1.2 1.0 1.2

Table 2.8 Quantitative measurements of burrow casts of J-shaped (J), helical (H), and O-shaped (O) burrows produced by F. penneri.

Average of All FB2I FB2J FB2K FB2L FB7G FB2H FB4B FB1 FB5F FB6B FB5G Burrows OB (2) OC OB Architecture J J J J J JB H HB (2) Type 1 Type 1 Type 2

Surface Openings 1 1 1 1 1 1 1 1 1 1 1 1

Maximum Depth (cm) 6.5 7.8 8.1 2.9 8.4 5.8 3.1 2.8 7.7 4.4 1.1 4.8

Total Length (cm) 10.7 11.9 11.8 7.5 14.7 13.0 11.1 11.1 17.5 13.0 10.1 7.6

Maximum Width (mm) 11.5 16.6 12.4 11.4 13.0 13.0 13.6 13.5 12.5 24.8 11.9 14.4 Minimum Width (mm) 8.4 9.3 9.5 7.9 9.0 7.2 10.0 7.5 9.1 10.0 9.0 9.7 Average Width (mm) 9.9 12.0 11.0 9.4 11.3 10.8 11.6 9.8 10.8 17.7 10.2 11.9

Maximum Height (mm) 13.0 16.5 14.8 12.1 15.7 14.7 11.4 7.0 13.7 16.0 11.2 13.5 Minimum Height (mm) 9.2 9.2 10.3 7.4 10.4 7.7 7.5 5.1 10.0 7.7 6.2 9.5 Average Height (mm) 10.7 11.8 13.0 9.5 12.4 11.0 10.0 6.1 12.2 12.1 8.3 11.4

Average W/H Ratio 0.9 1.0 0.9 1.0 0.9 1.0 1.2 1.6 0.9 1.5 1.3 1.1

Maximu m Circumference (cm) 3.7 5.3 4.2 3.5 4.2 6.4 4.3 3.4 4.1 6.1 3.5 4.5 Minimum Circumference (cm) 2.9 2.8 3 2.6 3.1 2.4 3.1 2.2 3.2 2.6 2.7 3.1 Average Circumference (cm) 3.2 3.8 3.8 3.1 3.9 3.7 3.6 2.7 3.7 4.4 3.1 3.8

Maximum Slope (Degrees) 80 90 55 55 75 65 70 50 85 90 20 72 Minimum Slope (Degrees) 15 50 50 45 75 25 0 25 85 40 20 58 Average Slope (Degrees) 47 70 53 50 75 45 35 38 85 65 20 65

Branching Angle (Degrees) n/a n/a n/a n/a n/a 70 n/a 10,4 5 12, 25 n/a 10 31

Complexity 2.0 2.0 2.0 2.0 2.0 3.0 2.0 6.0 6.0 4.0 4.0 2.5

Tortuosity 2.2 2.0 2.0 5.8 2.4 1.4 4.3 1.1 17.6 53.0 1.4 3.1

75 soil /25 carbonate sand trial in which the specimen did not produce any burrows in 16

days. In trials with sediment consisting of both fiber and soil or just soil, the millipedes

used a compaction technique of burrowing. Specimens lowered their heads and rammed

into the sediment using the collum like a plow. Once the front few segments were

submerged the individual lifted its head and pushed upward, likely with the collum, to

compact the sediment into the ceiling, then moved forward and repeated the process. In

this way, the millipede would slowly continue to enter the subsurface. In the sandy

sediment, a brief period of excavation was used to start the burrow. The specimens used

their front legs to manipulate grains and pushed them farther along their body until the

grains were deposited. Excavation was observed to be a temporary technique until an

entry into the sediment was established that allowed for compaction. The time to

complete submergence varied from five minutes to almost an hour (Fig. 2.5A–D). In

some instances, the individual would attempt to burrow horizontally before reaching a

depth greater than the height of the individual, eventually causing it to resurface.

Individuals were found up to 26 cm below the surface; molting individuals were found 10

cm from the surface. Most surface activity was seen during laboratory’s dark hours.

2.5.1.2 Floridobolus penneri

When placed on the sediment surface, some specimens of F. penneri would begin burrowing almost immediately in all sediment types and moisture conditions. Some individuals, however, would travel several times around the edges of the enclosure prior to starting a burrow. In all experimental trials with F. penneri, individuals burrowed 55

within 30 minutes of the start of the trial. During the laboratory’s light hours, individuals were sometimes at the surface traveling around the edges of the tank or eating. Surface activity was most common, however, during the laboratory’s dark hours. Floridobolus penneri was observed to only use a compaction burrowing technique at the surface. In the subsurface, however, excavated by using their mouthparts to move sediment grains to their front legs and then along several diplosegments until the grains were deposited.

Specimens rotated their body to excavate along all sides of the burrow. In this way F. penneri was able to excavate a tunnel larger than its body. Similar to N. americanus, F. 56

penneri started and then abandoned burrows leaving only a small divot in the sediment

surface. Specimens of F. penneri also attempted shallow horizontal movements causing the formation of surface trails. Burrows were up to 33 cm deep (Fig. 2.6A). Molting was observed both at the surface (Fig. 2.6B), several centimeters below the surface, and at depths of up to 33 cm. When long periods of inactivity were observed, individuals were found anywhere from 2–40 cm in the subsurface (Fig. 2.6C–D). When exiting burrows,

some individuals emerged backwards, indicating that there was likely no turn-around

point in the burrow.

Both species were observed to either use the same burrow multiple times or attempt

to enter a burrow that was created by another individual, even when it was still occupied.

This activity led to the development of multiple communal structures in the holding tanks

and one possible communal structure in a 50 soil /50 carbonate sand trial with F. penneri

(Fig. 2.6E). It is possible, however, that due to repeated use by one specimen the structure

was modified by only one individual. Occupation of burrows with a length equal to or

greater than the millipede’s body ranged from several hours to ninety-four days when

specimens were excavated. It is likely that those individuals could have remained at depth

for much longer periods. Both species exhibited this ability. In many experiments,

burrow openings collapsed or became filled in while the individual was still deep within

the sediment. In order to resurface, the millipedes produced a new burrow and surface

opening. Of the 13 experiments conducted between August 15th and February 1st, only

38% (n=5) were completed within 5 days of the expected experimental end date. Of the

other 10 experiments (June 6th –August 8th), 90% (n=9) were completed within 5 days 57

2.5.2 Surface Trace Morphology

At the start of each experiment, the sediment surface was leveled and had a homogenous grain distribution. Surface traces created by the millipedes consisted primarily of trails and divots made while attempting to burrow, grain size separations that resulted from movement on the surface, and burrow openings. Trails ranged greatly in size and shape, but were made by all species and were present in all sediment compositions. The trails were sinuous to straight and were generally characterized by a shallow trenching of sediment in a semi-continuous line (Fig. 2.7A–B). Divots created by attempted burrowing were characterized by shallow indentations from 0.1–0.7 cm deep.

Where specimens of N. americanus used excavation to begin a burrow, very small mounds of sediment were observed near burrow entrances. Often, individuals of either species constantly circled the outer edges of the tanks while on the surface. This movement created pathways in which large sediment grains were pushed to the edges and outlined the path (Fig. 2.7C–D). These paths may represent a response to the space limitation imposed by the experiments and, therefore, may not be present in natural conditions. Burrow openings created by the millipedes were almost always circular in shape, entered the surface anywhere from 0–90°, and had a diameters closely related to the diameter of the producer (Fig. 2.7E–F). The only exception to this was when burrows were made against the sides of the enclosure where the burrow openings were larger and 59

more elliptical. From the observations of these surface traces and their temporary

existence in a controlled environment, with the exception of the burrow openings, these

traces would have a poor preservation potential.

2.5.3 Burrow Morphology

Burrows produced by N. americanus and F. penneri were always formed as open structures that were never directly observed to be actively backfilled. Over time, burrow openings would fill in with loose sediment surrounding the entrance. In some instances, especially when the individual entered the surface at low angles, the sediment surface would collapse shortly after the specimen was completely burrowed. This passive fill process did not always fill the entire burrow; when the millipedes were excavated from beneath these closed entrances, open tunnels were still present below the surface.

Burrows with more than one entrance (n=1) were rarely cast in experimental trials.

The millipedes produced five basic architectures including vertical, subvertical, J- shaped, helical, and O-shaped burrows. These basic architectures represent the dominant features present in the burrow casts (Fig. 2.4A). In addition to these base structures, four modifying architectural features were observed including branches, chambers, partial spirals, and additional entrances (Fig. 2.4B). Only F. penneri produced distinct J-shaped burrows and occurrences were restricted to trials lacking carbonate sand. The shafts, tunnels, and chambers produced by both species were circular to elliptical in cross section but had slightly different dimensions, likely reflecting the body size differences between the two species used in the study. Narceus americanus burrows had an average width-to- 61

height ratio of 1.14 (0.9–1.4, SD=0.13) with an average circumference of 3.31 cm (2.6–

4.9, SD=0.53) (Tables 2–4), whereas F. penneri burrows had an average width-to-height

ratio of 1.06 (0.7–1.6, SD=0.18) and an average circumference of 3.80 cm (2.7–5.2,

SD=0.6) (Tables 5–8). The average width and height of the shafts, tunnels, and chambers

varied widely from 8.2–15.6 mm (x=10.6, SD=1.7) and 7.8–12.9 mm (x=9.5, SD=1.5)

respectively for N. americanus (Table� 2–4) and 3.95–17.7 mm (x=12.0,� SD=2.5) and

5.7–16.7 mm (x=11.3, SD=2.24) respectively for F. penneri (Table� 5–8). Branching only

occurred in 11.2%� (n=8) of the burrows cast with branching angles ranging from 10–90°

(Tables 2, 3, 6, 8). Burrow entrances were commonly larger than the burrow, possibly

indicating the use of excavation to remove material near the burrow opening, sometimes

causing a downward-tapering shape in simple (vertical and subvertical) burrows.

Only rarely were recognizable surficial features in preserved. At the terminus of

some burrows, vertically-oriented, wedge-shaped indentations were visible (Fig. 2.8A–B)

commonly in association with fecal pellets and burrow chambers. The fecal pellets were

incorporated into the floor of the burrows of both species. The pellets were found in

groups of four or five, commonly at a burrow endpoint, and arranged in a straight line or

were randomly dispersed (Fig. 2.8C–E). Fecal pellets were most abundant in burrows

with sediments that had a higher soil percentage.

2.5.3.1 Vertical Shafts

The dominant feature of vertical shafts is a slope going into the subsurface at 80–90°

(x=87.8°, SD=3.6°). This architecture represents 24% (n=7) and 21% (n=9) of

� 62

burrows produced by N. americanus and F. penneri respectively. Vertical shafts extended

1.9–6.85 cm (x=3.44, SD=1.6) below the surface with a total length of 1.9–11.8 cm

(x=4.15, SD=2.7)� in both species. All vertical shafts had only one entrance and a

complexity� of 2.

Narceus americanus produced vertical shafts with widths of 8.15–14 mm (x=11.1,

SD=2.2), heights of 8.25–12.9 mm (x=10.2, SD=2.0), width-to-height ratios of 0.89–1.3�

(x=1.11, SD=0.14), and circumferences� of 2.6–4.35 cm (x=3.5, SD=0.7) (Fig. 2.9A, B)

(Table� 3). Narceus americanus produced only one variant� with a vertical shaft ending in

a horizontally oriented partial spiral (Fig. 2.9C). The addition of the partial spiral

increased the length and tortuosity of the burrow system significantly making this variant

the longest (11.8 cm) and most tortuous (1.98) of the vertical shafts. The tortuosity of N.

americanus produced vertical shafts was 1.00–1.98 (x=1.19, SD=0.36).Vertical shafts

were produced in sediment lacking sand, all moisture� conditions, in 65 gallon terrariums,

and 86% (n=6) occurred in tanks with one individual.

Floridobolus penneri produced vertical shafts with widths of 9.9–16.6 mm (x=13.1,

SD=2.0), heights of 9.4–16.7 mm (x=12.6, SD=2.2), width-to-height ratios of 1.21–0.74�

(x=1.02, SD=0.15), and circumferences� of 3.3–5.15 cm (x=4.13, SD=0.66) (Fig. 2.10A,

B)� (Table 7). A partial downward spiral variant of the vertical� shaft architecture was

produced (Fig. 2.10C). Unlike the partial spiral produced by N. americanus, this variant

contains the spiral in the middle of the burrow, rather than at its terminus, is not

horizontally oriented, and does not drastically change the overall morphology. The

tortuosity values for these burrows ranged from 1.00–1.23 (x=1.06, SD=0.08). This

� 64

burrow architecture was produced by F. penneri in all sediment compositions, higher moisture conditions, all tank sizes, and 78% (n=7) occurred in tanks with multiple individuals.

2.5.3.2 Subvertical Burrows

Burrows were designated as subvertical burrows if the burrow’s dominant feature was the presence of an average slope of less than 80° (20–78°, x=60.9, SD=14.5). This burrow architecture represented 45% (n=13) of burrows produced� by N. americanus and

52% (n=22) of burrows produced by F. penneri. Subvertical burrows were 1.5–13.4 cm

(x=5.3, SD=2.8) deep and 1.7–18.6 cm long (x=7.0, SD=3.9) with a single surface

opening� in both species. All simple subvertical� burrows had a complexity of 2.

The shafts, tunnels, and chambers of subvertical burrows produced by N. americanus

were 8.8–15.5 mm (x=10.8, SD=1.8) wide, 7.9–12.2 mm (x=9.4, SD=1.4) high, with width-to-height ratios� of 0.96–1.40 (x=1.17, SD=0.15), and� circumferences of 2.65–4.9

cm (x=3.3, SD=0.58) (Fig. 2.11A, B)� (Table 3). Only one subvertical burrow produced

by N.� americanus had a branch (C=4) (Fig. 2.11C), and four had chambers (C=3, 4) (Fig.

2.11D–E). The tortuosity of the subvertical burrows produced by N. americanus ranged

from 1.0–1.7 (x=1.14, SD=0.18). Only 8% (n=1) of N. americanus subvertical burrows

were produced� in sediment with sand; the remaining occurred in 50 organic /50 soil

sediment compositions under all moisture conditions and tank sizes. Of the subvertical

burrows produced by N. americanus, 69% (n=9) were in tanks with more than one individual.

Figure 2.10 Vertical shafts produced by F. penneri. A, B) Side views of two simple, vertical shafts (FB2A and FB2B). C) Side view of a vertical shaft with an intermediate helical modification (FB7D).

Subvertical burrows produced by F. penneri were slightly larger and had widths of

3.95–16.8 mm (x=11.8, SD=2.6), heights of 5.7–16.5 mm (x=11.3, SD=2.3), width-to-

height ratios of 0.70–1.38� (x=1.05, SD=0.17), and circumferences� of 2.65–5.15 cm

(x=3.8, SD=0.61) (Fig. 2.12A,� B) (Tables 5, 6). Two subvertical burrows produced by F.

penneri� had an added branch (C=3, 4) and one had an added chamber (C=3) (Fig. 2.12C, 67

D). There was also one large subvertical burrow that had a large chamber and a branch

(C=4) (Fig. 2.12E). Subvertical burrows produced by F. penneri had tortuosity values

that ranged from 1.0–1.6 (x=1.17, SD=0.16) and occurred in all sediment compositions,

high moisture trials, and tank� sizes. Of all subvertical burrows produced by F. penneri,

64% (n=14) were in tanks with multiple individuals.

2.5.3.3 Helical Burrows

This burrow architecture was defined by the presence of an upward or downward

spiraling morphology resulting in a tortuosity >2.3. Helical burrows accounted for 17%

(n=5) of the burrows produced by N. americanus and 5% (n=2) of the burrows produced

by F. penneri. Helical burrows had one entrance, were 2.5–3.4 cm (x=2.92, SD=0.3) deep, and 6.8–11.1 cm (x=9.3, SD=1.9) long. All simple helical structures� had a complexity of 2. �

Narceus americanus produced helical burrows with widths of 8.4–11.64 mm (x=9.7,

SD=1.3), heights of 7.8–9.8 mm (x=8.7, SD=0.9), width-to-height ratios of 0.98–1.3�

(x=1.12, SD=0.12), and circumferences� of 2.7–3.4 cm (x=3.04, SD=0.29) (Fig. 2.13A)

(Table� 3). The spiraling nature of these burrows generally� caused a lower average slope for the burrow system with slopes ranging from 25–75° (x=47, SD=22.8). Two variations of the helical structures were produced by N. americanus�, one with a branch (C=4; n=1) and one with a chamber (C=4; n=1) (Fig. 2.13B, C). The addition of straight branches and chambers to the structure lowered the overall tortuosity of the burrow system from an average of 3.8 (2.3–5.6, SD=1.7) in burrows without these modifications to 1.4 (1.2–1.5,

SD=0.19). Helical structures were produced by N. americanus in sediments that excluded 68

carbonate sand, under all moisture conditions and tank sizes, and in tanks with multiple

(60%) and single (40%) specimens.

Floridobolus penneri produced two helical burrows, one simple and one with two branches. The simple helical burrow and variant had average widths of 11.6 and 9.8 mm

(x=10.7, SD=1.25), heights of 9.9 and 6.1 mm (x=8.0, SD=2.8), width-to-height ratios of

1.17� and 1.6 (x=1.4, SD=0.32), and circumferences� of 3.6 and 2.7 mm (x=3.1, SD=0.7) respectively (Fig.� 2.14A, B) (Table 8). The average slopes of these burrows� ranged from

35–38° (x=36.25°, SD=1.76). While the simple helical structure (C=2) had a tortuosity of

4.27, the �tortuosity of the variant (C=6) was only 1.14. Both helical structures produced by F. penneri occurred in trials with higher moisture conditions and single specimens.

They were produced in tanks of different sizes and in sediment with 50soil /50 carbonate sand or coconut fiber.

2.5.3.4 O-shaped Burrows

O-shaped burrows were characterized by a tunnel that looped around and reconnected with the burrow. The loops occurred either at the terminal end of a subvertical or vertical shaft (Type 1) or as horizontally oriented structures just below the surface (Type 2). Both species produced both types of O-shaped burrows. Due to these morphological variations, the average slope of these burrow systems varied widely from

20° to 85° (x=47.3, SD=24.1). O-shaped burrows accounted for 14% (n=4) and 7% (n=3) of architectur� es produced by N. americanus and F. penneri respectively. The presence of

O-shaped burrows drastically increased the tortuosity of a burrow system as long as the

Figure 2.13 Helical burrows produced by N. americanus. A) Side view of a simple, helical burrow (OS25B). B) Side view of a helical burrow with a small branch (OS29B). C) Oblique view of a helical burrow with a chamber in the midsection of the burrow (OS21F). Arrow points to a vertically oriented, wedge-shaped indent.

Figure 2.14 Helical burrows produced by F. penneri. A) Side view of a simple, helical burrow (FB4B). B) Oblique view of a helical burrow with two small branches (FB1).

continuity of the tunnel was not interrupted by the presence of a branch. The burrows

were 1.1–7.7 cm (x=4.0, SD=2.5) deep and 10.0–17.5 cm (x=12.3, SD=2.6) long.

O-shaped burrows� of N. americanus had widths of 10.1–10.9� mm (x=10.5,

SD=0.34), heights of 8.2–10.4 mm (x=9.5, SD=1.0), width-to-height ratios� of 1.0–1.3

(x= 1.1, SD=0.13), and circumferences� of 3.1–3.5 cm (x=3.3, SD=0.18) (Fig. 2.15A–C)

(Table� 4). Narceus americanus produced one variant of� the Type 2 O-shaped burrow that

had two entrances (C=6) (Fig. 2.15A), one simple Type 2 O-shaped burrow (C=2) (Fig.

2.15B), and two Type 1 O-shaped burrows attached to subvertical shafts (C=3) (Fig.

2.15C). The tortuosity of these burrow systems varied from 1.8–99.0 (x=45.7, SD=40.1).

Narceus americanus constructed this burrow architecture in 50/50 soil� mixtures with both

carbonate sand and coconut fiber, under all moisture conditions, tanks sizes, and equally

in individual and group trials. Type 2 O-shaped burrows were only produced in trials

with carbonate sand.

Floridobolus penneri produced O-shaped burrows with widths of 10.1–17.7 mm

(x=12.9, SD=4.2), heights of 8.3–12.2 mm (x=10.8, SD=2.2), width-to-height ratios of

0.9–1.46� (x=1.16, SD=0.2), and circumferences� of 3.0–4.4 cm (x=3.5, SD=0.5) (Fig.

2.16A–C) �(Table 8). Two Type 1 O-shaped burrow variants were� produced by F.

penneri, both of which were associated with vertical shafts. One variant had two

additional branches (C=6) (Fig. 2.16A) and the other contained a chamber within the

heavily curved portion of the O structure (C=4) (Fig. 2.16B). One Type 2 O-shaped

burrow variant was produced that had an additional branch (C=4) (Fig. 2.16C). The

tortuosity of these burrow systems ranged from 1.4–53.0 (x=24, SD=26.4). All O-shaped

� 73

burrows produced by F. penneri occurred in sandy soil sediments, under higher moisture conditions, and in trials with multiple individuals using 30 gallon tanks.

2.5.3.5 J-shaped Burrows

This burrow architecture consists of a vertically to subvertically oriented shaft that, upon reaching the maximum depth of the burrow, shifts horizontally for a short distance then shifts upwards creating a J-shape. Floridobolus penneri was the only species to

produce this burrow architecture which accounted for 14% (n=6) of its burrows. These

burrows were 2.9–8.4 cm (x=6.6, SD=2.1) deep and 7.5–14.7 cm (x=11.6, SD=2.4) long.

J-shaped burrows had widths� of 9.4–12 mm (x=10.7, SD=0.94), heights� of 9.5–13 mm

(x=11.4, SD=1.2), width-to-height ratios of 0.85–1.0� (x=0.95, SD=0.06), and circumferences� of 3.1–3.9 cm (x=3.6, SD=0.32) (Fig. 2.17A–C)� (Table 8). The slope of

J-shaped burrows ranged from 45–75°� (x=56.5°, SD=12.7) and simple burrows had a complexity of 2 (Fig. 2.17A, B). One variant� was produced that had a branch at the entrance of the burrow (C=3) (Fig. 2.17C). All occurrences of J-shaped burrows were produced in sediments that did not include carbonate sand, were under higher moisture conditions, and in tanks that housed multiple individuals. Five of the six occurrences were in the same 50 coconut fiber /50 soil experiment.

2.5.3.6 Chambers

Chambers were defined as areas in the burrow that were at least two times the width or height of the smallest portion of the burrow. Only eight chambers produced by N. americanus or F. penneri were cast successfully (Figs. 2.11D–E, 2.12D–E, 2.13C,

2.16B). Activity within any of the cast chambers was not directly observed. Chambers typically outlined the general size and shape of the individual that occupied it when in a curled position. An exception was FB7H (Fig. 2.12E) in which the chamber was particularly large (three times the size of the smallest width) and was oriented at an upward angle to the access shaft, an architecture not seen in any other burrow. The time of production and occupation of burrow FB7H was a maximum of seven days. Other chambers constructed against the side of the tank that were of a similar size to the chamber in FB7H (Fig. 2.6A) were observed to be used for molting or resting and were occupied for much longer periods (>10 days).

2.5.4 Environmental Effects

Specimens of both species of millipedes produced burrows of varying complexity

and tortuosity in all sediment compositions and moisture conditions (Table 1).

Environmental variations did, however, have a noticeable effect on the animals and

burrow preservation. Low moisture conditions were found to decrease the potential for

burrow entrances to remain open for the duration of the experiment. In the 50 organic /50

soil trials, burrows became passively filled as animal surface activity and constant re-

wetting caused grains to collapse into the openings. In nine trials with N. americanus

under 30–40% moisture conditions, only 14 burrows were successfully cast (0–6 burrows

per trial). For this reason, all subsequent trials were increased to ≥50% moisture. The

moisture change increased the number of successfully cast burrows to nine in only two

trials (3–6 burrows per trial). In addition, casts of burrows constructed by N. americanus

under drier conditions reached a maximum depth of 13.4 cm (x=5.4 SD=3.6) below the surface but a maximum depth of only 6.6 cm (x=3.8 SD=1.8) under� wetter conditions.

A lack of successful burrow casts was also� observed in experiments with carbonate sand in which the individuals remained in their burrows longer than the expected duration of the trial. In these experiments, the lack of consistent use of the entrance and gravitational collapse of sand grains into the burrow caused the burrow openings to close. As the concentration of carbonate sand increased, the maximum depth of burrows produced by both species decreased. Casts of burrows produced by N. americanus reached a maximum depth of 4.1 cm in 25 carbonate sand /75 soil but an average of only 2.2 cm (1.9–2.5, SD=0.4) in 50/50 sediment. A similar trend was 78

observed in casts of burrows produced by F. penneri; maximum burrow depths reached an average of 4.1 cm (1.1–7.7, SD=2.3) in 25 carbonate sand /75 soil and an average of only 3.1 cm (1.8–4.4, SD=1.1) in 50/50 sediment.

The application of some of these environmental stresses did prove to increase the

mortality of some of the individuals. While specimens of both species perished in

experiments and in holding tanks, N. americanus seemed to have been the most adversely

affected by the environmental changes. While N. americanus did burrow in sediment

containing carbonate sand, N. americanus survivorship through these trials and soon after

was very low. Floridobolus penneri also exhibited increased mortality in carbonate sand,

but not as severely as N. americanus. Floridobolus penneri was a more proficient

burrower in sandy sediments producing 11 preserved structures with seven different

architectures. Narceus americanus produced only three structures with three

architectures. Tank size and sediment depth appeared to have no effect on burrow

architecture. While individuals were observed to reach depths of 33 cm, this was not the

bottom of the enclosure. When retrieved, no individuals were found at the bottom of the

tanks.

2.6 Analysis of Burrow Architecture

2.6.1 Burrows of N. americanus

Burrows produced by N. americanus were found to range from dissimilar (0.5–0.3)

to identical (1.0) (Appendix 1). The average similarity for all burrows produced by N.

americanus was a 0.8, indicating a highly similar suite of burrows based on the 10 79

quantitative characteristics (Fig. 2.18). Similarity values within each burrow architecture

averaged 0.8 for subvertical burrows, 0.9 for vertical shafts, 0.8 for helical burrows, and

0.7 for O-shaped burrows (Fig. 2.19A–D). In most cases, moderate similarities within

burrow architectures were restricted to only a few specimens. Of all subvertical burrows

(n=13), for example, only 15% (n=2) were responsible for all occurrences of moderate

similarity (0.7). Among vertical burrows (n=7), only one sample (OS30F) produced all

results of moderate similarity (0.7). Similarities between helical burrows (n=5) were less

well defined. Only one helical burrow (OS1) was highly similar to all other helical

burrows while the rest were highly similar (0.9–0.8) to only two and moderately similar

(0.7) to the remaining two burrows. O-shaped burrows were the least similar to each

other. Within the O-shaped burrows (n=4), the comparison of OS26A and OS26B

produced the only result of high similarity (0.9). All other comparisons resulted in

moderate similarity (0.7–0.6) with the exception of the comparison of OS31A and

OS31B which produced the only result of dissimilarity (0.5) among the burrows of N.

americanus. When different architectures were compared there was a tendency toward

decreased similarity as the average angle of the burrow system decreased and tortuosity

increased (Fig. 2.18). Vertical burrows, for example, had an average similarity of 0.8

with subvertical burrows, 0.7 with helical burrows, and 0.6 with O-shaped burrows. A few burrows that were qualitatively characterized as having different architectures were found to be highly similar indicating that other properties were also contributing to similarity. For example, two helical burrows (OS33C, OS29B) were highly similar to all 80

A. Subvertical Burrows OS32 OS23 OS25A OS21A OS21B OS21C OS30B OS30D OS21D OS24 OS21E OS26A OS30E OS32 0.8 0.7 0.7 1.0 0.9 1.0 1.0 0.9 0.8 0.9 0.8 0.9 OS23 0.8 0.9 0.8 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.8 0.8 OS25A 0.7 0.9 0.9 0.7 0.8 0.7 0.8 0.8 0.9 0.7 0.8 0.7 OS21A 0.7 0.8 0.9 0.8 0.7 0.7 0.7 0.7 0.8 0.7 0.8 0.7 OS21B 1.0 0.8 0.7 0.8 0.9 1.0 0.9 0.9 0.8 0.8 0.9 0.9 OS21C 0.9 0.9 0.8 0.7 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 OS30B 1.0 0.8 0.7 0.7 1.0 0.9 1.0 0.9 0.8 0.9 0.8 0.9 OS30D 1.0 0.8 0.8 0.7 0.9 0.9 1.0 0.9 0.8 0.9 0.9 0.9 OS21D 0.9 0.8 0.8 0.7 0.9 0.9 0.9 0.9 0.8 1.0 0.9 0.9 OS24 0.8 0.9 0.9 0.8 0.8 0.9 0.8 0.8 0.8 0.8 0.9 0.8 OS21E 0.9 0.8 0.7 0.7 0.8 0.9 0.9 0.9 1.0 0.8 0.8 0.9 OS26A 0.8 0.8 0.8 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.8 0.9 OS30E 0.9 0.8 0.7 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9

B. Vertical Shafts OS28 OS29C OS30A OS30C OS33A OS33B OS30F OS28 0.9 0.9 0.9 1.0 1.0 0.7 OS29C 0.9 0.9 1.0 0.9 0.9 0.7 OS30A 0.9 0.9 0.9 1.0 1.0 0.7 OS30C 0.9 1.0 0.9 0.9 0.9 0.8 OS33A 1.0 0.9 1.0 0.9 1.0 0.7 OS33B 1.0 0.9 1.0 0.9 1.0 0.7 OS30F 0.7 0.7 0.7 0.8 0.7 0.7

C. Helical Burrows OS1 OS25B OS33C OS29B OS21F OS1 0.8 0.9 0.8 0.8 OS25B 0.8 0.7 0.7 0.9 OS33C 0.9 0.7 0.9 0.7 OS29B 0.8 0.7 0.9 0.7 OS21F 0.8 0.9 0.7 0.7

D. O-Shaped Burrows OS29A OS26B OS31A OS31B OS29A 0.9 0.7 0.7 OS26B 0.9 0.7 0.6 OS31A 0.7 0.7 0.5 OS31B 0.7 0.6 0.5

vertical burrows, and most subvertical burrows while one helical burrow (OS29B) was

highly similar to two O-shaped burrows (OS26B, OS31A) (Appendix 1). Burrows

categorized by the Bray Curtis analysis to be identical (n=13) were limited to those in the

same architecture with the exception of two burrows, OS33C (helical burrow) and

OS30D (subvertical burrow) (Appendix 1).

2.6.2 Burrows of F. penneri

Burrows produced by F. penneri were found to range from dissimilar (0.5) to

identical (1.0) (Appendix 1). The average similarity of all burrows produced by F.

penneri was 0.8 and indicated that the suite was highly similar (Fig. 2.18). These similarities were highest within burrow architectures (Fig. 2.20A–E). Subvertical

burrows, vertical shafts, J-shaped burrows, and helical burrows all had average similarity

values of 0.9 indicating very high similarity. Only O-shaped burrows had an average

similarity (0.6) that indicated that burrows within this architecture were only moderately

similar. Burrows of the Type 1 O-shaped variety, however, did show a high level of

similarity (0.8) among themselves and dissimilar values (0.5) when compared with Type

2 O-shaped structures. Within the same burrow architectures, only two burrows, FB6A

(subvertical) and FB5G (O-shaped), accounted for the majority of moderately similar

(0.7–0.6) and dissimilar (0.5) results (Fig. 2.20A, D). When burrows of different

architectures were compared, a similar trend to that seen in N. americanus burrows was evident; as the average angle of the burrow system decreased and tortuosity increased, similarity decreased. Vertical burrows had an average similarity of 0.9 with subvertical 83 burrows, 0.8 with J-shaped burrows, 0.7 with helical burrows, and 0.7 with O-shaped burrows (Fig. 2.18). An exception to this trend was one Type 1 O-shaped burrow (FB5F) with a low tortuosity resulting from two branches which was highly similar to all vertical burrows and most (77%) subvertical burrows (Appendix 1). The occurrence of identical burrows between different architectures (n=19) was limited to comparisons between vertical, subvertical, and J-shaped burrows (Appendix 1).

2.6.3 Narceus americanus and F. penneri Burrows

The burrows of both species had an overall high similarity value (0.8) (Fig. 2.18).

Comparisons of each of the four common architectures resulted in similarity values that were close to those of the individual species (Figs. 2.18, 2.21). The average similarity of subvertical and vertical burrows produced by both species was 0.9. Within the subvertical architecture, only three (OS21A, OS25A, FB6A) out of 35 total burrows produced most

(86%) of the moderately similar or dissimilar values (Fig. 2.21A). Within the 16 burrows of the vertical architecture, a single burrow (OS30F) with an added helical component produced all moderate similarity values (Fig. 2.21B). Helical burrows were also found to be highly similar (0.8) between the species with only one case of moderate similarity between two (FB4B, OS29B) out of seven burrows (Fig. 2.21C). The O-shaped burrows of each species had a moderate (0.7) level of similarity. When split into Type 1 and Type

2 structures, however, Type 1 O-shaped burrows averaged a high similarity value (0.8) whereas Type 2 O-shaped burrows averaged a moderate similarity value (0.6) (Fig.

2.21D). The lower level of similarity within Type 2 structures is due to the simple Type 2 84

A. Subvertical Burrows FB2C FB3C FB3D FB3E FB3F FB3G FB3H FB3I FB2E FB2F FB2G FB6A FB3A FB5B FB5C FB5D FB7A FB7C FB7E FB7F FB7H FB5E FB2C 0.9 1.0 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.8 0.9 1.0 0.9 0.9 1.0 0.9 0.9 0.8 0.9 FB3C 0.9 0.9 0.9 1.0 0.9 0.9 0.9 0.9 0.8 0.9 0.6 0.8 0.8 0.9 0.8 1.0 0.9 0.9 0.9 0.7 0.8 FB3D 1.0 0.9 1.0 1.0 0.9 1.0 0.9 0.9 0.9 0.9 0.7 0.8 0.8 1.0 0.9 0.9 0.9 0.9 0.9 0.8 0.9 FB3E 1.0 0.9 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 FB3F 0.9 1.0 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.7 0.8 0.8 1.0 0.9 1.0 0.9 0.9 0.9 0.8 0.9 FB3G 0.9 0.9 0.9 0.9 0.9 1.0 0.9 0.9 0.9 0.9 0.6 0.8 0.7 0.9 0.9 0.9 0.9 1.0 0.9 0.8 0.8 FB3H 0.9 0.9 1.0 0.9 0.9 1.0 1.0 1.0 0.9 0.9 0.6 0.8 0.8 1.0 0.9 0.9 0.9 0.9 1.0 0.8 0.9 FB3I 0.9 0.9 0.9 0.9 0.9 0.9 1.0 1.0 0.9 0.9 0.7 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 FB2E 0.9 0.9 0.9 0.9 0.9 0.9 1.0 1.0 0.9 0.9 0.7 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 FB2F 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.8 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.9 0.9 FB2G 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.8 0.5 0.7 0.7 0.9 0.8 0.9 0.8 0.9 0.9 0.7 0.8 FB6A 0.7 0.6 0.7 0.7 0.7 0.6 0.6 0.7 0.7 0.7 0.5 0.7 0.8 0.7 0.7 0.6 0.7 0.6 0.6 0.7 0.7 FB3A 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.7 0.7 0.9 0.8 0.8 0.8 0.8 0.7 0.7 0.8 0.8 FB5B 0.9 0.8 0.8 0.8 0.8 0.7 0.8 0.8 0.8 0.8 0.7 0.8 0.9 0.8 0.9 0.8 0.9 0.7 0.8 0.8 0.9 FB5C 1.0 0.9 1.0 0.9 1.0 0.9 1.0 0.9 0.9 0.9 0.9 0.7 0.8 0.8 0.9 1.0 0.9 0.9 0.9 0.8 0.9 FB5D 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.9 1.0 FB7A 0.9 1.0 0.9 0.9 1.0 0.9 0.9 0.9 0.9 0.8 0.9 0.6 0.8 0.8 1.0 0.8 0.9 0.9 0.9 0.7 0.8 FB7C 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 FB7E 0.9 0.9 0.9 0.9 0.9 1.0 0.9 0.9 0.9 0.9 0.9 0.6 0.7 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.8 FB7F 0.9 0.9 0.9 0.9 0.9 0.9 1.0 0.9 0.9 0.9 0.9 0.6 0.7 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 FB7H 0.8 0.7 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.9 0.7 0.7 0.8 0.8 0.8 0.9 0.7 0.8 0.8 0.9 0.9 FB5E 0.9 0.8 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.9 0.8 0.7 0.8 0.9 0.9 1.0 0.8 0.9 0.8 0.9 0.9

B. Vertical Shafts FB3B FB2A FB2B FB2D FB4A FB5A FB7B FB2M FB7D FB3B 0.9 1.0 0.9 1.0 1.0 0.9 0.9 0.9 FB2A 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 C. J-Shaped Burrows FB2B 1.0 0.9 0.9 1.0 1.0 0.9 1.0 0.9 FB2I FB2J FB2K FB2L FB7G FB2H FB2D 0.9 0.9 0.9 0.9 0.9 0.9 0.9 1.0 FB2I 0.9 0.9 0.9 0.8 1.0 FB4A 1.0 0.9 1.0 0.9 1.0 0.9 1.0 0.9 FB2J 0.9 0.9 0.8 1.0 0.9 D. O-Shaped Burrows FB5A 1.0 0.9 1.0 0.9 1.0 0.9 1.0 0.9 FB2K 0.9 0.9 0.9 0.9 0.9 FB5F FB6B FB5G FB7B 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 FB2L 0.9 0.8 0.9 0.8 0.9 FB5F 0.8 0.5 FB2M 0.9 0.9 1.0 0.9 1.0 1.0 0.9 0.9 FB7G 0.8 1.0 0.9 0.8 0.8 FB6B 0.8 0.5 FB7D 0.9 0.9 0.9 1.0 0.9 0.9 0.9 0.9 FB2H 1.0 0.9 0.9 0.9 0.8 FB5G 0.5 0.5

E. Helical Burrows FB4B FB1 FB4B 0.9 FB1 0.9

structure (OS31B) and was likely related to the burrow’s high tortuosity and very low maximum depth and average angle. Type 1 and Type 2 O-shaped burrows have moderate

(0.6) similarity. There were several burrows produced by a different species that were found to be identical using the Bray Curtis analysis. Most of these occurrences (78%) 85

were between burrows of the same architecture (Fig. 2.21). Other identical burrows,

however, were assigned to different architectures (Appendix 1). These mostly resulted

(71%) from comparisons of vertical and subvertical burrows; for example, a vertical

burrow of F. penneri with a spiral in its midsection (FB7D) was identical to three

subvertical burrows of N. americanus (OS21B, OS30D, OS30E) (Appendix 1). A few occurrences of identical burrows between the other architectures did occur such as with a vertical burrow of N. americanus with a helical structure at its terminus (OS30F) with to two J-shaped burrows of F. penneri (FB2H, FB2I) as well as with the comparison of a

helical burrow (OS33C) of N. americanus with a vertical (FB7B) and a subvertical

burrow (FB3D) of F. penneri (Appendix 1).

2.6.4 Spirobolid and Spirostreptid Burrows

Burrows produced by two species of millipedes of the Order Spirostreptida,

Orthoporus ornatus and Archispirostreptus gigas, (Hembree, 2009) had a moderate

similarity (0.7) to those of the species of the Order Spirobolida from this study. Within

each species, the burrows of both O. ornatus and A. gigas had an average similarity value

of 0.8 (Fig. 2.18). When each species’ suite of burrows were compared to each other,

N.americanus (n=29), F. penneri (n=42), and O. ornatus (n=13) burrows all had high

similarity values (0.8) (Figs. 2.18, 2.21–2.23). Burrows produced by A. gigas (n=8),

however, were found to be only moderately similar to N. americanus (0.6), F. penneri

(0.6), and O. ornatus (0.7) (Figs. 2.18, 2.24–2.26). The four species of millipedes did

produce many similar burrow architectures that could be compared. Vertical, subvertical, 86

A. Subvertical Burrows OS32 OS23 OS25A OS21A OS21B OS21C OS30B OS30D OS21D OS24 OS21E OS26A OS30E FB2C 0.9 0.8 0.8 0.8 1.0 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 FB3C 0.9 0.7 0.7 0.7 0.9 0.8 1.0 0.9 0.8 0.8 0.8 0.8 0.9 FB3D 1.0 0.8 0.8 0.8 1.0 0.9 1.0 1.0 0.9 0.8 0.9 0.9 0.9 FB3E 0.9 0.8 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 FB3F 0.9 0.7 0.7 0.7 1.0 0.8 0.9 0.9 0.8 0.8 0.8 0.9 0.9 FB3G 0.9 0.8 0.7 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.8 1.0 FB3H 1.0 0.8 0.7 0.7 1.0 0.9 0.9 1.0 0.9 0.8 0.9 0.9 0.9 FB3I 0.9 0.8 0.8 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 FB2E 0.9 0.8 0.8 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 FB2F 0.9 0.9 0.8 0.8 0.9 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9 FB2G 0.9 0.7 0.7 0.6 0.9 0.8 0.9 0.9 0.8 0.8 0.8 0.8 0.9 FB6A 0.6 0.8 0.8 0.8 0.7 0.7 0.6 0.6 0.6 0.8 0.6 0.7 0.6 FB3A 0.8 0.9 0.9 0.8 0.8 0.9 0.8 0.8 0.8 0.9 0.7 0.8 0.7 FB5B 0.8 0.8 0.8 0.9 0.8 0.8 0.8 0.8 0.7 0.9 0.7 0.9 0.7 FB5C 1.0 0.8 0.7 0.8 1.0 0.9 1.0 1.0 0.9 0.8 0.9 0.9 0.9 FB5D 0.8 0.8 0.8 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.8 1.0 0.8 FB7A 0.9 0.7 0.7 0.8 1.0 0.8 1.0 0.9 0.8 0.8 0.8 0.8 0.9 FB7C 0.9 0.8 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 FB7E 0.9 0.8 0.7 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.8 1.0 FB7F 0.9 0.8 0.7 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 FB7H 0.8 0.8 0.8 0.7 0.8 0.8 0.7 0.8 0.8 0.8 0.9 0.9 0.8 FB5E 0.8 0.8 0.8 0.8 0.9 0.9 0.8 0.9 0.8 0.9 0.8 1.0 0.8

B. Vertical Shafts OS28 OS29C OS30A OS30C OS33A OS33B OS30F FB3B 0.9 1.0 1.0 0.9 1.0 1.0 0.7 FB2A 1.0 0.9 0.9 1.0 1.0 0.9 0.7 FB2B 1.0 0.9 0.9 0.9 1.0 1.0 0.7 FB2D 0.9 0.9 0.9 0.9 0.9 0.9 0.8 FB4A 1.0 0.9 0.9 0.9 1.0 1.0 0.7 FB5A 1.0 0.9 0.9 0.9 1.0 1.0 0.7 FB7B 0.9 0.9 0.8 0.9 0.9 0.9 0.8 FB2M 0.9 0.9 0.9 0.9 1.0 1.0 0.7 FB7D 0.9 0.9 0.9 0.9 0.9 0.9 0.8

C. Helical Burrows OS1 OS25B OS33C OS29B OS21F FB4B 0.9 0.9 0.8 0.7 0.9 FB1 0.9 0.8 0.8 0.8 0.9

D. O-Shaped Burrows OS29A OS26B FB5F FB6B OS31A OS31B FB5G OS29A 0.9 0.7 0.8 0.7 0.7 0.7 OS26B 0.9 0.8 0.9 0.7 0.6 0.6 FB5F 0.7 0.8 0.8 0.7 0.5 0.5 FB6B 0.8 0.9 0.8 0.7 0.7 0.5 OS31A 0.7 0.7 0.7 0.7 0.5 0.8 OS31B 0.7 0.6 0.5 0.7 0.5 0.5 FB5G 0.7 0.6 0.5 0.5 0.8 0.5 Figure 2.21 Bray Curtis similarity measure results comparing burrows produced by N. americanus (prefix OS) and F. penneri (prefix FB) of the same architectures. A) Comparison matrix of subvertical burrows. B) Comparison matrix of vertical shafts. C) Comparison matrix of helical burrows. D) Comparison matrix of O-shaped burrows. Green cells indicate identical burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows. 87 and J-shaped burrows, of N. americanus, F. penneri, and O. ornatus, had high similarity values (0.9–0.8) (Figs. 2.18, 2.21–2.23). Helical burrows produced by A. gigas (n=4), however, had only a moderate similarity (0.6) to those of N. americanus and F. penneri

(Figs. 2.18, 2.24–2.25). Orthoporus ornatus and A. gigas produced U-shaped (n=3) and sinuous (n=3) burrows that were not produced by either N. americanus or F. penneri. The

U-shaped burrows of both species, however, had a high average similarity (0.8) to the J- shaped burrows of F. penneri (Figs. 2.18, 2.23, 2.25). The sinuous burrow (n=1) of O. ornatus also had a high similarity (0.9) to the J-shaped burrows (Figs. 2.18, 2.23). The sinuous burrows of A. gigas (n=2), however, had only moderate similarity (0.7–0.6) to most other burrow architectures and were dissimilar to the O-shaped burrows (Figs. 2.18,

2.24–2.26). Four O. ornatus burrows were found to be identical to burrows of F. penneri

(Fig. 2.23). Three vertical burrows of O. ornatus, SB4, SB6, and SB8, were identical to a vertical burrow with a helical mid-section (FB7D), a vertical (FB2D) and subvertical burrow (FB3G), and a vertical burrow (FB4A) respectively (Fig. 2.23). Also, a J-shaped burrow of O. ornatus (SB11) was identical to two subvertical burrows (FB3I, FB2E) and one J-shaped burrow (FB2J) (Fig. 2.23).

2.6.5 Environmental Conditions and Burrow Morphology

Despite differences in average maximum burrow depth measured from casts, percent clay content and moisture conditions had no significant effect on any of the eight quantitative measurements tested (complexity, tortuosity, average circumference, total

N. americanus vs. O. ornatus

SB1 SB7 SB10 SB2 SB4 SB8 SB6 SB9 SB5 SB3 SB11 SB12 SB13 OS32 0.8 0.9 0.6 0.9 0.9 0.8 0.9 0.8 0.7 0.7 0.9 0.7 0.8 OS23 0.7 0.7 0.8 0.7 0.8 0.7 0.7 0.7 0.8 0.9 0.8 0.9 0.7 OS25A 0.7 0.7 0.8 0.7 0.7 0.7 0.7 0.7 0.8 0.9 0.8 0.8 0.7 OS21A 0.6 0.7 0.8 0.6 0.7 0.7 0.7 0.7 0.7 0.9 0.7 0.8 0.6 OS21B 0.9 0.9 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.9 0.7 0.9 OS21C 0.8 0.8 0.7 0.8 0.9 0.8 0.8 0.8 0.8 0.8 0.9 0.8 0.8 OS30B 0.8 0.8 0.6 0.9 0.9 0.8 0.9 0.8 0.7 0.7 0.9 0.7 0.8 OS30D 0.8 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.9 0.8 0.9 OS21D 0.9 0.9 0.7 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.9 0.8 0.9 OS24 0.7 0.7 0.8 0.7 0.8 0.7 0.8 0.7 0.9 0.9 0.8 0.8 0.7 OS21E 0.9 0.9 0.7 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.9 0.8 0.9 OS26A 0.8 0.8 0.7 0.8 0.9 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.8 OS30E 0.9 0.9 0.6 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.9 0.7 0.9 OS28 0.9 0.8 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.8 0.7 0.9 OS29C 0.9 0.8 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.8 0.7 0.9 OS30A 0.8 0.8 0.5 0.9 0.8 0.9 0.9 0.9 0.7 0.6 0.8 0.6 0.8 OS30C 0.8 0.8 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.8 0.7 0.9 OS33A 0.8 0.8 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.8 0.7 0.9 OS33B 0.9 0.8 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.8 0.7 0.9 OS30F 0.7 0.8 0.8 0.7 0.8 0.7 0.8 0.7 0.9 0.9 0.8 0.9 0.7 OS1 0.7 0.7 0.7 0.7 0.8 0.7 0.7 0.7 0.8 0.8 0.8 0.8 0.7 OS25B 0.6 0.6 0.8 0.6 0.6 0.6 0.6 0.6 0.7 0.8 0.7 0.7 0.6 OS33C 0.8 0.8 0.7 0.9 0.9 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.8 OS29B 0.9 0.9 0.6 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.9 0.7 0.9 OS21F 0.6 0.7 0.9 0.6 0.7 0.6 0.7 0.6 0.8 0.9 0.7 0.8 0.6 OS29A 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.7 0.7 0.7 0.7 0.6 OS26B 0.7 0.8 0.6 0.7 0.8 0.7 0.7 0.7 0.7 0.7 0.8 0.7 0.7 OS31A 0.7 0.8 0.8 0.7 0.8 0.7 0.7 0.7 0.9 0.9 0.8 0.9 0.7 OS31B 0.4 0.4 0.5 0.4 0.4 0.4 0.4 0.4 0.5 0.5 0.4 0.5 0.4

F. penneri vs. O. ornatus

SB1 SB7 SB10 SB2 SB4 SB8 SB6 SB9 SB5 SB3 SB11 SB12 SB13 FB2C 0.8 0.9 0.7 0.8 0.9 0.8 0.9 0.9 0.8 0.8 0.9 0.8 0.8 FB3C 0.8 0.8 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.9 0.7 0.8 FB3D 0.8 0.9 0.6 0.9 0.9 0.8 0.9 0.9 0.8 0.7 0.9 0.7 0.8 FB3E 0.8 0.9 0.6 0.8 0.9 0.8 0.9 0.8 0.8 0.7 0.9 0.8 0.8 FB3F 0.9 0.9 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.9 0.7 0.9 FB3G 0.9 0.9 0.6 0.9 0.9 0.9 1.0 0.9 0.8 0.7 0.9 0.7 0.9 FB3H 0.9 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.9 0.8 0.9 FB3I 0.9 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.8 1.0 0.8 0.9 FB2E 0.9 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.8 1.0 0.8 0.9 FB2F 0.8 0.8 0.8 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.9 0.8 0.8 FB2G 0.9 0.8 0.6 0.9 0.9 0.8 0.9 0.9 0.7 0.7 0.8 0.7 0.9 FB6A 0.6 0.6 0.9 0.6 0.6 0.6 0.6 0.6 0.7 0.8 0.6 0.7 0.6 FB3A 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.8 0.8 0.8 0.8 0.7 FB5B 0.7 0.8 0.7 0.7 0.8 0.7 0.8 0.7 0.8 0.8 0.8 0.8 0.7 FB5C 0.8 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.9 0.8 0.9 FB5D 0.8 0.9 0.7 0.8 0.9 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.8 FB7A 0.8 0.8 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.9 0.7 0.9 FB7C 0.8 0.9 0.7 0.8 0.9 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.8 FB7E 0.9 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.9 0.8 0.9 FB7F 0.9 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.9 0.8 0.9 FB7H 0.8 0.9 0.7 0.7 0.8 0.8 0.8 0.8 0.9 0.8 0.9 0.9 0.8 FB5E 0.8 0.9 0.7 0.8 0.9 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.8 FB3B 0.8 0.8 0.5 0.9 0.8 0.9 0.9 0.9 0.7 0.6 0.8 0.6 0.8 FB2A 0.9 0.8 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.8 0.7 0.9 FB2B 0.9 0.8 0.6 0.9 0.8 0.9 0.9 0.9 0.7 0.7 0.8 0.7 0.9 FB2D 0.9 0.9 0.7 0.9 0.9 0.9 1.0 0.9 0.8 0.8 0.9 0.8 0.9 FB4A 0.9 0.8 0.6 0.9 0.9 1.0 0.9 0.9 0.7 0.7 0.8 0.7 0.9 FB5A 0.9 0.8 0.5 0.9 0.8 0.9 0.9 0.9 0.7 0.6 0.8 0.7 0.9 FB7B 0.8 0.9 0.7 0.8 0.9 0.8 0.9 0.9 0.8 0.8 0.9 0.8 0.8 FB2M 0.9 0.8 0.6 0.9 0.8 0.9 0.9 0.9 0.7 0.7 0.8 0.7 0.9 FB7D 0.9 0.9 0.7 0.9 1.0 0.9 0.9 0.9 0.8 0.8 0.9 0.8 0.9 FB2I 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.9 0.9 0.9 0.9 0.8 FB2J 0.9 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.8 1.0 0.8 0.9 FB2K 0.8 0.9 0.8 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.9 0.9 0.8 FB2L 0.7 0.8 0.7 0.8 0.8 0.7 0.8 0.7 0.8 0.8 0.8 0.8 0.7 FB7G 0.9 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.9 0.8 0.9 FB2H 0.8 0.8 0.8 0.8 0.8 0.7 0.8 0.8 0.9 0.9 0.9 0.9 0.8 FB4B 0.7 0.7 0.8 0.7 0.7 0.7 0.7 0.7 0.8 0.9 0.8 0.9 0.7 FB1 0.7 0.7 0.8 0.7 0.7 0.6 0.7 0.7 0.8 0.9 0.8 0.8 0.7 FB5F 0.9 0.8 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.8 0.7 0.9 FB6B 0.7 0.8 0.6 0.7 0.7 0.7 0.7 0.7 0.7 0.6 0.8 0.6 0.7 FB5G 0.6 0.6 0.9 0.6 0.6 0.6 0.6 0.6 0.7 0.8 0.6 0.7 0.6

N. americanus vs. A. gigas

AB8 AB2 AB1 AB3 AB4 AB6 AB7 AB5 OS32 0.5 0.6 0.7 0.5 0.6 0.6 0.6 0.6 OS23 0.6 0.6 0.6 0.6 0.6 0.6 0.8 0.7 OS25A 0.6 0.6 0.6 0.6 0.6 0.6 0.7 0.7 OS21A 0.6 0.6 0.6 0.5 0.5 0.6 0.7 0.6 OS21B 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 OS21C 0.6 0.6 0.7 0.5 0.7 0.7 0.7 0.6 OS30B 0.5 0.6 0.7 0.4 0.6 0.6 0.6 0.6 OS30D 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 OS21D 0.6 0.7 0.8 0.6 0.7 0.7 0.7 0.7 OS24 0.6 0.6 0.6 0.5 0.6 0.7 0.7 0.7 OS21E 0.6 0.7 0.8 0.6 0.8 0.7 0.7 0.7 OS26A 0.6 0.7 0.8 0.6 0.7 0.7 0.8 0.7 OS30E 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 OS28 0.5 0.6 0.7 0.5 0.6 0.6 0.6 0.6 OS29C 0.5 0.5 0.7 0.4 0.6 0.6 0.6 0.5 OS30A 0.4 0.5 0.6 0.4 0.6 0.5 0.6 0.5 OS30C 0.5 0.5 0.7 0.4 0.6 0.6 0.6 0.5 OS33A 0.5 0.6 0.7 0.4 0.6 0.6 0.6 0.6 OS33B 0.5 0.6 0.7 0.5 0.6 0.6 0.6 0.6 OS30F 0.6 0.7 0.7 0.6 0.6 0.7 0.8 0.7 OS1 0.6 0.6 0.6 0.5 0.6 0.6 0.7 0.6 OS25B 0.6 0.5 0.5 0.6 0.5 0.5 0.6 0.6 OS33C 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 OS29B 0.5 0.6 0.7 0.5 0.7 0.6 0.6 0.6 OS21F 0.7 0.6 0.6 0.6 0.5 0.6 0.7 0.6 OS29A 0.5 0.5 0.5 0.5 0.5 0.5 0.6 0.6 OS26B 0.5 0.6 0.7 0.5 0.6 0.6 0.6 0.6 OS31A 0.6 0.7 0.7 0.6 0.6 0.7 0.8 0.7 OS31B 0.4 0.4 0.4 0.4 0.3 0.4 0.4 0.4

F. penneri vs A. gigas

AB8 AB2 AB1 AB3 AB4 AB6 AB7 AB5 FB2C 0.6 0.6 0.7 0.5 0.7 0.6 0.7 0.6 FB3C 0.5 0.5 0.7 0.4 0.6 0.6 0.6 0.5 FB3D 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 FB3E 0.6 0.6 0.7 0.5 0.7 0.6 0.7 0.6 FB3F 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 FB3G 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 FB3H 0.6 0.6 0.7 0.5 0.7 0.7 0.7 0.6 FB3I 0.6 0.6 0.8 0.5 0.7 0.7 0.7 0.6 FB2E 0.6 0.6 0.8 0.5 0.7 0.7 0.7 0.6 FB2F 0.6 0.7 0.7 0.6 0.7 0.7 0.7 0.7 FB2G 0.5 0.5 0.7 0.4 0.6 0.6 0.6 0.6 FB6A 0.6 0.5 0.5 0.6 0.5 0.5 0.6 0.6 FB3A 0.5 0.6 0.6 0.5 0.5 0.6 0.7 0.6 FB5B 0.7 0.7 0.7 0.6 0.6 0.7 0.8 0.7 FB5C 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 FB5D 0.6 0.7 0.8 0.6 0.7 0.7 0.8 0.7 FB7A 0.5 0.6 0.7 0.5 0.6 0.6 0.6 0.6 FB7C 0.6 0.6 0.8 0.5 0.7 0.7 0.7 0.6 FB7E 0.6 0.6 0.7 0.5 0.7 0.7 0.7 0.6 FB7F 0.6 0.7 0.8 0.6 0.7 0.7 0.7 0.7 FB7H 0.7 0.8 0.8 0.7 0.8 0.8 0.8 0.8 FB5E 0.6 0.7 0.8 0.6 0.7 0.7 0.8 0.7 FB3B 0.5 0.5 0.6 0.4 0.6 0.6 0.6 0.5 FB2A 0.5 0.6 0.7 0.4 0.6 0.6 0.6 0.6 FB2B 0.5 0.6 0.7 0.5 0.7 0.6 0.6 0.6 FB2D 0.6 0.6 0.7 0.5 0.7 0.7 0.7 0.6 FB4A 0.5 0.6 0.7 0.5 0.6 0.6 0.6 0.6 FB5A 0.5 0.6 0.7 0.5 0.6 0.6 0.6 0.6 FB7B 0.6 0.6 0.7 0.5 0.7 0.6 0.7 0.6 FB2M 0.6 0.6 0.7 0.5 0.7 0.6 0.7 0.6 FB7D 0.6 0.6 0.7 0.5 0.7 0.7 0.7 0.6 FB2I 0.6 0.7 0.7 0.6 0.6 0.7 0.8 0.7 FB2J 0.6 0.7 0.8 0.6 0.7 0.7 0.7 0.7 FB2K 0.7 0.7 0.8 0.6 0.7 0.7 0.8 0.7 FB2L 0.6 0.6 0.7 0.5 0.6 0.7 0.7 0.6 FB7G 0.6 0.7 0.8 0.6 0.7 0.7 0.7 0.7 FB2H 0.7 0.7 0.7 0.6 0.7 0.7 0.8 0.7 FB4B 0.7 0.6 0.6 0.6 0.6 0.6 0.7 0.7 FB1 0.6 0.6 0.6 0.5 0.6 0.6 0.7 0.7 FB5F 0.6 0.6 0.7 0.5 0.7 0.6 0.6 0.6 FB6B 0.5 0.6 0.7 0.5 0.7 0.6 0.6 0.6 FB5G 0.6 0.5 0.5 0.5 0.5 0.5 0.6 0.6

Figure 2.25 Bray Curtis similarity matrix comparing burrows produced by F. penneri (prefix FB) to burrows produced by A. gigas (prefix FB). Cells outlined in thick black lines in the matrix indicate comparison of burrows of the same architecture. AB2 and AB8 are sinuous burrows. AB1, AB3, AB4, and AB6 are helical burrows. AB7 and AB5 are U-shaped burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows. 92

O. ornatus vs. A. gigas

AB8 AB2 AB1 AB3 AB4 AB6 AB7 AB5 SB1 0.7 0.7 0.8 0.6 0.8 0.7 0.7 0.7 SB7 0.7 0.7 0.8 0.6 0.8 0.7 0.8 0.7 SB10 0.7 0.6 0.6 0.6 0.5 0.6 0.7 0.7 SB2 0.5 0.6 0.7 0.5 0.7 0.6 0.6 0.6 SB4 0.6 0.7 0.8 0.5 0.7 0.7 0.7 0.7 SB8 0.6 0.6 0.7 0.5 0.7 0.6 0.7 0.6 SB6 0.6 0.6 0.7 0.5 0.7 0.7 0.7 0.6 SB9 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 SB5 0.7 0.8 0.8 0.7 0.7 0.7 0.8 0.8 SB3 0.7 0.7 0.7 0.6 0.6 0.7 0.8 0.8 SB11 0.6 0.7 0.8 0.6 0.7 0.7 0.7 0.7 SB12 0.7 0.7 0.7 0.7 0.7 0.7 0.8 0.8 SB13 0.6 0.7 0.8 0.6 0.8 0.7 0.7 0.7

Figure 2.26 Bray Curtis similarity matrix comparing burrows produced by O. ornatus (prefix SB) to burrows produced by A. gigas (prefix AB). Cells outlined in thick black lines in the matrix indicate comparison of burrows of the same architecture. SB1, SB7, and SB10 are subvertical burrows. SB2, SB4, SB6, SB8, and SB9 are vertical burrows. SB5 is a sinuous burrow. SB3 is a U-shaped burrow. SB11–13 are J-shaped burrows. AB2 and AB8 are sinuous burrows. AB1, AB3, AB4, and AB6 are helical burrows. AB7 and AB5 are U-shaped burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows.

length, average width, average height, maximum depth and average slope). The

Spearman’s rank correlation produced Rs values between -0.39–0.42 for percent clay

sediment composition and -0.33–0.46 for moisture conditions in comparison with the

morphologic measurements (Figs 2.27–2.28). These values indicated that the millipedes did not significantly change their behavior in a way that was reflected in their burrowmorphology since Rs values greater than 0.8 are considered high enough for a correlation to be made. There was however, a difference in the diversity of burrow types

(primary architectures and modifications) produced in the different sediments. 93

Floridobolus penneri produced the highest diversity of burrow types in a 100% soil

sediment (n=6) and in 25 carbonate sand /75 soil sediments (n=5) under higher (≥50%)

moisture conditions. Narceus americanus produced the most types in 50 coconut fiber

/50 soil sediments (n=4) under both high and low (30–40%) moisture conditions.

2.7 Discussion

Narceus americanus produced four distinct burrow architectures under varying sediment compositions and moisture conditions. Floridobolus penneri produced five distinct burrow architectures, one of which was not produced by N. americanus. A comparison of the burrows produced by the Order Spirobolida with those produced by two species of the Order Spirostreptida found that some burrows were very similar while others were unique to one of the orders or species. It is well known that an individual is often capable of producing many burrow architectures and that many different species are capable of making the same architectures (Bromley, 1996). Burrow morphology is generally influenced by organism morphology, behavior, and their response to variations in environmental stimuli, including biotic and abiotic factors.

2.7.1 Organism and Burrow Morphology

The average similarity of burrows produced by all species in this study and those studied by Hembree (2009) ranged from the low end of moderately similar to the high end of highly similar (0.6–0.9), one average quantitative characteristic was found to be nearly constant among all millipede burrows: width-to-height ratio (1.0–1.14). The 94

Figure 2.28 Scatter plots of data used in Spearman’s rank correlation tests of F. penneri burrows. Rs values indicate no significant relationship between sediment clay composition and sediment moisture to any of the eight different quantitative burrow properties tested. 96 burrow properties of average width (10.6–12.1 mm), average height (9.5–11.9 mm), and average slope (59–66°) of all burrows produced by N. americanus, F. penneri, and

O.ornatus were very similar, but those same metrics for A. gigas were much different (32 mm, 29 mm, and 44° respectively). The difference in all of the aforementioned characteristics, with the exception of average slope, is directly related to the size and cross sectional dimensions of the burrowing individual. The average width and average height of burrows produced by A. gigas were nearly three times those of burrows produced by the other three species. This relationship was also seen in the body diameters of individuals used; N. americanus: 3–7 mm, F. penneri: 6–9 mm, O. ornatus: 4–7 mm

(Hembree, 2009), and A. gigas: 15–30 mm (Hembree, 2009). Despite this difference in size, the average width-to-height ratios of burrows produced were almost identical. The close relationship between millipede body shape and burrow morphology suggests that the width-to-height ratio of 1.00–1.14 may be useful in the identification of burrows produced by millipedes of the superorder Juliformia.

The average widths of the tunnels and shafts, but not chambers, were 30–51% larger than the average diameter of the millipedes (N. americanus: 51%, F. penneri: 36% O. ornatus: 46%, A. gigas 30%). Even though millipede burrow morphology is closely related to body morphology, this difference indicates that burrow size is not an exact match to the tracemakers size. Variations in burrow width are likely caused by the burrowing technique used by the individual. Both compaction and excavation can be used to make burrows with larger dimensions than the tracemaker. This increase in burrow size relative to the tracemaker is well illustrated by the construction of chambers (Figs. 97

2.6A, 2.11E, 2.13C). It is also likely that some portion of this difference is due to fluctuations in sediment permeability which allowed the plaster to penetrate deeper into the walls of the burrow in highly permeable sediments or that gravitational collapse of the burrow sides into the bottom of the burrow caused decreased burrow heights but increased widths.

The wedge-shaped indentations and curving portions of some chambers represent indentations of the millipedes body (Fig. 2.8A–B). The wedge-shaped indentations, typically associated with burrows containing fecal pellets, are similar in appearance to the anal segment of the millipede. The presence of fecal pellets suggests that these chambers were occupied for extended periods of time. The millipedes were only observed to burrow head first and the anal segment was never involved in the burrow process.

Therefore the indentations are likely body impressions rather than an expression of behavior. It is likely that the millipedes were buried under sediment as a result of gravitational collapse of the burrow; the millipedes then re-excavated the burrow and moved to the surface, leaving behind an indentation of the back portion of its body.

Curved portions of burrow chambers likely represent the individual curling around itself in the subsurface (Figs. 2.6A, 2.11E, 2.13C) or points where the individual turned around

(Figs. 2.11D, 2.12D), requiring the formation of a larger void space.

2.7.2 Burrow Morphology and Behavior

As the direct result of behavioral interaction with a medium (Bromley, 1996), variations in burrow morphology reflect differences in organism behavior. Burrows and 98 surficial traces produced by N. americanus and F. penneri represent dwelling, feeding, and locomotive behaviors. As highly mobile detritivores, millipedes are able to travel several kilometers in search of hospitable environments (Kania and Tracz, 2005). Over the course of these experiments, N. americanus and F. penneri continually attempted to move outside the bounds of the terrariums while on the surface, possibly in search of a more preferential habitat, food, or for mating purposes. This movement resulted in trails outlined by large grains. While these paths have a poor preservation potential and may only occur in closed environments, they represent a surface locomotive behavior. Extant millipedes are known to migrate in large numbers in response to detrimental changes in the environment (Kania and Tracz, 2005).

Additional trails were produced when specimens began to burrow but moved laterally prior to being deep enough to produce a structurally stable burrow (Fig. 2.7A,

B). This type of trail is evidence of the head-ramming compaction technique used by both species. Shallow burrows that were never fully occupied were considered probing structures. These burrows were cone shaped, usually <3 cm long, and represented abandoned attempts at burrowing. These structures were limited to the vertical and subvertical architectures.

The millipede species used in this study were diurnal, but primarily nocturnal. In response to light stimuli, specimens commonly either began to burrow or would enter a previously constructed burrow. Burrows that were occupied for short periods (<12 hours) were usually produced as a means of avoiding light exposure, likely to avoid evaporative desiccation and predation. These temporary dwellings generally had a total length that 99

was long enough to accommodate the individual’s entire body (4.0–12.5 cm) but had a

relatively shallow maximum depth (1.1–8.2 cm). Vertical, subvertical, J-shaped, helical,

and Type-2 O-shaped structures were produced for this purpose.

Structures that were occupied for long periods of time (>2 days) generally had a

longer total length (7.7–33.0+ cm) and a deeper maximum depth (5.7–33.0 cm) in both

observed and cast burrows than burrows occupied for shorter periods. In addition,

burrows that were occupied for long periods commonly contained more fecal pellets and

had chambers. These burrows likely served a dual purpose of dwelling and feeding. Fecal

pellets were commonly composed of clay material as well as organics indicating the

specimens were consuming the soil, though this was not directly observed. Narceus

americanus is known to eat and dwell in rotting wood (Ausmus, 1977), therefore, wood

splinters or the organic coconut fiber present in the soil mixture may have been an

additional food source for the millipedes. The occurrence of fewer fecal pellets in

burrows produced in the sandy sediments supports this conclusion. All architectures,

except for Type-2 O-shaped structures, were produced for long-term occupation. When burrows were occupied for long periods, they were observed to be used for molting or entering a state of torpor likely as a result of adverse surface conditions. During experimental trials, there was a point at which surface activity drastically decreased in all specimens. On average, experiments conducted between August 15th and February 1st

took eight times longer past the expected duration than those conducted at other times

(Table 1). Even though laboratory conditions were kept relatively constant, and since this

activity decrease was also seen in holding tanks, it seems that there were other 100

environmental or internal cues for these animals to remain underground for long periods.

Structures used for the purpose of aestivation or molting were those that contained a

chamber large enough to accommodate an entire individual; the chambers were usually

wider horizontally than vertically. Since individuals were found as shallow as 4 cm and

as deep as 33 cm below the surface after being inactive for more than two weeks,

structures produced for this behavior may be at any depth range.

When specimens were found at depths of >7 cm, the casting of burrow openings

never affected the individual. In many cases the cast burrow did not represent the total depth that the specimen burrowed suggesting that sediment plugs were created to prevent surface conditions from affecting the individual as seen with O. ornatus (Hembree,

2009). Other explanations for the shallow burrow casts may be that accumulations of

fecal pellets behind the individual, debris from the surface, or subsurface collapse

prevented the casting material from reaching the end of the burrow. These passive fill

methods have been observed to halt the progress of the casting plaster. Regardless of the

cause, roughly 40% of the cast burrows likely do not represent maximum burrow depths.

As a result, some vertical or subvertical burrows could have had additional features that

may have led to their categorization as a different architecture. Structures with terminal

chambers, all J-shaped and O-shaped structures, most helical structures, and a few

vertical or subvertical burrows, however, were considered to represent complete burrow

preservation.

Branches were never longer than a few centimeters in N. americanus or F. penneri burrows. Most branches (9 of 10) were at a 10–70° angle from the horizontal off of the 101

main shaft and occurred as a modification to any architecture. Since these branches did

not continue any great distance and were only present in 11% of burrows, it is unlikely

that they served any functional purpose. Their length and branching angle suggest that

these may have been probing structures similar to abandoned burrows observed at the

surface. The individual may have attempted to extend the burrow in one direction, but

then possibly finding a less resistant path, changed direction and continued to burrow.

2.7.3 Burrow Morphology and Sediment Properties

An overall decrease in the average maximum depth of burrows produced in sandy

sediment was observed, the results of the Spearman’s rank correlation show that the

sediment properties (clay percent and sediment moisture) had no significant effect on the

eight quantitative measurements of burrow casts that were analyzed. Spearman’s rank

correlation showed no significant correlation between sediment composition and the

complexity, tortuosity, average circumference, total length, average width, average

height, maximum depth, and average slope of the burrows of either species. The average

correlation values for N. americanus and F. penneri burrow measurements and sediment clay composition were 0.24 and 0.19 respectively. The highest correlation (Rs= 0.42,

0.36) was between the average height and clay composition in both species (Figs. 2.27–

2.28). Narceus americanus also had a higher than average negative correlation (Rs=-

0.39) between average slope and clay content (Fig. 2.27).

No significant correlation was found between sediment moisture and any of the quantitative measurements. The average correlation values for N. americanus and F. 102

penneri were 0.23 and 0.08 respectively. The sediment moisture values for the F. penneri

experiments only ranged from 49–58% and may not represent a wide enough range to

reflect morphological changes in burrow structures due to moisture conditions. The

highest correlation for F. penneri burrows was associated with average width (Rs=0.26)

whereas those of N. americanus burrows associated with average slope (Rs=0.46),

average height (Rs=0.41), and maximum depth (Rs=-0.33). Positive Spearman’s rank values indicate that a burrow parameter increased with increases in the sediment property being measured.

Millipede burrow morphology is interpreted to be controlled primarily by organism

morphology and behavior. Architectural diversity of the burrows produced, however, did

seem to be affected by sediment properties. In general, specimens of both species had

more difficulty burrowing in sandy sediments and collapse was more common as the

surface of these sediments dried. Sediments containing coconut fiber and higher amounts

of clay were able to hold moisture longer and, therefore, burrow stability was maintained

for longer periods. Increased burrow diversity in coconut fiber and clay sediments as

opposed to sandy sediments may have been influenced by the greater number of

experiments conducted with organic- and soil-rich sediments or due to lower surface

stability in sandy sediments.

2.7.4 Millipede Burrows: Function and Similarity

The four millipede species discussed in this study are different in many ways: their

habitats consist of scrublands, woodlands, dry grasslands, and tropical rain forests; their 103

body sizes vary from 3–24 cm long and from 0.3–3.0 cm in width; they burrow by

excavation, compaction, and a combination of both techniques; and they represent two

different orders of Diplopoda. Despite these differences, burrows produced by N.

americanus, F. penneri, O. ornatus and A. gigas were not found to be dissimilar based on

the 10 quantitative measurements of burrow morphology. It was determined that the

burrow morphology of N. americanus and F. penneri was primarily controlled by

organism morphology and behavior. The similarities observed between burrows produced

by these four species help to support this conclusion. The morphology of juliform

millipedes restricts the burrowing techniques that they can use and the cross-sectional

shape of the burrows they produce. Due to obvious differences in the sizes of the species

being compared, it could be expected that the burrows of A. gigas would be less similar

to those produced by the other species. The Bray-Curtis similarity test results obtained

did show that A. gigas burrows were the least similar to any of the other species. This

difference, however, cannot solely be attributed to the difference in the size of the

specimens. An additional Bray-Curtis similarity test was conducted after the burrow measurements that were most closely related to size of the specimen (average height, average width, and average circumference) were removed. The average similarity of A. gigas burrows compared to the burrows of the other species improved, but still had the lowest similarity value compared to any other species (0.7). Hembree (2009) determined that the function of burrows produced by A. gigas was for feeding and locomotion while

O. ornatus used their burrows primarily for refuge and dwelling. The function of burrowing behavior observed in N. americanus and F. penneri was determined to be 104

related to dwelling, refuge from adverse conditions, feeding, and molting. Similarity

values between burrows produced by different millipede species were the highest

between N. americanus, F. penneri and O. ornatus, even after the organism-size related measurements were removed. A likely conclusion, therefore, is that the similarity of the burrows produced by these millipedes is most strongly related to the function of the burrow.

2.8 Significance

2.8.1 Recognition of Juliform Millipede Burrows in the Fossil Record

In order to properly interpret trace fossils, a thorough understanding of modern tracemakers and behaviors is required. The importance of understanding modern tracemakers is increased when the morphology of the species under investigation is suspected to have undergone few changes over geologic time. The ring-form body plan of the superorder Juliformia was present in the Early Devonian (Wilson, 2006b; Cong et al.,

2009), but despite the longevity of a body plan that is well adapted to burrowing, few fossil burrows have been attributed to millipedes. This lack of trace fossil evidence is likely due to a lack of recognition rather than true absence. The proper description of extant millipede burrows using identifiable characteristics may allow millipede burrows to be accurately identified in the fossil record.

In order to facilitate the accurate identification of juliform millipede burrows in the fossil record, the definable characteristics of the burrows produced by two modern 105

spirobolid millipedes, N. americanus, and F. penneri, are summarized using the

suggested morphological ichnotaxobases as defined by Bertling et al. (2006):

2.8.1.1 Architecture

Spirobolid millipede burrows consist of vertical, subvertical, J-shaped, helical, and

horizontally or vertically oriented O-shaped burrows with one or two surface openings.

Branching is uncommon; branches are generally much smaller than the primary burrow shaft and can occur within all burrow architectures. Chambers can be horizontally and vertically expanded and are most commonly constructed at the end of a burrow, but may be present anywhere within the burrow. Chambers are 2–3 times the size of the primary burrow shaft or tunnel.

2.8.1.2 Overall Shape

Shafts and tunnels are nearly circular in cross-section with an average width-height ratio of 1.1. Burrow heights and widths commonly increase toward burrow entrances and decrease near the end of the burrow. Chambers vary in size and shape but commonly outline the individual. Burrows vary from straight to sinuous depending on the presence of branches, chambers, and helical additions. The most distinct architecture, O-shaped burrows, consist of a primary shaft that follows either an elliptical, circular, or tear drop shaped path connecting back to itself. J-shaped burrows follow a similar path but stop just prior to connecting back to the primary shaft.

2.8.1.3 Orientation

Burrows are oriented from 20–90° to the horizontal. Branches are typically oriented

12–60° from the primary shaft in the direction the individual is burrowing. 106

2.8.1.4 Internal Structure

Spirobolid millipede burrows are constructed using compaction and may have a compressed lining depending on the substrate. Burrows are passively filled, but may contain loose or plugs of fecal pellets.

2.8.1.5 Surficial Features

Floors can be somewhat irregular, but ceilings and walls are relatively smooth.

Chambers and burrow end points may have wedge-shaped impressions from the anal segment of the animal. Fecal pellets are commonly incorporated into the walls and floor of the burrow and can be in groups, in straight lines, or randomly placed.

2.8.2 Paleontologic and Paleoecologic Significance

Millipede ecology, physiology, and behavior have been well studied and their burrowing behavior is widely known, but, little work has been done to understand their burrow morphology (Hembree, 2009). Many modern soil biotas are poorly understood, particularly in their trace-making abilities. These organisms tend to have a low preservation potential since they often reside in an environment where organic matter is quickly broken down, recylced, or fragmented through bioturbation (Retallack, 2001b;

Hättenschwiler et al., 2005; Zhang et al., 2008; Shear and Edgecombe, 2009). Therefore, body fossils of these organisms may not accurately represent true biodiversity or abundance. In addition, terrestrial organisms are exposed to extreme variances in temperature, precipitation, evaporation, and habitats. While body fossils can be used to interpret environmental conditions based on a modern analogue, organisms can change 107 over time and become adapted to different conditions while not significantly or predictably changing their morphology. Conversely, behaviors are considered relatively constant through time. As direct representations of behaviors, modern traces are well suited to be used as proxies for past environmental conditions if similar trace fossils are found (Bromley, 1996). Neoichnological studies are vital to understanding historical abundance and how environmental conditions can affect burrow morphology.

Burrows produced by N. americanus and F. penneri primarily consisted of straight to sinuous, vertical to subvertical burrows that were modified by connecting back to the primary shaft, adding branches, chambers, or helices. From this, five different burrow architectures were produced, with only J-shaped burrows being specific to one species.

Not only do the two species produce similar burrow architectures, but individuals were found to produce multiple burrows of different architectures. While individuals were surface active, burrowing was an almost daily task. If this need to burrow has not changed over millipede evolution, burrows produced by millipedes should be much more common in the fossil record than is currently represented. Furthermore, if all burrows produced by millipedes in the fossil record were identified, their abundance may be overestimated by burrow abundance.

The sizes of the burrows produced in this study were closely related to the sizes of the tracemakers. This relation, however, can only be used to estimate the maximum size of the individual. Specimens used excavation and compressive techniques to construct chambers that were much larger than the individual. Additionally, when burrowing, millipedes are not restricted to remaining upright. As individuals are slightly taller than 108

they are wide, the shift from burrowing right-side-up to sideways causes shifts in the cross-sectional shape of the burrow. This orientation shift likely contributed to burrow widths that were approximately 30–51% larger than the width of the individuals considered in this study.

Millipede burrows have a moderate to high preservation potential. Millipede burrows produced in this study were all open to the surface, primarily produced via compacting and stabilizing the surrounding sediment, and were commonly able to penetrate the sediment to depths greater than 20 cm. The open burrows could be passively filled by flood and windblown sediment that are different from the surrounding sediment allowing the filled burrow to stand out if preserved. In many experiments the passive fill of the millipede burrows from the surface stopped after several centimeters. Upon excavation of the sediment, the deeper burrows were found to be intact and open. It may be possible that sinuous portions of burrows act to prevent passive fill of deeper burrows from the surface. The open subsurface burrows could then be filled as a result of water infiltration with minerals precipitating in the void spaces or the accumulation of translocated clays.

The burrows, whether open or passively filled, are more permeable than the surrounding sediment. This was directly observed when burrows produced against the side of the tank served as conduits for water when the surface of the tank was sprayed. High permeability increases the likelihood of burrow visibility as diagenetic redox processes highlight the burrow fill.

Burrowing in millipedes may have been an early adaptation since the ring-form body plan and diplosegment condition were present in Devonian fossils (Wilson and Anderson, 109

2004, Wilson, 2006b; Cong et al., 2009). Widely accepted as one of the first macrofauna

on land, it is possible that the accurate identification of millipede burrows would increase

the temporal and geographic range of the Diplopoda.

2.8.3 Paleopedologic and Paleoenvironmental Significance

As the recognition and interest in paleosols has grown in the last few decades, there

has been some controversy over the identification of continental vs. marine settings. As

air-breathing detritivores, millipedes require a terrestrial environment with decomposing

vegetation. This necessitates that where burrows of millipedes are present, some form of

vegetation and terrestrial conditions must be present. Fossil millipede burrows may then

be used as a proxy for aerated continental deposits with surface vegetation.

Differences in the morphology of millipede burrows compared in this study have shown that millipede burrows constructed for different purposes may be discernible. If burrows constructed for the purpose of environmental isolation can be identified in the fossil record, it may be possible to infer a seasonal climate from a stable one. Narceus americanus is widely distributed and is primarily found in temperate forests in the eastern

United States (O’Neill, 1968; Ausmus, 1977; Shelley et al., 2006). The soils of its habitat are subject to yearly freeze-thaw cycles with frozen soil extending to 11.7 cm in the absence of snowpack and 2.9 cm in the presence of snow pack in New York (Vermette and Christopher, 2008). For N. americanus, burrowing to depths greater than 12 cm may be an evolutionary advantage to avoiding freezing soil conditions. Florida scrublands are known for soils with low water retention and increasing soil moistures with depth 110

(Weekley et al., 2007). Surviving only in the scrublands of Florida, F. penneri would need to burrow to depths of 50 cm or more to encounter soil moisture levels of 10%

(Weekley et al., 2007). With strong evolutionary requirements like these, it is not surprising that similarity tests would indicate that burrow function may play a stronger role in burrow morphology than specific environmental factors. Maximum burrow depth may be directly related to survivability during extreme climate variability. This does not limit the survivability to only drier conditions. Millipedes are capable of surviving flooding conditions with species surviving from 40–688 hours completely submerged

(Tufová and Tuf, 2003). The periods of low activity observed in the laboratory, also roughly correlate with seasonally cold temperatures and seasonally dry conditions in N. americanus and F. penneri habitats, respectively.

The requirement of many millipedes for the calcium that is incorporated into their cuticles may be linked to a preference toward calcium-rich environments (Kime and

Golovatch, 2000). As burrowing arthropods that are known to consume sediment along with decaying plant matter, millipedes may be able to consume the calcium needed directly from calcium-rich soils and plants. This requirement restricts where millipedes may have made their first landward incursions. The earliest millipedes may have fed on bryophytes that grew on limestone, lichens that grew near the seashore, or fungi, all of which have been shown to have elevated calcium contents in modern studies (Cromack et al., 1977; Bates, 1982; Rhoades, 1999). Coprolites from the Early Devonian attributed to millipedes contained fragments of nematophytes which may represent another nutritional source for early Diplopoda (Edwards et al., 2012). The presence of millipede burrows 111

may be able to allow the inference of an environment that had calcium readily available

despite soil leaching.

Numerous studies have been conducted on the effect millipedes have on soil

formation and nutrient cycling as detritivores (Ausmus, 1977; Crawford, 1992;

Bonkowski et al., 1998; Cárcamo et al., 2000; Fujimaki et al., 2010), but little has been

done to determine how millipede burrows affect soil formation. The burrowing

techniques employed by the millipedes used in this study allowed for the construction of

open channels deep into the soil subsurface. These burrows would allow oxygen, water,

and other organisms access to deeper soil horizons than they would normally be able to

reach (Hole, 1981; Wilkinson et al., 2009). As a result, the physical and chemical

processes that break down minerals within the soil to clay could be accelerated (Schaetzl

and Anderson, 2005). In addition, these millipedes were found to consume plant material

above and below the surface and deposit their fecal pellets both on the surface and in

their burrows. This physical and chemical breakdown of plant material allows these

nutrients to become available to soil microbes and bacteria (Schaetzl and Anderson,

2005). The overall effect would be an increase in organics into the soil.

Millipede fecal pellets are already known to be an important food source for some

earthworms (Bonkowski et al., 1998). Farfan (2010) suggested that through the act of

self-coprophagy, millipedes may be able to survive instances of human mediated accidental transportation with little substrate present. Some millipedes stash eggs within fecal pellets below the surface but no chambers constructed in this study were observed to have been for this purpose. Accumulations of fecal pellets, sometimes in high volumes, 112 within the burrows of millipedes may, therefore, also be used as a nutrient source to help sustain the individual when remaining underground for long periods. The growth of fungi and bacteria on the fecal pellets may even be considered a “farming” technique if further studies support intentional cultivation from fecal pellets. Large accumulations of fecal pellets suggested as possibly being produced by millipedes have been reported from within fossil fern stems of the Upper Pennsylvanian in Ohio (Rothwell and Scott, 1983).

Though widely distributed, millipedes are unable to survive in permanently frozen environments excluding Gelisols as a soil in which millipede ichnofossils would be expected. Millipede ichnofossils would likely be found in Entisols, Inceptisols, Aridisols,

Alfisols, Vertisols, Mollisols, Oxisols, and Ultisols. Their preference for calcic environments may mean that calcium-rich soils would be most likely. Being detritivores, millipedes require decomposing plant material for consumption meaning that along with millipede burrows, rhizoliths should be common. The long temporal range of millipedes places them in time periods with all other terrestrial macrofauna. The co-occurrence of millipede burrows with many other soil dwelling arthropod, insect, arachnid, worm, reptile, amphibian, and mammal burrows is very likely. Waterlogged and ever-wet soils are unlikely to contain millipede burrows.

2.9 Conclusions

Understanding ancient environments begins with the study of modern ecosystems.

Some aspects of modern ecosystems have been well studied, but soil animals and traces have been widely ignored. Neoichnological studies are required to address the key 113 aspects of understanding continental trace fossils such as what the tracemaker may have been, what behavior the trace fossil represents, and what method was used to produce the trace fossil. Despite the high diversity, modern abundance, vital ecosystem role, and wide geographic and temporal range of millipedes very few studies have been conducted on their trace-making abilities. A better understanding of the types of traces these macrodetritivores produce will allow for the production of more complete paleoecologic, paleoclimatic, and paleoenvironmental reconstructions.

Specimens of N. americanus produced four different basic burrow architectures.

These architectures included vertical shafts, subvertical burrows, helical burrows, and O- shaped burrows. Specimens of F. penneri produced all of the architectures of N. americanus in addition to J-shaped burrows for a total of five distinct architectures. These architectures were modified with four different accessory features: branches, chambers, helical sections, and additional entrances. When burrows produced by the species used in this study were compared to those produced by O. ornatus and A. gigas in a similar study conducted by Hembree (2009) using a nonparametric statistical analysis, the burrows were found to have some highly similar quantitative elements. An average width-to- height ratio of 1.0–1.14 was found to be consistent among burrows produced by all four species of millipedes. Burrows produced by N. americanus, F. penneri, and O. ornatus were found to have similar average widths, average heights, and average slopes. Burrows produced by A. gigas were found to be the least similar. When properties considered to be the most related to the size of the tracemaker were removed from the analysis, burrows produced by A. gigas were still considered to be the least similar. This difference was 114

ultimately attributed to morphological differences that resulted from the burrows being

produced for different functions. Narceus americanus, F. penneri, and O. ornatus were all found to construct burrows for dwelling and environmental isolation, while A. gigas produced burrows for feeding and locomotion. The quantitative morphologic characteristics used in this study were, therefore, able to differentiate millipede burrows produced by different orders and for different functions.

It is commonly expected that burrow morphology is controlled by environmental conditions such as sediment composition and moisture content. This study found that the environmental conditions tested had no significant effect on burrow morphology. Instead entrenched evolutionary behaviors may be the strongest control on millipede burrow morphology.

This study, therefore, illustrates the importance of tracemaker body morphology and behavior in the morphology of burrows. Burrowing technique was shown to have little effect on the similarity of burrows produced by millipedes with very similar body plans.

While N. americanus and F. penneri were found to use a combination of head-ramming compaction and small amounts of excavation, their burrows were found to be highly similar and even identical in some cases to burrows produced by O. ornatus that only uses an excavation technique. Burrows produced by juliform millipedes must be at least the width of the largest body segment, and the height of the largest body segment plus the height of the legs. Burrow shafts produced by millipedes in this study, however, were usually 2–3 mm larger than the individual indicating that burrow size is an 115 overestimation of body size. Chambers were sometimes even larger than the individual and varied in shape and size.

No terrestrial macrodetritivore has a longer history than millipedes. A large portion of their behavior which may be well represented in the fossil record has been vastly ignored. Thorough neoichnological studies on the traces produced by millipedes will aid in uncovering the true diversity and abundance of millipedes in the fossil record.

2.10 References

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Banerjee, B. 1967. Diurnal and seasonal variations in the activity of the millipedes Cylindroiulus punctatus (Leach), Tachypodoiulus niger (Leach) and Polydesmus angustus Latzel. Oikos 18, 141–144.

Bates, J.W. 1982. The role of exchangeable calcium in saxicolous calcicole and calcifuge mosses. New Phytologist 90, 239–252.

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3 A MULTI-PROXY APPROACH TO COMPLEX VARIABILITY IN ANCIENT

TERRESTRIAL LANDSCAPES

3.1 Abstract

The upper Monongahela and lower Dunkard groups of southeastern Ohio include an abundance of paleosols containing ichnofossils, vertebrate and invertebrate body fossils, and compression plant fossils. These paleosols formed on diverse Late Pennsylvanian to early Permian landscapes during the Alleghenian orogeny. This study investigated the small-scale, (<200 m) lateral and vertical variability of the paleosols which formed at the distal edge of the Dunkard basin.

Three detailed, 32 m high stratigraphic sections across a 70 m outcrop were measured along a roadcut of US 50 in eastern Athens County, Ohio. Eight distinct pedotypes representing soil formation in nine subenvironments were identified through bulk geochemical, clay mineralogical, and petrographic analyses as well as a detailed study of the ichnofossils, body fossils, and other macromorphological features of the paleosols. Vertical transitions between the subenvironments were due to both fluvial channel migration and climatic changes.

Ichnofossils were abundant in the paleosols and included rhizohaloes, root casts, calcareous rhizotubules and rhizoconcretions, ferruginous rhizoconcretions, actively and passively filled burrows, insect feeding traces on leaves, and coprolites. These ichnofossils were produced by various plants, larval and adult arthropods, and micro- to 125 macro-vertebrates. Body fossils within the paleosols included micro- and macro bone fragments and teeth, compression plant fossils, ostracodes, and gastropods.

Precipitation was seasonally distributed and MAP estimates are generally higher in less well-developed paleosols that are proximal to channel deposits and lower in more well- developed paleosols distal to channel deposits. This combination of features suggests that

MAP during the formation of these paleosols was approximately steady and varied from

300–1000 mm/yr and that channel migration rather than actual precipitation amounts affected MAP estimates. By studying the small scale lateral and vertical variations in paleosols, finer resolution paleoclimatic, paleoenvironmental, and paleoecological reconstructions are possible.

3.2 Introduction

The purpose of this study is to describe the paleopedologic, ichnologic, paleontologic, and stratigraphic significance of an upper Monongahela–lower Dunkard

Group (Permo-Pennsylvanian) outcrop in eastern Athens County, Ohio. Many studies of

Pennsylvanian and Permian paleosols have been conducted in the western portions of the

United States (Kenny and Neet, 1993; Miller et al., 1996; Joeckel, 1991; Kessler et al.,

2001; Tabor et al., 2002; Hembree et al., 2004; Tabor and Montañez, 2004; DiMichele et al., 2006; Joeckel et al., 2007; Mack et al., 2010; Hartig et al., 2011) and while some studies have addressed the presence of paleosols in the Appalachians (Donaldson et al.,

1985; Martin, 1998; King, 2008; Greb et al., 2009; Hembree et al., 2011; DiMichele et al., 2011; Cecil et al., 2011) few have constructed small scale detailed stratigraphic 126 columns (Cecil, 2011; Cecil and Skema, 2011; Skema, 2011) or performed comprehensive studies of these units (Joeckel, 1995; Mora and Driese, 1999, Driese and

Ober, 2005; Hembree and Nadon, 2011; Catena and Hembree, 2012; Dzenowski and

Hembree, 2012). The only exception to this trend has been the prevalence of studies on the economically important histic epipedon from Histosols (coal) of the Pennsylvanian and Permian in the Appalachians (Kosanke, 1943; Phillips et al., 1985; Chyi et al., 1987;

Renton and Hamilton, 1988; Repine Jr. et al., 1993; Ruppert and Rice, 2001; Eble et al.,

2003; Milici, 2005).

The occurrences of these coals have been used to correlate the majority of the

Pennsylvanian and Permian deposits in the Appalachian region. In addition, the composition, thickness, extent, development, and the plant fossils of these coals and surrounding units have been used to interpret paleoecologic, paleoclimatic, and paleoenvironmental conditions (Phillips and Peppers, 1984; Phillips et al., 1985;

Donaldson et al., 1985; Renton and Hamilton, 1988; DiMichele et al., 1996; Pryor, 1996;

Eble et al., 2003, 2011; DiMichele et al, 2011). Coals are known to preserve plant fossils and body fossils of some organisms with hard parts like gastropods or ostracodes, but rarely contain trace fossils and are generally limited to ever-wet or waterlogged, lowland areas (Retallack, 2001). Ichnofossils that are found in coals are usually restricted to coprolites or fecal pellets preserved in plant material (Baxendale, 1979; Scott and Taylor,

1983; Labandeira et al., 1997). These limitations hinder the use of coal as paleoenvironmental indicators outside of their temporal and geographic formational range. Studies in the North American Midcontinent have indicated that during the 127

Pennsylvanian to Permian transition the climate was undergoing extreme fluctuations with a general increase in aridity (Chumakov and Zharkov, 2002; DiMichele et al., 2006;

Tabor and Poulsen, 2008) and an increase in temperature (Tabor, 2007). This pattern was recognized in the Appalachian region as early as 1858 by the decrease in the thickness and number of coal beds in Pennsylvania (Fedorko and Skema, 2011). More recently, the presence of calcic Vertisols in the region has also been used to support a drier climate

(Cecil et al, 2011; DiMichele et al, 2011). The apparent preservational bias toward wetter climate plants in some landscapes may limit the information that plants can provide during dry periods in the Appalachians (DiMichele, et al., 2011). Therefore, in order to better understand variations in past environmental, ecologic, and climatic conditions all paleosols and ichnofossils within a landscape should be considered together. Paleosols previously referred to as underclay, seat earth, clay shale, red beds, and mudstone have been underutilized for the interpretation of terrestrial conditions in the Permo-

Pennsylvanian Appalachian basin.

Paleosols and their constituents have been increasingly utilized to interpret paleoenvironmental, paleoecological, and paleoclimatic conditions (Driese et al., 1995;

Bestland et al., 1997; McCarthy and Plint, 1998; Rodríguez-Aranda and Calvo, 1998;

Kraus, 1999; Retallack, 1997, 1999, 2001, 2004, 2005; Stiles et al., 2001; Bestland et al.,

2002; Sheldon et al., 2002; Tabor et al., 2002;Melchor et al., 2002; Retallack et al., 2003;

Hembree et al., 2004; Driese and Ober, 2005; Driese et al., 2000, 2005, 2007; Kraus and

Hasiotis, 2006; Hembree and Hasiotis, 2007, 2008; Tabor, 2007; Melchor and Hasiotis,

2008; Driese and Medaris, 2008; Smith et al., 2008a, 2008b; Sheldon and Tabor, 2009; 128

Hembree and Nadon, 2011; Kearsey et al., 2012). The five modern soil forming factors of

climate, biota, topographic relief, parent material, and time influenced the formation of

ancient soils (Jenny, 1994). Large- and small-scale variations in these factors lead to lateral variability in terrestrial environments which fundamentally affects soil properties.

The recognition of this variability in outcrop-scale paleosol studies combined with the

knowledge that the paleosols formed in direct exposure to ancient atmospheric and

ecologic terrestrial conditions makes paleosols ideal tools for continental

paleoenvironment reconstructions (Sheldon and Tabor, 2009) including at local scales.

The presence of large slickenside features indicative of shrinking and swelling of

expanding clays during dry and wet seasons, and the level of development of pedogenic

calcite are two examples of macroscopic features used as proxies for seasonal conditions.

Other macroscopic features such as paleosol colors, ped formation, presence and types of

glaebules, rhizolith preservation and morphology, other large trace fossils, and the types

of body fossils preserved can all be used as proxies for paleoenvironmental conditions

(Retallack, 2001). Petrographic features such as clay skins, micropeds, grain and plasma

microfabrics, and micro-trace fossils are additional, visible paleoenvironmental proxies

from paleosols (Retallack, 2001). Geochemical signatures derived from modern soils may

even be used as proxies for provenance, weathering intensity, mean annual precipitation

and temperature during pedogenesis, and atmospheric composition of CO2 and O2 among

others (Sheldon and Tabor, 2009).

The abundance of bacteria, fungi, and other decomposers present in many soils

generally leads to a taphonomic bias against body fossil preservation (Retallack, 2001). 129

Even where body fossils are absent, however, ichnofossils are commonly still preserved

in both marine and terrestrial settings (Bromley, 1996; Retallack, 2001). Therefore,

ichnofossils can preserve a record of biodiversity that would not otherwise be recognized.

Since paleosols are unlikely to be transported as large cohesive bodies, ichnofossils in

paleosols are in situ traces of organism behavior (e.g. Bromley, 1996; Retallack, 2001).

When this behavior is modified by external stimuli, paleoenvironmental or even

paleoclimatic interpretations may be possible (Hasiotis, 2007; Hasiotis et al., 2007a).

Using the information available from paleosols, ichnofossils, and body fossils in tandem

allows finer resolution of paleoenvironmental, paleoecologic, and paleoclimatic

reconstructions.

3.3 Geologic Setting

The Dunkard Group, which was first described in 1839, is a mixed clastic and

carbonate unit consisting of sandstone, siltstone, shale, mudstone, limestone, and coal upt

to 363 m thick (Martin, 1998; Fedorko and Skema, 2011). The Dunkard Group occurs in

southeastern Ohio, northwest West Virginia, and southwest Pennsylvania. The 12,800

km2 exposure of the Dunkard Group sits in the middle of the Pittsburgh-Huntington

Synclinorium that is aligned approximately parallel to the Appalachian fold belt (Martin,

1998; Fedorko and Skema, 2011). These deposits formed during the Allegheny orogeny

and most source rock is located to the southeast (Martin, 1998; Becker et al., 2006).

These strata have been interpreted as the deposits of a lower and upper fluvial plain as well as a fluvial-lacustrine-deltaic plain with many freshwater lakes and swamp basins 130

(Beerbower, 1961; Phillips and Peppers, 1984; Martin, 1998, Cecil et al., 2011). An 11-

member cyclothem has been observed for the upper Monongehela and lower Dunkard

while an 8-member cycle has been identified in the upper Dunkard Group (Beerbower,

1961). Previous studies have attributed these cycles to alluvial autocyclic mechanisms in

the south and southeast (Beerbower, 1961, 1969) and allocyclic processes, predominantly

precipitation, in the northern lacustrine basin (Cecil et al., 2011). Although many studies

have tried to establish a definitive age for the Dunkard Group no conclusive data have

been found and most consider the Dunkard to represent a transitional period from the

Pennsylvanian to Permian (Beerbower, 1961, 1969; Martin and Henniger, 1969; Martin,

1998; Greb et al., 2009; Fedorko and Skema, 2011).

The study area is along the east bound James A. Rhodes Appalachian Highway (US

Route 50) approximately 2.5 km southwest from Coolville, just east of Dixon Rd.,

eastern Athens County, Ohio (Lat: 39.212823°, Long: -81.826446°) (Fig. 3.1). During the

latest Pennsylvanian, the study area was near 7° S paleolatitude and to the northwest of

the epicenter of the Allegheny orogeny that was pushing the Pangean continent

northward (Opdyke and DiVenere, 1994; Scotese, 1994). By the Permo-Pennsylvanian

the region was located in tropical latitudes (Tabor and Poulsen, 2008). The site was

situated at the distal portion of the lower fluvial plain environment of anastomosing

streams with small lakes and swamps (Martin, 1998). Late Pennsylvanian to Permian

rocks in Ohio are divided into the Conemaugh, Monongahela, and Dunkard groups.

While the age of the Monongahela and Dunkard groups are contentious, the age of the

middle of the Conemaugh Group (Ames Limestone) is well constrained to the Late 131

Virgilian by conodont biostratigraphy (Merrill, 1973). Regionally, the Monongahela

Group is divided into the Pittsburgh and Uniontown Formations and the Dunkard Group is divided into the Waynesburg, Washington, and Greene Formations (Fig. 3.2B–C). The top of the Uniontown Formation and bottom of the Waynesburg Formation is traditionally placed at the bottom of the Waynesburg Coal or Hockingport Sandstone.

The top of the Waynesburg Formation and bottom of the Washington Formation is placed at the bottom of the Little Washington Coal. The Greene Formation traditionally begins

at the top of the Upper Washington Limestone (Fedorko and Skema, 2011). Due to the

lack of easily correlative beds between states however, divisions and nomenclature within

the Monongahela and Dunkard groups are not recognized by the Ohio Geological Survey

as official names but rather, informal names (Larsen, 1991).

The difficulty in establishing the age of the sediments stems from the lack of major

uncomformities or widespread marine deposits. Although the occurrence of the

brachiopod Lingula sp. in a limited area of the Washington Coal indicates a marine influence, without the presence of stratigraphically important fauna no age relations can be determined (Fedorko and Skema, 2011). Plants, invertebrate, and vertebrate fossils have been found in the Dunkard Group and have provided some limited and debated biostratigraphic control (Fig. 3.2A). Plants, in particular have been found in high abundance and diversity in Dunkard Group deposits (Fontaine and White, 1880). The seed fern Autunia conferta has commonly been used as an index fossil of the Permian; its presence in the Washington Coal and units above have been used to place the upper portion of the Dunkard in the Permian (Martin, 1998). The use of A. conferta as an index 132

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fossil has been controversial, however, due to reports of A. conferta from the

Pennsylvanian of Europe and Kansas (Blake Jr. and Gillespie, 2011). The cycad

Taeniopteris and the conifer Walchia have also been found above the Washington Coal further suggesting an early Permian age (Martin, 1998). A thorough review of currently known Dunkard Group macroflora, however, concluded that any attempt to date the

Dunkard Group deposits based on these flora would be an approximation (Blake and

Gillespie, 2011). Palynological data suggesting a Pennsylvanian age for the Dunkard

Group (Clendening, 1972), may reflect a sampling bias toward wetter environments and, therefore, a palynological assemblage more akin to the Pennsylvanian (Eble et al., 2011).

Conchostracan branchiopods have indicated an early Permian age for the Washington

Coal and overlying strata, while freshwater bivalves have been used to imply an entirely

Permian age for all Dunkard Group strata (Martin, 1998). Ostracode assemblages have been used to determine a Permian age for the Nineveh Limestone and above and

Pennsylvanian for all lower deposits (Tibert, 2011; Tibert et al., 2011). The fossil insect fauna have indicated a Permian age for the Cassville Shale and overlying strata, (Martin, 135

1998; Schneider and Werneburg, 2006), while fossil eurypterids have indicated a

Pennsylvanian age for the same strata (Scott, 1971). Fossil tetrapods have recently been used to indicate that the Washington Formation must be close to the Pennsylvanian-

Permian boundary and that the entire Dunkard may well be Permian (Lucas, 2011). Other vertebrates indicate only a Late Pennsylvanian or early Permian age (Martin, 1998).

In Ohio, the uppermost Pennsylvanian Monongahela Group (Uniontown Formation in neighboring states) is represented by thin beds of sandstone, light-gray to green laminated shale, red to purple mudstone, and limestone (Sturgeon, 1958). The sandstone bodies have been interpreted as fluvial channels and levees, while the adjacent blocky mudstones have been interpreted as paleosols (Hembree et al., 2011). The carbonate deposits are laterally continuous and have been interpreted as being lacustrine or palustrine in origin (King, 2008).

Mudstone and shale comprise 65% of measured stratigraphic sections of the

Dunkard Group and range in color from red and maroon to green-gray reflecting different environmental conditions (Martin, 1998). The red mudstone units have previously been interpreted as paleosols and more recently have been classified in increasing level of development from Inceptisols to calcic Vertisols (Martin, 1998; Cecil et al., 2011). It is likely that many of the green-grey mudstone units are also paleosols that formed under more reducing conditions resulting from greater water content due to either proximity to a body of water, high water table, or increased annual precipitation. The large proportion of terrestrial lithologies within the upper Monongahela and Dunkard groups makes them ideal for studying paleosols in order to interpret the paleoenvironmental, paleoclimatic 136 and paleoecological conditions of the terrestrial landscape in the distal Appalachian basin during the Pennsylvanian-Permian transition. Previous studies have investigated the parent material, time, and topographic relief related to the Dunkard Group paleosols

(Beerbower, 1961, 1969; Dodson, 2008; Greenlee, 1985; Martin, 1998; Mora and Driese,

1999; Becker et al., 2006) as well as what trends in climate the Dunkard Group paleosols represent (Cecil, 2011; Cecil and Skema 2011; Cecil et al., 2011; Skema, 2011). This study focuses on the influence and interpretation of biota, local environmental change, and climate as they pertain to Late Pennsylvanian–early Permian soil development.

3.4 Methodology

Three, 31–33 m high vertical trenches approximately 33 m apart were excavated in a roadcut approximately 2.5 km southwest from Coolville, just east of Dixon Rd., eastern

Athens County, Ohio (Lat: 39.212823° N, Long: -81.826446° W) (Fig. 3.1B). Trench locations were chosen on the basis of the areas with the least amount of cover and sampling the maximum vertical extent of the roadcut. Where trench locations were shifted (2–67 m) laterally to more complete exposures; the direction and distance of each of these shifts were noted. General stratigraphic columns for each trench were prepared to identify major lithologic changes and identify paleosol units. Color changes, ichnofossils, and body fossils found in non-paleosol units were noted and, where possible, sampled.

Paleosol units were described and sampled more thoroughly. Field descriptions of paleosols consisted of: color, lithology, structure, thickness, horizonation, slickenside size and abundance, presence, abundance and color of mottling, type, size and abundance of 137

nodules, presence, size, color and orientation of root traces (rhizoliths, rhizoconcretions,

and rhizotubules) and other ichnofossils, and body fossils. Descriptions were made and

samples taken every 20 cm for laboratory analysis unless a noticeable change in the

paleosol occurred within that descriptive unit. In these cases 2–3 samples and

descriptions for that unit were taken. The color of wet samples was recorded using a

Munsell Rock-Color chart (The Rock-Color Chart Committee, 1995). Paleosols were

classified using the Mack et al. (1993) nomenclature as well as the modern soil

classification system of the Soil Survey Staff (1996). Detailed stratigraphic sections of

each paleosol profile were created for all three trenches. The lateral continuity of the

horizons, the sharpness of horizon boundaries, and the composition and distribution of

nodules were used to interpret the relative seasonality of precipitation and local drainage

conditions. Bulk samples of paleosols were taken at representative locations within the

sections for X-ray diffraction (XRD) (20 g) and X-ray fluorescence (XRF) (100 g)

analysis.

Samples of paleosols for thin-section preparation (n=67) were taken at every horizon

in each paleosol profile and where high concentrations of root traces or other ichnofossils

were found. In addition seven thin-sections (n=7) of limestone beds were examined in order to determine the origin (i.e. marine, brackish, freshwater, or pedogenic). Thin- section samples were prepared by a commercial laboratory (Texas Petrographic Services,

Inc., Houston, Texas) and mounted on 2.5 x 5 cm and 5 x 7.5 cm slides.

Micromorphological descriptions of paleosol thin-sections follow the nomenclature of

Brewer (1976) and Fitzpatrick (1993) and limestone thin-sections were named using the 138 classification of Folk (1959). Thin sections were described using a Motic BA300 polarizing microscope and photographed using a Moticam 10 megapixel microscope- mounted camera.

Bulk geochemistry of samples taken from horizons in different paleosol profiles were measured by a commercial laboratory (ALS Chemex, Reno, Nevada) using XRF

(n=29). Dried and pulverized samples were analyzed using lithium borate fusion XRF.

Results were reported as oxide weight percents then normalized to their molecular weight. These values were then used to calculate the chemical weathering ratios that represent the effects of base loss (Al2O3/CaO + MgO+Na2O+K2O), hydrolysis

(Al2O3/SiO2), salinization (Na2O/K2O), calcification (CaO+MgO/Al2O3), and leaching of various oxides (CaO, MgO, Na2O, K2O/TiO2) on soil geochemistry (Retallack, 2001;

Sheldon and Tabor, 2009). Mean annual precipitation using the chemical index of alteration minus potash (CIA-K) (Sheldon et al., 2002) as well as provenance

(TiO2/Al2O3) (Sheldon and Tabor, 2009) were also calculated using oxide weight percentages.

Representative samples from different paleosol profiles were analyzed for their clay mineralogy by a commercial laboratory (K/T Geoservices Inc., Gunnison, Colorado) using XRD (n=16). Samples were disaggregated and placed into a centrifuge in order to separate the clay-size fraction. This fraction was then decanted and vacuum filtrated on nylon membrane filters in order to produce oriented mounts. These mounts were then exposed to ethylene glycol vapor for 24 hours to aid in the detection and characterization of expandable clays. Mounts were analyzed using a Rigaku automated powder 139 diffractometer with a CuKa radiation source (40Kv, 35mA) and a solid state scintillation detector over a range of 2–36° 2 theta at a scan rate of 1°/min. The weight percentage data were considered semi-quantitative. Since XRD methods can only quantify crystalline material, organic or non-crystalline material was not included. X-ray diffraction can only detect material on the order of one to five weight percent and this detection limit depends on the mineral. The wide range of crystallinities of clay minerals as well as differences between sample clay minerals present and the standard used for that mineral can also affect the accuracy of the detection results. Finally, if mineral content is overestimated this caused other minerals present to be underestimated and vice versa. This also occurred if other minerals were present but not detected. This was the result of the data being reported as always summing to 100%.

3.5 Stratigraphy and Sedimentology

Correlation of Monongahela and Dunkard group deposits from Pennsylvania and

West Virginia to Ohio has, historically, been controversial and difficult due to the discontinuous nature of the continental deposits, lack of well-developed coal horizons, and the decrease in thickness and development of beds that are deposited in the distal portions of the basin (Sturgeon, 1958; Larsen, 1991; Martin, 1998; Milici, 2004).

Stratigraphic control was established using units of the upper Monongahela and lower

Dunkard to the west of the study area (Sturgeon, 1958; Greenlee, 1985; Dodson, 2008;

Hembree and Nadon personal communication, 2013). Previous studies that refer to this locality (Sturgeon, 1958; Greenlee, 1985) were conducted prior to the widening of US 140

Route 50 between 1997 and 1999. This project cut into the previous road cut approximately 45 meters and improved the quality of the exposure of this locality and adjacent road cuts. The presence of the Gilboy Sandstone approximately 2.3 km west of this locality and the recent road cut exposures allow an improved visual correlation of upper Monongahela Group units along US Route 50.

3.5.1 Upper Monongahela Group

The Uniontown Mudstone (Fig. 3.3A) is the lowest stratigraphic unit exposed at the study location. This mudstone is from 3.5–4.6 m thick in described sections and can be recognized by its maroon color, purple, green, and yellow mottling, and its calcareous, non-bedded character (Greenlee, 1985). The top 1.5–2.8 m of the Uniontown Mudstone in the sections are gray to dark gray, and commonly contain pyrite and rounded limestone clasts of > 10 cm in diameter. The Waynesburg Marlstone/Limestone overlies the

Uniontown Mudstone (Fig. 3.3B) (Greenlee, 1985). The conglomeritic marlstone varies in thickness from 40–90 cm, contains large limestone clasts (4– >100 mm), and varies from two to four beds. Immediately above the marlstone is the Waynesburg Limestone described by Greenlee (1985) as a biomicritic limestone with a fissile, calcareous shale intercalation (Fig. 3.3C). The Waynesburg Limestone varies from 11–15 cm in thickness, with the intercalation approximately 1.5 cm thick. Previous studies of this road cut

(Sturgeon, 1958; Greenlee, 1985) did not recognize a coal above the Waynesburg

Limestone, but did recognize a coal at this stratigraphic level in other nearby sections

(Greenlee, 1985). The coal is present at this location, however, and is approximately 4 cm 141

thick (Fig. 3.3C). Though the lateral correlation of carbonaceous layers to fully developed coal beds within the Dunkard Group and related deposits has been debated

(Sturgeon, 1958), the presence of this coal in the same stratigraphic position as the Little

Waynesburg Coal allows for the correlation of equivalent coal-forming horizons (i.e. landscape surfaces) even if the beds are not directly related. For the purpose of this study, this coal forming horizon is referred to as the Little Waynesburg Coal.

The Little Waynesburg Coal grades vertically into a black, fissile, carbonaceous shale that grades upward into a grayish green, sandy shale. The two shale units combined are 2.0–2.2 m thick and decrease in thickness to the east within the road cut. The Gilboy

Sandstone caps the shale. The Gilboy Sandstone is 2.2–3.0 m thick and decreases to the east end of the road cut. The base of the Gilboy is a fine-grained, cross-laminated sandstone that grades up-section into a medium-grained, massively bedded, and micaceous with a heavily bioturbated top.

Directly above the Gilboy Sandstone is a mostly grayish-blue-green, fossiliferous mudstone and fine-grained sandstone complex. Grain sizes within the mudstone vary from clay and silt to very fine-grained sand. The thickness of the complex increases from

3.5 m to 3.9 m from east to west along the road cut. In Section 1 the grain size of the upper sandstone decreases upward and grades into a red mudstone. Greenlee (1985) placed this unit on the approximate horizon of the Waynesburg #11 Coal. In further support of this interpretation, Sturgeon (1958) reported that the Little Waynesburg Coal averages 7.2 m below the Waynesburg Coal. This relationship places the possible horizon 142

of the Waynesburg Coal within this mudstone-sandstone complex. Based on this correlation this study places the base of the Dunkard Group within this portion of the section. Additionally, Sturgeon (1958) describes the Waynesburg Sandstone in eastern

Athens County, now termed the Hockingport Sandstone Lentil (Martin and Henniger,

1969), as a coalescence of the Gilboy, Waynesburg, Mannington, and Lower Washington sandstones in some localities. A similar coalescing or pinching out of the sandstones in this complex is seen between Sections 1–3.

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3.5.2 Lower Dunkard Group

Directly above the upper sandstone and exposure surface of the grayish blue

mudstone and sandstone complex is an alternating green to red mudstone with a laterally

continuous organic layer and topped by a laterally pinching out calcareous sandstone.

This interval varies in thickness across the exposures from 2.3 m in the east to 4 m in the

west. Within the red mudstone is a thinly laminated organic and clay-rich layer approximately 1.5 cm thick. Sturgeon (1958) identified similar layers that were 3.0–4.5 m above the Waynesburg Coal as the Elm Grove Coal. Sturgeon (1958) noted, however, that the Elm Grove is poorly developed in Athens County. The position of the Elm Grove

Coal under the Waynesburg (Hockingport) Sandstone according (Sturgeon, 1958) and the absence of any similar horizon in this study area suggest that the Elm Grove is not present or at least greatly reduced. The sandstone above the coal mainly present in

Section 1, but found laterally as highly calcareous, very fine-grained, thinly laminated, trough cross-bedded, biotite- and muscovite-rich sandstone lenses match the description of the Mannington Sandstone presented by Stauffer and Schroyer (1920). The position of the organic-rich layer below the sandstone matches the description of the Waynesburg

“A” coal that Stauffer and Schroyer (1920) present as being approximately 1 m below the

Mannington Sandstone and 1.5–3.0 m above the Waynesburg (Hockingport) Sandstone.

The overlying 5.6–8.2 m of outcrop from Section 1–3 (increasing thickness to the east) is largely made up of brown-to-red mudstone, thin bedded (3 cm), laminated claystone, with grey-to-green mudstone, and capped by an approximately 1 m thick sandstone. Plant fossils are common in portions of the mudstone. This section is 144

considered to be the red bed associated with the Lower Washington Sandstone (Sturgeon,

1958; Greenlee, 1985). Greenlee (1985) identified the Lower Washington Sandstone in

an outcrop approximately 4.4 km to the west of this road cut along Route 50 and this may

be correlative with the 1 m thick sandstone capping the mudstone sequence. Assuming that the base of the Lower Washington Sandstone of Greenlee (1985) and the base of the sandstone that occurs above the red beds were at equal elevations during deposition, an apparent dip of approximately 8.1 m/1.6 km (5 m/km) to the southeast would be required in order to correlate the two beds. Martin and Henniger (1969) report a southeastward regional dip of nearly 9 m/ 1.6 km (5.6 m/km) for the Hockingport Sandstone in northwestern portions. As sandstone lenses that are seldom deposited as flat, continuous beds variations in this dip are to be expected. Their dip calculation, however, does allow the correlation of the Lower Washington Sandstone in the study road cut. Greenlee

(1985) referred to a carbonaceous layer approximately 1.5 cm thick immediately above the Lower Washington Sandstone as the Washington Coal.

A dark green, highly organic-rich mudstone is present in the position where the

Washington Coal has previously been identified by Greenlee (1985). The mudstone

alternates from green to red upwards, sporadically contains plant fossils, and decreases in

thickness slightly from 1.4–1.2 m to the east along the road cut. This mudstone is capped

by a lens of bioturbated sandstone that increases in thickness from 1.4–1.7 m to the east.

The sandstone has an erosional lower contact, contains large, vertically oriented burrows,

and may correlate with the Lower Marietta Sandstone (e.g. Stauffer and Schroyer, 1920). 145

Above the bioturbated sandstone is the uppermost red bed in this study. Where the

Lower Marietta Sandstone is not present between Sections 2 and 3, the red bed mudstone is approximately 5 m thick. In measured sections the mudstone is 2.0–1.7 m thick, decreasing to the east. This mudstone unit may be related to the Creston Reds described from other localities. Above the mudstone is a unit of interbedded sandstone and mudstone that thickens to the east. The sandstone is commonly bioturbated with large, vertically oriented burrows. The mudstone is composed of varying amounts of silt and sand and commonly contains well-preserved plant fossils. In the eastern portion of the outcrop, the sandstone is capped by a relatively thin gray mudstone beneath a thick, highly friable, coarse-grained sandstone. These deposits were mainly covered and weathered, and therefore, not included in this study.

3.6 Continental Ichnology of the Uppermost Monongahela and Lower Dunkard Groups

The paleosols and other mudstone lithologies of the upper Monongahela and lower

Dunkard groups contain a diverse array of micro- to macroscopic ichnofossils produced by plants and animals representing a diverse set of behaviors including feeding, dwelling, and locomotion produced by wide variety of possible trace-makers suggestive of a highly diverse biota. The morphology of biogenic structures produced by modern soil animals vary depending on differences in soil composition, moisture content, depth to the water table, temperature, landscape, and precipitation (Hasiotis, 2004, 2007; Bardgett, 2005;

Smith et al., 2008a; Hembree and Nadon, 2011). Rhizoliths can be additional indicators of variations in soil saturation, soil drainage, water table depths, and, in certain instances 146 temperature (Rodriguez-Aranda and Calvo, 1996; Mora and Driese, 1999; Kraus and

Hasiotis, 2006; Tabor, 2007; Smith et al., 2008a). It is possible, therefore, to estimate vertical and lateral changes in paleoenvironment through changes in the type and distribution of ichnofossils within and adjacent to ancient soil ecosystems (e.g. Hasiotis,

2004; Hembree et al., 2004; Hasiotis et al., 2007a; Hembree and Hasiotis, 2007, 2008;

Smith et al., 2008a).

Pennsylvanian and Permian soils of Ohio likely contained a diverse soil ecosystem.

The soil fauna, however, would have been significantly different from that of modern soils. The majority of modern, soil-dwelling invertebrates consist of earthworms, ants, and termites; the earliest fossil evidence of any of these animals is from the Cretaceous

(Humphreys, 2003). Among vertebrates, mammals are an important part of modern soil communities, but they were also not present in the Pennsylvanian or Permian although burrows of mammal-like reptiles do occur in Late Permian paleosols (Damiani et al.,

2003). Despite differences in faunal characteristics, soil ecosystems during this time were likely dependent on a similar trophic hierarchy. Although some groups of modern soil arthropods were not present, arthropods were likely still the most abundant soil-dwelling fauna including detritivores, herbivores, and predators (Shear and Kukalová-Peck, 1990;

Behrensmeyer et al., 1992; Shear and Seldon, 2001; Humphreys, 2003; Hembree and

Nadon, 2011). Known Permo-Pennsylvanian arthropod detritivores consisted of arthropleurids, mites, millipedes, and insects which would leave feeding and dwelling traces (Shear and Kukalová-Peck, 1990; Behrensmeyer et al., 1992; Labandeira et al.,

1997; Hembree, 2009; Hembree and Nadon, 2011). Known arthropod herbivores of this 147 time are primarily insects (Behrensmeyer et al., 1992; Labandeira, 1998; Lubkin and

Engel, 2005) and may have left reproductive traces when in short contact with the soil during oviposition (Hembree and Nadon, 2011), by directly burrowing through the sediment possibly producing nests or brood burrows (Hasiotis, 2002; Smith et al, 2008), or by creating galls and feeding traces within plants (Behrensmeyer et al., 1992;

Jarzembowski, 2012; Stull et al., 2013). Many arthropod predators present in the Permo-

Pennsylvanian were arachnids including scorpions, whip scorpions (Uropygi), whip spiders (Amblypygi), harvestmen (Opiliones), Solpugida, anthracomartids, trigonotarbids, and spiders (Shear and Kukalová-Peck, 1990; Behrensmeyer et al., 1992;

Shear and Seldon, 2001). Some modern species of predatory arthropods are known to produce burrows for dwelling, refuge from adverse conditions, reproduction, and ambush predation (Cloudsley-Thompson, 1975; Villani et al., 1999; Bond et al., 2001; Vollrath and Selden, 2007; Hembree et al., 2012; Hembree, 2013). Other late Paleozoic predatory arthropods included centipedes (Shear and Kukalová-Peck, 1990); some modern species of centipedes produce open to back-filled burrows for locomotion, dwelling, and reproduction (Personal observation). Finally, Late Pennsylvanian–early Permian tetrapods including various amphibians and reptiles likely produced burrows for dwelling, nesting, or aestivation as do extant members of these clades (Hasiotis et al.,

2007b; Storm et al., 2010; Hembree and Nadon, 2011).

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3.6.1 Rhizoliths

Rhizoliths in the study area vary widely in size, shape, orientation, and style of preservation. The types of rhizoliths present include rhizohaloes, root casts, calcareous rhizotubules, and rhizoconcretions (Klappa, 1980; Stieglitz and Van Horn, 1982; Kraus and Hasiotis, 2006). In some specimens the roots were preserved as carbonaceous films in the center of rhizohaloes or intact inside ferruginous rhizoconcretions as root petrifactions (Klappa, 1980).

3.6.1.1 Rhizohaloes

Red, green, and purple paleosols contain elongate vertically to horizontally oriented, downward or laterally tapering mottles that may or may not branch (Fig. 3.4). The mottles may contain black cores and vary in color from yellow, green, red, light gray, to combinations of two colors (Fig. 3.4A–E). When no black core is present, the mottles are either a solid color or the inner portion is the same color as the surrounding matrix (Fig.

3.4C, E, G). The mottles are circular to irregular in cross section with diameters from 0.5 to 4.0 mm, although mottles with diameters up to 6.5 cm are present in some paleosols

(Fig. 3.4F). The length of continuous macro-sized mottles varies from 1.0 mm to 9.0 cm

(Fig. 3.4A). Small-scale rhizohaloes are a minimum of 0.16 mm wide and 0.36 mm long

(Fig. 3.4G).

Rhizohaloes are defined by color variations within paleosols resulting from depletions of iron and manganese that highlight areas in a soil that were chemically altered around roots due to fluctuations in soil-moisture levels or root decay (Kraus and

Hasiotis, 2006). By using color variations in rhizohaloes as an indicator for the presence 149

of different minerals, a basic interpretation of environmental conditions during

pedogenesis is possible (Kraus and Hasiotis, 2006). Differences in these chemicals and

resulting color variations have been used to indicate variations in seasonal soil moisture

as well as soil drainage conditions (Kraus and Hasiotis, 2006). The presence of pooled stagnant water on a landscape for long periods can cause surrounding sediments and areas of higher permeability in the soil (i.e., roots, burrows, cracks, etc.) to become drab-

colored or green through a process of surface-water gleization (PiPujol and Buurman,

1994). Oxygen-rich conditions would result in the oxidation of ferrous iron to relatively

immobile ferric iron staining the surrounding area red (PiPujol and Buurman, 1994;

Retallack, 2001; Kraus and Hasiotis, 2006). Red rhizohaloes therefore, indicate oxygen-

rich and moderately to well-drained soil horizons, the presence of highly oxygenated

water, or locally dry conditions (Hasiotis, 2001; Kraus and Hasiotis, 2006). Oxygenated

soils with continuously high moisture and high organic matter content are more likely to

form goethite than hematite giving the material a yellow-brown color (Kraus and

Hasiotis, 2006). Yellow rhizohaloes suggest moderately to imperfectly drained soil

horizons that retain moisture and organics forming in a seasonally dry environment with

long wet periods (Kraus and Hasiotis, 2006). Under oxygen-poor conditions, iron is

reduced or depleted causing the soil area around a root to have a green or gray tint,

respectively (Kraus and Hasiotis, 2006; Hembree and Nadon, 2011). Green or gray

rhizohaloes reflect deposition in poorly drained soil horizons with stagnant water or

locally wet conditions (Kraus and Hasiotis, 2006). The oxidation of iron can occur

rapidly under atmospheric conditions in the presence of water but the reduction of iron 150

and depletion of oxygen in organic-rich soil water involves oxygen mixing, which allows iron reduction by microbial organic matter decomposition as the primary color-producing reaction (Roden and Wetzel, 1996; Retallack, 2001; Schaetzl and Anderson, 2009).

Organic-rich cores in the center of rhizohaloes are the carbonaceous remains of the original root and are most likely preserved in very poorly drained paleosols with anoxic 151

soil water content where all available ferric iron has been reduced and anaerobic

decomposition of organic matter is no longer possible (Kraus and Hasiotis, 2006).

3.6.1.2 Root Casts

Root casts are 15.0–31.0 cm long and 1.4–10.0 cm wide, are composed of sandstone,

claystone, and carbonate with various cements, taper either downward or laterally, and

sometimes branch. Root casts are uncommon in red, purple, and green paleosols.

Vertically oriented calcareous sandstone root casts occur in a green paleosol (S1: P#16)

(Fig. 3.5A), green claystone root casts occur in a red paleosol between Sections 1 and 2

(P#14) (Fig. 3.5B), and carbonate root casts occur near a calcareous nodule horizon in all

three Sections (S1: P#14, S2: P#15, S3: P#12) (Fig. 3.5A). In addition, a large (25.0 x

22.0 cm), circular, calcareous mudstone cast occurs in a unit of non-calcareous, grayish-

blue-green sandstone approximately 5.0 cm above a large calcareous, horizontally

oriented, sandstone root cast in Section 1 (P#16) (Fig. 3.5E). Small-scale root casts are

0.14–2.30 mm wide and >2.5 cm long (Fig. 3.5C, D). Small root casts occur in thin

sections from Section 2 in a purple paleosol (P#27) and a green paleosol (P#22).

Root casts are sediment and cement-filled void spaces that were created from the in situ decomposition of roots (Klappa, 1980). These void spaces must have been connected to the surface in order to be filled with sediment via wind-blown or water-mediated sediment distribution processes. The large sand root cast in S1: P#16 is similar to

Stigmaria but does not bear the surficial indentations characteristic of this root (Phillips and DiMichele, 1992). The large, red mudstone cast overlying this root cast is interpreted 152

as a tree stump. The close proximity of the stump cast, large horizontal root cast, and smaller, vertically-oriented root casts suggests that these features are related.

3.6.1.3 Calcareous Rhizotubules

Red, green, and purple paleosols contain elongate, commonly bifurcating and

tapering, calcareous, cylindrical structures with circular cross sections (Fig. 3.6). The

rhizotubules have diameters from 0.5 to 2.0 mm and lengths of 0.5 to 6.0 cm (Fig. 3.6D,

E). Rhizotubules are composed primarily of coarsely crystalline calcite and may also

contain clastic sediment up to very fine-grained sand (Fig. 3.6A–C).

Calcareous rhizotubules form from the accumulation of calcite around roots during

life or after the death of the roots that could then fill with sediment or cement forming a

root cast within the soil B horizon (Klappa, 1980; Kraus and Hasiotis, 2006). As rain

water enters the soil, small amounts of calcite dissolve and percolate downward into

lower soil horizons and may be drawn toward roots. As this water evaporates or is

removed from the rhizosphere by roots the calcium carbonate precipitates in the voids

and open channels around roots. Once an enclosing sheath is formed, the root

decomposes forming an open mold. When this mold fills with sediment or cement a root

cast is formed (Klappa, 1980). This process requires periodic drying and wetting typical

of regions with seasonal climates (Retallack, 2001). Additionally, once the calcium

carbonate precipitates the channels and voids are closed. The closed pathways decrease

porosity and permeability of the soil inhibiting water infiltration allowing portions if not

153

all of these features to survive any subsequent gley processes (Hembree and Nadon,

2011). This process allows for the recognition of episodes of periodic drying in a paleosol that would otherwise be interpreted as having formed in a wetter environment.

3.6.1.4 Rhizoconcretions

Large-scale, calcareous rhizoconcretions occur as vertically oriented, stacked, calcareous nodules (Fig. 3.7A). The nodules are gray to red and are typically discoid to cylindrical in shape. In some specimens, bifurcations or other small cylindrical tubes are preserved within a single nodule. The nodules are commonly 1.0–7.0 cm in diameter although some larger ones up to 21 cm do occur. Small-scale calcareous rhizoconcretions observed in thin section consist of 0.7–1.3 mm diameter, circular to oblong cross sections. These small rhizoconcretions typically have a coarsely crystalline, calcite core enveloped by alternations of micrite, hematite, or calcite spar (Fig. 3.7B, C). Large-scale calcareous rhizoconcretions occur in a 50 cm thick horizon within a red paleosol 18.5 m that is more prominent in Section 2 than in other sections (Fig. 3.7A). Small-scale calcareous rhizoconcretions are common in units approximately 13.9–16.5 m above the base of the section.

Ferruginous rhizoconcretions are up to 11 cm long (Fig. 3.8A), have circular to elliptical cross sections up to 1.5 cm in diameter (Fig. 3.8B, C, F, G), and are horizontally to vertically oriented (Fig. 3.8D). Some ferruginous rhizoconcretions are more root-like in morphology and may preserve details of the inside of the root (Fig. 3.8C, E). These

156

rhizoconcretions have less or no calcite than normal and many have cracked or wrinkled surfaces with small-scale (<0.5 mm) longitudinal striations. Branching or bifurcation of the root is rarely preserved. The ferruginous layers of the rhizoconcretions commonly alternate with calcite, clay minerals and possibly manganese oxides or goethite, but some are preserved as entirely hematite. Large-scale ferruginous rhizoconcretions occur with other ferruginous pedotubules in red paleosols between 16.0 and 21.5 m (Fig. 3.8A).

They are most highly concentrated in a horizon from 17.3 m in Section 1 (P#17) to 16.2 m in Section 3 (P#15) where they co-occur with irregularly shaped, concretions of similar composition (Fig. 3.24F, G). Micro-rhizoconcretions are found in red and green paleosols in Section 1 (P#4) and Section 3 (P#17), respectively (Fig. 3.8F, G). These ferruginous rhizoconcretions are oblong in cross section and 0.7–1.5 mm in diameter in the long axis. 157

The calcareous rhizoconcretions form from the accumulation of calcite around the root and root hairs primarily while the root was alive (Klappa, 1980; Kraus and Hasiotis,

2006). During life the roots draw in water that contains dissolved calcium carbonate and other ions. As water is removed from the soil, calcium carbonate precipitates around the root causing an encrusting sheath to form (Klappa, 1980; Retallack, 2001). After root death, the rhizoconcretion is likely formed using the root or previously established rhizoconcretion as an initiation point for precipitation. The formation of calcareous rhizoconcretions requires a periodically dry soil environment (Hembree and Nadon,

2011; Retallack, 2001).

Ferruginous rhizoconcretions were likely formed in a similar manner to calcareous rhizoconcretions. In addition to a strong seasonal component, however, fluctuating geochemical environment in the rhizosphere is required to mobilize the ferrous iron during wet periods and then precipitate ferric iron during dry periods in an anoxic and oxygenated localized environment, respectively (Steiglitz and Van Horn, 1982; Retallack,

1997, 2001). Modern ferruginous rhizoconcretions similar to those observed, however, have been described as forming around the roots of salt marsh plants in metal-rich, anoxic estuaries in only a few weeks (Sundby et al., 1998). Rhizoconcretions composed of alternating layers of calcite and iron oxide likely formed calcite layers during dry periods and ferruginous layers in the wet season (Retallack, 2001). The presence of these rhizoliths suggests a well-drained soil with varying geochemical conditions and a strong wet-dry seasonality (Retallack, 2001).

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3.6.2 Animal-Soil Interactions

3.6.2.1 Mottled Burrows

Burrows with by colors different from the surrounding matrix occur in a variety of morphologies. These burrows occur in both Monongahela and Dunkard group paleosols that are green, light gray, purple, and red. Due to the nature of their preservation the full three-dimensional architecture of these burrows is difficult to discern. Many of the mottled burrows are irregularly shaped so that the two-dimensional views may not represent the entirety of the burrow architecture (Fig. 3.9A–D, G). Other specimens, however, have distinct cross-sectional shapes (Fig. 3.9E–H). Horizontally and vertically oriented, unlined, and unbranched burrows with or without chambers are common and range in size from 0.03 mm to 2.9 cm in diameter (Fig. 3.9B–D, I). Less common are vertically oriented O-shaped burrows that are unlined, may have small branches, and range in size from <1 mm to 5 mm in diameter (Fig. 3.9E, F). The O-shaped burrows tend to have a purple-tinted center and green tunnels in a red matrix.

Mottled burrows with compressional linings were rare and included J-shaped and vertically sinuous architectures with no branches that range in size from 0.6 mm to 1.3 mm in diameter (Fig. 3.9A, H). While most mottled burrows consist of green tunnels in a red or brown matrix, a few light purple burrows (S1: P#29) and some small green burrows (S3: P#16 and S1: P#12) also have a red rim that separates the fill of the burrow from the surrounding matrix (Fig. 3.9D, I). The red-rimmed burrows may lead downward to an unlined, enlarged chamber, but primarily consist of cross-sectional views of horizontally oriented burrows. 159

Cross section of a ferruginous petrifaction of Stigmaria from a PT4B paleosol with the vascular bundle preserved with calcite. D) Horizontally oriented, ferruginous root petrifaction from a PT4B paleosol. E) Ferruginous or manganiferous root petrifaction showing a central core from a PT4B paleosol. F) Thin section of a ferruginous rhizoconcretion from a DPT2 paleosol (S1, P#4-Btss) (normal light). G) Thin section of a ferruginous rhizoconcretion from a PT3 paleosol (S3, P#17-Bgkss) (normal light).

Mottled burrows are interpreted as the product of either surface-active detritivores or soil-dwelling deposit feeders. The O- and lined J-shaped burrows are highly similar to burrows produced by extant juliform millipedes that use a compressional burrowing technique (Chapter 1). There is currently no ichnogenus that matches the description of these burrows. The disruption of the sediment during production of the burrow and subsequent filling of the shafts, tunnels, and chambers via active or passive processes would have produced preferential flow paths for water. The green color of the burrow fill is therefore likely a result of microbially mediated iron reduction and depletion in the presence of stagnant anoxic or dysoxic water and organic material (Retallack, 2001). This process of gleization is supported by the presence of a gleyed or highly organic soil surface approximately 50 cm above these burrows. Mottled burrows without red outer rims were likely passively filled relatively quickly or actively back-filled. Red-rimmed burrows, however, were likely open to the surface for a longer period and passively filled allowing oxidation of the matrix surrounding the burrow. Millipedes are terraphilic to hygrophilic while deposit-feeding soil animals are generally hygrophillic and require 10-

30% soil moisture conditions (Hasiotis, 2007). The presence of green mottled burrows in a paleosol profile suggests a moderately well-drained soil that was generally moist with abundant organic material (PiPujol and Buurman, 1994; Retallack, 1997; Hembree and 161

Nadon, 2011). The presence of millipede burrows specifically also implies the presence

of decomposing vegetation and may indicate a seasonal climate (Behrensmeyer et al.,

1992; Lawrence and Samways, 2003; Hättenschwiler and Gasser, 2005).

3.6.2.2 Actively Filled Burrows

Actively filled burrows contain structures such as menisci or evidence of

unstructured displacement of matrix material from one position of a burrow to another.

Actively filled burrows are horizontally to vertically oriented, sharp-walled, unlined,

seldomly branched, and up to 4 cm long and 8 mm in diameter. Actively filled burrows

are found in red and purple paleosols, olive green sandy paleosols, and clay- and organic-

rich paleosols. Actively filled burrows in sandy paleosols tend to be vertically oriented

and are visible due to color differences between the burrow fill and host rock.

Burrows with structured backfill contain material that is identical to the surrounding

matrix in sandy micaceous and organic-rich clay substrates; the sediment was reworked and relocated in poorly defined packets with a tightly meniscate shape (Fig. 3.10A–D).

Backfilled burrows with thick, meniscate backfill packets are assigned to the ichnogenus

Taenidium (D’Alessandro and Bromley, 1987) whereas those with tightly packed, arcuate menisci are assigned to the ichnogenus Naktodemasis (Fig. 3.10B, C)(Smith et al.,

2008c). Back-filled burrows with poorly defined menisci are assigned to the ichnogenus cf. Taenidium (Fig. 3.10D). Meniscate back-filled burrows are similar to those produced by extant hemipterans or coleopterans in a larval stage (Hasiotis, 2002; Smith et al.,

2008c). If insects with similar physiological requirements to extant species produced these burrows, the burrows would indicate moderately to well-drained soils with a soil 162

163

moisture content of 5–45% and an A or upper B horizon (Smith and Hasiotis, 2008;

Smith et al., 2008c).

Actively filled burrows that lack meniscate backfills are characterized by a decreased organic content relative to the surrounding matrix and tend to be randomly oriented or follow concentrations of opaques within the paleosol (Fig. 3.10E, F). Small, round, opaque glaebules within the burrows are interpreted as fecal pellets (Fig. 3.10E). These

actively filled burrows are interpreted as having been produced by deposit feeders and are

assigned to cf. Planolites (Häntzshel, 1975; Pemberton and Frey, 1982). The sharp

contact of the wall of the burrow with the matrix and the level of grain manipulation

within the burrow suggest that the trace-maker had appendages (Smith and Hasiotis,

2008; Counts and Hasiotis, 2009). Typically, continental deposit feeders such as insect

larvae, symphyla, and some mites are hygrophilic and their presence suggests a

moderately well drained, moist soil (Dindal, 1990; Hasiotis, 2007). 164

3.6.2.3 Passively Filled Burrows

Passively filled burrows are common and vary in both size and morphology. The

burrow fill consists of material either similar to the surrounding matrix (homogeneous

fill) or different from the surrounding matrix (heterogeneous fill).

Homogeneous fill burrows are visible through differences in mineral alignment, linings, or differential weathering. They are only found in green and olive colored paleosols. Morphologies include: 1) lined, nonbranching, sinuous to straight, horizontally to subvertically oriented tunnels and chambers (Fig. 3.11A–C); 2) unlined, nonbranching,

subvertically oriented J-shaped burrows (Fig. 3.11D); 3) unlined, nonbranching,

subvertically oriented burrows that end in an ovoid-shaped chamber (Fig. 3.11E); or 4)

burrows that are not morphologically distinguishable (Fig. 3.11F–G). The composition of

linings varies, consisting of organics (Fig. 3.11A), compressed clays (Fig. 3.11B), and

illuviated clays (Fig. 3.11C). Homogenous fill burrows are typically 1.3–13.1 mm long

and 0.12–2.0 mm wide. Lined burrows are tentatively interpreted as cf. Palaeophycus

based on the rare branching, distinctly lined wall, orientation, and nature of fill of these

burrows; however, Palaeophycus has not previously been associated with chambers. The

lining and passive fill of these burrows suggest that they were used for dwelling

purposes. During occupation the burrow was maintained as an open structure and was

only filled after the producer abandoned the burrow or perished. The passive fill and lack

of evidence indicating that the tracemaker was deposit feeding supports the conclusion

that the tracemaker was a small predatory arthropod (Hembree and Nadon, 2011). The

preservation of organic linings would have been unlikely in oxidizing conditions; 165

therefore, their presence is suggestive of a reducing environment, likely shortly after burrow construction.

Unlined, J-shaped, homogenous fill burrows occur in very poorly developed

paleosols with a high sand content and are assigned the ichnogenus cf. Psilonichnus (Frey

et al., 1984; Nesbitt and Campbell, 2006). Burrows of this morphology have been

described from neoichnological experiments with millipedes and were shown to be

temporary dwelling structures (L= 11.6 cm, W= 1.1 cm) (Hembree, 2009). The

terraphilic to hygrophilic nature of millipedes suggests that their burrows would be

present in oxidized paleosols where chemical weathering would remove mica quickly

(Retallack, 2001) decreasing the likelihood of millipedes being the trace-maker. Similar,

larger, J-shaped burrows have also been produced by modern crabs (L= ~24.0 cm, W=

~4.0 cm) (Frey et al., 1984) and mud-shrimp (L= <80.0 cm, W= 0.5–3.0 cm) (Nesbitt and

Campbell, 2002). Psilonichnus attributed to mud-shrimp, however, are lined eliminating

them as a possible trace-maker (Nesbitt and Campbell, 2002). A decapod of small stature

(w= 9.5 mm) has been previously described from Mississippian age marine deposits

(Schram and Mapes, 1984) suggesting that small decapods may have been present.

Under the presumption of millipedes or small decapods as possible trace makers, the

presence of this burrow morphology likely indicates a moderately to poorly drained soil.

Unlined, homogeneous fill burrows typically have indistinguishable morphologies. One

specimen that can be distinguished is a subvertically oriented shaft leading to an egg-

shaped chamber. Differences in clay mineral alignment or the presence of a small amount 166

paleosol (S1, P#15-Bc). C) Scanned thin section of a tightly meniscate, back-filled burrow from a PT4B paleosol (S2, P#16-ABss). Arrows point to green rhizohaloes with yellow cores. D) Thin section of a poorly meniscate, back-filled burrow from a PT1 paleosol (S2, P#28-Bc) (normal light). E) Thin section of an actively filled burrow in a DPT2 paleosol (S1, P#5-Agk) (normal light). Arrows point to possible fecal pellets. F) Thin section of actively filled burrows from a DPT2 paleosol (S1, P#5-Agk) (normal light).

of illuviated clay are commonly the only means of establishing the burrow perimeter. In some specimens, the changes in mineral alignment are sudden, indicating the burrow had

a sharply defined wall. A sharply defined wall indicates the clay was relatively firm at the

time of burrow excavation (Savrda, 2007). After construction of the burrow the structure

may be passively filled by overlying clay or by gravitational collapse with material from

the surrounding matrix. The passive fill process or the preferential flow of fluids through

the more porous and permeable sediment filling the burrow causes the burrow fill to be

oriented differently relative to matrix grains allowing the structure to stand out when

viewed under a microscope (Gingras et al., 2007). Burrows that are distinguishable by

differences in grain orientation are typically irregular and cannot be assigned an

ichnogenus. As open structures, unlined, homogeneous fill burrows likely represent

dwelling or brood structures possibly of small insects like beetles or soil bugs (Hasiotis,

2002).

Heterogeneous fill burrows are common in green to red paleosols with fill that is

commonly similar to the lithology of the overlying strata. The burrow fill contains grains

larger (Fig. 3.12A, D–E) or smaller (Fig. 3.12B) than the surrounding matrix, or are

calcite cemented in a non-calcareous matrix (Fig. 3.12C). Heterogeneous fill burrows are 168

169

unlined, typically sharp walled, vertically to subvertically oriented, may have chambers, and rarely branch. Burrow diameters range from a tunnel 0.04 mm in diameter in a green paleosol to a large chamber 7.0 cm in diameter present in a light purple calcareous paleosol (Fig. 3.12D, E).

Heterogeneous fill indicates that the burrows were open to the surface and likely filled after the burrow was abandoned (Bromley, 1996; Savrda, 2007). Heterogeneous fill burrows with calcite cement could mean the fill material was calcium-rich or may indicate a seasonal environment in which calcium-rich soil water that preferentially flowed through filled burrows precipitated calcite upon evaporation during dry seasons.

The variable orientation, difference in fill, rare branching, and absence of lining allow many of these burrows to be assigned cf. Planolites (Pemberton and Frey, 1982).

Unbranched burrows that are vertically oriented can be assigned cf. Skolithos. Burrows with interconnected tunnels that are homogeneous and heterogeneously filled (Fig. 3.12F) and have tunnels of varying diameter (0.8–5.2 mm) do not fit any known ichnogenus. 170

While the three dimensional characteristics of these burrows are not discernable in thin section, branching occurs as T-shaped junctions, and burrow cross sections and termini are rounded similar to Thalassinoides. The co-occurrence of homogenous and heterogenous fill may indicate that the burrow was filled prior to evacuation of the burrow by the producer. Similar burrows have been produced by the activities of coleopterans and hemipterans in the A horizons and upper parts of immature soils

(Hasiotis, 2002). Overall, heterogeneous fill burrows suggest production in a soil that is firm enough to support an open burrow without a lining and that the soil is cohesive since the walls are sharply defined (MacEachern et al., 2007). In a paleosol, these burrows suggest a moderately to well-drained, cohesive soil and likely represent the activity of adult and larval coleopterans, hemipterans, millipedes, and small vertebrates.

Burrows that are filled with coarsely crystalline calcite spar have the most highly variable morphology of the burrows observed. Spar-filled burrows are horizontally to vertically oriented (Fig. 3.13B, D), sinuous to straight (Fig. 3.13B, I), Y- or U- shaped burrows (Fig. 3.13C, E), that may or may not possess branches, chambers, or linings (Fig.

3.13D, F, H, I). Spar-filled burrows range in diameter from 0.03–0.6 mm, with chambers from 1.6–8.5 times the diameter of burrow tunnels. Spar-filled burrows are sinuous when horizontally oriented (Fig. 3.13B, F) and commonly contain chambers at the top of vertically to subvertically oriented shafts (Fig. 3.13D, H). Spar-filled burrows were only observable in thin section and red and green paleosols from 10.7 m in Section 2 (P#23) to

15.0 m in Section 1 (P#20).

171

172

Figure 3.12 Passive, heterogeneous-fill burrows from upper Monongahela and lower Dunkard group paleosols. A) Thin section of a vertically oriented burrow with fill that is coarser than the surrounding matrix from a MPT2 paleosol (S2, P#22-Bg) (normal light). B) Thin section of a burrow with fill that is finer than the surrounding matrix from a MPT2 paleosol (S2, P#22-C) (cross-polarized light). C) Calcite cemented, vertically oriented burrow in a non-calcareous matrix from a MPT2 paleosol (S1, P#24-Btg). D) Large burrow chamber filled with coarser-grained material (light gray) than the surrounding matrix (light purple) in a PT1 paleosol (S3, P#25). E) Thin section of a subvertically oriented burrow with fill that is coarser than the surrounding matrix from a MPT2 paleosol (S1, P#25-Btg) (normal light). F) Scanned thin section of a burrow network with coarser fill than the surrounding matrix in a MPT2 paleosol (S1, P#23-Bk). Black arrows point to large diameter (upper) and small diameter (lower) tunnels. White arrow indicates up direction.

In order to be spar-filled these burrows were open but likely not connected to the surface due to a lack of passive fill from burial. The spar, therefore, suggests that the soil experienced seasonal fluctuations in water content if the calcite is pedogenic in origin or if it was precipitated from groundwater shortly after burial (Retallack, 2001). Most spar- filled burrows contain organic linings. The preservation of organic linings usually suggests that soil waters were anoxic, but may also indicate that soil conditions changed rapidly. Rapid changes in soil conditions could occur as a result of rapid burial which would prevent organic matter decomposition by depositing a layer of impermeable clay that prevents further aerobic bacterial decay. A lined Y-shaped burrow (Fig. 3.13E) possesses indentations into the matrix at several points along the tunnel walls. This is evidence of a compaction burrowing technique based on experimental trials (Hembree and Hasiotis, 2006). The high organic content, tunnel-to-chamber morphology, slightly sinuous nature, and branching style of several spar-filled burrows are similar to portions of beetle burrows produced by larvae in wood (Hasiotis, 2002). The size and morphology 173

of spar-filled burrows are, therefore, most similar to traces produced by beetle larvae in firm substrates and are likely associated with feeding behavior due to the high concentrations of organics within the burrows. The spar-filled burrows do not conform to any currently defined ichnogenus. The presence of these burrows in a paleosol are suggestive of a seasonal climate in a moderately to well-drained paleosol.

3.6.3 Coprolites

Coprolites and fecal pellets are common in thin sections of highly calcareous purple

paleosols below 4.0 m and organic-rich horizons throughout the sections (Fig. 3.14).

Fecal pellets observed in thin section occur as: 1) round to oblong dark grey glaebules

arranged in a roughly straight line (h=0.017 mm, w=0.027 mm) (S3: P#25) (Fig. 3.14A);

2) rectangular glaebules with rounded edges, a dark brown center, and finely crystalline

rind (h=0.7 mm, w=1.8 mm) (S2: P#30) (Fig. 3.14B); 3) tear-drop shaped glaebules with

a crystalline fill (l=0.4 mm, w=0.17 mm) (S2: P#28) (Fig. 3.14C); 4) light brown,

tapering glaebule with an organically enriched rind in an all clay matrix (h=0.35 mm,

l=2.00 mm) (S1: P#25) (Fig. 3.14D); 5) rounded tear-drop shape with a spiral pattern

(l=0.6 mm, w=0.37 mm) (S3; P#10) (Fig. 3.14E); and 6) very small (w=<0.01–0.05 mm)

somewhat rounded, may be irregular, dark grey to black glaebules (Figs. 3.10E, 3.11G,

3.12E). An additional, very large coprolite (l=5.5 cm, w= 3.4 cm, h= 1.4 cm) was located

east of Section 3 between 22.0 m and 24.0 m weathering out of a red paleosol (Fig.

3.14F). The large coprolite has five bands that circumscribe one half of the coprolite

(heteropolar spiral) in a step-wise tapering fashion. The coprolite appears to be 174

175

preserved with blue silica but surficial cracks are calcite filled. Other potential fecal pellets are visible in thin sections from all three sections, but are very small, sometimes poorly-defined, and may also simply be organic fragments or hematite masses unrelated to fecal pellets.

Round to oblong glaebules that occur within a straight line are interpreted to be the fecal pellets of an infaunal deposit feeder indicating a moderately drained, wet soil environment (Hasiotis, 2007). Two-dimensional views of the rectangular coprolites resemble the cross section of fecal pellets produced by isopods or the larvae of

Lymnophilidae (Retallack, 1997). Although distinct particles are visible within the coprolite, none are identifiable. The presence of a heterogeneous fill burrow with a chamber inside of a coprolite is evidence that at the time of preservation the burrow was open, produced for feeding or dwelling, and likely produced in a seasonally dry environment (Fig. 3.14B). This coprolite displays clear evidence of coprophagy. The 176 tear-drop shaped coprolite, though very small, closely resembles much larger (apprx.

150x), non-spiraling coprolites from the early Permian of Texas (Hunt and Lucas, 2005).

These coprolites are therefore assigned cf. Dakyronocopros and were likely produced by very small vertebrates or invertebrates that produce a similar-shaped coprolite of terrestrial or aquatic origins (Hunt and Lucas, 2005). The light brown coprolite with an organic rind occurs in a green paleosol and was likely preserved due to anoxic conditions.

This coprolite may also be assigned to cf. Dakyronocopros as an elongate variation of the tear-drop shape. This coprolite morphology may have been produced by a hydrophilic organism, possibly a small amphibian. Heteropolar spiraling coprolites have previously been found in the Creston Reds of the Washington Formation and were interpreted as having been produced by amphibians (Stauffer and Schroyer, 1920). More recent studies, however, attribute these coprolites to fish and sharks deposited in an aquatic environment and later subaerially exposed (Dentzien-Dias et al., 2012).

3.6.4 Plant-Animal Interactions

Several occurrences of damage sustained by plants from herbivorous animals are present in compressed plant fossils above 23 m in all sections (Fig. 3.15). Damage is present only in specimens of Neuropteris and Cordaites. Damage to Cordaites consists of circular features with well-defined edges that are either 4.8 mm in diameter with a high concentration of black spheres surrounding one edge of the structure (Fig. 3.15A) or 6.5 mm in diameter lacking additional features (Fig. 3.15B). Damage to Neuropteris specimens occurs primarily as crescent- to V-shaped patterns starting from the outer edges of the leaf (Fig. 3.15C, D, F). Other damage to Neuropteris specimens includes 177

Figure 3.14 Coprolites from upper Monongahela and lower Dunkard group paleosols. A) Thin section of small, oblong to circular pellets in a gleyed burrow channel from a PT1 paleosol (S3, P#25-BC) (cross-polarized light). B) Thin section of a rectangular coprolite with rounded edges from a PT1 paleosol (S2, P#30-B) (cross-polarized light). Arrow points to a horizontally oriented burrow leading to a chamber within the coprolite. C) Thin section of a small, tear drop-shaped coprolite from a PT1 paleosol (S2, P#28-Bg) (cross-polarized light). D) Thin section of an elongate tear drop-shaped coprolite from a MPT2 paleosol (S1, P#25-Btg) (normal light). E) Thin section of a rounded, tear drop- shaped coprolite with a spiraled morphology from a PT6 paleosol (S3, #10-Bss) (cross- 178 polarized light). Arrow points to an organic fragment with gleyed outline. F) Silica- replaced coprolite with a heteropolar spiral from a PT6 paleosol.

deeply penetrating patterns that preferentially excise material from the primary vein (Fig.

3.15D), and a small, relatively shallow, excision of material from the outer edge of the leaf crossing secondary veins at an acute angle (l= 2.0 mm, w= 0.45 mm) (Fig. 3.15E).

Labandeira et al. (2007) described a morphotypic characterization system for damage on compressed plant fossils by insects and mites. Circular excisions of Cordaites specimens belong to the DT02 (Fig. 3.15A) and DT04 (Fig. 3.15B) morphotypes of hole feeding in which circular sections are removed from foliage. Hole feeding in Cordaites has been recorded from the Lower Permian of southern Brazil and was attributed to early relatives of orthopteroids or coleopterans (de Souza Pinheiro et al., 2012). Damage in most

Neuropteris specimens can be classified as DT12 (Fig. 3.15C, D, F) and DT13 (Fig.

3.15D) of margin feeding morphotypes. The DT12 morphotype is designated as

Phagopytichnus ekowskii (Labandeira et al., 2007; Jarzembowski, 2012) and has been suggested to have been produced by orthopteroid insects (Jarzembowski, 2012). Other leaf margin biting traces are assigned the ichnogenus Phagophytichnus. The excision that crosses secondary veins observed in Neuropteris does not fit any currently designated type of damage (Fig. 3.15E).

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3.7 Body Fossils

3.7.1 Flora

Plant fossils consist of: 1) compression or impression fossil foliage in siltstone (Fig.

3.16C, D, I), shale, mudstone (Fig. 3.16A, B, F, G), or fine-grained sandy mudstone (Fig.

16E, H) that may preserve some organics; 2) poorly preserved compression fossils in the

Little Waynesburg Coal; 3) impressions and charcoal remains of trunks just above the

Waynesburg Limestone (Fig. 3.17B); 4) root petrifactions in mudstone from 15.0 m in

Section 1 to 18.0 m in Section 3 (Fig. 3.8); and 5) as a preserved seed in a red mudstone

(S1: P#20) (Fig. 3.13G).

The most common fossil foliage include Macroneuropteris (Fig. 3.16A), Cordaites

(Fig. 3.16B), and many varieties of Pecopteris (Fig. 3.16D, E). The overall combination

of these plants represents a mesophytic to wetland assemblage and a rooting environment

that was moderately well-drained (Blake Jr. and Gillespie, 2011). Less common are

aspects of poorly drained, standing water environments which include Calamites

(Asterophyllites (Fig. 3.16C) and Annularia) and Sphenophyllum (Fig. 3.16F),

Lepidophylloides (Fig. 3.16G), Danaeites emersonii Lesquereux (Fig. 3.16H) and

Odontopteris (Fig. 3.16I). Least common in collected specimens is the callipterid Autunia

conferta (Sternberg) Kerp (Fig. 3.17A) (S1: P#8). The presence of Autunia conferta is

commonly interpreted as an indication of a seasonally dry environment or well-drained

soil conditions (DiMichele et al., 2011; Blake Jr. and Gillespie, 2011).

In a carbonate- and organic-rich layer between the Waynesburg Limestone and the

Little Waynesburg Coal of some sections, charcoal- or organic- filled impressions of tree 180

181

Figure 3.15 Ichnofossils in plants found in lower Dunkard group paleosols. A) Circular damage (DT02) in Cordaites from a DPT2 paleosol (S1, P#8-Bss). B) Circular damage (DT04) in Cordaites from a DPT2 paleosol (S3, P#8-B). C) Crescent-shaped damage (DT12) in Neuropteris from a sandy shale capping a PT7 paleosol (S3). D) Margin feeding (DT13) in Neuropteris from a DPT2 paleosol (S2, P#8-Bssg). E) Margin feeding that crosses secondary veins of Neuropteris at an acute angle from a DPT2 paleosol (S2, P#8-Bssg). F) Crescent-shaped damage (DT12) in a Neuropteris from a DPT2 paleosol (S2, P#10-Bss).

trunks are preserved (Fig. 3.17B). These trunks are similar in morphology to the lycopsid trunks of Pfefferkorn and Wang (2007, Fig. 4E). The presence of charcoal in the trunk impressions suggests the occurrence of a wildfire suggesting a seasonal climate (Falcon-

Lang, 2003).

Root petrifactions are exceptionally well preserved in several horizons that are capped by green to olive colored paleosols and are typically preserved with calcite or iron and manganese oxide minerals (Fig. 3.8). Permineralized roots, some of which are concentrically ringed and range from 0.4–1.5 cm in diameter, occur in red paleosol horizons with ferruginous concretions (S1: P#17– S3: P#15, S1: P#15, S3: P#13, 14).

Ferruginous root preservation typically ceases upon reaching the capping green or olive paleosol. Some of these fossil roots have an indentation that runs longitudinally along the entire length of the root (Fig. 3.8B, C). Cross sections show the presence of a thin, roughly circular structure attached to the outer wall of the root (Fig. 3.8C). Commonly, very thin (<0.5 mm) longitudinal striations are visible around the outsides of the root.

Some specimens are preserved with a small calcareous core. 182

183

The variable nature of preservation of the fossil roots likely suggests that they are

from different types of plants. While it is difficult to identify the species of a plant by its

roots, some of these permineralized roots exhibit features distinctive of Stigmaria

belonging to a tree of the Sigillaria (Eggert, 1972) or possibly more specific the Sigillaria brardii-ichthyolepis group (Pfefferkorn and Wang, 2009). The rootlets of Stigmaria in general are recognizable by hollow aerenchyma surrounding a protruding vascular bundle

(Eggert, 1972) while the roots of the Sigillaria brardii-ichthyolepis group are characterized by a small axial width (20–30 mm) and a horizontal to vertical transition within single rootlets (Pfefferkorn and Wang, 2009; Green, 2010). Although the root fossils were not able to be traced long enough to see the L-shape that can be used to identify the fossils as Stigmaria asiatica, the horizontal and vertical orientation of similarly preserved roots in the same horizon may indicate a similar root morphology

(Pfefferkorn and Wang, 2009). Roots with an indentation larger than the striations that 184 run longitudinally along the root or that have a protrusion extending into the root from the outer wall are interpreted to be the rootlets of Sigillaria (Eggert, 1972, Fig. 19). The preservational style of these roots provides additional support for their identification.

Green (2010) describes the “lycopsid photosynthetic pathway” as requiring the enrichment of CO2 in the aerenchyma of subaerial portions of the plant and O2 in buried portions (roots). This enrichment of oxygen in a moderately to well drained soil may have helped facilitate the permineralization of the root via the uptake of ferrous iron during the wet season and oxidation to ferric iron during the dry season. Though lycopsids are typically associated with poorly drained to aquatic settings (DiMichele and

Aronson, 1992; Falcon-Lang, 2003; Pfefferkorn and Wang, 2007; DiMichele et al., 2010;

Green, 2010; Moisan and Voigt, 2013), the survival of Sigillaria brardii in seasonally dry conditions has been noted (Pfefferkorn and Wang, 2009; Blake Jr. and Gillespie, 2011).

The presence of a sigillarian Stigmaria in a red paleosol suggests that it grew under seasonal conditions. In addition, the displacement of the vascular bundle to the side of the root in thin section (Fig. 3.17C) likely indicates that crystallization within the root occurred either while the plant was still alive or shortly after death and can be used as an indicator of seasonality in which this particular root may not have survived the infill of the aerenchyma with calcite during a dry season (Phillips and DiMichele, 1992).

Other exceptionally well preserved rhizoliths may represent the preservation of other plants with a hollow internal structure, such as Calamites, or simply the precipitation of ferric iron in the rhizosphere around a root. 185

In a thin section (S1: P#20) a calcite-filled, roughly oblong feature with a thick wall of organic material and a bifurcating system of elongate organic strands extending from its base is interpreted as a well-preserved seed or ovule (Fig. 3.13G). The seed is 1.4 mm tall and 0.6 mm wide and is set in a red mudstone. The seed is preserved in an early growth stage or as an ovule grounded by roots (Linkies et al., 2010). In order to prevent the decomposition of organic matter around the seed, the system was either buried rapidly or quickly dehydrated.

3.7.2 Fauna

Body fossils of animals preserved in paleosols consist of complete gastropods (Fig.

3.18A–C), shell fragments (Fig. 3.18D, E), isolated teeth (Fig. 3.18H, J), and bone fragments (Fig. 3.18F, G, I, K, L). Gastropods primarily occur in green paleosols (S2:

P#22, 16), but one specimen did occur in a red paleosol (S2: P#14). The identity of the gastropods in the green paleosols is uncertain, but the gastropod in the red paleosol (Fig.

3.18C) is likely the terrestrial pulmonate snail Anthracopupa ohioensis Whitfield, 1881

(Solem and Yochelson, 1979). Shell fragments are found in: 1) paleosols of the

Uniontown Mudstone; 2) inside a stump cast (S1: P#16); and 3) in the uppermost red paleosol (S1–3: P#1). Uniontown Mudstone shell fragments are similar to the shells of full specimens of ostracodes seen in the overlying marlstone and limestone and occur throughout the paleosol matrix and in limestone clasts. The presence of these shells in a highly calcareous, purple paleosol likely indicates that they originated in a seasonal pond and became disarticulated during later periods of exposure and were either: 1) transported 186

and deposited on the paleosol surface during pedogenesis; or 2) remained in situ at the

location of the pond. Shell fragments present higher in the road cut represent a different assemblage and are less common. The close proximity to sandstone units suggests that these fragments were transported to the current position. Bones and teeth are present primarily in the Uniontown Mudstone and from Section 2 at 10.74 m (P#23). These fragments are typically <1.0 mm, but one bone fragment >2.0 mm occurs in the upper portions of the Gilboy Sandstone (P#23) (Fig. 3.18I). Small bone fragments and teeth are interpreted as the remains of small vertebrates, possibly amphibians or fish. In contrast to the overlying limestone and marlstone as well as a limestone that is only locally present near Section 2 (~2 m), no evidence of a fully aquatic system exists where these bone fragments and teeth are found. These remains, therefore, likely represent the existence of ephemeral ponds possibly only existing during wet seasons. A large bone fragment (S2:

P#11) has been identified as the sacral rib of a large tetrapod (David Berman, personal communication). Large tetrapods characteristic of Dunkard Group deposits include

Eryops, Diadectes, Edaphosaurus, and Dimetrodon (Lucas, 2011). The fragment was

likely transported to the area after disarticulation as no other bones were present.

3.8 Paleosols of the Upper Monongahela and Lower Dunkard Groups

Paleosols of the upper Monongahela Group (Uniontown Formation) and lower

Dunkard Group were distinguished by color, geochemistry, structure, trace, and body fossil content (Appendix 6). The paleosols were grouped into different pedotypes based on similarities in their bulk geochemistry, clay mineralogy, and macro- and micromorphological features (Fig. 3.19). Twelve paleosols were identified within the 187

Figure 3.18 Fossil fauna in upper Monongahela and lower Dunkard group paleosols. A) Gastropod from a MPT2 paleosol (S2, P#22-C). B) Gastropod from a PT4B paleosol (S2, P#16-Cg). C) Terrestrial gastropod Anthrocopupa ohioensis (Whitfield) from a PT4A paleosol (S2, P#14-A). D) Thin section of an ostracode (?) shell fragment from a PT1 paleosol (S2, P#27-Bk) (normal light). E) Thin section of an ostracode shell fragment from a PT1 paleosol (S2, P#28-Bg) (cross-polarized light). F) Thin section of bone fragment from a PT1 paleosol (S2, P#27-Bk) (under normal light). G) Thin section of a small bone from a PT1 paleosol (S2, P#26-BCg) (cross-polarized light). H) Thin section of a tooth from a PT1 paleosol (S2, P#27-Bk) (normal light). I) Thin section of a bone 188 fragment in a MPT2 paleosol immediately above the Gilboy Sandstone (S2, P#23-C) (normal light). J) Thin section of a fish (?) tooth in a PT1 paleosol (T2, P#26-BCg) (normal light). K–L) Sacral rib of a large tetrapod from a PT6 paleosol (S2, P#11-B).

Monongahela Group from the Uniontown Mudstone to the top of the Hockinport

Sandstone and were divided into three pedotypes. Twenty one paleosols were identified from the top of the Hockingport Sandstone to the bottom of the well-exposed sandstone unit capping the three sections in the Dunkard Group. The Dunkard Group paleosols were divided into six pedotypes, one of which was also present in the Monongahela Group.

3.8.1 Monongahela Group Paleosols

3.8.1.1 Pedotype 1 (PT1)

Description: Pedotype 1 paleosols (Fig. 3.20) (n=7) (Appendix 6) occur in the

Uniontown Mudstone below other PT1 paleosols and ultimately below a series of brecciated marlstone beds. Single PT1 profiles are 0.5–1.6 m thick and are characterized by generally weak horizonation with the exception of locally moderately developed Bk horizons. PT1 profiles are best distinguished by color variations, patterns of bioturbation, and erosional contacts. Paleosols 29–33, 27–30, and 23–26 in Sections 1, 2, and 3, respectively, are a variegated, very dusky purple (5p 2/2) to blackish red (5R 2/2) mudstone with sometimes pervasive, massive to elongate yellow and green mottles.

Paleosols 27–28, 25–26, and 21–22 in Sections 1, 2, and 3, respectively, transition to predominantly grayish blue green (5BG 5/2) to grayish olive (10y 4/2) mudstone.

Disperse carbonate nodules and limestone clasts are common in all PT1 paleosols and are 189

190

<2–45mm in diameter. Some elongate or massive concentrations of carbonate nodules do occur and are commonly associated with green mudstone (Fig. 3.20G). All PT1 paleosols are highly calcareous and react vigorously to dilute hydrochloric acid.

Ichnofossils of PT1 paleosols are dominantly rhizoliths that are vertically oriented and laterally branching (Figs. 3.4B, 3.20F). The majority of well-defined rhizohaloes are yellow (Fig. 3.20F), but they vary in color from yellow, green, and gray, and commonly contain a black inner core. Organically preserved roots (Fig. 3.20B) and yellow rhizohaloes are especially common in the upper 20–60 cm of most profiles. The rhizohalo cores may be up to 2.6 cm wide and 6.3 cm long near 40 cm from the top of the visible profile, but most roots are <1 mm thick and <4 cm long. Heterogeneous filled (Fig.

3.12D), poorly meniscate back-filled (Fig. 3.10D), red-rimmed (Fig. 3.9I), and other mottled burrows (Fig. 3.9A, H) are also present, but not common, and occur at variable levels within the profiles.

The micromorphology of PT1 paleosols is characterized by a plasmic microfabric that is calciasepic to inundulic (Fig. 3.20B–D), rarely insepic, and a soil microfabric that is intertextic to porphyroskelic. Grains are mostly calcite microspar with some quartz as well as some rock fragments that are typically ostracodal biomicrites or poorly laminated micrites. Opaques, including fragmental to illuviated organics, euhedral to irregular pyrite (Fig. 3.20B), and other iron minerals are dispersed throughout the profiles but are mostly concentrated in the upper horizons. Additional grains include common shell fragments and lesser bone, teeth, and fecal material. Other biological features in thin section consist of organically preserved roots and abundant rhizohaloes. In addition to 191

192

Figure 3.20 Representative stratigraphic column of PT1 paleosols and the Little Waynesburg Coal in Section 2. A) Desiccation cracks on a surface of Waynesburg Marlstone. Note poorly sorted black to tan micrite clasts. B) Thin section of pyrite (S1, P#27-BCg) (normal light). C) Thin section of dendritic iron/manganese also showing calciasepic plasmic microfabric and intertextic grain microfabric (S2, P#25-BCg) (normal light). D) Thin section of a prismatic ped also showing calciasepic plasmic microfabric (S3, P#22-BCgc) (normal light). E) Thin section of a locally present ostracodal biopelmicrite (S2, P#28) (cross-polarized light). F) Large yellow rhizohalo (S1, P#32-A). G) Fracture fill (S2, P#29-A).

coalescing, channelized, or disperse carbonate nodules of varying sizes, some carbonate

nodules are cracked and stained yellow or reddish-brown. Dendritic manganese originating from cracks (Fig. 3.20C), burrows, or nodules are present in the upper 30 cm of a single profile. Wedge-shaped, blocky, angular blocky, and prismatic peds (Fig.

3.20D) commonly occur throughout PT1 paleosols.

A calcareous layer locally present in Section 2 paleosol #28 is 13 cm thick, light gray, and composed primarily of intraclasts <1 cm in diameter. In thin section the layer is composed of abundant complete ostracode shells and shell fragments with finely crystalline micrite and lesser coarse calcite spar. The outlines of the intraclasts are not obvious and, in places, the clasts are replaced by micrite. The spar tends to outline abundant, rounded calcite nodules, intraclasts, and pellets (Fig. 3.20E).

Four samples of PT1 paleosols in Section 3 and one sample in Section 2 were taken from three different paleosol profiles for determination of bulk geochemistry and clay mineralogy (Table 1, 2). Molecular weathering ratios and mean annual precipitation were calculated from the bulk geochemical analysis of these samples (Table 1). Base loss, hydrolysis, salinization, provenance, and sodium and potassium oxides vary little from 193

one sample to the next, though base loss shows a slight spike in sample #3, and

salinization and sodium oxides slightly increase upward (Table 1). Calcification, calcium

and magnesium oxides are highest in sample #2 and 4 and are lowest in sample #3 (Table

1). The overall values of these properties, however, are exceptionally high compared to

other paleosols examined. The chemical index of alteration without potash (CIA-K)

values range from 11.8 to 14.5% with the smallest values associated with horizons rich in

calcite nodules. Clay mineralogy results revealed a clay composition of primarily illite and smectite, very little kaolinite and plagioclase, and twice as much quartz as chlorite

(Table 2). Calcite, smectite, illite and mica, and ankerite made up the majority (89.9–

97.0%) of the clay fraction.

The marlstone capping PT1 paleosols is up to 85 cm thick and contains intraclasts of

other marlstone and ostracodal and poorly laminated micrite fragments that range up to 9

cm in diameter. The marlstone beds are highly variable in thickness (7–30 cm) and black,

bluish gray, and light gray in color (Fig. 3.3B). The marlstone beds can be distinguished

from one another due to scoured contacts, changes in color, and intraclastic size and

abundance variations. Other components of the marlstone include microconchids (Fig.

3.21D), shell fragments (Fig. 3.21C), charophytes (Fig. 3.21A), fish scales (Fig. 3.21B),

pyrite usually present around channels (Fig. 3.20B), nodules, clasts, and rarely pyrite

replaced ostracodes, and rare gastropods. Intraclasts vary from black to light tan in color

with more abundant gray and tan clasts. In thin section, the variation in the marlstone

beds becomes more apparent. The beds vary in size and abundance of intraclasts, amount

and distribution of pyrite, ostracodes, and organics. Dissolution of several marlstone

Table 3.1 Molecular weathering ratios, chemical index of alteration (CIA-K), estimated mean annual precipitation (MAP), and bulk geochemistry data calculated from whole-rock X-ray fluorescence (XRF) of samples from upper Monongahela and lower Dunkard group paleosols. Bulk geochemical data are given as weight percents. Pedotype Number Sample Paleosol-Horizon Section Measurement Base Loss Hydrolysis Salinization Calcification Leaching : (CaO) (MgO) (Na2O) (K2O) CIA-K MAP (mm) Weight LOI SiO2 Al2O3 Fe2O3 CaO MgO Na2O K2O Cr2O3 TiO2 MnO P2O5 SrO BaO PT7 1 Bkg 1 2978 0.46 0.19 0.07 1.91 23.80 5.72 0.29 3.83 39.13 521 0.21 16.05 44.72 14.23 5.22 12.03 2.08 0.16 3.25 0.01 0.72 0.26 0.369 0.02 0.03 2 Bss 1 2878 0.71 0.19 0.07 1.14 12.00 5.62 0.27 3.85 55.70 757 0.15 12.70 49.2 15.76 7.93 6.74 2.27 0.17 3.63 0.01 0.8 0.07 0.288 0.02 0.03 3 Bss 1 2810 0.89 0.20 0.06 0.87 8.23 5.30 0.24 3.79 64.81 887 0.19 11.55 51.44 17.13 7.23 4.97 2.3 0.16 3.84 0.01 0.86 0.04 0.293 0.02 0.04 4 Cg 1 2778 1.26 0.14 0.58 0.52 3.29 3.12 1.22 2.12 73.13 1006 0.17 6.19 65.45 15.54 4.09 2.29 1.56 0.94 2.48 0.01 0.99 0.05 0.098 0.01 0.04 DPT2 5 2-BC 1 2655 1.93 0.25 0.10 0.31 0.45 5.12 0.32 3.37 95.88 1330 0.16 7.70 53.38 21.9 8.73 0.3 2.48 0.24 3.82 0.01 0.96 0.02 0.095 0.01 0.05 6 3-BCg 1 2594 2.02 0.24 0.11 0.29 0.46 4.46 0.35 3.15 95.46 1324 0.15 7.99 54.06 21.55 8.51 0.32 2.23 0.27 3.68 0.01 0.99 0.02 0.059 0.02 0.06 7 4-Btss 1 2574 2.08 0.25 0.09 0.28 0.46 4.71 0.30 3.52 96.08 1333 0.15 8.17 52.12 22.22 9.34 0.3 2.21 0.22 3.86 0.01 0.93 0.02 0.075 0.02 0.05 8 5-Agk 1 2554 1.49 0.24 0.18 0.47 4.96 2.87 0.52 2.81 75.28 1036 0.14 8.99 52.23 21.27 4.46 3.48 1.45 0.4 3.32 0.01 1 0.01 2.112 0.06 0.05 9 5-B 1 2534 1.98 0.17 0.27 0.26 0.31 3.12 0.71 2.64 92.92 1288 0.16 6.03 61.26 17.33 8.49 0.22 1.59 0.56 3.14 0.01 1.01 0.01 0.031 0.01 0.05 10 5-C 1 2514 1.44 0.20 0.25 0.47 3.51 3.66 0.68 2.75 78.49 1082 0.16 8.79 56.87 19.31 4.87 2.44 1.83 0.52 3.21 0.01 0.99 0.05 0.161 0.01 0.06 PT6 12 12-BC 1 2142 2.12 0.26 0.08 0.27 0.58 4.95 0.31 3.78 95.85 1330 0.15 8.73 50.15 21.89 11.79 0.34 2.1 0.2 3.74 0.01 0.84 0.02 0.094 0.02 0.06 PT5 14 16-Ag 1 1803 1.63 0.17 0.40 0.35 0.81 4.02 1.02 2.54 88.22 1221 0.15 6.17 62.61 17.87 5.2 0.58 2.07 0.81 3.06 0.01 1.02 0.03 0.15 0.02 0.05 16 16-Cg 1 1744 1.73 0.23 0.14 0.35 1.07 4.76 0.46 3.26 91.53 1268 0.15 7.82 55.75 21.13 6.04 0.75 2.4 0.36 3.85 0.01 1 0.03 0.163 0.02 0.05 PT3 17 18-O 1 1677 1.60 0.19 0.11 0.33 0.88 4.24 0.42 4.04 92.18 1277 0.17 8.30 57.89 18.45 6.33 0.58 2.01 0.31 4.48 0.01 0.94 0.01 0.111 0.02 0.05 19 20-A 1 1520 1.37 0.24 0.13 0.51 2.85 5.77 0.43 3.32 83.78 1157 0.15 8.37 50.55 20.1 10.63 1.86 2.71 0.31 3.64 0.01 0.93 0.04 0.119 0.02 0.05 20 20-Bki 1 1464 0.27 0.22 0.24 3.46 57.02 8.47 0.81 3.39 24.67 314 0.16 20.20 33.78 12.33 7.42 20.42 2.18 0.32 2.04 <0.01 0.51 0.31 0.34 0.02 0.04 21 21-Btg 1 1394 1.49 0.22 0.29 0.43 1.56 5.21 0.86 2.94 86.65 1198 0.16 7.19 54.43 20.48 7.82 1.12 2.68 0.68 3.54 0.01 1.02 0.04 0.22 0.02 0.06 22 21-BCgn 1 1350 1.19 0.16 0.63 0.55 3.44 3.78 1.46 2.31 72.72 1000 0.17 6.34 61.34 16.35 5.3 2.37 1.87 1.11 2.67 <0.01 0.98 0.06 0.126 0.01 0.05 MPT2 23 22-C 1 1321 1.33 0.18 0.53 0.48 2.98 3.86 1.31 2.49 76.71 1057 0.19 7.03 59.76 17.87 5.43 2.07 1.93 1.01 2.91 0.01 0.99 0.06 0.18 0.02 0.06 24 23-Bk 1 1261 1.21 0.21 0.37 0.59 5.36 4.11 1.03 2.82 71.53 983 0.16 9.06 54.86 19.67 5.21 3.61 1.99 0.77 3.19 0.01 0.96 0.07 0.21 0.02 0.08 25 24-Btg 1 1221 1.70 0.24 0.23 0.35 0.49 5.43 0.74 3.22 93.15 1291 0.13 6.82 54.61 21.63 7.96 0.35 2.77 0.58 3.83 0.01 1.01 0.03 0.141 0.02 0.06 26 24-BC 1 1181 1.38 0.21 0.38 0.47 1.52 5.46 1.04 2.69 85.22 1178 0.17 6.71 55.64 19.2 8.7 1.09 2.81 0.82 3.24 0.01 1.02 0.05 0.174 0.01 0.05 27 25-Btg 1 1161 1.63 0.24 0.26 0.38 0.68 5.67 0.77 3.01 91.92 1274 0.12 7.12 53 21.55 8.75 0.49 2.92 0.61 3.62 0.01 1.02 0.04 0.077 0.01 0.05 29 25-BCn 1 1121 1.15 0.14 0.78 0.56 2.65 4.67 1.79 2.29 74.75 1029 0.15 5.52 64.1 15.44 5.67 1.71 2.17 1.28 2.48 <0.01 0.92 0.03 0.131 0.01 0.04 PT1 31 25-BCg 2 440 0.12 0.17 0.23 7.73 108.60 21.58 0.97 4.15 13.32 152 0.15 27.40 26.64 7.74 2.76 27.45 3.92 0.27 1.76 <0.01 0.36 0.14 0.257 0.07 0.03 32 22-BCgc 3 280 0.11 0.17 0.20 8.76 121.98 21.74 0.83 4.16 11.78 130 0.17 28.00 24.98 7.12 2.95 29.12 3.73 0.22 1.67 <0.01 0.34 0.15 0.206 0.07 0.02 33 23-Bg 3 220 0.14 0.17 0.20 7.07 98.42 20.34 0.85 4.31 14.47 169 0.18 26.70 28.37 8.15 3.33 26.26 3.9 0.25 1.93 <0.01 0.38 0.14 0.248 0.07 0.03 34 24-Bk 3 160 0.11 0.17 0.19 8.41 115.45 26.22 0.80 4.29 12.66 143 0.17 28.30 25.72 7.31 3.26 27.56 4.5 0.21 1.72 <0.01 0.34 0.17 0.263 0.07 0.03 35 25-BC 3 60 0.14 0.18 0.16 7.08 100.97 17.68 0.68 4.28 14.15 164 0.26 27.00 27.18 8.13 4.12 26.94 3.39 0.2 1.92 <0.01 0.38 0.15 0.259 0.06 0.03 195

Table 3.2 Clay mineralogy from X-ray diffraction (XRD) of the <4 micron fraction of upper Monongahela and lower Dunkard group paleosols. R1 M-L I/S 30%S: ordered mixed-layer illite/smectite with 30% smectite. R1 M-L I/S 20%S: ordered mixed-layer illite/smectite with 20% smectite Pedotype Number Sample Paleosol-Horizon Section Measurement 30% S R1 I/S M-L 20%S R1 I/S M-L Illite & Mica Kaolinite Chlorite Quartz K-Feldspar Plagioclase Calcite Ankerite Fe-Dolomite Dolomite Hematite <4 micron wt% PT7 1 Bkg 1 2978 33.8 0 22.8 3.3 6.7 3.3 0.8 1.5 19.7 0 0 0 8.1 24.29 4 Cg 1 2778 0 9.2 26.7 38.8 14.2 6.7 0.7 3.7 0 0 0 0 0 11.01 DPT2 5 2-BC 1 2655 0 10.7 32.9 19.9 20.7 11 1.1 3.7 0 0 0 0 0 14.44 10 5-C 1 2514 16.7 0 33.5 30.4 7.2 8.6 0.7 2.9 0 0 0 0 0 12.88 PT6 11 10-Bss 3 2210 10.5 0 26.3 18.5 10.2 10.2 0.9 2.6 0 0 0 0 20.8 21.10 PT4A 13 14-Bkss2 2 1911 18.4 0 24.4 13.4 4.6 8.2 0 0 7.7 0 3.9 0 19.4 20.84 PT5 14 16-Ag 1 1803 13.5 0 29.5 29 11 8 0.5 3.2 0 0 0 5.3 0 15.75 PT4B 15 16-ABss 2 1791 0 11.7 31.3 18.8 11.7 11.2 0.9 4 0 0 0 0 10.4 19.94 PT3 17 18-O 1 1677 44.1 0 34.3 2.2 7.3 10.4 0 1.7 0 0 0 0 0 17.06 18 16-Bk 3 1571 26 0 25.8 13.3 4.7 5.3 0 0 7.9 0 0 0 17 21.00 MPT2 23 22-C 1 1321 14.5 0 33.4 29.7 13.4 5.5 0.4 1.8 1.3 0 0 0 0 11.18 24 23-Bk 1 1261 13.2 0 34.1 29.9 10.5 5.7 0.6 2.2 3.8 0 0 0 0 13.72 28 22-Bg 2 1134 11.5 0 35.2 12.2 26.8 6.3 0.4 2.3 5.3 0 0 0 0 15.35 30 23-Bg 2 1094 12 0 35.1 28.2 15.4 4.8 0.7 3.8 0 0 0 0 0 14.96 PT1 31 25-BCg 2 440 17.5 0 27.1 0.7 2.5 5.6 0 0 40 6.6 0 0 0 16.42 34 24-Bk 3 160 16.8 0 24.1 0.7 2.6 5.8 0 1 35.5 13.5 0 0 0 19.24

samples has also produced shark and fish teeth, but due to the abundance of intraclasts, it is not known whether these teeth originated from the matrix or from the intraclasts. All marlstone layers are primarily composed of micrite and some have desiccation cracks on their upper surfaces (Fig. 3.20A).

Interpretation: PT1 paleosols represent the combined profiles of up to three different paleosols in which the A horizon of the previous soil becomes the C horizon of the subsequent soil. This process has led to the formation of four composite paleosol profiles

(Appendix 6). Composite paleosols are indicative of non-steady rates of deposition which are exceeded by the rate of pedogenesis (Kraus, 1999). The A horizons of PT1 paleosols are characterized by abundant yellow rhizohaloes and mottles, abundant organic fragments, and organic root preservation. The B horizons are characterized by high concentrations of calcareous nodule formation (Bk), higher abundance of green mottles and rhizohaloes, and the presence of slickensides or abundant clay skins. The limestone layer present near Section 2 is interpreted as forming in a pond that was buried and later subjected to pedogenesis. No distinct C horizon is recognized in PT1 paleosols, but B/C horizons are identifiable as they contain a mixture of remnant A horizon characteristics from the previous paleosol and B horizon characteristics of the subsequent paleosol. The

BC horizons, therefore, have a moderate amount of both yellow and green rhizohaloes and mottles, small disperse calcareous nodules, and may have illuviated argillans, but rarely large slickensides.

The macro- and microscopic features of PT1 paleosols allow them to be classified as vertic Calcisols where primary matrix colors are vibrant (purple, reddish black) and as 197

gleyed vertic Calcisols where primary matrix colors are drab (gray, bluish green) (Mack et al., 1993). Under the modern soil classification system, PT1 paleosols are interpreted as dry climate Vertisols, likely Torrerts or Xererts (Soil Survey Staff, 1996; Buol et al.,

2003). Shrink-swell features indicative of Vertisols include slickensides, large, filled cracks, wedge-shaped and prismatic peds (Fig. 3.20D), cracked calcite nodules, and high 198 amounts of clay minerals. The minimal leaching of base cations, hydrolysis, low MAP estimates, and presence of shallow calcareous horizons supports the interpretation of PT1 paleosols as low moisture Vertisols (Retallack, 2001).

Calcareous nodules within PT1 paleosols are interpreted as pedogenic carbonate nodules due to their fine-grained nature, and the coalescing of small nodules to form larger ones (Retallack, 2001). Many carbonate nodules are thoroughly cracked and have well defined outer edges indicating that they dried (e.g. Khadkikar et al., 1998; Retallack,

2001) and were affected by pedoturbation (Wieder and Yaalon, 1974). Not all nodules in a sample, however, are cracked. The co-occurrence of both types of calcareous nodules may be an indication of several periods of nodule formation in which older nodules have experienced weathering or that the cracked nodules experienced greater transport from shrink-swell processes or other types of pedoturbation. The existence of pedogenic carbonate nodules in PT1 paleosols and deep cracks are an indication of seasonal and dry conditions (Retallack, 2001).

The occurrence of pyrite in many PT1 paleosols is not surprising due to abundant organic material in much of the profile. Pyrite, however, requires anoxic conditions and sulfate in the presence of sulfate-reducing bacteria to form at surface conditions (Donald and Southam, 1999). Most pyrite in PT1 paleosols occurs in drab-colored horizons that are interpreted to have been gleyed by iron-reducing bacteria in stagnant anoxic waters while decomposing organic material (Retallack, 2001). This would be a suitable environment for pyrite formation. There are, however, occurrences of pyrite concentrated in dark yellow portions of reddish to purple paleosols. Bacterially mediated cubic pyrite 199 growth under approximated natural conditions in laboratory experiments has been shown to reach μm scales in five days (Donald and Southam, 1999). It is, therefore, likely that pyrite formation occurred while the soil was waterlogged during the wet season.

Indicators of poorly drained, waterlogged conditions in PT1 paleosols include purple color caused by the preferential removal of hematite over goethite and high organic content (Kämpf and Schwertmann, 1983; Kraus and Hasiotis, 2006), surface water gley

(PiPujol and Buurman, 1994), formation of goethite (Kraus and Hasiotis, 2006), goethite replaced calcite nodules (Mack et al., 2010), presence and segregation of manganese oxides from iron oxides (PiPujol and Buurman, 1994: Kraus and Hasiotis, 2006), preservation of organic matter (Retallack, 2001), lack of washing down-profile of base cations (Retallack, 2001) and abundant ostracode shell fragments. The abundance of ostracode shell fragments in PT1 paleosols also suggests that standing water or very damp conditions existed, likely on a seasonal basis (Martens et al., 2008).

The purple to reddish black color of lower PT1 paleosols is likely due to the presence of goethite, manganese oxides, abundant organics, and highly disperse hematite (PiPojul and Buurman, 1994; Wright et al., 2000; Kraus and Hasiotis, 2006). The XRD results of

PT1 paleosols indicate a complete lack of hematite in the clay sized fraction and bulk geochemical analysis shows little (2.8–4.1 wt %, lowest in drab paleosols) Fe2O3 present suggesting a wide dispersal within the profiles. Iron within PT1 paleosols is, therefore, likely in the form of ankerite, pyrite, goethite, siderite, or jarosite. While jarosite has not been identified, the formation of pyrite in a soil that was likely periodically exposed implies that the oxidation of pyrite to jarosite could occur (PiPojul and Buurman, 1994). 200

It is also possible that if the oxidation of pyrite was gradual it would oxidize to goethite or, if given enough time, jarosite would convert to goethite (Buurman, 1980; PiPojul and

Buurman, 1994).

Ichnofossil assemblages of PT1 paleosols also suggest a seasonal environment by indicating well-drained to poorly drained soil conditions: 1) yellow rhizohaloes indicate a soil horizon that retains moisture in a seasonally dry environment with long wet periods

(Kraus and Hasiotis, 2006); 2) green rhizohaloes, green mottled burrows, and organic root preservation indicate a poorly drained soil with little ferric iron (Kraus and Hasiotis,

2006); and 3) loosely meniscate and red-rimmed burrows indicate subsurface locomotion and construction of open burrows respectively, likely produced by soil arthropods in a moderately to well-drained soil (Smith and Hasiotis, 2008; Smith et al., 2008c).

Calculation of the mean annual precipitation (MAP) using the CIA-K formula based on bulk geochemical analyses (Sheldon et al., 2002) yields values of 143–169 mm/yr that, based on other macro- and micro-morphological features, would have been seasonally distributed. While the purple to reddish black paleosols that characterize the

Uniontown Mudstone exhibit abundant evidence of surface water gley processes, the upper, drab colored profiles contain much less. While maintaining very similar geochemical ratios, upper level PT1 paleosols show a decrease in ankerite and Fe2O3 as well as an increase in smectite, calcite, and sodium relative to lower level PT1 paleosols.

Upper level PT1 paleosols do, however, show a noticeable increase in pyrite and dendritic manganese growths. Upper level PT1 paleosols have concentrations of iron and manganese oxides in small fractures, cracks, around and on carbonate nodules, and in 201 lighter colored channels, rather than widespread distribution observed in lower level PT1 paleosols. Where the pyrite and manganese oxides occur they overprint other pedogenic features and where they co-occur the pyrite crystals overprint the manganese dendrites.

Manganese dendrites are commonly described as forming in palustrine carbonates after subaerial exposure and remobilization of manganese upon re-wetting (La Force et al.,

2002; Khalaf and Gaber, 2008; AlShuaibi and Khalaf, 2011). This can be due to seasonal exposure and involves the process of calcretization which is supported by the increase in calcium up section (La Force et al., 2002; Khalaf and Gaber, 2008). The manganese is mobilized during initial submergence and then crystallizes in cracks during exposure.

When the system is re-submerged during the wet season, pyrite crystallization is possible.

It is likely that this cycle of wetting and drying continually reduced and removed iron from the upper profiles of PT1 paleosols. Subaerial exposure of laterally associated limestone beds and subsequent pedogenesis explains the presence of large (4.5–10 cm) limestone clasts from 4.4 and 5.2 m upwards in Sections 1 and 2, respectively. PT1 paleosols are, therefore, interpreted as forming in a relatively dry fen to palustrine environment up section. The abundant evidence of surface water gley, the high amount of smectite, and the presence of seasonal indicators suggest that gleization was due to impeded drainage rather than ground water gley for lower portions of PT1 paleosols.

Highly calcareous, organic-rich, pyrite-forming fens have previously been reported and the preservation of calcareous fossils is distinctive of neutral to alkaline fen and carr environments over marsh and swamp environments (Chagué-Goff et al., 1996; Retallack,

2001) 202

The marlstone capping PT1 paleosols is interpreted as palustrine carbonate-filled channels or marshes (Alonso-Zarza and Wright, 2010). Rounded to angular clasts of limestone, fine-grained carbonates, desiccation cracks, ostracode fragments, charophytes, cyanobacteria, gastropods, erosional contacts, and <2 m thick deposits are common constituents of palustrine channel and marsh deposits and represent a progressive rise of the water table (Alonso-Zarza and Wright, 2010). The additional presence of shark

(xenacanth) and other fish teeth suggests that the environment may have reached greater depths than the minimum low water level of less than 2 m (Alonso-Zarza and Wright,

2010). Charophytes can be found in fresh to brackish but not saline water (Soulié-

Märsche, 2008) while microconchids suggest brackish water conditions (Schultze, 2009) with the invasion of fresh to brackish water habitats by microconchids well established by the Carboniferous (Zatoń et al., 2012). Xenacanth sharks have been described from a range of environments and were likely euryhaline (Schultze, 2009). The brackish to freshwater fauna present in the marlstone suggest the possible influence of marine conditions. The origin of black pebbles similar to those present in marlstones capping

PT1 paleosols have been attributed to the presence of organic matter within the pebble derived from decayed algae or burnt terrestrial plants as well as the presence of iron sulfides (Strasser, 1984; Shinn and Lidz, 1988). Although the black pebbles are usually dispersed throughout the marlstone, one marlstone bed is particularly dark and may represent a source for some of the black pebbles.

203

3.8.1.2 Waynesburg Limestone and Little Waynesburg Coal

The Waynesburg Limestone is an approximately 15 cm thick, light to dark gray, bedded wackestone (ostracodal algal biomicrite) that lies directly on top of an intraclastic marlstone (Fig. 3.20) (Appendix 6). The wackestone contains abundant pyrite crystals commonly concentrated in layers as well as downward tapering sparry calcite features limited to layers with lesser amounts of pyrite. Fossils include shark and fish teeth (Fig.

3.21F), algae (Fig. 3.21E), charophytes, microconchids, and abundant ostracodes.

Description: Immediately above the Waynesburg Limestone is a 4 cm thick coal, the

Little Waynesburg Coal. Although few identifiable plant impressions in the coal were found, abundant log impressions (Fig. 3.17B), microconchids, fish scales, and ostracodes are present on top of the underlying limestone. Unlike occurrences in the limestone and marlstone below, the coal contains framboids of pyrite approximately 1 cm in diameter.

Some log impressions contained charcoal in addition to coal. In Section 2, a large float block of the Waynesburg Limestone contained a highly organic layer with abundant conchostracan fossils 2 cm above the upper surface of the wackestone; but no such layer was found in situ.

In contrast to the marlstone below it, the Waynesburg Limestone contains little intraclastic material and is more consistent in thickness. In addition, pyrite is concentrated in layers instead of being dispersed or within cracks and other features conducive to fluid flow. This wackestone is interpreted as the deposit of a shallow, possibly brackish, palustrine environment. 204

Interpretation: The Little Waynesburg Coal is classified as a Histosol (Mack et al.,

1993; Soil Survey Staff, 1996). The vegetation of the Little Waynesburg Coal was likely rooted in the palustrine deposits directly below the coal. The charcoal in the upper layers of the Waynesburg Limestone supports the hypothesis that the climate was seasonally dry

(Retallack, 2001). The Florida Everglades have been proposed as a modern analogue for palustrine deposits (Platt and Wright, 1992). Coals above palustrine limestone as well as charcoal forming from forest fires are common in the Everglades (Platt and Wright, 1992;

Brown and Cohen, 1995). Close relationships between calcrete and coal in other late

Carboniferous palustrine environments in Canada have been attributed to changes in climate and sea-level (Tandon and Gibling, 1994). The changes seen from the lower marlstone to the Little Waynesburg Coal illustrate a transition from semi-arid (~80 days/yr submergence) to sub-humid (~300 days/yr submergence) palustrine deposition

(Platt and Wright, 1992). The presence of brackish water fauna in the palustrine deposits as well as the deposition of organic rich shale above the Little Waynesburg Coal suggests that both changes in sea-level and climate impacted the deposition of the Little

Waynesburg Coal and overlying sediments. These deposits are interpreted as forming in a very low gradient, seasonally dry environment that may reflect a coastal margin palustrine setting.

3.8.2 Monongahela and Dunkard Group Paleosols

3.8.2.1 Pedotype 2

Description: Pedotype 2 (PT2) paleosols (Fig. 3.22) (n=14) (Appendix 6) occur in both Monongahela (MPT2) and Dunkard (DPT2) group deposits below micaceous 205 sandstone, thin (<7 cm) lime mudstone, and other paleosols. Single PT2 paleosols are

0.2–0.9 m thick, but these rarely represent complete profiles. PT2 paleosols are dominantly grayish green (10G 4/2) to grayish blue green (5BG 5/2) with a weakly calcareous matrix and abundant, small, calcareous nodules, burrows, or rhizoliths. DPT2 paleosols in Section 1 (P#2–8), 2 (P#2–10), and 3 (P#3–10), transition to a darker color up profile that is primarily dusky brown (5YR 2/2). Slickensides are present in some PT2 profiles, but more commonly relict bedding, platy peds, and small clay skins are evident.

The ichnofossil assemblage of PT2 paleosols is dominated by calcareous rhizotubules, homogeneous and heterogeneous fill vertical to horizontal burrows (Figs. 3.10E–F,

3.11A–G, 3.12A–C, E–F, 3.13H–I, 3.22G), with lesser mottled burrows (Fig. 3.9E), rhizoconcretions (Fig. 3.8F), and rhizohaloes (Fig. 3.4G). Rhizoliths and carbonaceous root fossils are most commonly found at depths from 20–40 cm from the top of identifiable horizons (Fig. 3.22C). They are usually horizontally oriented and range from

1.1–3.0 cm long and 0.16–2.0 mm wide where exposed. DPT2 paleosols tend to have more vertically oriented roots preserved as rhizohaloes or carbonaceous cores than MPT2 paleosols. Burrows are very common in PT2 paleosols and are widely distributed throughout the profile. A small coprolite is also present in a MPT2 paleosol (S1: P#25)

(Fig. 3.14D).

PT2 paleosols more commonly contain compressed plant fossils than other pedotypes. MPT2 paleosols contain compression fossils of Lepidophylloides (Fig.

3.16G), neuropterids, pecopterids, with lesser Danaeites emersonii (?) (Fig. 3.16H), 206

207

Cordaites (Fig. 3.16B), and Annularia. The most abundant plant fossils found in DPT2 paleosols are macroneuropterids (Fig. 3.16A, Fig. 3.15D–F), pecopterids (Fig. 3.16D, E), and cordaitians (Fig. 3.15A, B), but the presence of the rarer Autunia conferta (Fig.

3.17A) is notable as it is the earliest occurrence of this plant in the Dunkard Group.

Several specimens of Macroneuropteris (Fig. 3.15D–F) and Cordaites (Fig. 3.15A, B)

show evidence of damage to their external morphology. Other body fossils in PT2

paleosols include a small bone found in the uppermost portions of the Gilboy Sandstone

(Section 2, #23) (Fig. 3.18I) and gastropods (Section 2, #22) (Fig. 3.18A).

Samples for thin section analysis were taken from two of the three PT2 paleosols

(Fig. 3.22). The micromomorphology of PT2 paleosols is characterized by a plasmic

microfabric that is inundulic to argillic in lower portions of the profile (Fig. 3.22B, C, F,

G) to insepic or mosepic and rarely omnisepic higher in the profile (Fig. 3.22A, E). Soil microfabrics increase in clay-size grain distribution up section from granular to porphyroskelic (Fig. 3.22E-G). Identifiable grains are mostly micas, quartz, plagioclase, 208 and some calcite. Opaques are primarily organic fragments including carbonaceous roots and rhizoids but manganese dendrites originating from burrows, rhizotubules, and cracks are also present (Fig. 3.22G). The majority of rhizotubules and carbonaceous roots are horizontally oriented, but some vertically oriented carbonaceous roots and calcareous rhizoliths are present in DPT2 paleosols. MPT2 and DPT2 paleosols primarily differ in the amount of iron stain and illuviated clay features. DPT2 paleosols may contain large amounts red-brown, dark gray, or dark yellow stain and networks of thick, stained, illuviated clay (Fig. 3.22B, C).

One additional thin section from a thin (6 cm) grayish green lime mudstone in

Section 2 at 11.3 m revealed a composition that was primarily micritic with two geopetal calcite spar-filled gastropods, numerous rhizotubules, and several occurrences of birefringent clays that have gradual contacts with the surrounding lime mudstone (Fig.

3.6D). Many instances of mosepic birefringent clays are associated with elongate, downward tapering calcite spar. When not found in a layer or associated with calcite spar, the clay fabric is undulic.

Six samples of both MPT2 and DPT2 paleosols were taken from eight paleosol profiles in Section 1 for bulk geochemical analysis (Table 1) (Fig. 3.22). Four samples of

MPT2 paleosols and two samples of DPT2 paleosols were taken from five different paleosol profiles for clay mineralogy analysis (Table 2). Potassium, calcium, and magnesium oxides as well as the levels of base loss, hydrolysis, and calcification are relatively low compared to the other pedotypes and vary little among MPT2 paleosols, although calcification does show a general upward increase in several profiles (Table 1). 209

Salinization and sodium oxide concentrations tend to increase down profile from sample

23–25. The CIA-K values of MPT2 paleosols range from 74.7–93.1% and are highest from samples 25–27. The clay size fraction of MPT2 paleosols are primarily composed of illite and mica, kaolinite, and chlorite. Only sample 28 shows an increase in the amount of chlorite present at the expense of kaolinite. Plagioclase, potassium feldspar, and calcite are lesser constituents and generally increase down profile, but calcite is not present in sample 30. DPT2 paleosols have a higher potassium concentration and less sodium and salinization levels than MPT2 paleosols. Sodium is concentrated toward the base of the

DPT2 profiles. DPT2 paleosols have similar magnesium levels to MPT2 paleosols.

Calcification and calcium oxide concentrations in DPT2 paleosols show similar values to

MPT2 paleosols, but have elevated concentrations lower in the profiles (Table 1). DPT2 paleosols also have slightly higher values for hydrolysis and base loss than MPT2 paleosols. The clay sized fraction of DPT2 paleosols are also mostly composed of illite and mica and kaolinite (Table 2). Sample #5 of a DPT2 paleosol, however, had a much lower composition of ordered mixed-layer illite-smectite and kaolinite, with a higher amount of chlorite than the sample taken in a lower profile. Quartz, potassium feldspar, and plagioclase also occur in higher amounts in the sample taken at the top of the paleosols. CIA-K values of DPT2 paleosols range from 75.3–96.1%.

Interpretation: PT2 paleosols represent the combined profiles of up to five different paleosols (Appendix 6) leading to the formation of compound to composite paleosol profiles indicating non-steady rates of sedimentation that are often exceeded by the rate of pedogenesis (Kraus, 1999). The A horizons are rarely present in PT2 paleosols, 210

particularly in MPT2 profiles. The B horizons are recognizable by the presence of blocky

peds (Fig. 22E), carbonate nodules, and increased illuviated clay content indicated by the

occurrence of abundant clay skins. Distinguishing the contact from one PT2 paleosol

from the next often depends on the presence of plant fossils, relict bedding, or the

occurrence of platy peds. These features most often occur together implying that pulses of sedimentation were responsible for the burial and preservation of plant compression fossils. MPT2 paleosols more commonly preserve recognizable C horizons than DPT2 paleosols likely indicating that sedimentation rates in MPT2 paleosols were greater than pedogenesis (e.g. Kraus, 1999).

Paleosols of the MPT2 are classified as gleyed argillic Protosols (Mack et al., 1993) and interpreted as gleyed Inceptisols (Soil Survey Staff, 1996). DPT2 paleosols are classified as argillic Protosols (Mack et al., 1993) and interpreted as Inceptisols (Soil

Survey Staff, 1996). The preservation of plant fossils and occurrence of relict bedding to platy peds is indicative of poorly developed soil horizons that are characteristic of

Protosols and Inceptisols (Mack et al., 1993; Retallack, 2001). Although the movement of clay down the profiles of PT2 paleosols is evident (Fig. 3.22F), clay cutans are not the defining feature of PT2 paleosols and can occur in poorly developed soils (Retallack,

2001). The dark green color, preservation of horizontally oriented organic roots, and the occurrence of a small lime mudstone bed suggests that MPT2 paleosols formed under waterlogged and reducing conditions (Retallack, 2001). The small amount of red mottling, the red color of some plant compression fossils, the abundant argillans, and spar-filled rhizotubules in MPT2 paleosols, however, suggests that the soil profile was 211 also periodically well drained and oxidizing (Retallack, 2001). The lack of oxidized paleosols in these profiles, therefore, suggests that the majority of the gley is from a rising and falling water table and justifies the gleyed modifier.

Calcareous nodules in PT2 paleosols are generally rare, but are interpreted to be pedogenic in origin. In addition to being formed of finely crystalline calcite and incorporating crystal grains that surround them, the nodules contain two layers of dark clay with finely crystalline calcite in between suggesting more than one period of formation (Fig. 3.22D). The presence of calcareous nodules, rhizotubules, and illuviated clay features suggests that that the soil was periodically well drained and that precipitation was seasonal (Retallack, 2001).

The ichnofossil assemblage of MPT2 paleosols supports the interpretation of a seasonal climate of formation despite strong gley overprints. Lined burrows are typically interpreted to be the dwelling and locomotion traces of animals that permanently reside in the soil (Hasiotis, 2002). The presence of lined burrows in MPT2 horizons that are relatively fine-grained suggests that the soil was at least periodically stable and oxygen rich allowing for permanent occupation. The preservation of the organic lining of some burrows in MPT2 paleosols also suggests that gley processes were primary and may have occurred rapidly. Unlined burrows with fill that is larger grained than the surrounding matrix (Fig. 3.22G) in addition to a microfabric that grades upward to a porphyroskelic grain fabric and then returns to a primarily granular silt-sized matrix is strong evidence of periodically rapid sedimentation events. The ichnofossil assemblage of DPT2 paleosols suggests a moderately to well-drained soil in which deposition was less common and 212 reducing conditions were significantly less prolonged. Burrows consist primarily of actively filled traces of deposit feeders as well as gleyed burrows likely produced by surface detritivores. The lack of heterogeneous fill burrows suggests that when deposition did occur the surface was stable long enough to allow renewed pedogenesis to rework the new sediment.

Calculation of MAP from the bulk geochemical analyses shows that MPT2 and

DPT2 paleosols had similar ranges of precipitation: 983–1273 mm/yr and 1036–1333 mm/yr, respectively. Clay composition data suggest that MPT2 and lower DPT2 paleosols form under similar environments, but the higher chlorite composition in MPT2 paleosols suggest cooler and drier conditions (Sheldon and Tabor, 2009). The high percentage of illite and mica in PT2 paleosols more likely reflects the abundance of micas in the parent material than clay forming processes. Biotite and muscovite micas commonly occur as medium to coarse grains in most upper Monongahela and Dunkard group deposits. Geochemical data shows that base concentrations are higher in the upper horizons of poorly drained portions of DPT2 paleosols while base concentrations in

MPT2 paleosols are more uniform throughout the profiles but show some concentration of bases toward the bottoms of the profiles. This is a strong indication that some MPT2 paleosols are better drained than DPT2 paleosols (e.g. Schaetzl and Anderson, 2005) illustrating that secondary gley processes are likely to have occurred in MPT2 paleosols

(Retallack, 2001). The increased amount of sodium oxides higher in MPT2 profiles also suggests the rising and falling of the water table allowing the concentration of sodium to increase at the maximum water table height upon evaporation similar to gypsum 213 precipitation in backswamps of Mississippi (Aslan and Autin, 1998). Finally, the amount of iron-oxide (red) and iron-oxyhydroxide (yellow) stain and illuviated clay in DPT2 profiles indicate that iron was not completely removed, but instead concentrated in certain areas of the profile.

PT2 paleosols are interpreted to have formed on natural distal levee deposits. MPT2 paleosols formed in close proximity to the fluctuating water table and were poorly drained during longer periods of the year whereas DPT2 paleosols formed with a lower water table and were more often relatively well-drained.

3.8.3 Dunkard Group Paleosols

3.8.3.1 Pedotype 3

Description: Pedotype 3 (PT3) paleosols (Fig. 3.23) (n=4) (Appendix 6) occur below other PT3 paleosols or PT4 paleosols. Single profiles are 1.6–2.7 m thick and are commonly complete. PT3 paleosols are mudstones characterized by an upper surface that is 45–65 cm thick, dark reddish brown (10R 3/4) to dusky brown (5YR 2/2) with abundant yellow to green mottles and rhizohaloes capped by a thin (2–5 cm) layer of loosely banded organic-rich claystone (Fig. 3.23A, B). PT3 paleosols generally contain abundant, dispersed carbonate nodules in a weakly calcareous matrix. Ten centimeters below the base of the upper, organic-rich layer, PT3 paleosols are typically highly calcareous with abundant yellow mottles and rhizohaloes. The lower portions of PT3 paleosols are typically 1.0–1.9 m thick, grayish green (10G 4/2) mudstone with abundant calcareous nodules. The color change between upper and lower horizons is typically 214 gradual and occurs over 20–50 cm. Large slickensides may be present in the upper red- brown portions of the profile.

The ichnofossil assemblage of PT3 paleosols is dominated by yellow and green rhizohaloes with lesser rhizotubules, red rhizohaloes, and ferruginous rhizoconcretions.

Yellow and green rhizohaloes are most common in the red to brown portions of PT3 paleosols and are less than 1.6 cm in diameter and 5 cm long. Red rhizohaloes are most common in association with diffuse red mottles in the green portions of PT3 paleosols and are less than 1 mm in diameter and 1.5 cm long. Rhizotubules are present throughout

PT3 profiles and were not seen in excess of 2.5 mm in diameter. Carbonized roots are preserved in some calcareous nodules in PT3 paleosols (Fig. 3.23C). Burrows in the red to brown upper portions of PT3 paleosols consist of horizontally to vertically oriented, sinuous to straight burrows that may lead to chambers or branch out in a Y-shape (Figs.

3.13B–F, 3.23D) as well as green mottled, sinuous to O-shaped burrows (Fig. 3.9F, G).

Most burrows in PT3 paleosols occur in conjunction with abundant organic matter and are filled with coarsely crystalline calcite spar. A few clay-lined burrows and larger- grained heterogeneous filled burrows (Fig. 3.23G) are present in grayish green PT3 paleosols.

The micromorphology of PT3 paleosols is characterized by a plasmic microfabric that is argillasepic to insepic but may also be crystic or calciasepic in some locations.

Grain microfabrics are typically porphyroskelic (Fig. 3.23D) but may be agglomeroplasmic as well. Insepic and agglomeroplasmic fabrics are more common 215

216

Figure 3.23 Representative stratigraphic column of PT3 paleosols in Section 1. A) Finely laminated organics and claystone from (S3, P#16-O). B) Thin section of finely laminated organics and claystone (S3, P#17-A) (cross-polarized light). C) Thin section of a carbonate nodule (S1, P#18-Bg) (normal light). The left side of the photograph is gleyed and the right side is primarily oxidized. Arrow points to a preserved rhizolith within the nodule. D) Thin section of isotic, calciasepic plasmic microfabrics and porphyroskelic grain fabric containing a calcite spar-filled burrow (black arrow) that avoids a grain that has shifted in the subsurface (white arrow) (S1, P#20-Bki) (cross-polarized light). E) Thin section of iron nodules accumulating around and replacing a dark brown fragment (S3, P#17-Bgkss) (cross-polarized light). F) Thin section showing calcareous rhizolith preservation in a carbonate nodule (S1, P#21-Btg) (normal light). G) Thin section of the side of a coarser-grain heterogeneous-fill burrow (S1, P#21-BCgn) (cross-polarized light). The matrix is to the bottom left and the inside of the burrow is to the upper right.

lower in PT3 profiles whereas argillic and porphyroskelic fabrics are more common higher in the profile. Grains typically consist of quartz, calcite and iron nodules, and organics. Iron stain is prevalent in thin sections of PT3 paleosols as red patches and the red and brown coloration in the upper portions. Alternating layers of organics and oriented clays are common in thin sections taken from the top of PT3 paleosols (Fig.

3.23B). Some nodules in PT3 paleosols are heavily coated in dark clay and have a more coarsely crystalline structure than other nodules, while others are more typical and may contain preserved branching, carbonized roots (Fig. 3.23C).

Five samples of PT3 paleosols were taken from two profiles in Section 1 for bulk geochemical analysis (Table 1). Two additional samples were taken near the tops of PT3 profiles from Section 1 and 3 for clay mineral analysis (Table 2). Sodium oxide and salinization values are relatively high and generally increase down PT3 profiles. In contrast, potassium and magnesium leaching, as well as hydrolysis, generally increase up profile. Base loss, calcification, and calcium oxide leaching are generally low, but base 217

loss is far lower in association with a large increase in calcium oxide content and calcification in sample #20. Magnesium oxide concentration is also highest in sample

#20. The CIA-K values range from 24.7–92.2%. The upper 20 cm of PT3 paleosols show substantial differences in clay mineralogy across horizons. The clay mineralogy within the top 10 cm of a PT3 profile in Section 1 (Paleosol #18, Sample #17) is dominated by ordered mixed-layer illite/smectite with 30% smectite, and illite and mica constituting almost 80% of the clay size fraction present. Quartz, chlorite, kaolinite, and plagioclase

make up the remainder of the composition in descending order of abundance. The upper

10–20 cm of PT3 paleosols in Section 3 (Paleosol #16, Sample #18), however, has just

under half the amount of ordered mixed-layer illite/smectite and 9% less illite and mica.

Hematite and kaolinite constitute approximately 30% of the remainder with calcite, quartz, and chlorite making up the remainder in descending order of abundance (Table 2).

Interpretation: PT3 paleosols represent cumulative to composite profiles (Appendix

6) in which pedogenesis is greater than the rate of sedimentation (Kraus, 1999). Under

conditions of steady but slow sedimentation, new material is deposited in thin layers and

immediately incorporated into the paleosol profile (Kraus, 1999). In some portions of

PT3 paleosols sudden decreases in the rate of sedimentation are evident by the presence

of multiple Bk horizons. The O to A horizons in PT3 paleosols are commonly present as

thinly bedded, moderately bioturbated, organic-rich claystone, and are typically calcite-

poor. High levels of organic preservation and calcite spar burrow fills are present in the

Bki horizon of a PT3 paleosol in Section 1 (Paleosol #20) suggesting either rapid

deposition or anoxic conditions (e.g. McCabe and Parrish, 1992). The Bki horizon is a 218 calcareous red mudstone with over seven weight percent Fe2O3 decreasing the likeliness of anoxic conditions leading to the preservation of organics in the B horizons. Other B horizons in PT3 paleosols typically contain green and yellow mottling or rhizohaloes with large slickensides in a red mudstone matrix or yellow and red mottling or rhizohaloes in a drab green mudstone matrix. The lowest B horizons in PT3 paleosols are typically a drab green color with abundant clay skins, calcareous nodules, or calcareous rhizotubules, although some have pervasive micro-scale iron nodules (Fig. 23E). C horizons of PT3 paleosols consist of sandstone, limestone, or the A or B horizons of other

PT3 paleosols.

Paleosols of PT3 are classified as gleyed vertic Calcisols (Mack et al., 1993) and interpreted as calcic Vertisols (Soil Survey Staff, 1996). The primary notable feature of

PT3 paleosols is the presence of abundant pedogenic calcite nodules commonly distributed in layers that is typical of Calcisols (Mack et al., 1993). The presence of red mottling and rhizohaloes within the upper portions of gleyed horizons, large to small slickensides, and calcite and iron nodules are indicative of seasonally distributed and fluctuating soil moisture conditions required of the gleyed and vertic prefixes of soil classification according to Mack et al. (1993) as well as the Vertisol interpretation

(Retallack, 2001).

Calcareous features in PT3 paleosols show a mixed origin. Carbonate nodules are interpreted as being pedogenic in origin due to the finely crystalline structure, and the preservation of root traces within calcareous nodules (Fig. 3.23C, F). Rhizotubules present in PT3 paleosols typically have a finely crystalline sheath that would have formed 219 during the life of the plant and, therefore, during pedogenesis (Fig. 3.6B) (Klappa, 1980).

The majority of rhizotubules, however, are filled with coarsely crystalline calcite, typically an indicator of formation during burial or in groundwater (Retallack, 2001). The presence of clay lined burrows, coarsely crystalline and finely crystalline calcite, and iron/manganese dendrites in green paleosols suggest that PT3 paleosols experienced seasonal wetting (Retallack, 2001; La Force et al., 2002). The overall drab color of the lower portions of PT3 paleosols is likely due to fluctuations in the local water table due to changes in precipitation. Seasonal fluctuations of water table levels in recent aggradational alluvial flood plains have previously been shown to influence the distribution of calcite within a profile by promoting nodule formation within the range of high and low water table levels (Aslan and Autin, 1998). This water table influence on calcite distribution has the potential to also influence MAP estimates and is therefore important to consider when assessing climatic conditions in an alluvial system (Aslan and

Autin, 1998). The exceptional amount of organic material preserved in one Bki horizon in a PT3 paleosol in Section 1 (Paleosol #20) along with numerous open burrows and lesser amounts of calcite above and below the horizon suggest that the position of the water table had little impact on the development of the calcite in the Bki horizon. In addition, the increase in Fe2O3 up section in this particular profile suggests longer periods of higher temperatures and lower water activity (Schwertmann and Taylor, 1989).

Finally, evidence of multiple generations of calcite formation, the micrite produced in this horizon showing a displacive texture (Fig. 3.23D), and the low silica content of this 220 caliche horizon may be reflective of a replacement of quartz grains with calcite that is common in calcic horizons formed above the water table (Retallack, 2001).

Rhizolith formation in PT3 paleosols reflects a seasonally dry environment with a water table between 0.8 and 1.7 m deep (e.g. Retallack, 2001). Yellow and green rhizohaloes reflect goethite and reduced iron accumulations that represent formation in a seasonally dry and locally wet environment respectively (Kraus and Hasiotis, 2006). The relatively limited occurrence of green mottles and rhizohaloes to small areas suggests that they formed during short periods of anoxic conditions due to surface water gley (PiPujol and Buurman, 1994). Red rhizohaloes present in green paleosols indicate that locally dry or oxidizing conditions were present at least 1.2 m into some profiles (e.g. Kraus and

Hasiotis, 2006). Burrows present in PT3 paleosols portray an active soil ecosystem in organic-rich deposits during seasonally dry periods while the lower occurrence of bioturbation in some organic-rich claystone layers is an indicator of the sparse biotic activity while under anoxic or waterlogged conditions (Fig. 3.23A, B).

PT3 paleosols are interpreted as the deposits of seasonally dry backswamps that formed in and adjacent to a small alluvial channel. These swamps are characterized by the accumulation of little surface peat, drab color, and the presence of gley minerals common in poorly drained soils (Retallack, 2001). Subsidence below the water table in lowland regions where seasonally dry swamps form may cause them to be overprinted with permanently waterlogged soil characteristics (Retallack, 2001). Clay mineral analyses of the upper horizons of PT3 paleosols show a clear dominance of both smectite, and illite and mica. Micas are abundant in most deposits present in the study area and do 221

not likely reflect environmental conditions. High smectite suggests intermittently poorly-

drained conditions in a monsoonal to xeric climate (Sheldon and Tabor, 2009).

Calculation of MAP from bulk geochemical data shows that precipitation mostly varied

from 1000 to 1277 mm/yr. One estimate from a Bki horizon in Section 1(Paleosol #20,

Sample #20), however, was only 314 mm/yr. This low estimate may not be an accurate

assessment, however, since calculating MAP from bulk geochemical analyses of

paleosols with near-surface carbonate minerals using the CIA-K method typically yields significantly lower MAP estimates (Sheldon et al., 2002). The laterally related deposit in

Section 3 (P#17) contains abundant, small iron/manganese oxide nodules that can be seen replacing organics and calcite nodules (Figs. 3.8G, 3.23E). The formation of iron/manganese nodules in a soil is typically due to the alternation of reducing and oxidizing conditions (Retallack, 2001). The small iron/manganese concentrations co- occur with a crystic fabric, iron stain, common clay skins, and dendritic manganese oxide growths with much of the iron/manganese oxides forming in voids and cracks. This portion of the PT3 paleosol likely represents an area close to an abandoned alluvial channel that was periodically poorly drained. Calcareous spar, nodules, and iron/manganese oxides would form in cracks and voids during the dry season, while during the wet season reducing conditions would dominate allowing iron and manganese to remobilize within the soil.

3.8.3.2 Pedotype 4

Description: Pedotype 4 (PT4) paleosols (Fig. 3.24) (n=7) (Appendix 6) are highly variable mudstones and can be broadly placed into two sub-types based on macro- 222 morphologic features. The first occurrence of abundant carbonate nodules separates

PT4A and PT4B paleosols. Along with this first occurrence, there is a general decrease in the amount of yellow mottles and rhizohaloes and an increase in green mottles and rhizohaloes. PT4A (n=3) paleosols occur below PT6 paleosols that commonly contain plant fossils. PT4B (n=4) paleosols occur below PT4A paleosols, small (<7 cm), calcareous, climbing-rippled, lenticular sandstone, and PT5 paleosols.

Single PT4A paleosol profiles are 0.35–2.4 m thick and typically represent complete profiles. PT4A paleosols are mudstones characterized by a matrix color that varies from very dusky red purple (5RP 2/2) to moderate brown (5YR 4/4) but grayish brown (5YR

3/2) tends to be the dominant color. Green mottles and rhizohaloes are abundant in PT4A paleosols while yellow mottles and rhizohaloes are uncommon and occur more often in

Section 1. Dispersed to concentrated carbonate nodules and calcareous rhizoliths, as well as large-scale slickensides are abundant in most PT4A paleosols. The amount of carbonate nodules, concretions, and rhizotubules decrease up section in Sections 2 and 3, but remain present in most of Section 1. Distinguishing single horizons using macro- morphologic features in PT4A paleosols typically depends on subtle changes in the distribution and abundance of calcareous features and organics.

Single PT4B paleosol profiles are 0.4–1.3 m thick and typically do not represent complete profiles. PT4B paleosols are mudstones characterized by a matrix colors that vary from very dusky red purple (5RP 2/2) and dark reddish brown (10R 3/4) to a dusky yellow green (5GY 5/2) and pale green (10G 6/2). Yellow mottles and rhizohaloes are abundant in PT4B paleosols (Fig. 3.24B) while green mottles and rhizohaloes are less 223

common. Purely calcareous features are rare in PT4B paleosols but nodules and

pedotubules composed of iron, manganese, siderite, and calcite (Fig. 3.24F, G) are

common in horizons that are topped by green paleosols. In several locations, PT4B

paleosols are overlain by thin (<7 cm) or thick (1.2 m) green deposits with red mottles

that consist of either calcareous, climbing-rippled to lenticular, sparsely bioturbated sandstone (Fig. 3.24D) with desiccation cracks or poorly developed PT5 paleosols, respectively.

The ichnofossil assemblage of PT4 paleosols is largely dominated by different forms of rhizoliths. Green rhizohaloes and calcareous rhizotubules, <1–2 mm wide and 0.2–1.5 cm long are most common. PT4A paleosols also contain large calcareous rhizoconcretions that are up to 20 cm long and 6 cm wide (Fig. 3.7A) and subhorizontal, green mudstone-filled root casts that are 29 cm long and 6 cm wide where exposed (Fig.

3.5B). Some green rhizohaloes with yellow cores are present in some PT4A paleosols in

Section 1 but are not common. PT4B paleosols, however, are dominated by yellow cored rhizohaloes with thin green rims that are densely arranged and horizontally to subvertically oriented (Fig. 3.24B). Additionally, some PT4B paleosols contain horizontal to vertical, tubular rhizoconcretions that are up to 11 cm long and 1.5 cm in diameter, consisting of variable amounts of hematite, manganese oxide, goethite, and calcite (Figs. 3.8A–E, 3.24F). The rhizoconcretions occur in brown to reddish brown paleosols associated with up to 10 cm diameter, irregularly shaped concretions of similar composition (Fig. 3.24F, G). Some rhizoconcretions may be root petrifactions where 224

225

internal structure is preserved. Organic cores in rhizoliths are more commonly preserved

in PT4B paleosols than in PT4A paleosols. Burrows in PT4B paleosols primarily consist

of tightly meniscate, horizontally oriented, back-filled burrows associated with rhizoliths

and alternating layers of claystone and organics (Fig. 3.10B, C).

The micromorphology of PT4A paleosols is characterized by a plasmic microfabric

that is primarily inundulic and heavily darkened with iron oxides (Fig. 3.24A). Within the

matrix are abundant, irregular clasts of un-oriented clay and grains with a porphyroskelic

grain fabric (Fig. 3.24A). In contrast to the matrix, the clasts are light-colored but do have

some red iron-oxide stain. Identifiable grains consist of small quartz fragments, dispersed carbonate nodules, and organic fragments.

The micromorphology of PT4B paleosols is characterized by a plasmic microfabric

that is argillasepic and heavily darkened with iron oxides (Fig. 3.24E). Grains are almost

entirely clay-sized with identifiable grains consisting of some small quartz fragments and

occasional coarsely crystalline, calcite spar. The presence of iron oxides is evident in the

vibrant red coloration of the clay material as well as in dark isotic concentrations (Fig. 226

3.24E). Alternations of clay and organics similar to PT3 paleosols are present in some

PT4B paleosols (Fig. 3.24C).

One sample of a PT4A (Sample #13) and one sample of a PT4B (Sample #15) paleosol was taken for clay mineralogical analysis. The clay fraction of the PT4A paleosol primarily consists of illite and mica, hematite, ordered mixed-layer

illite/smectite with 30% smectite, and kaolinite (~75%) in descending order of abundance. The remainder of the clay fraction consists of quartz, calcite, chlorite, and Fe- dolomite in descending order of abundance (Table 2). The clay fraction of the PT4B paleosol primarily consists of illite and mica, kaolinite, and approximately equal values of ordered mixed-layer illite and smectite with 20% smectite, chlorite, quartz, and hematite (~95%) in descending order of abundance. The remaining clay fraction consists of plagioclase and potassium feldspar in descending order of abundance (Table 2).

Interpretation: Together PT4A and PT4B paleosols represent a transition from

compound to composite paleosols (Appendix 6) in which sedimentation is non-steady

and the rate of sedimentation is sometimes greater than pedogenesis (PT4B) and sometimes less than the rate of pedogenesis (PT4A) (e.g. Kraus, 1999). The presence of small beds of calcareous sandstone containing climbing ripples as well as poorly developed paleosols (PT5) in the middle of several PT4B profiles is evidence of rapid depositional events, the products of which were not fully integrated into the paleosol profile by pedogenesis. In other PT4A and PT4B profiles, however, overprinting of previous paleosols by subsequent pedogenesis is evident by the presence of multiple Bss horizons. The A horizon in PT4 paleosols is only evident by the presence of plant fossils 227

or organics and are uncommon. The B horizons of PT4A paleosols are commonly

calcareous, slickensided, hematite-rich, and have abundant green mottles and rhizohaloes.

The B horizons in PT4B paleosols are also distinguished by the presence of large-scale

slickensides, yellow mottles and rhizohaloes, and iron-rich, tubular rhizoconcretions or

irregular concretions. The C horizons in PT4A paleosols are not distinguishable. The C

horizons of PT4B paleosols are distinguished by the lack of abundant pedogenic features

as well as relict bedding or platy peds.

Paleosols of PT4A are classified and interpreted as calcic Vertisols and paleosols of

PT4B are classified and interpreted as gleyed Vertisols or ferric concretionary Vertisols

(Mack et al., 1993; Soil Survey Staff, 1996). Large-scale slickensides, carbonate nodules

and rhizotubules are features that distinguish PT4A paleosols as calcic Vertisols (Mack et

al., 1993; Retallack, 2001). Additionally, the lateral variation seen in PT4A paleosols

from one section to the next are interpreted as the results of differences in micro-relief related to gilgai micro-topography (e.g. Knight, 1980; Driese et al., 2000). Shrink-swell features common in Vertisols that are present in PT4B paleosols are primarily large-scale slickensides. Other features indicative of shrink-swell processes and alternating reducing and oxidizing conditions are prismatic peds and large concretions that consist of alternations of goethite and hematite (Retallack, 2001). The combination of gleyed paleosols and slickensides suggests that PT4B Vertisols were under reducing conditions for some time (Buol et al., 2003). While the features of both pedotypes suggest seasonally distributed precipitation, PT4A paleosols were likely drier for longer periods than PT4B paleosols. 228

Calcareous features in PT4A paleosols are interpreted as pedogenic in origin due to their finely crystalline composition and co-occurrence with other seasonal indicators such as large slickensides (Retallack, 2001). The rarity and crystalline nature of calcareous features in PT4B paleosols suggest a secondary origin (Retallack, 2001). Calcareous, climbing rippled to lenticular sandstone units in PT4B paleosols are interpreted as crevasse splay deposits due to the presence of exposure features such as desiccation cracks and red mottles.

Green rhizohalo and calcareous rhizolith formation in PT4A paleosols suggests poorly drained or locally wet conditions and seasonally dry, well drained conditions, respectively (Retallack, 2001; Kraus and Hasiotis, 2006). The co-occurrence of high amounts of hematite, gleyed surface horizons with red rhizohaloes, and abundant slickensides suggests that the gley was caused by periodic surface water ponding and decomposition of organic material, likely in low spots of gilgai microrelief (PiPujol and

Buurman, 1994; Kraus and Hasiotis, 2006). Portions of PT4A paleosols where calcareous features are rare were likely formed in micro-lows where moisture levels were too high for calcite to precipitate. Micro-lows should have a higher preservation potential than micro-highs due to their lower topography and may explain why thicker Bk horizons are not present (Driese et al., 2000). Another possible explanation for the lack of calcareous features is a shift toward more humid conditions (Retallack, 2001). PT4A paleosols are, therefore, interpreted to have formed under seasonally hot and dry to hot and humid conditions in a gilgai topographic landscape with relatively well-drained to imperfectly- drained soils. 229

The yellow mottles and rhizohaloes in PT4 paleosols suggest that where they occur,

the soil was wet for longer periods in the presence of organic matter in moderately to

imperfectly drained soils (Kraus and Hasiotis, 2006). Tracemakers of the tightly

meniscate, horizontally oriented, back-filled burrows in PT4B paleosols would have

required moderately to well-drained soils with soil moisture ranging from 5–45% (Smith

and Hasiotis, 2008; Smith et al., 2008c). The general absence of calcareous nodules in

PT4B paleosols supports the conclusion that PT4B paleosols were imperfectly drained

and remained wet for longer periods of time than PT4A paleosols, but still experienced

dry periods.

Iron-rich roots, rhizoliths, and large concretions in PT4B paleosols are interpreted as

forming in marsh environments, possibly with brackish to salt-water influences. Similar

iron-rich rhizoliths and large concretions have been reported from modern salt marsh

(Pye et al., 1990; Sundby et al., 1998), modern lacustrine (Stieglitz and Van Horn, 1982),

lower Eocene alluvial (Bown and Kraus, 1981), and Permo-Pennsylvanian intermingled

fluvial and marine deposits (Tabor, 2007). Only in modern salt marshes, however, have

large, irregular concretions been reported in association with roots with a similar

preservational style to those in PT4B paleosols. Additionally, iron-rich rhizoconcretions

and irregular concretions in modern salt-water marshes are most commonly distributed in a 3–20 cm thick root zone similar to the 7–30 cm thick distributions observed in PT4B paleosols (Pye et al., 1990; Sundby et al., 1998, 2003). Pye et al. (1990) also found that iron-rich concretions nucleated around metal, wood, or had no specific nucleus. The irregular concretions likely began by forming as rhizoconcretions or by nucleating around 230

other objects. Oxidation of iron in the rhizosphere, changes in nutrient availability, pore-

water chemistry, and seasonal bacterial activity are likely responsible for the initiation

and alternating composition of the concentric layers (Pye et al., 1990, Sundby et al.,

1998, 2003).

The irregular to rounded aggregates of un-oriented clay and grains in thin sections of

PT4A paleosols are interpreted as gleyed pedogenic mud aggregates, or papules

(McCarthy and Plint, 1998). These aggregates would have originated as portions of a

gleyed paleosol and were transported to their current location. The fragile nature of such

aggregates suggests that transportation occurred by low energy means and over a short

distance (Brewer, 1976). The small amounts of iron oxides within some aggregates were

likely produced in situ after transport.

Clay mineralogical analyses provide further support for the formation of PT4

paleosols under different climate regimes. The dominance of illite and mica, hematite,

and smectite with lesser kaolinite in PT4A paleosols is suggestive of hot and dry

conditions for long periods with intermittently poorly drained conditions associated with

monsoonal or xeric climates (PiPujol and Buurman, 1994; Sheldon and Tabor, 2009).

PT4A paleosols are interpreted as forming in distal floodplains that displayed gilgai

micro-topography. The dominance of illite and mica, and kaolinite with lesser chlorite,

smectite, and hematite in PT4B paleosols is suggestive of a mix of well-drained systems under hot and humid conditions with periods of drier conditions (PiPujol and Buurman,

1994; Sheldon and Tabor, 2009). 231

3.8.3.3 Pedotype 5

Pedotype 5 (PT5) (Fig. 3.25) (Appendix 6) consists of a single paleosol profile in

Section 1 that occurs below a thin (11 cm) sandstone. The PT5 paleosol occurs between two PT4B paleosol profiles. The profile is approximately 1 m thick and represents a complete profile. The PT5 paleosol is a silty mudstone characterized by a dusky blue green (5BG 3/2) color with platy peds, large root casts filled with up to very fine sand- sized grains, and flattened, irregular goethite (?) nodules that are moderate yellowish

brown (10YR 5/4). Both root casts and the irregular nodules are calcareous features in an

otherwise non-calcareous silty mudstone.

The ichnofossils of the PT5 paleosol consists only of large calcareous root casts that

are vertically (Figs. 3.5A, 3.25A) to horizontally (Fig. 3.5E) oriented and a red mudstone-

filled trunk cast (Fig. 3.5E). The root casts penetrate up to 65 cm below the top of the

profile and are approximately 2 cm in diameter.

The micromorphology of the PT5 paleosol is characterized by a plasmic microfabric

that is argillasepic (Fig. 3.25C) to insepic (Fig. 3.25D). Grain microfabrics are typically

porphyroskelic and intertextic fabrics are rare. Grains are dominantly clay-sized and

recognizable grains consist of quartz, calcite, and chlorite. Opaques are dispersed as

small specs throughout the matrix.

Two samples of the PT5 paleosol were taken for bulk geochemical analysis and one

sample was taken for clay mineral analysis (Table1, 2, Fig. 3.25). Potassium, magnesium,

and calcium oxides as well as base loss and hydrolysis increase down profile.

Calcification is generally low and uniform. Salinization and sodium oxide concentration 232

is generally low but increases up section. The CIA-K of the PT5 paleosol ranges from

88.3–91.5% with the highest value at the bottom of the profile. The clay mineralogy of 233

the PT5 paleosol is dominated by illite and mica, and kaolinite, with lesser ordered

mixed-layer illite/smectite with 30% smectite and chlorite in descending order of

abundance (83%). The remaining clay fraction consists of quartz, dolomite, plagioclase,

and potassium feldspar.

Interpretation: The PT5 paleosol in conjunction with PT4B paleosols represent

compound paleosols (Appendix 6) in which sedimentation is generally greater than the

rate of pedogenesis (Kraus, 1999). Sedimentation would have been non-steady and likely

occurred in pulses of silt and sand. The A horizon in the PT5 paleosol is sandy and likely

reflects the burial of the horizon with a particularly thick episode of sedimentation. The

presence of horizontally oriented roots and a stump cast indicate that the A horizon was

buried by a single depositional event. The B horizon is recognized by the presence of

vertical calcareous-sand root casts and abundant, horizontal, moderate yellowish brown nodules. The C horizon is characterized by red-mottled sandy siltstone and likely

represents the burial and overprinting of the underlying PT4B paleosol.

The PT5 paleosol is classified as a gleyed Protosol (Mack et al., 1993) and is interpreted as a gleyed Inceptisol (Soil Survey Staff, 1996). The platy peds, argillasepic to insepic plasmic microfabric, and lack of distinct features of the parent material suggests that the PT5 paleosol is better developed than Entisols and fits the interpretation as an Inceptisol (Retallack, 2001).

Although their chemical composition was not determined, based on hand samples and petrographic analysis the common, flattened, yellowish brown nodules are composed of calcium carbonate, abundant, small flecks of iron or manganese oxides, and possibly 234 goethite. The matrix of the PT5 paleosol is low in calcite but root casts and nodules contain material that reacts with dilute HCl suggesting the carbonate may be secondary or related to root activity. The presence of goethite suggests the presence of organic material in poorly drained conditions (Kraus and Hasiotis, 2006). The green color of the PT5 paleosol and the low concentration of hematite support its formation in poorly drained, anoxic conditions. The presence of root traces up to 65 cm below the surface and lack of an oxidized surface horizon suggests that the level of the water table may have fluctuated seasonally or that root preservation and goethite formation occurred after burial (PiPujol and Buurman, 1994; Retallack, 2001; Kraus and Hasiotis, 2006). Petrographic analysis of the stump cast shows the presence of abundant calcareous nodules, organic matter, calcite cement, and occasional shell fragments (Fig. 3.25B). The oxidized state of the material suggests that it was subaerially exposed for some period prior to burial. The surrounding area, however, showed no evidence of extensive soil formation prior to deposition of the overlying sandstone suggesting that exposure was relatively short.

Calculation of MAP from bulk geochemical data of the PT5 paleosol yields estimates of 1221 and 1268 mm/yr at the top and bottom of the profile, respectively. The abundance of kaolinite is suggestive of a well-drained soil forming under warm and humid climatic conditions (Sheldon and Tabor, 2009). Relatively high values of illite and mica, smectite, and chlorite, however, suggest formation in intermittently poorly drained soils (Sheldon and Tabor, 2009). Similar values are found in distal levee deposits elsewhere in the road cut. The presence of larger vegetation a thicker profile in comparison to PT2 paleosols suggests formation on a more stable landscape. The PT5 235

paleosol is, therefore, interpreted as forming on over-bank deposits capped by crevasse- splay sandstone that was likely related to a shift in the position of the channel affecting local hydrology returning the environment to conditions favorable for the formation of

PT4B paleosols.

3.8.3.4 Pedotype 6

Description: Pedotype 6 (PT6) paleosols (Fig. 3.26) (n=4) (Appendix 6) occur below

DPT2 paleosols and bedded mudstone. Single profiles are 0.3–1.5 m thick and rarely represent complete profiles. PT6 paleosols are mudstones with dispersed up to very fine sand-sized grains characterized by a color that is dominantly grayish brown (5YR 3/2)

that contains relict bedding, weak platy peds, abundant to rare clay skins, and small (≤1

mm) rhizoliths. Some PT6 paleosols are highly bioturbated but still contain relict

bedding. Where present, small rhizohaloes, burrows, and mottles are typically green.

Large slickensides are present in some PT6 paleosols, but are not common.

The ichnofossil assemblage of PT6 paleosols is dominated by thin (≤1 mm), green

rhizohaloes that are up to 2.3 cm long and commonly occur dispersed throughout a

profile. Yellow rhizohaloes are also present in some profiles, but are generally rare (Fig.

3.26D). Rhizohaloes are typically horizontally oriented. Burrows in PT6 paleosols are

usually horizontally oriented with red or darkened rims and green centers (Fig. 3.26C).

One burrow from the upper horizon of a PT6 paleosol in Section 2 (Paleosol #12)

contained a plant fragment in close proximity to a horizontally oriented burrow with

larger-grained heterogeneous fill that was 4 mm wide and 9 cm long. Burrows present in 236 bedded silty to sandy mudstone associated with PT6 paleosols are commonly horizontally or vertically oriented with larger-grained heterogeneous-fill.

The micromorphology of PT6 paleosols is characterized by a plasmic microfabric that is argillasepic to insepic but may also be mosepic in large clasts of argillaceous material, particularly in Section 3 (Paleosol #10) (Fig. 3.26B). Grain microfabrics are typically porphyroskelic to granular. All PT6 paleosols have a matrix that is primarily red

(Fig. 3.26A–D). Grains are typically unidentifiable in areas dominated by clay sized material. Identifiable grains consist of quartz and micas. Large, angular or rounded clasts of bright clay stand out in contrast to the surrounding dark red matrix in some PT6 paleosols (Fig. 3.26B). Other clasts closely resemble material observed in other PT6 paleosols (Fig. 3.26A). Organics are common in the upper portions of some PT6 paleosols and are generally surrounded in lighter clay sized grains (Fig. 3.14E). One PT6 paleosol (Section 3, Paleosol #10) contained a small cast of a spiraled coprolite. A similar, larger, spiraled coprolite was found in approximately the same paleosol farther to the east of Section 3.

One sample of PT6 paleosols was taken for bulk geochemical analysis and one sample was taken for clay mineralogical analysis (Table 1, 2). Potassium oxides are generally higher relative to PT2 paleosols. Sodium oxide and calcium oxide values as well as salinization and calcification values are low in PT6 paleosols. Magnesium oxide values are close to those of PT2 and PT7 paleosols. Base loss and hydrolysis values in

PT6 paleosols are higher than in all other pedotypes. The CIA-K value for PT6 paleosols is 95.9%. The clay fraction of PT6 paleosols consists primarily of illite and mica, 237

hematite, kaolinite, and approximately equal amounts of ordered mixed layer illite/smectite with 30% smectite, chlorite, and quartz in descending order of abundance 238

(96.5%). The remainder consists of plagioclase and potassium feldspar in descending order of abundance.

Interpretation: PT6 paleosols represent compound paleosols (Appendix 6) in which the rate of sedimentation is often greater than the rate of pedogenesis (Kraus, 1999).

Under conditions of non-steady pulses of sedimentation, new material is deposited as relatively thick layers often preventing pedogenesis from penetrating into the previous paleosol profile (e.g. Kraus, 1999). The relatively thick layers of bedded mudstone in

PT6 paleosols likely represent such depositional events. The A horizon is only recognizable in PT6 paleosols where plant fossils are preserved above pedogenic indicators such as roots. The B horizons of PT6 paleosols commonly have large to small slickensides, green rhizohaloes and mottles, and commonly still have visible relict bedding. The C or R horizons of PT6 paleosols are commonly present as bedded mudstone with little to no evidence of pedogenesis.

Paleosols of PT6 are classified as Protosols (Mack et al., 1993) and interpreted as

Entisols or Inceptisols (Soil Survey Staff, 1996). The presence of strong relict bedding, lack of homogenization, and sparse rhizolith concentrations provide proper justification for the classification of PT6 paleosols as fairly under-developed soils despite the presence of some large slickensides (Mack et al., 1993; Retallack, 2001).

The absence of calcareous features in PT6 paleosols suggests formation in a humid climate (Retallack, 2001). Rhizolith formation, primarily as green rhizohaloes, suggests poorly drained soils or locally wet conditions (Kraus and Hasiotis, 2006). Where yellow rhizohaloes occur the soil was moist for longer periods allowing the formation of goethite 239

(Kraus and Hasiotis, 2006). The lack of gleization in large portions of PT6 paleosols as well as the common occurrence of horizontally oriented burrows with red rims suggests that portions of PT6 paleosols were well-drained indicating that precipitation was seasonal (e.g. Retallack, 2001; Kraus and Hasiotis, 2006).

The abundance of hematite in the bulk geochemistry and clay fraction of PT6 paleosols in conjunction with relatively high amounts of kaolinite compared to smectite and chlorite suggests hot and humid conditions with low water activity typical of environments exposed to periodically strong desiccation (Schwertmann and Taylor, 1989;

PiPujol and Buurman, 1994; Sheldon and Tabor, 2009). The presence of illite and mica, smectite, and chlorite additionally suggests that dry periods were present but the lack of calcareous features suggests that these dry periods were short (e.g. Kraus and Hasiotis,

2006; Sheldon and Tabor, 2009). Calculation of MAP from geochemical analyses yields

a value of approximately 1330 mm/yr that was likely weakly seasonally distributed.

PT6 paleosols are interpreted as forming in the mud-rich deposits of a moderately

well-drained proximal floodplain of an alluvial channel in a relatively hot and humid environment. The presence of large (>1 cm), angular to rounded, paleosol clasts suggests

the transport of desiccated material from the soil surface or the filling of mud cracks. The

presence of coprolites typically associated with aquatic environments within PT6

paleosols suggests that the material was transported outside of the environment in which

it was excreted. This is further evidence that the deposits in which PT6 paleosols formed

may have been flood deposits that quickly dried. 240

3.8.3.5 Pedotype 7

Description: Pedotype 7 (PT7) (Fig. 3.27) (Appendix 6) is represented by a single,

laterally continuous paleosol that occurs below mudstone and siltstone in all three

sections. The profile is 2.1–2.3 m thick and represents a complete profile. The PT7 paleosol is a mudstone characterized by a dark reddish brown (10R 3/4) to grayish brown

(5YR 3/2) color with abundant, large slickensides (Fig. 3.27C), green rhizohaloes commonly with organic cores (Fig. 3.4A), calcareous rhizotubules, and small dispersed calcareous nodules. The bottom 20–30 cm of the PT7 paleosol is typically larger-grained and pale green to blue green in color. The siltstone or mudstone capping the PT7 paleosol commonly has abundant compression plant fossils. In all measured sections the PT7 paleosol is positioned above bioturbated sandstone. This sandstone pinches out between

Sections 2 and 3 to the east and west, respectively. While much of this interval is covered, the paleosol appears to continue downward until the top of the Lower

Washington Sandstone. The top of the PT7 paleosol in Section 2 is organic-rich. The matrix of the PT7 paleosol is weakly to highly calcareous.

The ichnofossil assemblage of the PT7 paleosol is dominated by green rhizohaloes, but calcareous rhizotubules and green mottled burrows are also abundant. Yellow mottling is rare and was only observed in Section 2 near the top of the profile. Rhizoliths occur up to 1.9 m into PT7 paleosols. Rhizohaloes in PT7 paleosols are vertical to horizontal and 0.1–1.4 cm in diameter and up to 9.0 centimeters long in exposed sections.

Red rhizohaloes are rare and only occur at the top of the PT7 paleosol in Section 1

(Paleosol #1). Rhizotubules are usually subhorizontal and typically <1.5 mm in diameter 241

(Fig. 3.6C, E). Burrows in PT7 paleosols are variably oriented and consist of actively backfilled tunnels, mottled, and finer-grained heterogeneous fill burrows. PT7 paleosols are highly bioturbated making specific burrows commonly difficult to discern.

The micromorphology of PT7 paleosols is characterized by a plasmic microfabric that is argillasepic to inundulic in the lower half to a mix of fabrics that is primarily argillasepic, inundulic, but also has crystic and calciasepic areas above 29 m (Fig. 3.27 A,

B, D, E). Wedge-shaped (Fig. 3.27B) and blocky (Fig. 3.27D) peds are commonly present. Grain microfabrics are typically intertextic to porphyroskelic. Identifiable grains consist of shell fragments, opaques, quartz, calcite, and micas as well as light-colored clay and small-grain aggregates of varying sizes. The majority of the grains in PT7 paleosols are clay to sand-sized and fine upward. Iron staining is prevalent in red- and brown-colored portions of PT7 paleosols. Calcareous nodules are typically small and, where co-occuring with crystic fabrics, can be seen replacing finely crystalline spar.

Calcareous nodules in PT7 paleosols can be seen with sharp or diffuse boundaries, may have a slight red stain, and vary in crstallinity. In the upper half of PT7 paleosols, calcite spar is present as void fills (Fig. 3.27A). Burrows in thin sections of PT7 are often difficult to discern, but commonly occur as lighter-colored channels when compared with the surrounding red matrix. In the upper portions of PT7 paleosols, similar burrow channels are replaced with a micritic calcite.

Four samples of PT7 paleosols were taken from one profile in Section 1 for bulk geochemical analysis (Fig. 3.27, Table 1). Two additional samples, one from the top and one from the bottom of the PT7 paleosol in Section 1, were taken for clay mineral 242

showing an argillan in silasepic plasmic microfabric and granular grain fabric (S1, P#1- Cg) (cross-polarized light).

analysis (Table 2). Calcium, magnesium, and potassium oxides show a general increase

up section, but, calcium oxides increase sharply with relatively high values. Calcification

follows a similar pattern to calcium oxides. Sodium oxides and salinization increase

slightly up-section and are otherwise similar to the values in other pedotypes. Hydrolysis

remains low through PT7 profiles with values similar to PT1 paleosols. Base loss

increases down section, is relatively low compared to all but PT1 paleosols, and shows a

higher concentration of bases near the top of the profile. The CIA-K values range from

39–73% decreasing up section. The clay mineralogy of PT7 paleosols changes considerably from bottom to top. The clay fraction of the bottom of PT7 profiles consists primarily of kaolinite, illite and mica, and chlorite in descending order of abundance

(~80%). The remainder of the clay fraction consists of ordered mixed-layer illite/smectite with 20% smectite, quartz, plagioclase, and potassium feldspar in descending order of abundance. The clay fraction of the upper portion of PT7 paleosols is dominated by ordered mixed-layer illite/smectite with 30% smectite, illite and mica, calcite, and hematite in descending order of abundance (84%). The remainder of the clay fraction consists of chlorite, kaolinite, quartz, plagioclase, and potassium feldspar in descending order of abundance.

Interpretation: The PT7 paleosol represents a cumulative profile (Appendix 6) in

which the sedimentation rate is steady and slower than the rate of pedogenesis (Kraus, 244

1999). The A horizon is typically represented by an organic-rich horizon that may have

compressed plant fossil preservation. The B horizon is either highly calcareous with

abundant rhizotubules (Bk) or has abundant slickensides, small, dispersed calcite

nodules, and abundant green rhizohaloes (Bss). The C horizon is 20–30 cm thick, consists

of silt to very fine-grained sand, is gleyed a pale green to blue-green color, and is highly bioturbated. The presence of strong gley only occurring in the C horizons of PT7 paleosols suggests that the gley is caused by the position of the water table. The occurrence of preserved roots up to and within the C horizon may indicate that the water table was near the C horizon and varied little.

Paleosols of PT7 are classified and interpreted as Vertisols (Mack et al., 1993; Soil

Survey Staff, 1996). The primary notable feature of PT7 paleosols is the presence of

abundant, large slickensides and common wedge-shaped peds that, along with a high

smectite concentration, justify the classification and interpretation as Vertisols (Mack et

al., 1993; Retallack, 2001).

Calcareous features in the PT7 paleosol are interpreted as a mix of pedogenic and

burial origin due to the mixture of micritic and finely crystalline, sparry calcite. Thin

sections in the upper horizons of the PT7 paleosol show a complex mix of varying

crystalline development in calcareous features. The sharply defined edges of some

calcareous nodules indicate that they have been affected by bio- or pedoturbation (Wieder

and Yaalon, 1974) while others have a relatively diffuse boundary. Some show evidence

of recyrstallization with a more coarsely crystalline structure than a typical micritic

nodule. Evidence of overprinting of calcareous features is common, especially in the 245 replacement or cementation of burrows which were likely more conducive to the flow of calcium laden fluids. It is most likely that the PT7 paleosol was typically a dry soil that received precipitation and deposition in relatively short intervals. During the wettest periods, the PT7 paleosol was likely imperfectly drained and shallowly buried with sediment causing the formation of slightly coarser crystalline calcite. During relatively drier periods micritic nodules and burrow filling micritic cement would form.

The presence of clay and fine-grain aggregates, occasional shell fragments, heavy bioturbation, and abundant green mottling, rhizohaloes, and burrows in a red to brown paleosol suggests that erosional periods were relatively low energy, that sedimentation was occasional with longer periods of pedogenesis and likely sourced from a body of water, and that poor drainage was periodic (Brewer, 1976; PiPujol and Buurman., 1994;

Retallack, 2001). The abundance of calcareous features and large slickensides is further evidence of seasonally distributed precipitation (Retallack, 2001). The occurrence of roots in the lowest portions of PT7 paleosols with only a gleyed C horizon suggests that the water table was at least 1.8 m below the surface (e.g. Retallack, 2001).

The high retention of base cations and high calcification values suggest that the PT7 soil was periodically well drained but the semiarid to subhumid climactic conditions and biologic activity prevented rainwater (and cations) from washing deeper into the profile

(Retallack, 2001). The gradual increase in calcite up section suggests that drier conditions were not constant through paleosol formation. Calculations of MAP from bulk geochemical analysis yields a range from 520–1005 mm/yr from the C to A horizon decreasing up section indicating that during its formation the PT7 paleosol experienced 246 an overall decrease in MAP. Clay mineralogical analysis supports a drying and warming climate by showing an upward decrease in kaolinite and an upward increase in smectite, calcite, and hematite (Sheldon and Tabor, 2009).

The PT7 paleosol is interpreted as forming on interfluve deposits during a drying climactic regime. The sandstone underlying the PT7 paleosol likely represent deposits of drying fluvial channels. If the sandstones were coeval, then the presence of the PT7 paleosol between the channels is suggestive of an anastomosing river environment. As the rate of evapotranspiration exceeded the rate of precipitation, a decrease in the size of the channels and the amount of sediment they deposited would be expected. The amount of exposed sediment for soil development would, therefore, increase. Periodic deposition would have occurred during wet seasons in flooding events.

3.9 Discussion

Paleosols, ichnofossils, and body fossils described from the upper Monongahela and lower Dunkard groups of southeastern Ohio record high resolution changes in the biotic, topographic, and climatic components of Late Pennsylvanian-early Permian paleoenvironments in the Appalachian basin. While providing information on the types of plants and animals that interacted with the soil and each other, they can also be used to infer relationships regarding localized hydrology, climate, and sedimentation in environments prone to overprinting of pedogenic features. The results of this study can be used to relate local basin-scale variation in the distal Appalachian basin to other basins in the Late Pennsylvanian-early Permian. 247

3.9.1 Late Pennsylvanian-Early Permian Soil Ecosystems

The ichnofossil assemblage of upper Monongahela and lower Dunkard group paleosols is highly variable but dominated by rhizoliths. Rhizoliths and burrows of similar morphology, taphonomy, and orientation are commonly found in specific pedotypes, which suggests that the distribution of ichnofossils is directly related to the soil environment in which they were produced.

Three paleofloral assemblages dependent on soil moisture conditions are recognized in the Permo-Pennsylvanian and have been observed in the Dunkard Group (DiMichele and Hook, 1992; Blake Jr. et al., 2002; DiMichele et al., 2010; Blake Jr. and Gillespie,

2011). The wetland paleofloral assemblage of the upper Pennsylvanian were remnants of earlier Pennsylvanian floras and primarily survived in receding and low-lying landscapes characterized by poorly-drained soils (DiMichele, 2006; Falcon-Lang and DiMichele,

2010; Blake Jr. and Gillespie 2011). These assemblages include Sigillaria, Calamites, lycospora-bearing lycopsids, and pteridosperms (Blake Jr. and Gillespie, 2011).

Paleofloral assemblages adapted to living in moderately drained soils consisted of cordaitaleans, tree ferns, pteridosperms, sphenopsids, and rare lycopsids (DiMichele et al., 2001; Blake Jr. and Gillespie, 2011). Paleofloral assemblages adapted for the increasingly common well-drained soils that were previously restricted to highland areas consisted of taeniopterids, walchian conifers, Plagiozamites, Lescuropteris and

Odontopteris (pteridosperms), and callipterids (Blake Jr. and Gillespie, 2011). 248

The preservational bias toward wetland paleoflora is seen in the described paleofloral assemblage of upper Monongahela and lower Dunkard group deposits. This bias, however, does not prevent dryland floral assemblages from being preserved entirely. The common occurrence of Cordaites and the presence of Autunia conferta shows that dryland flora were present and abundant enough to overcome taphonomic bias.

Evidence of hot and dry seasonal conditions are prevalent in upper Monongahela and lower Dunkard group paleosols, but plant preservation more commonly occurs in association with hydromorphic paleosols. When no plant body fossils are available, information on the type of vegetation that was present as well as the environment of formation of the paleosols can be inferred from the size, orientation, and depth of penetration of rhizoliths, as well as from the internal structure of well-preserved roots.

Most rhizoliths represent the root and an area surrounding it termed the rhizosphere.

Rhizoliths are, therefore, often exaggerations of the original root size (Hembree and

Nadon, 2011). When available, rhizohalo cores, root casts, and rhizotubules are the most accurate for estimating the true size of the original root (Hembree and Nadon, 2011).

Using the sizes of organic root remains, color-outlined cores of rhizohaloes, filled cores of rhizotubules, and full root casts for the approximate size of roots during life for both macro- and micro-scale rhizoliths, many present in these paleosols were less than 1 mm in diameter. These roots may represent a large number of Permo-Pennsylvanian plants, however, the depth and density of these roots may be used to infer the type of vegetation that the roots represent, the position of the water table, and the drainage conditions of the soil (Klappa, 1980; Retallack, 2001; Kraus and Hasiotis, 2006). Densely packed, shallow 249

roots of this size likely represent the rhizomes of such ground covering vegetation as small ferns (Blake Jr. and Gillespie, 2011; Hembree and Nadon, 2011; Eble et al., 2011) and would require a moderately to poorly drained soil (Eble et al., 2011) with a high water table (Retallack, 1997). When present in deeper portions of the soil profile, these small roots were likely produced by cordaites or other flora with deeply penetrating roots

(Falcon-Lang, 2003). Rhizoliths in this size range are most common in PT1, PT2, PT4B and PT6 paleosols.

Rhizoliths that represent roots with diameters of 0.1 to 1.5 cm are generally less densely spaced and penetrate deeper into the soil profile. Additionally, they are preserved in a wider variety of taphonomic forms (rhizohaloes, rhizoconcretions, rhizotubules, and root casts) suggesting formation in different environments most likely by different types of plants. Roots of this size likely represent the distal roots or young individuals of large, free-standing plants such as lycopsids (specifically Sigillaria), pteridosperms, tree ferns,

and conifers (Pfefferkorn and Wang, 2009; DiMichele et al., 2010; Hembree and Nadon,

2011). Many occurrences of these roots are preserved with hematite or calcite. The style

of preservation and cracked or wrinkled nature of some of these rhizoliths suggest

seasonally and chemically varied water table levels and a shift to drier conditions in

which the roots were preserved (Retallack, 2001). These types of rhizoliths are most

common in PT3, PT4B, and PT7 paleosols.

Roots larger than 1.5 cm in diameter are primarily represented by root casts and large

rhizohaloes. Plants with roots large enough to form these rhizoliths are cordaitaleans,

conifers, and a range of tree ferns (DiMichele et al., 2010). Large root casts that penetrate 250 deeply into the soil profile and are cemented with calcite indicate well-drained soils with a low water table (Retallack, 1997). These types of rhizoliths are most common in PT4A and PT5 paleosols and are present in PT1 paleosols.

Plant damage evidence in the foliage of collected samples was likely produced by early relatives of coleopterans (beetles) and/or orthopterans (grasshoppers, crickets, locusts) (de Souza Pinheiro et al., 2012; Jarzembowski, 2012). Many of the burrows produced in upper Monongahela and lower Dunkard group paleosols are similarly attributed to the activities of coleopterans and their larvae as well as some hemipterans

(soil bugs). Vertical and horizontal beetle burrows are produced in proximal to distal alluvial and marginal-lacustrine environments in the upper horizons of the soil and their presence requires available plant material for food (Hasiotis, 2002). Other burrows with distinct morphologies are interpreted to have been produced by millipedes. The presence of millipedes infers abundant decaying vegetation within the environment under somewhat seasonal conditions and 10–30% soil moisture conditions (Behrensmeyer et al., 1992; Lawrence and Samways, 2003; Hättenschwiler and Gasser, 2005; Hasiotis,

2007). In addition to herbivore burrows, several lined, passively-filled burrows are interpreted as the locomotion and dwelling traces of small predatory arthropods. The presence of passively-filled, lined burrows without evidence for deposit feeding is evidence for well-drained soils (Hembree and Nadon, 2011). The presence of passively filled, organically lined burrows in a gleyed paleosol is strong evidence that at least some of the gley was primary and likely due to early burial or surface water gley. 251

PT1 paleosols have numerous features that are similar to modern soils that develop

in fen or carr environments where the natural acidity of decaying vegetation is

neutralized and plants grow in alkaline waters that preserve high amounts of organics and calcite (Retallack, 2001). While fens and carr require waterlogged soils (Retallack, 2001;

Schaetzl and Anderson, 2009), the lack of peat accumulation, the presence of calcite nodules, and presence of vertic features suggests that the fen experienced seasonally dry conditions. The vegetation would have been shallowly rooted due to either long periods with a seasonally high water table or the accumulation of water in surface horizons due to poor drainage (Kemmers and Jansen, 1988) and consisted of rhizomatous or rooted herbaceous plants or larger trees (Retallack, 2001). Soil fauna would have consisted of surface-active detritivores, deposit feeders, or arthropod and vertebrate predators. Some larger chambered burrows (Figs. 3.9I, 3.12D) may have been produced by vertebrates or invertebrates during periods of stressed environmental conditions.

The MPT2 paleosols and DPT2 paleosols have shallowly penetrating horizontal and

vertical rhizoliths in relatively thin, poorly developed profiles consistent with

development in poorly to moderately drained paleosols, respectively, of natural levee and

terrace deposits (Kraus, 1999). The plant fossils preserved in PT2 paleosols were likely

the plants rooted in place and buried during rapid depositional events. These plants would

have been early successional vegetation (Retallack, 2001). The macrofloral assemblage

of MPT2 paleosols is consistent with a close proximity to a water body and shifting

sediment (Blake and Gillespie, 2011). The abundance of Lepidophylloides in MPT2

paleosols and absence in DPT2 paleosols suggests that large lycopsids were locally 252 present in upper Monongahela Group paleosols, but less so in lower Dunkard Group paleosols. The dominance of heterogeneous-fill and lined burrows likely produced by arthropod predators and beetles in MPT2 paleosols reflect a biologically active, but commonly buried soil environment. The dominance of DPT2 paleosols by actively filled and passively homogeneous-filled burrows produced by soil deposit feeders and gleyed burrows likely produced by surface detritivores suggest a more stable, moderately drained soil environment. The dominantly Cordaites macrofloral assemblage of DPT2 paleosols also suggests a moderately drained soil environment (e.g. Blake and Gillespie,

2011).

PT3 paleosols have abundant characteristics similar to modern soil development in seasonally dry back swamps. These swamps likely formed in association with a drying alluvial channel. The abundance of rhizoliths up to 1.6 cm in diameter deep within the profile suggests the presence of lycopsids, pteridosperms, cordaitaleans, conifers, and tree ferns (Pfefferkorn and Wang, 2009; DiMichele et al., 2010; Hembree and Nadon, 2011).

A seed in PT3 paleosols indicates the presence of seed-bearing plants. PT3 paleosols were organic-rich and had an active soil fauna. Burrows and evidence of heavy bioturbation are abundant and in some cases well-preserved in PT3 paleosols. Open burrows with preserved organics are common in some horizons and likely represent the locomotion, feeding, and reproductive traces of coleopterans (e.g. Hasiotis, 2002). Some

PT3 horizons show sparse bioturbation and may indicate a stressful soil environment, likely linked with extended seasonally dry conditions. 253

PT4 paleosols contain some of the largest rhizoliths of any of the pedotypes. PT4B paleosols are similar to those that develop in marsh or salt marsh environments. PT4B paleosols are heavily rooted and contain abundant, small, yellow rhizoliths in dense accumulations with inner cores commonly less than 2 mm wide in addition to ferruginous rhizoliths that are 0.2–1.5 cm in diameter. Plants in this range of root sizes represent many that are present in the early Permian. The smallest roots likely represent abundant ground covering ferns (Blake Jr. and Gillespie, 2011; Hembree and Nadon, 2011; Eble et al., 2011) with a spreading pattern that likely stabilized the soil. The larger roots tend to penetrate deeper into the soil and were likely lycopsids, pteridosperms, and tree ferns

(Pfefferkorn and Wang, 2009; DiMichele et al., 2010; Hembree and Nadon, 2011). Many of the ferruginous roots are interpreted as Stigmaria of Sigillaria but many more are not identified. Marsh and salt marsh vegetation consists of rhizomatous or rooted herbaceous plants (Retallack, 2001). Organic matter accumulation (peat) is rare in PT4B paleosols, suggesting that waterlogged conditions did not persist for most of the year (Retallack,

2001). This conclusion is further supported by the occurrence of common, tightly meniscate, back-filled burrows occurring with abundant rhizoliths in organic and claystone laminated portions of PT4B soils. These burrows closely resemble those produced by cicada nymphs (hemipterans) (Smith and Hasiotis, 2008). Similar burrows have also been produced by extant coleopterans and represent the locomotion and feeding traces of insect larvae (Hasiotis, 2002). PT4A paleosols have characteristics similar to modern wooded grasslands with solitary trees scattered in grass (Retallack, 2001).

Although grasses were not present during the Permian, low story vegetation such as some 254

ferns may have been present. Tree canopies would have covered 10–40% of the ground

with some organic-rich surface horizons and shallow calcic horizons (Retallack, 2001).

Large, calcareous rhizoliths present in PT4A paleosols were likely cordaitaleans, conifers, or tree ferns (DiMichele et al., 2010) although lycopsids may have also been present (e.g. Pfefferkorn and Wang, 2009). PT4A paleosols were likely heavily pedoturbated and bioturbated, however, specific burrows are difficult to discern and are commonly only visible as green mottles, although some calcareous pedotubules may be burrows.

PT5 paleosols have characteristics of soils that formed in overbank, periodically ponded deposits that were likely associated with a low point in wooded grasslands or marsh environments. The presence of large root casts and a stump cast in PT5 paleosols suggests heavy vegetation. Vegetation present was likely cordaitaleans, tree ferns, and possibly lycopsids (DiMichele et al., 2010; Pfefferkorn and Wang, 2009). The lack of other rhizoliths or evidence of additional bioturbation in the lower portions of PT5 paleosols, however, may indicate that sedimentation was frequent enough that low-lying vegetation was unable to persist or that waterlogged, anoxic soil conditions prevented deep bioturbation. Low diversity assemblages consisting mainly of lycopsids and calamites have been shown to be tolerant of partial burial and flooding in the Late

Carboniferous (DiMichele et al., 2001). Wooded grasslands have a mix of woodland and open grassland characteristics including a moderately calcareous and clayey subsurface with a canopy cover over 10–40% of the ground area (Retallack, 2001). 255

The poor development and small rhizoliths of PT6 paleosols suggest formation in flood alluvium in a moderately well-drained, proximal flood plain that contained early successional vegetation (Retallack, 2001). Commonly preserved burrows, rhizoliths, and pedorelicts in oxidized paleosols with relict bedding would suggest subsequent deposition and a halt to pedogenesis relatively quickly after the establishment of early vegetation.

Ground cover such as pteridosperms and sphenopsids (DiMichele et al., 2007) may have been the primary vegetation in addition to burial tolerant Calamites (DiMichele et al.,

2001). The high abundance of small-diameter burrows in some PT6 paleosols suggests an active biota upon exposure of the flood deposits. The red rims around light-colored clay filled burrows suggest that they were open for a time and aerated the soil. The presence of a tetrapod bone and several aquatic coprolites additionally indicate the presence of vertebrates.

PT7 paleosols show characteristics similar to soils developing in modern wooded grasslands with abundant fine roots, occasional, larger roots, a moderately calcareous subsurface, shallow calcic horizons, and organic surface horizons (Retallack, 2001).

Trees would have covered 10–40% of the land area with abundant ground covering vegetation (Retallack, 2001). These paleosols represent pedogenesis occurring in a drying interfluve with occasional deposition, likely increasingly distal from the source. Roots and burrows are common in PT7 paleosols suggesting an active soil ecosystem. Based on the size of the roots present as well as climatic interpretations, the paleosols would have contained a relatively drier assemblage with tree ferns, seed ferns, conifers, and cordaitaleans (Pfefferkorn and Wang, 2009; DiMichele et al., 2010; Blake and Gillespie, 256

2011; Hembree and Nadon, 2011). Most burrows in PT7 paleosols are mottled and

irregular. The burrow fill is commonly similar to the surrounding matrix except for the

absence or partial removal of organic material or cementation with calcite. It is, therefore,

likely that many of the burrows present in PT7 paleosols were produced by soil deposit

feeders, such as coleopteran and hemipteran larvae, suggesting that the soil contained

abundant organic matter (Retallack, 2001; Hasiotis, 2007). The presence of crescent-

shaped damage to the margins of Neuropteris specimens in deposits just above PT7

paleosols indicates the presence of orthopteroids as well (Jarzembowski, 2012)

3.9.2 Monongahela and Dunkard Group Landscape Evolution

Upper Monongahela deposits have previously been interpreted as deposits within a fresh-to-brackish water basin on a distributary delta plain that changed to a well-drained swamp or marsh setting during coal formation (Greenlee, 1985; Martin, 1998). The

Gilboy Sandstone and underlying shale were likely the result of an increasing influx of fresh water, first delivering fine-grained sediment into the local basin and finally developing into a wide, shallow, meandering channel and floodplain system draining to the north-northwest (Greenlee, 1985). Dunkard Group deposits are generally interpreted as consisting of a combination of fluvial, lacustrine, swamp, and deltaic complexes on a low-lying, coastal plain (Martin, 1998).

These studies have widely focused on general facies relationships for large-scale interpretations. Small-scale studies of paleosols can provide high-resolution paleoenviromental and paleotopographic information including the distinction of specific 257 paleoenvironmental settings (McCarthy et al., 1997, 1998; McCarthy and Plint, 1998;

Kraus, 1997, 1999; Retallack, 2001; Hembree and Hasiotis, 2007). In addition paleosols can be used to estimate the effects of rates of sedimentation, erosion, time of exposure, and changes in local hydrologic conditions on landscape and soil ecosystem evolution

(PiPujol and Buurman, 1994, 1997; Kraus, 1999; Retallack, 2001; Hasiotis, 2007).

3.9.3 Sedimentation Rates and Time of Exposure

PT6 paleosols are interpreted as compound Entisols to Inceptisols and indicate landscape surfaces that are subject to non-steady, rapid deposition in a well-drained environment. PT6 paleosols represent the shortest period of subaerial exposure in any of the studied sections at approximately 101–102 years in duration (Retallack, 2001). The

Little Waynesburg Coal is a single Histosol with a thickness of approximately 4 cm that represents a subaerial exposure duration of 102 years (Retallack, 2001). Better developed

PT2 and PT5 paleosols are interpreted as compound to composite Inceptisols. PT2 paleosols are split according to differences in their relation with the water table into

Monongahela Pedotype 2 and Dunkard Pedotype 2 paleosols in which the former shows evidence of submergence under the water table during later stages of pedogenesis and the later does not. The poor development of calcareous nodules and moderate development of clay skins with platy peds and some relict bedding indicate subaerial exposure that was approximately 102–103 years in duration in poorly to moderately drained conditions

(Retallack, 2001). PT4B paleosols are interpreted as compound Vertisols with little to no calcareous nodule formation and prismatic peds suggesting an exposure duration that was 258

approximately 103 years (Retallack, 2001). Pedotypes 3, 4A, and 7 are interpreted as

cumulative to composite paleosols with a moderately to strongly developed calcic or

argillic horizon suggesting a subaerial exposure of approximately 104–105 years

(Retallack, 2001). These paleosols developed under relatively stable conditions

associated with strongly seasonal precipitation. The lack of abundant, oriented, highly

birefringent clays in these soils where sampled is a result of abundant iron oxides and

hydroxides and is typical of well-drained soils (Retallack, 2001). PT1 paleosols are interpreted as composite paleosols that formed under alternating poorly drained and well- drained conditions. The abundance of calcareous nodules and almost complete lack of easily weatherable minerals suggests that PT1 paleosols experienced subaerial exposure that was approximately 104 years in duration (Retallack, 2001). It is important to consider

deposition as well as pedogenesis in attempting to calculate the relative amount of time

represented in a section (Hembree and Nadon, 2011). The total approximate amount of

time required for pedogenesis in these pedotypes may be between 100,000 – 900,000

years. This estimate only takes into account portions of the sections that have been

pedogenetically altered. There are approximately 11 m of section not accounted for in

this estimate in addition to those deposits on which the paleosols first began to form.

3.9.4 Local Hydrology and Topography

Paleosols of the upper Monongahela and lower Dunkard groups record high

frequency changes in environmental conditions both laterally and vertically. In order to

properly assess the environmental differences, the distinction between different gley 259

processes should be made (PiPujol and Buurman, 1994). The co-occurrence of yellow, brown, and red colors in these paleosols suggests that late diagenesis did not greatly affect these deposits since late diagenesis would have affected all iron compounds in a similar way (PiPujol and Buurman, 1994). Drab color variations are, therefore, likely due to burial, surface, and groundwater gley.

Gley features within PT1 paleosols represent a succession from primarily surface water gley to groundwater gley influence. The heavily variegated lower portion of PT1 paleosols show ample evidence of surface water gley processes and seasonally dry conditions. The local presence of a micritic limestone near Section 2 that is not present in other sections suggests that ponding occurred locally in lower topography in the variegated portions of PT1 paleosols. A similar micrite at approximately the same stratigraphic location can be found in a neighboring roadcut. This repetitive occurrence is similar to highs and lows developed in gilgai microrelief (e.g. Russell and Moore, 1972;

Knight, 1980). The upper drab portions, however, show more evidence of increasingly longer wet periods including larger micrite clasts, possible fish teeth, lack of red or yellow rhizohaloes, higher organic content, more abundant pyrite, and fewer iron-oxides.

Since the basic composition of PT1 paleosols does not change up section, it is likely that the gleyed portions resulted from the formation of a perched water table. Ultimately this rising water table resulted in a palustrine environment with the formation of periodically exposed marlstone and eventually, the Waynesburg Limestone. The Little Waynesburg

Coal is, therefore, likely the result of the drying or shifting of the deeper water, palustrine environment. The overlying shale and Gilboy Sandstone show a progressive increase in 260

grain size up section supporting the conclusion of Greenlee (1985) as originating as an

increase in sediment deposition and formation of a sinuous channel and floodplain (Fig.

3.28).

MPT2 paleosols also display heavy groundwater gley overprints. MPT2 paleosols formed in natural distal levee deposits adjacent to an active river channel (Fig. 3.28).

During pedogenesis the levees would be heavily vegetated and relatively well-drained.

The lack of evidence for major climatic changes suggests that the deposition of the underlying Gilboy Sandstone likely contributed to subsidence that raised the water table relative to MPT2 paleosols. Additional deposition on the natural distal levee deposits would have kept MPT2 paleosols just above the water table during wet periods and higher above the water table during dry periods (Kraus, 1999). Gley in DPT2 paleosols, however, were likely less affected by groundwater levels related to subsidence and morely likely related to changes due to the migration of the adjacent river channel (e.g.

Aslan and Autin, 1998). Similar to MPT2 paleosols, DPT2 paleosols show little change in climatic conditions but do show a bottom-up decrease in gley as well as a top-down

gley increase in thinner profiles. It is, therefore, likely that local groundwater gley in

combination with burial gley were the major contributing gley processes in DPT2

paleosols.

PT3 paleosols have been affected by both burial and groundwater gley processes.

The lower portions of PT3 profiles typically have abundant slickensides and calcareous

nodules indicative of periodically well-drained soils. These lower portions are heavily gleyed from the bottom up and, like MPT2 paleosols, are affected by groundwater 261

262

gleying. Strong evidence, however, for severe changes in precipitation exists for a PT3

paleosol (Section 1: 20) that is directly related with a sandstone that thickens, and is

stratigraphically lower, to the east. A landscape surface line can be drawn that correlates

the S1:20 profile to the S3:17 profile. This surface represents a very dry period in which,

low, strongly seasonal precipitation slows deposition and pedogenesis, but seasonal re-

wetting in the channel continually re-mobilizes iron and forms abundant calcareous

nodules. Upon a return to higher levels of precipitation, a seasonally dry backswamp is

established. This backswamp effectively levels the landscape represented in the three

sections by accumulating more sediment in relatively low lying areas than in topographic

highs. The bottom-up gley of PT3 paleosols is likely due to subsidence that is common in

lowland sedimentary basins (Retallack, 2001).

Gleyed portions of PT4B paleosols were likely depressions that developed a very

local perched water table and burial gley. Pools of standing water, termed pans, may be

common in marsh environments (e.g. Pye et al., 1990) and are likely explanations for

areas with thicker gley in PT4B paleosols that are not laterally correlative. Where

associated with calcite-rich sandstone or alternating with layers of red to brown

paleosols, gley in PT4B paleosols is likely burial in origin suggesting periods of

relatively rapid deposition. Gley in PT5 paleosols is similarly due to both groundwater 263 and burial gley processes. The occurrence of large root casts and siderite suggests that the soil was moderately to poorly drained (Retallack, 2001). The gley in the B and C horizons of PT5 paleosols is likely due to a variably rising and falling perched water table that was likely influenced distally by a channel. The presence of a sandstone bed above

PT5 paleosols suggests that the gley in the A horizon of PT5 paleosols is the result of burial gley processes.

Upper Monongahela and lower Dunkard group paleosol profiles with gleyed horizons are most commonly associated with sandstone deposition and in many instances, calcareous nodule formation (Fig. 3.28). The presence of drab or green colored horizons in a paleosol may be interpreted as representing waterlogged conditions during pedogenesis (Retallack, 2001). When drab horizons occur with indicators of drier conditions, however, overprinting of original features by a rising groundwater table or subsiding basin causing a relative rise in the water table is a more favorable explanation for gley origins (e.g. Retallack, 2001). The farther removed the paleosols studied are from sandstone deposits, the more prevalent seasonal indicators become. PT3, PT4B–

PT4A, and PT7 paleosols all display increased evidence for strongly seasonal conditions up section as long as the landscape is relatively stable. Where channel formation and deposition are not the primary controls of topography and hydrology, these paleosols exhibit much higher variation. Gilgai microrelief is the most likely explanation for the topographic and hydrologic controls as well as the variation in micro- and macro- pedogenic features of PT1, PT3, PT4A, and PT7 paleosols. Where Vertisols develop gilgai microrelief differences in pedogenic features can be seen in meter scales both 264 horizontally and vertically (e.g. Russell and Moore, 1972; Knight, 1980; Driese et al.,

2000; Retallack, 2001; Kovda et al., 2003) as well as in vegetative distributions (e.g.

Russell et al., 1967). It should, therefore, not be surprising to find evidence of ponded water adjacent to paleosols reflecting drier climatic regimes.

The topography of upper Monongahela and lower Dunkard group paleosols represents a typically low-lying landscape with subtle changes in elevation. Variations in elevation are caused primarily by fluvial deposition with lesser erosion, and gilgai microrelief. An overall shift to better drained conditions from the Monongahela to

Dunkard group paleosols is evident and reflects a locally decreasing influence of the water table. The lesser influence of the water table may aid in explaining why deposits in the current study area are generally thinner than those toward the middle of the basin in addition to differences in the rates of subsidence.

3.9.5 Paleoclimate and Monongahela and Dunkard Group Paleosols

In assessing the climatic regime under which a set of paleosols formed it is important to consider the effects of other factors that influence paleosols during and after pedogenesis as other soil forming and diagenetic processes can produce features typically related to climate (McCarthy et al., 1997, 1998; Aslan and Autin, 1998; Retallack, 2001;

Tabor and Montañez, 2004; Smith et al., 2008b). Thus, detailed outcrop-scale studies are needed in order to tease apart the origin of pedogenic features in order to discern whether or not they reflect climatic conditions. 265

Overprinting of pedogenic features in Monongahela and Dunkard group paleosols is

common and includes indications of seasonally dry environments overprinted by

characteristics diagnostic of waterlogged conditions. Climate sensitive pedogenic features

in Monongahela and Dunkard group paleosols that may be used as proxies for

paleoclimatic conditions include depth to calcic horizons and relative proportions of clay

minerals (Retallack, 2001, 2005; Tabor and Montañez, 2004; Sheldon and Tabor, 2009).

In addition to depth to calcic horizon, quantitative paleoprecipitation estimates are

possible from CIA-K produced from bulk geochemical analyses (Sheldon et al., 2002;

Driese et al., 2005; Sheldon and Tabor, 2009).

The development of a Bk horizon is based on the effective depth of water

percolation within a soil in which calcium is precipitated below the Bk horizon and

leached above the Bk horizon (Retallack, 2001; Schaetzl and Anderson, 2009). The

calcium dissolved within soil water is precipitated upon evaporation or removal of the

water; therefore, in dry regions the Bk horizon is closer to the surface than in wet regions

(Retallack, 2001; Schaetzl and Anderson, 2009). Several criteria must be met to estimate

paleoprecipitation using the depth to Bk horizon as a proxy. These criteria include using

paleosols that: 1) are moderately developed (eliminating poorly developed or petrocalcic

horizons); 2) are not Vertisols; 3) the parent material is unconsolidated alluvium or loess;

and 4) the Bk horizon formation was not heavily influenced by a rising and falling

seasonal water table (Aslan and Autin, 1998; Retallack, 2001; Sheldon and Tabor, 2009).

In addition to these criteria three difficulties arise in properly applying the relationship

including surface erosion, compaction, and higher levels of atmospheric CO2 (Retallack, 266

2001). Paleosols with distinct Bk horizons and preserved surface horizons in

Monongahela and Dunkard group pedotypes generally do not fit requirements for the use of the depth to Bk horizon calculation. The depth to Bk horizon in PT1 paleosols ranges from 22–30 cm, in PT3 paleosols ranges from 15.5–50 cm, and in PT7 paleosols is 30 cm producing estimates of 285–342 mm/yr, 240–492 mm/yr, and 342 mm/yr, respectively, with a standard error of ± 147 mm (Fig. 3.29) (Retallack, 2005).

When estimating MAP from relative proportions of clay minerals, the parent material composition and grain size, temperature, rainfall seasonality, and time of pedogenesis need to be considered as all affect clay mineral formation (Retallack, 2001;

Sheldon and Tabor, 2009). In addition to pedogenic origins, clay minerals can be inherited from parent materials, added to a profile during periodic deposition, or altered after burial (Aslan and Autin, 1998; Retallack, 2001). Weathering of parent materials and clay minerals follows a general pattern in different climates from hot and humid to cool and dry of kaolinite, smectite, vermiculite, chlorite and mixed layer phyllosilicates, illite and mica (Retallack, 2001; Sheldon and Tabor, 2009). Illite and mica are the most abundant clay minerals in all but PT3 and PT7 paleosols (24–35%). This majority is likely due to deposition of detrital micas rather than climatically mediated mineral formation due to the abundance of mica in almost all deposits in the study area. The abundance of detrital micas remaining in PT1, PT2, PT4, PT5, and PT6 paleosols suggests at least periodically low levels of chemical weathering. The second most abundant clay mineral in PT2, PT4B, PT5, and PT6 paleosols is most commonly kaolinite. The highest concentrations of kaolinite are present in PT2, PT5, and the base of 267

268

PT7 paleosols. These concentrations range from approximately 28–38% and are highest in C horizons or B horizons that show evidence of deposition during pedogenesis. This likely indicates that deposition and subsequent pedogenesis in PT2, PT4B, PT5, and PT6 paleosols occurred under relatively hot and humid conditions that were intermitantly cool and dry. The presence of slickensides and general lack of calcareous nodules in these pedotypes supports this assertion. Two samples of PT2 paleosols (#5, #28) contain a high concentration of chlorite (~21–27%) that may indicate a period of particularly cool and dry conditions or horizons that were not highly altered by pedogenesis since chlorite is unstable in humid-tropical environments (Driese and Ober, 2005). Overall, the highly elevated concentrations of illite and mica, kaolinite, and chlorite appear to be at least partially inherited from the parent material. Where kaolinite is the second highest in abundance (PT2, PT4B, PT5, PT6), hot and humid conditions prevailed during pedogenesis and where chlorite is the second highest in abundance (PT2: #5, 28) drier and possibly cooler conditions prevailed during pedogenesis. In pedotypes with less rapid deposition and thicker, well-developed profiles a drier, more stable climate is evident.

The clay fraction of PT1 paleosols is dominated by calcite, but illite and mica, and 269 ordered mixed-layer illite/smectite with 30% smectite are the dominant clay minerals.

This mineral assemblage indicates cool and dry conditions in a soil that is intermittently poorly drained (Sheldon and Tabor, 2009). While PT1 paleosols were likely waterlogged for prolonged periods, clay mineralogy, abundant slickensides, lack of thick peat accumulation, and calcareous nodules suggest low, seasonal precipitation similar to a rich-fen described from Alberta, Canada in which precipitation ranged from 500–600 mm/yr (Chagué-Goff et al., 1996). PT4A paleosols also contain ordered mixed-layer illite/scmectite with 30% smectite as the second most abundant clay mineral and may similarly indicate precipitation less than 1000 mm/yr (Retallack, 2001). Other than in C horizons, ordered mixed-layer illite/smectite with 30% smectite is the dominant clay mineral in PT3 and PT7 paleosols. This dominance suggests MAP values less than 500 mm/yr for PT1, PT3, PT4A, and PT7 paleosols (Fig. 3.29) (Retallack, 2001). The transition in PT7 paleosols from a kaolinite dominated C horizon to a smectite dominated

Bk horizon is a strong indicator for a drying climate during pedogenesis.

Calculations of MAP from the CIA-K of the six pedotypes sampled for bulk geochemistry yield values similar to those interpreted from clay mineralogy. The CIA-K method of estimating paleoprecipitation from geochemical composition is based on the knowledge that soils of wet climates will have fewer alkali (Na+, K+) and alkaline earth cations (Ca2+, Mg2+) than in drier climates due to stronger hydrolytic weathering in wet climates (Retallack, 2001). Pedotypes considered to be relatively younger, less well developed, and to have had higher rates of deposition (PT2, PT5, PT6) have MAP estimates that are typically within 50 mm/yr of one another and range from 982–1333 270 mm/yr (Table 1). While the application of the CIA-K paleoprecipitation estimate works well for these pedotypes, it is not useful for paleosols with near-surface carbonate or evaporite minerals typical of desert soils, thick, highly weathered paleosols, waterlogged ground, eolian dunes, hillslope, and montane soils (Retallack, 2001; Sheldon et al., 2002).

This paleoprecipitation estimate, therefore, is should not be applied to PT1 paleosols which were likely waterlogged under alkaline conditions preventing hydrolysis, or a PT3 paleosol which contains a caliche layer (Section 1, #20). The estimates that this method produces are 130–169 mm/yr for PT1 paleosols and 314 mm/yr for the PT3 paleosol

(Section 1, #20). When compared with paleoprecipitation estimates of other methods, however, depth to Bk horizon (PT1: 285–342 mm/yr, PT3 #20: 306 mm/yr) and clay mineralogy (PT1 and PT3: ≤500 mm/yr) (Table 2) seem to substantiate a MAP estimate of less than 500 mm/yr (Fig. 3.29). Where properly applied to other PT3 and PT7 paleosols, the CIA-K method yields estimates of 999–1277 mm/yr and 520–1000 mm/yr

(decreasing up section), respectively. PT4 paleosols were not sampled for bulk geochemical analyses.

Precipitation throughout upper Monongahela and lower Dunkard group paleosols show strong evidence of seasonality with increases in precipitation associated with deposition and decreases in precipitation associated with the development of relatively stable landscapes. PT3 paleosol #20 in particular, displays evidence of a strong decrease in MAP (314 mm/yr) while other PT3 MAP estimates are 600–1000 mm/yr higher. PT3 paleosol #20 and related deposits likely represents a major depositional hiatus. The increases in precipitation may be directly related to channel migration rather than changes 271

in climate as has been demonstrated in modern aggradational floodplains (Aslan and

Autin, 1998). If this scenario is the case, MAP values were likely between 300 and 1000

mm/yr and seasonally distributed.

3.10 Conclusion

The Late Pennsylvanian–early Permian upper Monongahela and lower Dunkard groups of southeastern Ohio contain eight distinct pedotypes distinguishable by their macro- and micromorphological features, degree of pedogenic development, clay mineralogy, bulk geochemistry, ichnofossil, and body fossil content. Each pedotype corresponds to a fluvially influenced subenvironment in a series of largely aggradational alluvial floodplains. Identified subenvironments include palustrine, interfluve, natural distal levee, proximal floodplains, distal flooplains, backswamp, marsh, marsh channel overbank, and seasonally dry fen. Within and between these subenvironments, changes in local conditions manifest as vertical and lateral variability largely related to channel migration. Three pedotypes are identified in the upper Monongahela Group one of which

(PT2) is also present in the lower Dunkard Group. Pedotype 1 paleosols are interpreted as

Vertisols that formed in a highly alkaline, seasonally dry fen or carr. The Little

Waynesburg Pedotype is interpreted as a Histosol that formed in a palustrine environment. Monongahela Pedotype 2 (MPT2) and Dunkard Pedotype 2 (DPT2) paleosols are interpreted as gleyed Inceptisols and Inceptisols, respectively, which formed on natural distal levee deposits. Five pedotypes exclusive to the lower Dunkard

Group are identified. Pedotype 3 paleosols are interpreted as calcic Vertisols that formed 272 in a backswamp environment. Pedotype 4B paleosols are interpreted as ferric concretionary Vertisols that formed in a proximal marsh environment. Pedotype 5 is interpreted as a gleyed Inceptisol that formed on the overbank deposits of a small channel within a marsh environment. Pedotype 4A paleosols are interpreted as calcic Vertisols that formed on the distal floodplain. Pedotype 6 paleosols are interpreted as Entisols and

Inceptisols that formed in a proximal floodplain environment. Pedotype 7 is interpreted as a Vertisol that formed in a drying interfluve environment. Gleization within pedotypes is largely more prevalent in and below PT3 paleosols and is attributable to groundwater gley and surface water gley with lesser burial gley. Gleization in the upper half of PT1 paleosols is due to the presence of a perched water table that likely developed during increasing precipitation or a local shift in hydrologic conditions. MPT2 paleosols are almost entirely gleyed likely due to a combination of surface water gley during pedogenesis and groundwater gley post-pedogenesis. DPT2 paleosols show a similar combination of gley, however, to a much lesser degree suggesting that they formed under better drained conditions than MPT2 paleosols. PT3 paleosols are gleyed from the bottom up suggesting formation due to groundwater gley. PT5 paleosols are gleyed from a combination of groundwater and burial gley. PT4B paleosols are primarily gleyed from perched water tables and burial gley. All other pedotypes (PT4A, PT6, PT7) typically show drab colors due to surface water gley and burial gley. The amount of gley present in upper Monongahela and lower Dunkard group paleosols increases with proximity to sandstone or limestone deposits suggesting that channel migration and, therefore, changes in local hydrologic conditions are largely responsible for gley conditions. Up section 273 from PT3 to DPT2 paleosols, a clear transition in subenvironments occurs from a stable, seasonally dry landscape (PT3) to a relatively unstable, seasonally dry landscape (PT6,

DPT2) with unstable wet (PT4B, PT5) conditions and stable, seasonally dry (PT4A) conditions in between.

Ichnofossils are abundant in upper Monongahela and lower Dunkard group paleosols. Five different types of rhizoliths including rhizohaloes of varying compositions, root casts, calcareous rhizotubules and rhizoconcretions, and ferruginous rhizoconcretions have been identified. Burrows in upper Monongahela and lower

Dunkard group paleosols are highly variable and have been broadly categorized by fill and preservational characteristics. These categories include mottled, actively filled, passively filled with material similar to the surrounding matrix, passively filled with material that is larger or smaller grained than the surrounding matrix, and burrows filled with calcite spar. In addition to ichnofossils produced by organisms in direct contact with the soil, five traces produced by herbivory preserved in compressed plant fossils have been identified including hole feeding and margin feeding damage types. Finally, four types of distinct coprolites in addition to abundant non-distinct fecal pellets have been observed. While the body fossils of terrestrial and aquatic gastropods, ostracodes, micro- and macro- vertebrate bones and teeth as well as common compressed plant fossils have been identified, the abundance and variety of ichnofossils present in upper Monongahela and lower Dunkard group paleosols indicate a much more active soil ecosystem than suggested by body fossil evidence alone. The types of burrows and their preservational style indicate changes in deposition, hydrologic conditions, seasonality, soil organic 274 content, and can aid in the identification of soil profiles that have been overprinted.

Through the interpretation of these ichnofossils based on their morphological features, tracemakers have been attributed to arthropod coprophages, deposit feeders, herbivores, and carnivores as well as micro- and macro-vertebrates such as sharks, amphibians, and possibly early reptiles. These organisms would have been engaged in dwelling, feeding, locomotion, and reproduction behaviors on and in the soil causing the formation and destruction of voids, channels, and peds, altering soil porosity and permeability, and mixing, removing, and depositing organics in and on the soil (Buol et al., 2003; Schaetzl and Anderson, 2009; Wilkinson, 2009). Many ichnofossils in these paleosols, however, do not have a similar reported modern analog restricting the precision to which a possible tracemaker can be identified.

Rhizoliths in upper Monongahela and lower Dunkard group paleosols are highly variable but differences in their morphology, distribution, depth, and style of preservation can be used to interpret the density of surface biomass, soil moisture regimes, and depth to the water table. PT4A, PT5, and PT7 paleosols contain the largest rhizoliths and indicate a high amount of clumped vegetation in a seasonally dry environment with water tables that ranged from 0.6–1.9 m below the surface. PT1, The Little Waynesburg Coal,

PT4B and PT2 paleosols were highly vegetated and widespread but with plants that were well adapted to seasonally high moisture soils in close proximity to the water table. PT6 paleosols were the least vegetated of all the pedotypes due to high rates of deposition, but the presence of incipient vegetation, likely groundcover, is indicated by small, widely spaced rhizoliths. Variation in the distribution and abundance of vegetation seems to be 275

related to the pedotypes proximity to an active channel as well as seasonality and amount of precipitation.

Mean annual precipitation estimates from bulk geochemical analyses using CIA-K

range from 130 mm/yr to 1332 mm/yr. The lowest estimates are from samples with

highly calcareous parent material or were from caliche and represent underestimates

(PT1, PT3). The highest estimates were produced from samples obtained from poorly

developed paleosols or those with expected high water tables or periodically waterlogged conditions (PT2, PT3, PT5, PT6) and, therefore, may represent overestimates. PT7 MAP estimates using CIA-K suggest drying conditions during pedogenesis from ~1000 mm/yr to ~500 mm/yr up section. When used in conjunction with other paleoprecipitation estimates including clay mineralogy and depth to the Bk horizon, a trend forms with higher paleoprecipitation estimates from relatively poorly developed paleosols proximal to the channel that are interpreted to have had higher rates of deposition, and lower estimates from relatively well-developed paleosols distal from the channel interpreted to represent more stable landscapes. Two scenarios, therefore, are possible: 1) channel formation and deposition are associated with periods of higher precipitation and stable landscapes represent periods of drier climatic conditions or, 2) the stable landscape MAP estimates represent actual precipitation amounts (~300–1000 mm/yr) and higher estimates reflect channel migration rather than changes in climatic conditions. In either scenario, micro- and macromorphological features as well as clay mineralogy and bulk geochemistry indicate that precipitation was largely seasonally distributed. 276

Accurately reconstructing ancient continental paleoenvironments requires the integration

of data obtained from paleosols, ichnofossils, body fossils, and sedimentology.

Furthermore, reliable interpretation of paleosol-based proxies requires an understanding of the basic soil forming factors and how each one can aid in unraveling the often complex history of pedogenesis and the effects of post-pedogenic processes. This study exemplifies the extreme lateral and vertical variability in the biology, hydrology, topography, and parent material at small scales that is possible in ancient continental environments and stresses the importance of understanding biologic and taphonomic processes behind continental trace production and preservation.

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4 CONCLUSIONS

Variability is common in modern terrestrial environments and should be expected in

ancient environments as well. While large-scale studies can recognize large temporal variations, outcrop-scale studies can reveal subtle changes that may otherwise go un-

noticed. Local scale variations in water table level, topography, drainage, sedimentation

rates, and climate can greatly affect the distribution and diversity of organisms present in

a landscape and as a result, impact soil formation (e.g. Russell et al., 1967; Jenny, 1994;

Aslan and Autin, 1998; Retallack, 2001; Buol et al., 2003; Hembree et al., 2004; Kraus

and Hasiotis, 2006; MacEachern et al., 2007; Hembree and Hasiotis, 2007; Smith et al.,

2008; Schaetzl and Anderson, 2009). Neoichnological studies of extant terrestrial

organisms can reveal types of traces organisms produce under varying environmental

conditions and what behaviors those traces represent. From these studies it is possible to

interpret specific aspects of the paleoenvironment and paleoecology that would not have

been otherwise known (Hasiotis, 2002; Hembree and Hasiotis, 2007; Davis et al., 2007;

Smith and Hasiotis, 2008; Counts and Hasiotis, 2009; Genise et al., 2009; Hembree et al.,

2012; Hembree, 2013).

Chapter 2 concluded that Narceus americanus produced vertical shafts, subvertical

burrows, helical burrows, and O-shaped burrows while Floridobolus penneri produced all

of the burrow architectures of N. americanus as well as J-shaped burrows. Each of these

architectures was modified by four different accessory features including branches,

chambers, helical sections, and additional entrances. When compared with the burrows of

Orthoporus ornatus and Archispirostreptus gigas, all millipede burrows had an average 296 width-to-height ratio of 1.0–1.14. Burrow morphology was found to be most closely related to the function of the burrow and trace-maker morphology rather than due to environmental conditions. Behaviors included dwelling, environmental isolation, feeding, and locomotion.

Chapter 3 concluded that the paleosols in the upper Monongahela and lower

Dunkard groups in southeastern Ohio formed primarily in a highly variable aggradational floodplain. The paleosols consist of eight distinct pedotypes representing seven different subenvironments. Paleosols were interpreted largely as variations of Vertisols,

Inceptisols, Entisols, and a Histosol representing environments from proximal floodplains to a seasonally dry fen. Changes in the types of soil formation and depositional environments were attributed to channel migration and climatic changes. The preservational style and assemblage of ichnofossils varied with changes in environment in a predictable manner and aided in the identification of original soil conditions when overprinting was common. The deposits of the upper Monongahela and lower Dunkard group are perfect examples of the types of lateral and vertical variability that are possible in terrestrial paleoenvironments.

The multi-proxy approach to the study of ancient terrestrial landscapes used in this study has shown that by combining and applying ichnology, paleopedology, paleontology, and modern analogs the reconstruction of often complex and variable ancient landscapes is possible. While each proxy on its own provides valuable information, only after combining the interpretations is the most precise reconstruction produced. 297

4.1 REFERENCES

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Kraus, M.J., 1999. Paleosols in clastic sedimentary rocks; their geologic applications. Earth Science Reviews 47, 41–70.

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299

APPENDIX 1: BRAY CURTIS SIMILARITY MATRIX OF ALL BURROWS USED

From top-down and left-right; 29 N. americanus burrows (OS prefix), 42 F. penneri burrows (FB prefix), 13 O. ornatus burrows (SB prefix), and 8 A. gigas burrows (AB prefix). Colors along the sides and top indicate primary burrow architectures: Black=Subvertical Burrow, Gray=Vertical Shaft, Tan=J-Shaped Burrow, Brown=Helical Burrow, Magenta=O-Shaped Burrow, Dark Green=Sinuous Burrow, Yellow=U-Shaped Burrow. Colors inside the matrix indicate similarity: Green cells indicate identical burrows. Blue cells indicate highly similar burrows. Orange cells indicate moderately similar burrows. Red cells indicate dissimilar burrows.

OS 32 OS23 OS25A OS21A OS21B OS21C OS30B OS30D OS21D OS24 OS21E OS26A OS30E OS28 OS29C OS30A OS30C OS33A OS33B OS30F OS1 OS25B OS33C OS29B OS21F OS29A OS26B OS31A OS31B FB2C FB3C FB3D FB3E FB3F FB3G FB3H FB3I FB2E FB2F FB2G FB6A FB3A FB5B FB5C FB5D FB7A FB7C FB7E FB7F FB7H FB5E FB3B FB2A FB2B FB2D FB4A FB5A FB7B FB2M FB7D FB2I FB2J FB2K FB2L FB7G FB2H FB4B FB1 FB5F FB6B FB5G SB1 SB7 SB10 SB2 SB4 SB8 SB6 SB9 SB5 SB3 SB11 SB12 SB13 AB8 AB2 AB1 AB3 AB4 AB6 AB7 AB5 OS 32 0.8 0.7 0.7 1.0 0.9 1.0 1.0 0.9 0.8 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.7 0.9 0.9 0.7 0.6 0.7 0.8 0.4 0.9 0.9 1.0 0.9 0.9 0.9 1.0 0.9 0.9 0.9 0.9 0.6 0.8 0.8 1.0 0.8 0.9 0.9 0.9 0.9 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.8 0.9 0.8 0.8 0.9 0.8 0.7 0.7 0.8 0.7 0.6 0.8 0.9 0.6 0.9 0.9 0.8 0.9 0.8 0.7 0.7 0.9 0.7 0.8 0.5 0.6 0.7 0.5 0.6 0.6 0.6 0.6 OS23 0.8 0.9 0.8 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.8 0.8 0.7 0.7 0.7 0.7 0.7 0.7 0.9 0.9 0.8 0.8 0.8 0.8 0.8 0.7 0.9 0.5 0.8 0.7 0.8 0.8 0.7 0.8 0.8 0.8 0.8 0.9 0.7 0.8 0.9 0.8 0.8 0.8 0.7 0.8 0.8 0.8 0.8 0.8 0.7 0.7 0.7 0.8 0.7 0.7 0.8 0.7 0.8 0.9 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.7 0.6 0.8 0.7 0.7 0.8 0.7 0.8 0.7 0.7 0.7 0.8 0.9 0.8 0.9 0.7 0.6 0.6 0.6 0.6 0.6 0.6 0.8 0.7 OS25A 0.7 0.9 0.9 0.7 0.8 0.7 0.8 0.8 0.9 0.7 0.8 0.7 0.7 0.7 0.7 0.7 0.7 0.6 0.9 0.9 0.9 0.8 0.8 0.9 0.8 0.7 0.9 0.5 0.8 0.7 0.8 0.8 0.7 0.7 0.7 0.8 0.8 0.8 0.7 0.8 0.9 0.8 0.7 0.8 0.7 0.8 0.7 0.7 0.8 0.8 0.7 0.7 0.6 0.7 0.7 0.6 0.8 0.6 0.8 0.9 0.8 0.8 0.9 0.7 0.9 0.9 0.9 0.6 0.6 0.8 0.7 0.7 0.8 0.7 0.7 0.7 0.7 0.7 0.8 0.9 0.8 0.8 0.7 0.6 0.6 0.6 0.6 0.6 0.6 0.7 0.7 OS21A 0.7 0.8 0.9 0.8 0.7 0.7 0.7 0.7 0.8 0.7 0.8 0.7 0.7 0.7 0.6 0.7 0.7 0.7 0.8 0.8 0.8 0.7 0.7 0.8 0.7 0.6 0.8 0.5 0.8 0.7 0.8 0.8 0.7 0.7 0.7 0.7 0.7 0.8 0.6 0.8 0.8 0.9 0.8 0.8 0.8 0.8 0.7 0.7 0.7 0.8 0.7 0.7 0.7 0.7 0.7 0.7 0.8 0.7 0.7 0.8 0.7 0.8 0.8 0.7 0.8 0.9 0.8 0.6 0.6 0.8 0.6 0.7 0.8 0.6 0.7 0.7 0.7 0.7 0.7 0.9 0.7 0.8 0.6 0.6 0.6 0.6 0.5 0.5 0.6 0.7 0.6 OS21B 1.0 0.8 0.7 0.8 0.9 1.0 0.9 0.9 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.6 0.9 0.9 0.7 0.6 0.7 0.8 0.4 1.0 0.9 1.0 0.9 1.0 0.9 1.0 0.9 0.9 0.9 0.9 0.7 0.8 0.8 1.0 0.9 1.0 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.9 1.0 0.9 0.9 1.0 0.9 1.0 0.8 0.9 0.8 0.8 0.9 0.8 0.7 0.7 0.8 0.7 0.6 0.9 0.9 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.9 0.7 0.9 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 OS21C 0.9 0.9 0.8 0.7 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.8 0.8 0.8 0.8 0.9 0.9 0.7 0.9 0.9 0.7 0.7 0.8 0.8 0.4 0.9 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.9 1.0 0.8 0.7 0.9 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.8 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.8 0.8 0.7 0.7 0.7 0.8 0.8 0.7 0.8 0.9 0.8 0.8 0.8 0.8 0.8 0.9 0.8 0.8 0.6 0.6 0.7 0.5 0.7 0.7 0.7 0.6 OS30B 1.0 0.8 0.7 0.7 1.0 0.9 1.0 0.9 0.8 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.7 0.9 0.9 0.7 0.6 0.7 0.8 0.4 0.9 1.0 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.6 0.8 0.8 1.0 0.8 1.0 0.9 0.9 0.9 0.7 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.8 0.9 0.8 0.8 0.9 0.8 0.7 0.7 0.8 0.7 0.6 0.8 0.8 0.6 0.9 0.9 0.8 0.9 0.8 0.7 0.7 0.9 0.7 0.8 0.5 0.6 0.7 0.4 0.6 0.6 0.6 0.6 OS30D 1.0 0.8 0.8 0.7 0.9 0.9 1.0 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.7 1.0 0.9 0.7 0.6 0.8 0.8 0.4 0.9 0.9 1.0 0.9 0.9 0.9 1.0 0.9 0.9 0.9 0.9 0.6 0.8 0.8 1.0 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.8 1.0 0.9 0.8 0.9 0.8 1.0 0.8 0.9 0.9 0.9 0.9 0.8 0.7 0.7 0.8 0.7 0.6 0.8 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.9 0.8 0.9 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 OS21D 0.9 0.8 0.8 0.7 0.9 0.9 0.9 0.9 0.8 1.0 0.9 0.9 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.7 0.9 0.9 0.7 0.7 0.8 0.8 0.4 0.9 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.8 0.6 0.8 0.7 0.9 0.9 0.8 0.9 0.9 0.9 0.8 0.8 0.8 0.8 0.8 0.9 0.8 0.8 0.9 0.8 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.8 0.8 0.8 0.7 0.7 0.9 0.9 0.7 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.9 0.8 0.9 0.6 0.7 0.8 0.6 0.7 0.7 0.7 0.7 OS24 0.8 0.9 0.9 0.8 0.8 0.9 0.8 0.8 0.8 0.8 0.9 0.8 0.7 0.8 0.7 0.8 0.7 0.7 0.9 0.9 0.8 0.8 0.8 0.8 0.7 0.7 0.9 0.5 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.9 0.8 0.8 0.9 0.9 0.8 0.9 0.8 0.8 0.8 0.8 0.8 0.9 0.7 0.8 0.7 0.8 0.7 0.7 0.8 0.7 0.8 0.9 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.7 0.6 0.8 0.7 0.7 0.8 0.7 0.8 0.7 0.8 0.7 0.9 0.9 0.8 0.8 0.7 0.6 0.6 0.6 0.5 0.6 0.7 0.7 0.7 OS21E 0.9 0.8 0.7 0.7 0.8 0.9 0.9 0.9 1.0 0.8 0.8 0.9 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.7 0.9 0.9 0.7 0.7 0.8 0.8 0.4 0.9 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.8 0.6 0.7 0.7 0.9 0.8 0.8 0.9 0.9 0.9 0.9 0.8 0.8 0.8 0.8 0.9 0.8 0.8 0.9 0.7 0.9 0.8 0.9 0.9 0.8 0.9 0.8 0.8 0.8 0.8 0.7 0.7 0.9 0.9 0.7 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.9 0.8 0.9 0.6 0.7 0.8 0.6 0.8 0.7 0.7 0.7 OS26A 0.8 0.8 0.8 0.8 0.9 0.9 0.8 0.9 0.9 0.9 0.8 0.9 0.8 0.8 0.7 0.8 0.8 0.8 0.9 0.8 0.7 0.9 0.8 0.7 0.7 0.8 0.8 0.4 0.9 0.8 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.9 0.8 0.7 0.8 0.9 0.9 1.0 0.8 0.9 0.8 0.9 0.9 1.0 0.8 0.8 0.8 0.9 0.8 0.8 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.8 0.8 0.7 0.7 0.7 0.8 0.8 0.7 0.8 0.9 0.8 0.9 0.8 0.8 0.8 0.9 0.8 0.8 0.6 0.7 0.8 0.6 0.7 0.7 0.8 0.7 OS30E 0.9 0.8 0.7 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.7 0.9 0.9 0.7 0.6 0.8 0.8 0.4 0.9 0.9 0.9 0.9 0.9 1.0 0.9 0.9 0.9 0.9 0.9 0.6 0.7 0.7 0.9 0.8 0.9 0.9 1.0 0.9 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 1.0 0.8 0.9 0.8 0.8 0.9 0.8 0.7 0.7 0.9 0.7 0.6 0.9 0.9 0.6 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.9 0.7 0.9 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 OS28 0.9 0.7 0.7 0.7 0.9 0.8 0.9 0.9 0.8 0.7 0.8 0.8 0.9 0.9 0.9 0.9 1.0 1.0 0.7 0.7 0.6 0.9 0.9 0.6 0.6 0.7 0.7 0.4 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.8 0.8 0.6 0.7 0.8 0.9 0.8 0.9 0.9 0.9 0.9 0.7 0.8 0.9 1.0 1.0 0.9 1.0 1.0 0.9 0.9 0.9 0.7 0.9 0.8 0.8 0.9 0.7 0.7 0.6 0.8 0.7 0.5 0.9 0.8 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.8 0.7 0.9 0.5 0.6 0.7 0.5 0.6 0.6 0.6 0.6 OS29C 0.9 0.7 0.7 0.7 0.9 0.8 0.9 0.9 0.8 0.8 0.8 0.8 0.9 0.9 0.9 1.0 0.9 0.9 0.7 0.8 0.6 0.9 0.9 0.6 0.6 0.7 0.7 0.4 0.9 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.6 0.8 0.8 0.9 0.8 1.0 0.9 0.9 0.9 0.7 0.8 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.7 0.9 0.8 0.8 0.9 0.7 0.7 0.7 0.8 0.7 0.6 0.9 0.8 0.6 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.8 0.7 0.9 0.5 0.5 0.7 0.4 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0.8 0.9 0.8 0.9 0.9 0.7 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.8 0.9 0.8 0.8 0.9 0.8 0.7 0.7 0.9 0.7 0.6 0.9 0.8 0.6 0.9 1.0 0.9 1.0 0.7 0.7 0.9 0.7 0.9 0.5 0.6 0.7 0.5 0.7 0.6 0.6 0.6 SB4 0.9 0.8 0.7 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.8 0.8 0.6 0.9 0.9 0.7 0.6 0.8 0.8 0.4 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.6 0.7 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.8 0.9 0.8 0.9 0.9 0.8 0.9 0.8 1.0 0.8 0.9 0.9 0.8 0.9 0.8 0.7 0.7 0.9 0.7 0.6 0.9 0.9 0.7 0.9 0.9 0.9 0.9 0.8 0.8 0.9 0.8 0.9 0.6 0.7 0.8 0.5 0.7 0.7 0.7 0.7 SB8 0.8 0.7 0.7 0.7 0.9 0.8 0.8 0.9 0.8 0.7 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.6 0.8 0.9 0.6 0.6 0.7 0.7 0.4 0.8 0.9 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.6 0.7 0.7 0.9 0.8 0.9 0.8 0.9 0.9 0.8 0.8 0.9 0.9 0.9 0.9 1.0 0.9 0.8 0.9 0.9 0.8 0.9 0.8 0.7 0.9 0.7 0.7 0.6 0.9 0.7 0.6 0.9 0.9 0.6 1.0 0.9 0.9 1.0 0.7 0.7 0.9 0.7 0.9 0.6 0.6 0.7 0.5 0.7 0.6 0.7 0.6 SB6 0.9 0.7 0.7 0.7 0.9 0.8 0.9 0.9 0.8 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.6 0.9 0.9 0.7 0.6 0.7 0.7 0.4 0.9 0.9 0.9 0.9 0.9 1.0 0.9 0.9 0.9 0.8 0.9 0.6 0.7 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.9 1.0 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.8 0.8 0.9 0.8 0.7 0.7 0.9 0.7 0.6 0.9 0.9 0.6 0.9 0.9 0.9 0.9 0.7 0.7 0.9 0.7 0.9 0.6 0.6 0.7 0.5 0.7 0.7 0.7 0.6 SB9 0.8 0.7 0.7 0.7 0.9 0.8 0.8 0.9 0.8 0.7 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.7 0.7 0.6 0.8 0.9 0.6 0.6 0.7 0.7 0.4 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.6 0.7 0.7 0.9 0.8 0.9 0.8 0.9 0.9 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.8 0.7 0.9 0.8 0.7 0.7 0.9 0.7 0.6 0.9 0.9 0.6 1.0 0.9 1.0 0.9 0.7 0.7 0.9 0.7 0.9 0.5 0.6 0.7 0.5 0.7 0.6 0.7 0.6 SB5 0.7 0.8 0.8 0.7 0.7 0.8 0.7 0.8 0.9 0.9 0.9 0.8 0.8 0.7 0.7 0.7 0.7 0.7 0.7 0.9 0.8 0.7 0.8 0.8 0.8 0.7 0.7 0.9 0.5 0.8 0.7 0.8 0.8 0.7 0.8 0.8 0.8 0.8 0.9 0.7 0.7 0.8 0.8 0.8 0.8 0.7 0.8 0.8 0.8 0.9 0.8 0.7 0.7 0.7 0.8 0.7 0.7 0.8 0.7 0.8 0.9 0.8 0.9 0.8 0.8 0.9 0.8 0.8 0.7 0.7 0.7 0.8 0.8 0.8 0.7 0.8 0.7 0.7 0.7 0.9 0.8 0.9 0.8 0.7 0.8 0.8 0.7 0.7 0.7 0.8 0.8 SB3 0.7 0.9 0.9 0.9 0.7 0.8 0.7 0.7 0.8 0.9 0.8 0.8 0.7 0.7 0.7 0.6 0.7 0.7 0.7 0.9 0.8 0.8 0.8 0.7 0.9 0.7 0.7 0.9 0.5 0.8 0.7 0.7 0.7 0.7 0.7 0.8 0.8 0.8 0.8 0.7 0.8 0.8 0.8 0.7 0.8 0.7 0.8 0.7 0.8 0.8 0.8 0.6 0.7 0.7 0.8 0.7 0.6 0.8 0.7 0.8 0.9 0.8 0.8 0.8 0.8 0.9 0.9 0.9 0.7 0.6 0.8 0.7 0.8 0.9 0.7 0.8 0.7 0.7 0.7 0.9 0.8 0.9 0.7 0.7 0.7 0.7 0.6 0.6 0.7 0.8 0.8 SB11 0.9 0.8 0.8 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.7 0.9 0.9 0.7 0.7 0.8 0.8 0.4 0.9 0.9 0.9 0.9 0.9 0.9 0.9 1.0 1.0 0.9 0.8 0.6 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.8 0.9 0.8 0.8 0.9 0.8 0.9 0.9 1.0 0.9 0.8 0.9 0.9 0.8 0.8 0.8 0.8 0.6 0.9 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.8 0.9 0.6 0.7 0.8 0.6 0.7 0.7 0.7 0.7 SB12 0.7 0.9 0.8 0.8 0.7 0.8 0.7 0.8 0.8 0.8 0.8 0.8 0.7 0.7 0.7 0.6 0.7 0.7 0.7 0.9 0.8 0.7 0.8 0.7 0.8 0.7 0.7 0.9 0.5 0.8 0.7 0.7 0.8 0.7 0.7 0.8 0.8 0.8 0.8 0.7 0.7 0.8 0.8 0.8 0.8 0.7 0.8 0.8 0.8 0.9 0.8 0.6 0.7 0.7 0.8 0.7 0.7 0.8 0.7 0.8 0.9 0.8 0.9 0.8 0.8 0.9 0.9 0.8 0.7 0.6 0.7 0.8 0.8 0.8 0.7 0.8 0.7 0.7 0.7 0.9 0.9 0.8 0.8 0.7 0.7 0.7 0.7 0.7 0.7 0.8 0.8 SB13 0.8 0.7 0.7 0.6 0.9 0.8 0.8 0.9 0.9 0.7 0.9 0.8 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.7 0.7 0.6 0.8 0.9 0.6 0.6 0.7 0.7 0.4 0.8 0.8 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.6 0.7 0.7 0.9 0.8 0.9 0.8 0.9 0.9 0.8 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.8 0.9 0.8 0.7 0.9 0.8 0.7 0.7 0.9 0.7 0.6 1.0 0.9 0.7 0.9 0.9 0.9 0.9 0.9 0.8 0.7 0.9 0.8 0.6 0.7 0.8 0.6 0.8 0.7 0.7 0.7 AB8 0.5 0.6 0.6 0.6 0.5 0.6 0.5 0.5 0.6 0.6 0.6 0.6 0.5 0.5 0.5 0.4 0.5 0.5 0.5 0.6 0.6 0.6 0.5 0.5 0.7 0.5 0.5 0.6 0.4 0.6 0.5 0.5 0.6 0.5 0.5 0.6 0.6 0.6 0.6 0.5 0.6 0.5 0.7 0.5 0.6 0.5 0.6 0.6 0.6 0.7 0.6 0.5 0.5 0.5 0.6 0.5 0.5 0.6 0.6 0.6 0.6 0.6 0.7 0.6 0.6 0.7 0.7 0.6 0.6 0.5 0.6 0.7 0.7 0.7 0.5 0.6 0.6 0.6 0.5 0.7 0.7 0.6 0.7 0.6 0.8 0.8 0.9 0.8 0.8 0.9 0.9 AB2 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.7 0.6 0.7 0.7 0.6 0.6 0.5 0.5 0.5 0.6 0.6 0.7 0.6 0.5 0.6 0.6 0.6 0.5 0.6 0.7 0.4 0.6 0.5 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.7 0.5 0.5 0.6 0.7 0.6 0.7 0.6 0.6 0.6 0.7 0.8 0.7 0.5 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.7 0.7 0.7 0.6 0.7 0.7 0.6 0.6 0.6 0.6 0.5 0.7 0.7 0.6 0.6 0.7 0.6 0.6 0.6 0.8 0.7 0.7 0.7 0.7 0.8 0.9 0.8 0.8 0.8 0.8 0.9 AB1 0.7 0.6 0.6 0.6 0.7 0.7 0.7 0.7 0.8 0.6 0.8 0.8 0.7 0.7 0.7 0.6 0.7 0.7 0.7 0.7 0.6 0.5 0.7 0.7 0.6 0.5 0.7 0.7 0.4 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.8 0.8 0.7 0.7 0.5 0.6 0.7 0.7 0.8 0.7 0.8 0.7 0.8 0.8 0.8 0.6 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.8 0.8 0.7 0.8 0.7 0.6 0.6 0.7 0.7 0.5 0.8 0.8 0.6 0.7 0.8 0.7 0.7 0.7 0.8 0.7 0.8 0.7 0.8 0.8 0.9 0.8 0.9 0.8 0.8 0.9 AB3 0.5 0.6 0.6 0.5 0.5 0.5 0.4 0.5 0.6 0.5 0.6 0.6 0.5 0.5 0.4 0.4 0.4 0.4 0.5 0.6 0.5 0.6 0.5 0.5 0.6 0.5 0.5 0.6 0.4 0.5 0.4 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.6 0.4 0.6 0.5 0.6 0.5 0.6 0.5 0.5 0.5 0.6 0.7 0.6 0.4 0.4 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.6 0.6 0.6 0.5 0.6 0.6 0.6 0.5 0.5 0.5 0.5 0.6 0.6 0.6 0.5 0.5 0.5 0.5 0.5 0.7 0.6 0.6 0.7 0.6 0.9 0.8 0.8 0.8 0.9 0.8 0.8 AB4 0.6 0.6 0.6 0.5 0.7 0.7 0.6 0.7 0.7 0.6 0.8 0.7 0.7 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.5 0.7 0.7 0.5 0.5 0.6 0.6 0.3 0.7 0.6 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.6 0.5 0.5 0.6 0.7 0.7 0.6 0.7 0.7 0.7 0.8 0.7 0.6 0.6 0.7 0.7 0.6 0.6 0.7 0.7 0.7 0.6 0.7 0.7 0.6 0.7 0.7 0.6 0.6 0.7 0.7 0.5 0.8 0.8 0.5 0.7 0.7 0.7 0.7 0.7 0.7 0.6 0.7 0.7 0.8 0.8 0.8 0.9 0.8 0.9 0.8 0.8 AB6 0.6 0.6 0.6 0.6 0.6 0.7 0.6 0.6 0.7 0.7 0.7 0.7 0.6 0.6 0.6 0.5 0.6 0.6 0.6 0.7 0.6 0.5 0.6 0.6 0.6 0.5 0.6 0.7 0.4 0.6 0.6 0.6 0.6 0.6 0.6 0.7 0.7 0.7 0.7 0.6 0.5 0.6 0.7 0.6 0.7 0.6 0.7 0.7 0.7 0.8 0.7 0.6 0.6 0.6 0.7 0.6 0.6 0.6 0.6 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.6 0.6 0.6 0.6 0.5 0.7 0.7 0.6 0.6 0.7 0.6 0.7 0.6 0.7 0.7 0.7 0.7 0.7 0.8 0.8 0.8 0.9 0.9 0.9 0.8 AB7 0.6 0.8 0.7 0.7 0.7 0.7 0.6 0.7 0.7 0.7 0.7 0.8 0.7 0.6 0.6 0.6 0.6 0.6 0.6 0.8 0.7 0.6 0.7 0.6 0.7 0.6 0.6 0.8 0.4 0.7 0.6 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.6 0.6 0.7 0.8 0.7 0.8 0.6 0.7 0.7 0.7 0.8 0.8 0.6 0.6 0.6 0.7 0.6 0.6 0.7 0.7 0.7 0.8 0.7 0.8 0.7 0.7 0.8 0.7 0.7 0.6 0.6 0.6 0.7 0.8 0.7 0.6 0.7 0.7 0.7 0.7 0.8 0.8 0.7 0.8 0.7 0.9 0.8 0.8 0.8 0.8 0.9 0.9 AB5 0.6 0.7 0.7 0.6 0.6 0.6 0.6 0.6 0.7 0.7 0.7 0.7 0.6 0.6 0.5 0.5 0.5 0.6 0.6 0.7 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.7 0.4 0.6 0.5 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.7 0.6 0.6 0.6 0.7 0.6 0.7 0.6 0.6 0.6 0.7 0.8 0.7 0.5 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.7 0.7 0.7 0.6 0.7 0.7 0.7 0.7 0.6 0.6 0.6 0.7 0.7 0.7 0.6 0.7 0.6 0.6 0.6 0.8 0.8 0.7 0.8 0.7 0.9 0.9 0.9 0.8 0.8 0.8 0.9

300

APPENDIX 2: SPEARMAN’S RANK ANALYSIS FOR N. AMERICANUS

Data used in the Spearman’s rank correlation analysis of eight quantitative properties of N. americanus burrows and sediment clay composition.

1. Complexity vs Clay Composition 2. Tortuosity vs Clay Composition 3. Circumference vs Clay Composition 4. Total Length vs Clay Composition XY XY XY XY 50 2.0 50 3.5 50 2.8 50 7.0 50 2.0 50 1.0 50 3.9 50 2.3 50 2.0 50 1.1 50 3.7 50 4.3 50 2.0 50 1.1 50 2.7 50 8.0 50 4.0 50 1.1 50 3.1 50 13.8 50 4.0 50 1.1 50 3.2 50 15.7 50 4.0 50 1.2 50 3.4 50 10.0 50 2.0 50 1.2 50 3.1 50 8.2 50 3.0 50 1.5 50 3.3 50 7.2 50 2.0 50 1.7 50 3.1 50 9.4 50 2.0 50 5.6 50 3.2 50 8.4 50 3.0 50 1.1 50 4.9 50 6.8 50 3.0 50 39.0 50 3.4 50 12.5 50 2.0 50 1.3 50 4.4 50 3.0 50 3.0 50 43.0 50 3.1 50 10.6 50 4.0 50 1.5 50 2.7 50 10.7 50 2.0 50 1.0 50 3.5 50 1.9 50 2.0 50 1.0 50 2.6 50 2.5 50 2.0 50 1.2 50 2.9 50 3.1 50 2.0 50 1.1 50 3.0 50 2.6 50 2.0 50 1.2 50 3.1 50 6.8 50 4.0 50 1.1 50 3.5 50 7.5 50 2.0 50 2.0 50 2.8 50 11.8 50 6.0 50 1.8 50 3.5 50 12.3 50 2.0 50 99.0 50 3.3 50 10.0 75 2.0 75 1.0 75 2.8 75 4.3 100 2.0 100 1.0 100 3.9 100 3.1 100 2.0 100 1.0 100 4.2 100 3.0 100 2.0 100 2.3 100 3.1 100 6.8 Rs= -0.28 Rs= -0.3 Rs= -0.13 Rs= -0.31

5. Width vs Clay Composition 6. Height vs Clay Composition 7. Maximum Depth vs Clay Composition8.Slope vs Clay Composition XY XY XY XY 50 8.9 50 8.3 50 2.8 50 45.0 50 11.8 50 12.2 50 1.9 50 33.0 50 12.4 50 11.4 50 4.0 50 71.5 50 9.3 50 8.1 50 7.1 50 56.7 50 10.2 50 9.3 50 11.9 50 63.3 50 10.5 50 9.1 50 13.4 50 63.7 50 11.6 50 9.7 50 2.9 50 25.0 50 10.4 50 8.3 50 6.7 50 38.3 50 10.9 50 8.0 50 4.0 50 43.5 50 10.2 50 7.9 50 3.0 50 35.0 50 10.1 50 8.0 50 2.5 50 25.0 50 15.6 50 11.6 50 5.8 50 55.0 50 10.9 50 9.3 50 6.9 50 60.0 50 14.0 50 11.7 50 2.4 50 85.0 50 10.5 50 8.2 50 3.4 50 37.5 50 8.4 50 7.8 50 3.4 50 75.0 50 11.7 50 9.0 50 1.9 50 80.0 50 8.2 50 8.3 50 2.5 50 90.0 50 9.6 50 9.0 50 2.6 50 70.0 50 9.9 50 8.7 50 2.3 50 80.0 50 9.3 50 9.4 50 5.9 50 70.0 50 11.4 50 8.4 50 6.6 50 77.5 50 9.1 50 8.3 50 5.9 50 45.0 50 10.4 50 10.4 50 2.5 50 43.3 50 10.1 50 9.9 50 1.9 50 20.0 75 8.8 75 9.2 75 4.1 75 70.0 100 11.2 100 12.9 100 3.1 100 90.0 100 13.4 100 12.4 100 2.2 100 90.0 100 9.6 100 9.8 100 3.0 100 65.0 Rs= 0.01 Rs= 0.42 Rs= -0.1 Rs= -0.39 301

APPENDIX 3: SPEARMAN’S RANK ANALYSIS FOR N. AMERICANUS

Data used in the Spearman’s rank correlation analysis of eight quantitative properties of N. americanus burrows and sediment moisture content.

1. Complexity vs Sediment Moisture 2. Tortuosity vs Sediment Moisture 3. Circumference vs Sediment Moisture 4. Total Length vs Sediment Moisture XY XY XY XY 30 3.0 30 1.5 30 3.3 30 7.2 32 2.0 32 1.2 32 3.1 32 8.2 35 2.0 35 3.5 35 2.8 35 7.0 35 2.0 35 1.7 35 3.1 35 9.4 35 2.0 35 5.6 35 3.2 35 8.4 37 2.0 37 1.0 37 3.9 37 2.3 37 2.0 37 1.1 37 3.7 37 4.3 37 2.0 37 1.1 37 2.7 37 8.0 37 4.0 37 1.1 37 3.1 37 13.8 37 4.0 37 1.1 37 3.2 37 15.7 37 4.0 37 1.2 37 3.4 37 10.0 37 3.0 37 1.1 37 4.9 37 6.8 37 3.0 37 39.0 37 3.4 37 12.5 40 2.0 40 1.3 40 4.4 40 3.0 51 2.0 51 1.0 51 2.8 51 4.3 52 3.0 52 43.0 52 3.1 52 10.6 52 4.0 52 1.5 52 2.7 52 10.7 52 2.0 52 1.0 52 3.5 52 1.9 56 2.0 56 1.0 56 2.6 56 2.5 56 2.0 56 1.2 56 2.9 56 3.1 56 2.0 56 1.1 56 3.0 56 2.6 56 2.0 56 1.2 56 3.1 56 6.8 56 4.0 56 1.1 56 3.5 56 7.5 56 2.0 56 2.0 56 2.8 56 11.8 60 6.0 60 1.8 60 3.5 60 12.3 60 2.0 60 99.0 60 3.3 60 10.0 60 2.0 60 1.0 60 3.9 60 3.1 60 2.0 60 1.0 60 4.2 60 3.0 60 2.0 60 2.3 60 3.1 60 6.8 Rs= -0.1 Rs= -0.11 Rs= 0.04 Rs= -0.22

5. Width vs Sediment Moisture 6. Height vs Sediment Moisture 7. Maximum Depth vs Sediment Moisture 8. Slope vs Sediment Moisture XY XY XY XY 30 10.9 30 8.0 30 4.0 30 43.5 32 10.4 32 8.3 32 6.7 32 38.3 35 8.9 35 8.3 35 2.8 35 45.0 35 10.2 35 7.9 35 3.0 35 35.0 35 10.1 35 8.0 35 2.5 35 25.0 37 11.8 37 12.2 37 1.9 37 33.0 37 12.4 37 11.4 37 4.0 37 71.5 37 9.3 37 8.1 37 7.1 37 56.7 37 10.2 37 9.3 37 11.9 37 63.3 37 10.5 37 9.1 37 13.4 37 63.7 37 11.6 37 9.7 37 2.9 37 25.0 37 15.6 37 11.6 37 5.8 37 55.0 37 10.9 37 9.3 37 6.9 37 60.0 40 14.0 40 11.7 40 2.4 40 85.0 51 8.8 51 9.2 51 4.1 51 70.0 52 10.5 52 8.2 52 3.4 52 37.5 52 8.4 52 7.8 52 3.4 52 75.0 52 11.7 52 9.0 52 1.9 52 80.0 56 8.2 56 8.3 56 2.5 56 90.0 56 9.6 56 9.0 56 2.6 56 70.0 56 9.9 56 8.7 56 2.3 56 80.0 56 9.3 56 9.4 56 5.9 56 70.0 56 11.4 56 8.4 56 6.6 56 77.5 56 9.1 56 8.3 56 5.9 56 45.0 60 10.4 60 10.4 60 2.5 60 43.3 60 10.1 60 9.9 60 1.9 60 20.0 60 11.2 60 12.9 60 3.1 60 90.0 60 13.4 60 12.4 60 2.2 60 90.0 60 9.6 60 9.8 60 3.0 60 65.0 Rs= -0.13 Rs= 0.41 Rs= -0.33 Rs= 0.46

302

APPENDIX 4: SPEARMAN’S RANK ANALYSIS FOR F. PENNERI

Data used in the Spearman’s rank correlation analysis of eight quantitative properties of F. penneri burrows and sediment clay composition.

1. Complexity vs Clay Composition 2. Tortuosity vs Clay Composition 3. Average Circumference vs Clay Composition 4. Total Length vs Clay Composition XY XY XY XY 50 6.0 50 1.1 50 2.7 50 11.1 50 2.0 50 1.0 50 3.6 50 4.1 50 2.0 50 1.0 50 4.9 50 3.1 50 2.0 50 1.0 50 4.0 50 4.0 50 2.0 50 1.1 50 4.4 50 6.7 50 2.0 50 1.1 50 3.6 50 9.6 50 2.0 50 1.2 50 3.4 50 9.5 50 4.0 50 1.1 50 3.2 50 10.0 50 3.0 50 1.4 50 3.7 50 13.0 50 2.0 50 2.2 50 3.2 50 10.7 50 2.0 50 2.0 50 3.8 50 11.9 50 2.0 50 2.0 50 3.8 50 11.8 50 2.0 50 5.8 50 3.1 50 7.5 50 2.0 50 1.0 50 5.2 50 3.6 50 2.0 50 1.6 50 2.7 50 3.3 50 2.0 50 1.0 50 3.3 50 2.2 50 2.0 50 1.0 50 3.2 50 1.7 50 2.0 50 1.2 50 3.4 50 4.2 50 2.0 50 1.0 50 4.1 50 3.3 50 2.0 50 1.2 50 3.9 50 4.2 50 2.0 50 1.1 50 3.3 50 7.4 50 2.0 50 1.0 50 3.6 50 6.8 50 2.0 50 1.1 50 3.6 50 8.6 50 2.0 50 1.1 50 4.6 50 3.6 50 2.0 50 4.3 50 3.6 50 11.1 50 2.0 50 1.4 50 3.7 50 4.3 50 4.0 50 53.0 50 4.4 50 13.0 75 2.0 75 1.0 75 4.0 75 2.1 75 2.0 75 1.1 75 5.2 75 3.4 75 2.0 75 1.1 75 3.7 75 4.9 75 2.0 75 1.2 75 4.5 75 7.7 75 3.0 75 1.3 75 4.7 75 6.8 75 6.0 75 17.6 75 3.7 75 17.5 75 4.0 75 1.4 75 3.1 75 10.1 100 2.0 100 1.1 100 3.4 100 2.4 100 2.0 100 1.2 100 3.6 100 4.7 100 2.0 100 1.3 100 3.9 100 5.5 100 2.0 100 1.2 100 3.6 100 8.4 100 2.0 100 1.1 100 3.6 100 9.2 100 3.0 100 1.1 100 4.0 100 12.4 100 2.0 100 2.4 100 3.9 100 14.7 100 4.0 100 1.5 100 5.0 100 18.6 Rs= 0.17 Rs= 0.14 Rs= 0.22 Rs= 0.15

5. Average Width vs Clay Composition 6. Average Height vs Clay Composition 7. Maximum Depth vs Clay Composition 8. Average Slope vs Clay Composition XY XY XY XY 50 9.8 50 6.1 50 2.8 50 37.5 50 9.9 50 11.1 50 4.1 50 85.0 50 14.3 50 14.9 50 3.1 50 90.0 50 12.1 50 12.8 50 3.5 50 65.0 50 13.2 50 11.5 50 6.0 50 72.5 50 11.0 50 10.9 50 7.9 50 65.0 50 10.8 50 10.1 50 6.9 50 55.0 50 4.0 50 5.8 50 4.4 50 78.0 50 10.8 50 11.0 50 5.8 50 45.0 50 9.9 50 10.7 50 6.5 50 46.7 50 12.0 50 11.8 50 7.8 50 70.0 50 11.0 50 13.0 50 8.1 50 52.5 50 9.4 50 9.5 50 2.9 50 50.0 50 16.6 50 16.7 50 3.6 50 90.0 50 7.8 50 8.1 50 1.5 50 45.0 50 11.2 50 9.4 50 2.2 50 90.0 50 9.4 50 10.6 50 1.7 50 75.0 50 11.1 50 10.0 50 3.3 50 68.0 50 13.7 50 10.2 50 3.3 50 65.0 50 13.2 50 10.4 50 3.6 50 75.0 50 10.1 50 10.5 50 6.8 50 78.0 50 11.4 50 11.5 50 6.5 50 70.0 50 11.4 50 10.5 50 8.2 50 65.0 50 14.7 50 12.2 50 3.3 50 90.0 50 11.6 50 10.0 50 3.1 50 35.0 50 13.7 50 10.3 50 1.8 50 20.0 50 17.7 50 12.1 50 4.4 50 65.0 75 13.6 75 13.7 75 2.1 75 90.0 75 15.2 75 16.5 75 2.8 75 45.0 75 11.0 75 11.5 75 4.2 75 70.0 75 13.9 75 13.9 75 5.7 75 55.0 75 12.7 75 15.6 75 5.2 75 55.0 75 10.8 75 12.2 75 7.7 75 85.0 75 10.2 75 8.3 75 1.1 75 20.0 100 10.8 100 11.4 100 2.1 100 75.0 100 12.0 100 12.7 100 3.6 100 65.0 100 12.8 100 12.7 100 4.1 100 61.7 100 12.1 100 11.0 100 6.9 100 72.5 100 12.3 100 10.0 100 8.7 100 77.5 100 13.6 100 11.3 100 8.0 100 70.0 100 11.3 100 12.4 100 8.4 100 75.0 100 16.8 100 13.4 100 7.4 100 50.0 Rs= 0.24 Rs= 0.36 Rs= 0.19 Rs= 0.03 303

APPENDIX 5: SPEARMAN’S RANK ANALYSIS FOR F. PENNERI

Data used in the Spearman’s rank correlation analysis of eight quantitative properties of F. penneri burrows and sediment moisture content. 1. Complexity vs Sediment Moisture 2. Tortuosity vs Sediment Moisture 3. Average Circumference vs Sediment Moisture 4. Total Length vs Sediment Moisture XY XY XY XY 49 2.0 49 1.0 49 3.6 49 4.1 49 2.0 49 1.0 49 4.9 49 3.1 49 2.0 49 1.0 49 4.0 49 4.0 49 2.0 49 1.1 49 4.4 49 6.7 49 2.0 49 1.1 49 3.6 49 9.6 49 2.0 49 1.2 49 3.4 49 9.5 49 4.0 49 1.1 49 3.2 49 10.0 49 3.0 49 1.4 49 3.7 49 13.0 49 2.0 49 2.2 49 3.2 49 10.7 49 2.0 49 2.0 49 3.8 49 11.9 49 2.0 49 2.0 49 3.8 49 11.8 49 2.0 49 5.8 49 3.1 49 7.5 49 2.0 49 1.0 49 5.2 49 3.6 50 2.0 50 1.6 50 2.7 50 3.3 50 2.0 50 1.0 50 3.3 50 2.2 50 2.0 50 1.0 50 3.2 50 1.7 50 2.0 50 1.2 50 3.4 50 4.2 50 2.0 50 1.0 50 4.1 50 3.3 50 2.0 50 1.2 50 3.9 50 4.2 50 2.0 50 1.1 50 3.3 50 7.4 50 2.0 50 1.0 50 3.6 50 6.8 50 2.0 50 1.1 50 3.6 50 8.6 50 2.0 50 1.4 50 3.7 50 4.3 50 4.0 50 53.0 50 4.4 50 13.0 50 2.0 50 1.0 50 4.0 50 2.1 50 2.0 50 1.1 50 5.2 50 3.4 50 2.0 50 1.1 50 3.7 50 4.9 50 2.0 50 1.2 50 4.5 50 7.7 50 3.0 50 1.3 50 4.7 50 6.8 50 6.0 50 17.6 50 3.7 50 17.5 50 4.0 50 1.4 50 3.1 50 10.1 52 6.0 52 1.1 52 2.7 52 11.1 54 2.0 54 1.1 54 3.4 54 2.4 54 2.0 54 1.2 54 3.6 54 4.7 54 2.0 54 1.3 54 3.9 54 5.5 54 2.0 54 1.2 54 3.6 54 8.4 54 2.0 54 1.1 54 3.6 54 9.2 54 3.0 54 1.1 54 4.0 54 12.4 54 2.0 54 2.4 54 3.9 54 14.7 54 4.0 54 1.5 54 5.0 54 18.6 58 2.0 58 1.1 58 4.6 58 3.6 58 2.0 58 4.3 58 3.6 58 11.1 Rs= 0.09 Rs= 0.11 Rs= 0.04 Rs= 0.03 5. Average Width vs Sediment Moisture 6. Average Height vs Sediment Moisture 7. Maximum Depth vs Sediment Moisture 8. Average Slope vs Sediment Moisture XY XY XY XY 49 9.9 49 11.1 49 4.1 49 85.0 49 14.3 49 14.9 49 3.1 49 90.0 49 12.1 49 12.8 49 3.5 49 65.0 49 13.2 49 11.5 49 6.0 49 72.5 49 11.0 49 10.9 49 7.9 49 65.0 49 10.8 49 10.1 49 6.9 49 55.0 49 4.0 49 5.8 49 4.4 49 78.0 49 10.8 49 11.0 49 5.8 49 45.0 49 9.9 49 10.7 49 6.5 49 46.7 49 12.0 49 11.8 49 7.8 49 70.0 49 11.0 49 13.0 49 8.1 49 52.5 49 9.4 49 9.5 49 2.9 49 50.0 49 16.6 49 16.7 49 3.6 49 90.0 50 7.8 50 8.1 50 1.5 50 45.0 50 11.2 50 9.4 50 2.2 50 90.0 50 9.4 50 10.6 50 1.7 50 75.0 50 11.1 50 10.0 50 3.3 50 68.0 50 13.7 50 10.2 50 3.3 50 65.0 50 13.2 50 10.4 50 3.6 50 75.0 50 10.1 50 10.5 50 6.8 50 78.0 50 11.4 50 11.5 50 6.5 50 70.0 50 11.4 50 10.5 50 8.2 50 65.0 50 13.7 50 10.3 50 1.8 50 20.0 50 17.7 50 12.1 50 4.4 50 65.0 50 13.6 50 13.7 50 2.1 50 90.0 50 15.2 50 16.5 50 2.8 50 45.0 50 11.0 50 11.5 50 4.2 50 70.0 50 13.9 50 13.9 50 5.7 50 55.0 50 12.7 50 15.6 50 5.2 50 55.0 50 10.8 50 12.2 50 7.7 50 85.0 50 10.2 50 8.3 50 1.1 50 20.0 52 9.8 52 6.1 52 2.8 52 37.5 54 10.8 54 11.4 54 2.1 54 75.0 54 12.0 54 12.7 54 3.6 54 65.0 54 12.8 54 12.7 54 4.1 54 61.7 54 12.1 54 11.0 54 6.9 54 72.5 54 12.3 54 10.0 54 8.7 54 77.5 54 13.6 54 11.3 54 8.0 54 70.0 54 11.3 54 12.4 54 8.4 54 75.0 54 16.8 54 13.4 54 7.4 54 50.0 58 14.7 58 12.2 58 3.3 58 90.0 58 11.6 58 10.0 58 3.1 58 35.0 Rs= 0.26 Rs= -0.01 Rs= -0.07 Rs= -0.01

304

APPENDIX 6: DETAILED STRATIGRAPHIC COLUMNS

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