A PALEODEPOSITIONAL RECONSTRUCTION OF MIDDLE MIOCENE CETACEAN BONEBEDS FROM THE TOPANGA FORMATION, NORTHERN SAN JOAQUIN HILLS, ORANGE COUNTY, CA ______
A Thesis
Presented to the
Faculty of
California State University, Fullerton ______
In Partial Fulfillment
of the Requirements for the Degree
Master of Science
in
Geological Sciences ______
By
Alyssa Beach
Adam D. Woods, Committee Chair Nicole Bonuso, Member, Department of Geology Jere Lipps, Member,Department of Geology
Spring 2016
ABSTRACT
Cetacean bonebeds containing multiple articulated individuals are extremely rare, with only a handful of occurrences documented worldwide. In 1997, three bonebeds containing mostly articulated and well preserved cetacean remains were uncovered during grading in sedimentary rocks assigned to the Paularino Member of the Topanga Formation near Bonita Canyon, Newport
Beach, California. Multiple bonebeds within a single stratigraphic unit, such as those discovered at Bonita Canyon Planning Area 26, represent a rare class of deep marine fossil accumulations that have not been previously studied in detail. Taphonomic, stratigraphic, and geochemical data was collected from fourteen jacketed specimens removed from Bonita Canyon Planning Area 26 in order to determine the paleoenvironmental conditions that led to the accumulation of the bonebeds and to shed more light on these types of fossil accumulations. Results of this study indicate that the Bonita Canyon bonebeds do not represent a condensed facies, as previously proposed (The Keith Companies, 1998); rather they represent a composite concentration deposited in a continental shelf environment during a period of high sedimentation rates, where episodes of high energy gravity flows alternated with periods of low energy accumulation along a
NE-SW trending submarine fan sequence. High net rates of sedimentation correspond with the creation of high accommodation space as the result of the opening of the Los Angeles Basin, a progressive marine transgression, and subsidence of the Topanga Basin as the result of the shift in the tectonic regime along western North America from a subduction zone to transform margin during the mid to late Miocene. Overall, this study provides valuable insight into the
ii sedimentologic and taphonomic processes that lead to the formation of cetacean bonebeds, and demonstrate that high sedimentation rates may lead to well-preserved cetacean remains.
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TABLE OF CONTENTS
ABSTRACT ...... iii
LIST OF TABLES ...... vi
LIST OF FIGURES ...... vii
ACKNOWLEDGMENTS ...... viii
Chapter 1. INTRODUCTION ...... 1
Background ...... 1 Topanga Formation, Orange County ...... 7 Shark Tooth Hill ...... 11 Bonita Canyon Planning Area 26 ...... 12 Goals and Objectives ...... 19
2. METHODS ...... 21
Specimen Removal ...... 21 Specimen Preparation ...... 22 Taphonomy ...... 23 Field Map Reconstruction ...... 24 Paleocurrent Analysis ...... 24 Sedimentology ...... 25 Petrography ...... 25 Microfossils ...... 26 Geochemistry ...... 26
3. RESULTS ...... 28
Bonebed of Origin ...... 28 Taphonomy ...... 29 Paleocurrent Analysis ...... 35 Sedimentology ...... 38 Microfossils ...... 41 Geochemistry ...... 42
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4. DISCUSSION ...... 44
Taphonomy ...... 44 Geochemistry ...... 45 Sedimentology ...... 47 Paleocurrents ...... 48 Microfossils and Age ...... 48 Depositional Model...... 48
5. CONCLUSION ...... 53
BIBLIOGRAPHY ...... 56
APPENDICES ...... 59
A. FIELD MAPS ...... 59 B. JACKET DATA SHEETS ...... 157 C. TAPHONOMY MEASUREMENTS ...... 172 D. JACKET SPECIMEN PHOTOGRAPHS AND PHOTO LOG ...... 178 E. THIN SECTION PHOTOGRAPHS ...... 205
LIST OF TABLES
Table Page
1. Biostratinomic Features ...... 2
2. Taphonomic Results ...... 30
3. Geochemical Results...... 43
LIST OF FIGURES
Figure Page
1. Simplified Cross-section ...... 8
2. Generalized Miocene Lithostratigraphy and Paleoenvironments ...... 9
3. Location Map of Bonita Canyon Planning Area 26 ...... 13
4a. Stratigraphic Column of the Upper Section ...... 15
4b. Stratigraphic Column of the Lower Section ...... 16
5. Map of Excavation Area ...... 20
6. Photograph of Fossil Preparation ...... 22
7. Photographs of Fossil Preservation ...... 31
8. Photographs of Coatings ...... 32
9. Photographs of Matrix Infilling ...... 33
10. Photograph of Fossil Fragmentation ...... 34
11. Pie Graph of Degrees of Articulation ...... 35
12. 180° Rose Diagrams ...... 37
13. Photographs of Tuff in Thin Section ...... 39
14. Photograph of Burrows ...... 40
15. Photograph of a Cross-section with Burrows ...... 40
16. Photograph Lenticular Features ...... 41
17. Photograph of Microfossils ...... 42
ACKNOWLEDGMENTS
I wish to express my upmost gratitude to Dr. Adam Woods who was eager to give constant support, invaluable guidance, and encouragement throughout my thesis project. I would also like to thank Dr. Jere Lipps for granting me access to the Bonita Canyon fossils, providing me with a space to conduct my research while at The Cooper Center, and providing valuable expertise. I thank Dr. Nicole Bonuso for providing me with valuable feedback during my thesis review period. I am grateful for the staff at The Cooper Center, namely Meredith Rivin, Crystal Cortez, Michelle Barboza, and Gabriel Santos, for showing me the ropes and assisting me during my research while at The Cooper Center. I recognize all the professors and staff at CSU, Fullerton for providing world-class instructional support during my career as a graduate student. I thank Dr. Ken Finger of UC Berkeley for identifying the sponge spicules. Lastly, I would like to express my gratefulness and appreciation to my close family and friends, specifically my mother and husband, for providing me with much needed emotional support and countless hours of babysitting services for my two children, who without, none of this would have been possible. And a big thanks to Sean and Ivory for being such awesome kids.
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1
CHAPTER 1
INTRODUCTION
Bonebeds are stratigraphically-thin accumulation of vertebrate hard parts that consist of multiple individual of one or more species (Pyenson et al., 2009). Taphonomic, sedimentological, and geochemical observations have been used as proxies for paleodepositional conditions for both terrestrial and shallow marine bonebeds (Brett and
Baird, 1986; Kidwell, 1991; Tribovillard, 2006). However, since deep marine environments are difficult to access, modern analogs for the accumulation of vertebrate hard parts in deeper marine setting are not well established. Therefore relatively little is known about the taphanomic processes and depositional conditions that lead to deep marine fossil accumulations (Roger et al., 2007).
Background
Taphonomy is the study of the processes involved in fossil preservation, which can be divided into two general stages: 1) biostratinomy, which are the mechanical, chemical and biological processes acting on an organism beginning at the time of death until final burial, and 2) diagenesis, which are the mechanical, chemical and biological processes that ensure following burial (Brett and Baird, 1986). The biostratinomy stage can be further subdivided into four generally sequential processes: 1) reorientation and transportation, 2) disarticulation, 3) fragmentations, and 4) corrosion (i.e. abrasion and bioerosion) (Brett and
Baird, 1986). Reorientation and disarticulation typically occur immediately following death
2 and have been documented even in low energy environments (Brett and Baird, 1986); fragmentation and corrosion occur after protective soft tissue is removed, indicating more prolonged exposure on the seafloor (Brett and Baird, 1986). The quality of preservation of fossil material is mostly the result of biostratinomy and early diagenesis, which are closely related to original environmental conditions (Brett and Baird, 1986); therefore, the effect of both stages on fossil material can be used as proxies for paleoenvironmental reconstructions
(Table 1).
Table 1. Biostratinomic features produced by different sedimentation rates and depositional energies seen on three main skeletal types. Complete removal of soft tissue is assumed. (Modified from Brett and Baird, 1986).
Sedimentation Rate Energy Skeletal Type Very Rapid Intermediate Low
Fragile Minor Fragmentation Strong Fragmentation Absent
Partially Articulated; Disarticulated; High Robust Mostly Articulated Some Fragmentation Fragmented; Abraded Partially Articulated; Disarticulated; Pieces Multi-element Mostly Articulated Pieces Sorted Sorted Strong Fragmentation; Fragile Intact Some Fragmentation Corrosion Disarticulated; Minor Low Robust Articulated Mostly Articulated Fragmentation; Corrosion Partially Articulated; Disarticulated; Non- Multi-element Completely Articulated non-sorted sorted
Dense accumulations of marine fossils can be organized into four broad categories based on accumulation history (Kidwell, 1991), with each exhibiting characteristic stratigraphy and taphonomy, as follows:
(1) Event Concentrations record single depositional events within the scale of a
single laminae or bed (Kidwell, 1991). Evidence for these accumulations include
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erosional surfaces, hydraulic winnowing, infilled burrows and lenticular scour
that typify rapid burial such as storms events, turbidity currents, and gravity flows
(Kidwell, 1991). If specimens were buried soon after death, fossils will be
articulated and well preserved. However, due to the large array of possible
depositional scenarios, event concentrations can show great variation in terms of
geometry, sedimentology, and taphonomy (Kidwell, 1991).
(2) Composite Concentrations are amalgamated beds or bedsets that record multiple
depositional events, often with more complex and lengthier histories than single
event concentrations, and are typically equal or greater in thickness relative to
coeval strata (Kidwell, 1991). While not all events may be preserved, and each
layer may have its own unique set of characteristics, which, when combined, can
provide information about the overall depositional conditions over time. These
accumulations may vary significantly with regards to stratigraphic thickness,
matrix content, and taphonomic characteristics (Kidwell, 1991).
(3) Condensed or Hiatal Concentrations are similar to composite concentrations,
however they are thin relative to coeval strata due to slow net rates of
sedimentation (Kidwell, 1991). Fossils and surrounding sediment may exhibit
evidence of long-term exposure, such as poor preservation, bioturbation, matrix
infilling, and mineral precipitation as coatings or infillings of porous bone
structures (Kidwell, 1991). Small skeletal elements may exhibit preferred
orientations or be missing completely (Brett and Baird, 1986). The base of large
elements may show a greater degree of preservation compared to bone surfaces
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that were exposed for longer periods higher above the sediment-water interface
(Brett and Baird, 1986).
(4) Lag Concentrations represent significant stratigraphic truncation either by erosion
or corrosion, which uncovers and concentrates fossils and sediment via selective
removal. Evidence for this process includes well sorted, coarse grains; bones may
exhibit unimodal or bimodal orientations, fragmentation, or abrasion (Kidwell,
1991).
Furthermore, the cause of death may also provide evidence of paleodepositional conditions, as follows:
(1) Mass die-offs typically result from environmental stress (e.g., volcanic eruptions,
temperature changes, anoxia, etc.); evidence of environmental stress may be recorded
in the sediment with the fossils (e.g. volcanic ash, mineral precipitation, etc.; Woods
and Bottjer, 2000). Mass die-offs typically affect large areas and/or ecosystems
resulting in contemporaneous polyspecific fossil accumulations containing all age
groups.
(2) Mass strandings typically occur to entire whale pods in intertidal marine
environments; therefore fossils will represent all age groups belonging to a single
species and may contain evidence of predation, scavenging, and abrasion from wave
action unless burial is very rapid (Brett and Baird, 1986).
(3) Calving grounds typically occur in protected, quiet, shallow marine environments,
similar to modern calving grounds in lagoons along Baja California (Olson, 1990).
Fossil accumulations of calving grounds will be composed exclusively of female
adults and newborn cetacean individuals, however, rare juvenile skeletons may also
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be found. Calving grounds commonly attract predators (see Predation), which may
contribute teeth and the rare skeleton of a predator to the fossil deposit.
(4) Predation typically befalls weaker individuals, such as the injured, elderly, or young,
and may involve multiple species. However, since cetaceans are migratory species,
accumulations of multiple individuals in one location from predation is unlikely,
except, for example if predation occurs in an established calving or feeding ground.
Bones may exhibit evidence of predation, such as bite marks and the sediments may
contain teeth and the rare skeleton of a predator.
Most whale carcasses sink immediately following death (Allison et al., 1991). Bloat and Float occurs when the abdominal cavity of a carcass bloats from gases produced during decay, causing the carcass to buoyantly rise to the surface (Allison et al., 1991). Soft tissue rupture releases these gases and typically occurs during scavenging by large predators
(Allison et al., 1991). The skull, fluke, and fins are often lost from carcasses subjected to prolonged post-mortem floatation (Allison et al., 1991). Floatation may not occur under certain conditions, such as rapid removal of soft tissue (which typically results in disarticulation), cold temperatures that inhibit microbial activity, sufficient and catastrophic burial, and if the carcass initially sinks to depths where pressures are greater than 200 atm, and prevents subsequent flotation (Allison et al., 1991). However, the precise conditions necessary to prevent floatation depends on the size and species of the carcass (Allison et al.,
1991).
Whale falls involve an individual carcass deposited on the seafloor, which provides an abundant source of organic matter in a setting that is typically scarce in resources (Smith and Baco, 2003). Studies of modern deep-sea whale falls demonstrate that carcasses undergo a predictable sequence of ecological stages determined by benthic conditions (Belaústegui et
6 al., 2012; Smith and Baco, 2003). Each of the four stages yield distinctive sedimentological and taphonomic signatures, keeping in mind that extreme conditions such as low temperature, high pressure and anoxia may hinder or even halt biologic activities (Allison et al., 1991), as follows:
STAGE I: The Mobile Scavenger Stage occurs when the majority of protective soft tissue is removed by large, mobile scavengers (e.g. sharks and hagfish) (Smith and Baco,
2003), which may leave marks, scratches, and grooves on bone as well as embedded or loose fossil shark teeth. This stage may take month to years to complete (Smith and Baco, 2003).
STAGE II: The Enrichment Opportunist Stage occurs when heterotrophic macrofaunal opportunistic species, such as polychaetes and crustaceans, colonize the bone and nutrient-rich sediments adjacent to the skeleton (introduced by the decaying whale carcass and affecting an area of up to 3 meters around the remains) (Smith and Baco, 2003).
STAGE III: The sulphophilic Stage involves sulfide-tolerant and chemoautotrophic organisms that consume sulfide emitted by the anaerobic decomposition of bone lipids
(Smith and Baco, 2003). Decay of remaining soft tissue might also emit methane via endosymbiotic methanotrophs (Smith and Baco, 2003). Some bacteria promote in vivo mineral precipitation, which may preserve outlines of any remaining soft parts (Allison et al.,
1991). Evidence for this stage may include precipitates, such as iron sulfides, caused by bacterial growth in sediments and on bone surfaces, cracks, and Haversian canals, as well as fossil and trace fossil evidence of isopods, mytilidae, limpets, and polychaetes (Smith and
Baco, 2003). Growth of sulfide minerals (e.g. pyrite) and enrichment of related trace elements, such as zinc and copper, may also occur (Tribovillard et al., 2006). This stage may
7 take several decades to complete, depending on the size of the carcass (Smith and Baco,
2003).
STAGE IV: The Reed Stage only occurs once all organic matter is completely removed, possibly decades after death, allowing epifaunal suspension feeders to colonize the hard substrate of the skeletal remains (Smith and Baco, 2003). Evidence for this stage may include abundant fossilized epifaunal organisms and extensive bioerosion, abrasion, and fragmentation of bone material (Smith and Baco, 2003).
Topanga Formation, Orange County
During the early to middle Miocene (23-11 Ma), much of coastal California experienced a progressive marine transgression (Raschke, 1984). By the end of the middle
Miocene, Orange County was nearly all marine except for the tops of the ancestral Santa Ana
Mountains (Figure 1) with an array of isolated, tectonically subsiding marine basins located offshore (Cooper and Sawlan, 2008). These conditions led to the accumulation of one of the most complete, thick, and interfingered marine and terrestrial fossil-bearing sedimentary sequences known from this time period (Raschke, 1984), and includes the Topanga
Formation (Figure 2).
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Figure 1. Simplified cross-section showing bathymetry and geology from the Santa Ana Mountains (east) to the San Pedro Basin (west) during the late Miocene (Modified from Cooper and Sawlan, 2008).
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Accomodation Epoch Stage Formation Member Paleoenvironment Mega-sequence Tectonism Low High
Deep marine; slope to basin
Messinian
Siltstone Los Angeles Basin
Capistrano filling
Upper Miocene Upper Outer Shelf to slope to Transpression
Tortonian basin floor
Monterrey
Nonmarine Outer Shelf landslides, to slope debris flows, Paulerino alluvial fans,
Serravallian marine debris
San Onofre Breccia San Los Angeles Basin Nearshore to flows, opening Transtension
Topanga mid to outer turbitidy
Middle Miocene Middle shelf flows
Los TrancosLos
Langhian Marine shoreface to Transrotation offshore to inner shelf
Bommer
Offshore marine: mid to
Burdigalian outer shelf Coastal Clastic Wedge
Vaqueros Nearshore marine: LowerMiocene shoreface to inner shelf; Aquitanian tidal flat
Figure 2. Generalized Miocene lithostratigraphy and paleoenvironments of the San Joaquin Hills, and the regional accommodation curve related to the tectonic evolution of the Los Angeles Basin (Modified from Cooper and Sawlan, 2008).
The Topanga Formation marks the beginning of serval pulses of late to early middle
Miocene tectonic extension that opened a series of depocenters, which later culminated to form the Los Angeles Basin (Cooper and Sawlan, 2008). Also during this time, the region experienced a major shift in plate boundary regimes with the subduction of the Farallon plate coming to an end and the development of the San Andreas transform fault system.
In the Santa Ana Mountains, the Topanga Formation consists of cross-bedded sandstone with interbedded siltstone, and contains abundant near-shore, shallow-marine fauna such as mollusks, barnacles, and sand dollars (Cooper and Sawlan, 2008). In the San
Joaquin Hills, southeast of the Santa Ana Mountains, the Topanga Formation formed on the
10 edge of a rapidly subsiding structural trough, termed the Capistrano Embayment, during a subtropical to warm climatic period (Ingle, 1979), and is much thicker, exemplifying the increasing accommodation space indicative of a marine transgression (Cooper and Sawlan,
2008).
Overall, the Topanga Formation was deposited near the depocenter of the Topanga
Basin, which was located on the edge of the rapidly subsiding Capistrano Embayment, during the transtensional phase of the Los Angeles Basin evolution (Ingersoll and Rumelhart,
1999).
Except in the eastern San Joaquin Hills where the Topanga Formation is undifferentiated, it is divided into three members, from oldest to youngest, the lower
Bommer Member, the middle Los Trancos Member, and the upper Paularino Member
(Vedder et al., 1957). The Bommer Member is a fine to coarse, thickly bedded sandstone with local cross-stratification, and contains marine invertebrates and vertical trace fossils indicative of a shallow marine shelf to shoreface depositional environment (Cooper and
Sawlan, 2008). The middle Los Trancos Member consists of fine to medium grained sandstone interbedded with mudstone containing horizontal trace fossils, abundant plant remains as well as some paleocurrent structures and graded bedding (Cooper and Sawlan,
2008). The Paularino Member is composed of interbedded tuffaceous sandstone, siltstone, and mudstone (Cooper and Sawlan, 2008); the base of which is marked by discontinuous andesite flow breccias (Cooper and Sawlan, 2008). Foraminiferal microfauna indicates a neritic outer shelf to bathyal slope paleoenvironment that was subjected to marine debris flows and turbidity flows (Ingle, 1976; Cooper and Sawlan, 2008). The Paularino Member also includes non-marine facies, including landslides, debris flows, and alluvial fans (Figure
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2; Cooper and Sawlan, 2008). In the San Joaquin Hills, the Topanga Formation is found intertonguing with and is overlain by the San Onofre Breccia, which is derived from Catalina
Schist to the west (Cooper and Sawlan, 2008). Small scale cross-beds documented in the
Topanga Formation exposed in the San Joaquin Hills indicate a dominant flow direction to the southwest in a submarine fan depositional environment (Blair, 1978).
Shark Tooth Hill
Shark Tooth Hill is located in the southeastern San Joaquin Basin, California and is one of the largest marine vertebrate bone accumulations known (Pyenson et al., 2009). Shark
Tooth Hill has been correlated with the Topanga Formation based on the presence of similar taxonomic fauna, including seven genera of odontocetes and three genera pinnipeds
(Raschke, 1984). The Shark Tooth Hill bonebed is a single, thin (10-50 cm) layer containing abundant marine and rare terrestrial vertebrate elements underlain by bioturbated mudstone and embedded in a 180 m thick unit of poorly consolidated siliciclastic silts and sands
(Pyenson et al., 2009). Vertebrate remains within the bonebed are disarticulated and dissociated, and show evidence of abrasion and scavenging (Pyenson et al., 2009).
Specimens above the bonebed are articulated or the bones are associated in close proximity to each other, but not articulated, and are commonly surrounded by carbonate concretions
(Pyenson et al., 2009). Overall, the degree of preservation strongly indicates that Shark Tooth
Hill represents a condensed bone accumulation deposited over a long period of time, with little or no net sedimentation, followed by an increase in sedimentation rates, which led to deposition of an overlying gradation unit containing well preserved associated and articulated fossils (Pyenson et al., 2009).
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Only a handful of documented, well preserved and articulated cetacean fossils have been discovered in southern California, and include: 1) fossils from Monarch Beach, located in Aliso Viejo, California (The Keith Companies, 1998), which yielded two partly articulated cetacean skeletons; 2) a well preserved ‘bonebed’ containing cetaceans, pinnipeds, shark teeth and a bat ray tooth discovered in undifferentiated Topanga Formation in the northern
Santa Ana Mountains (Cooper and Sawlan, 2008); and, 3) the Bonita Canyon Planning Area
26 bonebeds, which are the focus of this study.
Bonita Canyon Planning Area 26
In 1997, the Bonita Canyon Planning Area 26 grading project uncovered three bonebeds of cetacean skeletal remains in Newport Beach, California (The Keith Companies,
1998). The site yielded at least 11 articulated to semi-articulated specimens, including multiple large and small Mysticeti, one primitive Archaeoceti, possibly one Odontoceti, and one large rare or previously undocumented specimen (The Keith Companies, 1998).
Additionally, the site contained fossil fragments and teeth from several shark species, invertebrate burrows, coprolites, fish fragments, woody plant fragments, bivalve casts, and two leaf impressions (The Keith Companies, 1998).
Bonita Canyon Planning Area 26 lies on a Pleistocene-age wave cut bench formed during local uplift of the San Joaquin Hills (Cooper and Sawlan, 2008). The main area of discovery was located on the east-facing slope of a north-trending tributary to Bonita Canyon
(The Keith Companies, 1998), approximately 100 meters from the Bonita Canyon Drive bridge and east of the intersection between MacArthur Blvd and Bonita Canyon Drive
(Figure 3).
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Bonita Canyon Bonebeds
Figure 3. Location map of Bonita Canyon Planning Area 26, northern San Joaquin Hills (SJH), Newport Beach, California (Modified from Cooper and Sawlan, 2008). Red lines delineate major faults. Inset: the approximate area of excavation is delineated in yellow (Google Earth™, 2015).
The lowermost sediments exposed at Bonita Canyon Planning Area 26 consist of gray to dark gray, massive, tuffaceous siltstone with lenses of coarse, poorly sorted sand, pebbles, and boulders, some of which may be reworked from the San Onofre Breccia (Figure 4b; The
Keith Companies, 1998) and are typical of the Paularino Member (Miller and Tan, 1976).
Samples from this unit indicate deposition in a deep marine, low energy environment (The
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Keith Companies, 1998). On the contrary, the uppermost sediments at Bonita Canyon
Planning Area 26 are tan to brown with coarser matrix comprised of fine to coarse sand with silt and reddish oxidation streaks (Figure 4a; The Keith Companies, 1998). Although the upper sediments were initially assigned to the overlying Capistrano Formation (Morton and
Miller, 1981), The Keith Companies (1998) suggest this unit may be a physically different facies than in previously documented Paularino Member outcrops, or may possibly be the result of localized reworking of older Paularino Member sediments.
The Keith Companies (1998) mitigation report describes three cetacean bonebeds, and refer to the lower two bonebeds as the ‘main bonebed’, along with isolated specimens occurring above and below the three bonebeds (Figure 4a and b). While most of the upper bonebed and isolated specimens consisted of scrappy fragments not worth of salvage, many specimens from the lower two bonebeds were excavated and removed from the site (The
Keith Companies, 1998). The initial excavation, composed of a North and South Block, was quarried using a metric grid system with an arbitrary datum (Figure 5) and measured approximately 20 by 25 meters. This area yielded at least 11 cetacean individuals and some shark remains, most of which were photographed and illustrated (Appendix A; The Keith
Companies, 1998). A second, smaller excavated area was locate approximately 100 meters south of the initial excavation; although well preserved, all of the specimens found in this area were considered outside of the scope of recovery and were subsequently covered and preserved in situ (The Keith Companies, 1998). Bone fragments recovered from two boring adjacent to the site indicate that bonebeds extend beyond the excavated areas (The Keith
Companies, 1998).
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Figure 4a. Stratigraphic column of the upper section (continues uninterrupted with the lower section) of Bonita Canyon Planning Area 26 excavation; modified from field descriptions by John D. Cooper (The Keith Companies, 1998). Cl = Clay, St = Silt, FS = Fine Sand, MS = Medium Sand, CS = Coarse Sand, G = Gravel.
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Figure 4b. Stratigraphic column of the lower section (continues uninterrupted with the upper section) of Bonita Canyon Planning Area 26 excavation; modified from field descriptions by John D. Cooper (The Keith Companies, 1998). Cl = Clay, St = Silt, FS = Fine Sand, MS = Medium Sand, CS = Coarse Sand, G = Gravel.
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Bonebed 1, the uppermost bonebed, contains the initial discovery that led to unearthing of the fossils. This level occurs in a sandy pebble to boulder conglomerate lens surrounded by a massive sandy silt (The Keith Companies, 1998). This bonebed contains disrupted skeletal remains of at least three cetacean specimens: 1) the articulated vertebral column and ribs of a primitive Archaeocete species; 2) associated lower jaws of a large Mysticete; and 3) a small disarticulated Mysticete skeleton, partially imbedded into finer siltstone at the base of Bonebed 1 (The Keith Companies, 1998). Some shark teeth, including a Carcharocles megalodon tooth fragment, and the majority of Laminid shark vertebrae found at Bonita Canyon Planning Area 26 were recovered from this bonebed, as well as a leaf impression (The Keith Companies, 1998). Specimens found at the top of this bonebed are fragmented and exhibit evidence of abrasion and were not considered worth of salvage (The Keith Companies, 1998).
The lower two bone-bearing zones (Bonebed 2 and 3) are described as separate levels within a ‘main bonebed’ by the Keith Companies (1998). The appearance of separate bonebeds may be an artifact of how the quarry was exposed, with specimens simply deposited sequentially on top of one another (The Keith Companies, 1998).
According to The Keith Companies (1998) mitigation report, all specimens considered worthy of salvage from Bonita Canyon Planning Area 26 originated from Bonebeds 2 and 3.
Bonebed 2 contains well preserved, loosely clustered remains of at least four small Mysticetes and possibly one Odontocete discovered in a sandy siltstone that coarsens upwards to fine sand with sparse, floating coarse sand and gravel (The Keith
Companies, 1998). Several specimens were semi-articulated, however the lower
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18 dentaries’, phalanges, and tympanic bullae were found a short distance away from the skulls (The Keith Companies, 1998). The ribs and sternal elements were not found in close associated with the skulls and vertebral columns (The Keith Companies, 1998).
The lowermost bonebed, Bonebed 3, contains at least four small to large
Mysticete specimens occurring in the lower gray siltstone as clustered skeletal elements that are partly or completely articulated (The Keith Companies, 1998). A large articulated
Mysticete skeleton was missing the fluke and some caudal vertebrae, yet measured 28 feet from the tip of the lower jaw to the end of the vertebral column (The Keith
Companies, 1998). Elements present for each of these specimens includes skulls, shoulders, tympanic bullae, ribs, and pectoral girdle elements found in anatomical position or in close association (The Keith Companies, 1998). All of these skeletal elements were enveloped in a soft, dense, concretionary silt and are well preserved (The
Keith Companies, 1998). Skeletal elements from two or three individuals occur immediately below these specimens, however they are not encased in concretions (The
Keith Companies, 1998). Sparse, tube-shaped vertical burrow (~1 cm in diameter) occurred throughout this bonebed (The Keith Companies, 1998).
Only a few bone fragments have been recovered from the Paularino Member outside of Bonita Canyon Planning Area 26; therefore, this discovery represents virtually
100% of all known vertebrate fossils from the Paularino Member, and represents the entire paleontological sample of marine life during this slice of the Miocene in Orange
County (Cooper and Sawlan, 2008). The high density of mostly articulated cetacean individuals and the low diversity of taxa found within three stratigraphic bonebeds within
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19 the Paularino Member makes this site regionally unique and globally significant in the fossil record.
Goals and Objectives
The primary goal of this study is to test the hypothesis proposed by The Keith
Companies (1998) that the main bonebeds accumulated in a low energy, deep marine environment over a long period of time, as the result of low sedimentation rates, and therefore represent a condensed concentration. The taphonomic, sedimentologic, and geochemical methods performed during this study were selected to evaluate if evidence of prolonged exposure exist in the Bonita Canyon bonebeds. In addition, this study represents the first comprehensive scientific analysis of the cetacean remains discovered at Bonita Canyon Planning Area 26. Data presented herein provides new paleontological, sedimentological, and geochemical results that allow a better understanding of paleoenvironmental conditions from the Relizian to the Luisian ages of the middle
Miocene in Orange County, California, which had previously been disproportionately lacking when compared to the wealth of information gathered from elsewhere in the region during the other ages of the Miocene. Furthermore, the Bonita Canyon bonebeds represent a very rare class of deep marine fossil accumulations from which relatively little is known. This study provide insight into the taphonomic processes and depositional conditions that can lead to the accumulation of multiple bonebeds containing well preserved and articulated specimens within a single stratigraphic unit and adds to the world’s repertoire of such occurrences.
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Figure 5. Map of excavation area, showing grids where specimens were discovered, as well as whether specimens were collected or not collected (Compiled from The Keith Companies, 1998)
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CHAPTER 2
METHODS
Specimen Removal
The majority of fossil specimens exposed during the excavation phase at Bonita
Canyon Planning Area 26 were bagged or encased in plaster jackets before being removed from the site; approximately 140 jackets were prepared and removed (The Keith Companies,
1998). The jacketed specimens were prepared in situ, as follows: First, the upper surface of each skeletal element was exposed using trowels, brushes, and dental picks in order to determine its position, which was mapped, and the fossils were photographed. Fourth to ten inches of sediment was left intact around the sides and base of each element to support and protect the bone. Each block was then undercut and encased in layers of wet paper, plaster- saturated burlap, and an outer coating of plaster (The Keith Companies, 1998). The remains of at least four well preserved whales, several shark vertebrae, and several poorly preserved specimens were beyond the defined scope of recovery, and were subsequently stabilized and covered with up to seven feet of fill and left in situ (The Keith Companies, 1998). The jacketed specimens were removed from the site and taken to the Advanced Technology &
Education Park in Tustin, California were they remained in storage in two 10 by 40 foot shipping containers until 2012 when they were transported to The Dr. John D. Cooper
Archaeological and Paleontological Center (The Cooper Center), located in Santa Ana,
California.
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Specimen Preparation
Preparation of accessible, smaller jackets began in March 2014 at The Cooper Center and is ongoing. The preparation process begin with cutting open the plaster jacket using a reciprocating saw (Figure 6). Care is taken to not cut beyond the plaster to avoid damaging the encased skeletal element(s).
Figure 6. Photograph of fossil preparation, a jacket opened at The Cooper Center using a reciprocating saw.
Unless marked, it is assumed that the top of each jacket is equivalent to the side containing the exposed skeletal element(s), that were exposed during excavation, Sediment is then meticulously removed using dental tools, trowels, brushes, and utility knives to expose any additional bone or trace fossils. Once the upper surface of an element of interest is exposed, approximately one inch of sediment is left intact underneath the element for support. Next, an acrylic paraloid resin is generously applied and allowed to penetrate the
bone and/or sediment. Resin is repeatedly applied until it is no longer absorbed. A minimum 22
23 of one hour is given to allow the resin to dry completely before removed the remaining sediment. Any significant sedimentary structures or burrows are notes and/or preserved if possible. Elements removed from the jackets are assigned an Orange County Paleontological
Collection (OCPC) number and placed in storage at The Cooper Center for further study. At the time of this study, at total of 26 jackets had been opened and preparation begun or completed. Fourteen of the 26 opened jackets were sampled and documented for this project, however seven of the jackets studied had been prepared prior to this study and most or all of the sediment had been discarded; therefore data from these jackets was limited.
Taphonomy
Taphonomic features were documented for 27 skeletal elements collected from thirteen of the fourteen observed jackets, and included quality of preservation (Appendix B), orientation (See Paleocurrent Analysis and Appendix C), and articulation (Appendix C).
Individual ratings were given for abrasion, fragmentation, remineralization, bioerosion, and overall quality of preservation as observed on each skeletal element. Assuming no soft tissue was preserved, a scale of 1 to 5 was used, as follows: (1) none observed, (2) minor, (3) significant, (4) highly, and (5) completely (Brett and Baird, 1986; Kidwell, 1991). If a specimen was completely fragmented or if the outer bone surface was absent, then no rating was given for abrasion or bioerosion. Quality of preservation was quantified separately based on the overall taphonomic characteristics of each skeletal element. Since taphonomic features were similar for jackets containing multiple elements, only one set of ratings was recorded for each jackets (Appendix B).
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Field Map Reconstruction
The excavation areas were mapped using a (1 m by 1 m) metric grid system to archive the spatial relationships of specimens as they were uncovered (The Keith Companies,
1998). Each field map consists of a block number, coordinate, a north arrow, jackets number(s), and additional information such as cast number, type of skeletal element, etc., which were not noted on all field maps (Appendix A). Over 90 pages of field maps consisting of one or more specimens were used to reconstruct a map view of the excavated areas to show the aerial extent, orientation, and degree of articulation of the skeletal remains.
Unfortunately, several field maps were mislabeled or missing important information (e.g. coordinates, north arrow, etc.); therefore the locations of these jackets had to be inferred.
The degree of articulation was determined or approximated for most specimens
(Appendix C) based on the distribution of skeletal elements as seen in the reconstructed field map as well as from descriptions in The Keith Companies (1998) mitigation report. Elements in, or very near anatomical position were considered to be articulated or semi-articulated, respectively. Elements that were not in anatomical position but found clustered near other elements considered to be from the same individual were determined to be associated. Lastly, isolated elements were considered to be disarticulated.
Paleocurrent Analysis
Where possible, the in situ, azimuthal orientation of the long-axis of elongate skeletal elements (primarily ribs and dentaries’) and articulated components (primarily vertebral columns and skulls) were measured from the field maps (Appendix C). These measurements were plotted on 180° rose diagrams to determine if any preferred orientation of skeletal elements exists, which indicate paleocurrent direction.
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Sedimentology
Sedimentological features, including lithology (e.g. matrix, color, grain size, and coatings), sedimentary structures (e.g. erosional surfaces, imbrication, and grading), and bioturbation were documented from the fourteen observed jackets (Appendix B).
Sedimentological features were assessed from eight jackets that contained sufficient sediment, which were cut perpendicular to bedding and sanded smooth to expose a large, flat surface. Features from jackets with little remaining sediment were described as best as possible.
Petrography
Thirteen samples of competent bone and/or sediment were collected from eight jackets in order to make thin sections; sediment samples were collected above, at, and below the level as the bone in order to determine if any difference existed between the locations.
Acrylic paraloid resin was generously applied to all surfaces of each sample and allowed to penetrate the bone and/or sediment. Once the resin was dry, the samples were transported to the Department of Geological Sciences at CSU Fullerton. The samples were cut in half using an MK-101 2-horsepower tile water saw then placed in a Thermo-Electron Corp. Precision oven for a minimum of 30 minutes. Once the samples were completely dry, they were impregnated with Hillquist Thin Section Epoxy in a Castable Vacuum System. The cut surfaces were polished and cleaned before being fixed onto a 1-inch by 1-inch optical-grade glass microscope slide using Hillquist Thin Section Epoxy. The samples were then ground to the appropriate thickness and polished for petrographic analysis.
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Microfossils
Microfossils, particularly foraminifera, can be useful in estimating paleodepth in marine environments (Lipps, 1993). Six sediment samples from four jackets were collected for microfossil analysis. Care was taken to remove sediment in as large of a chunk as possible to prevent damaging any microfossils present (Lipps, 1993). The sediment samples were then placed into glass beakers and disaggregated using a combination of heat, water and hydrogen peroxide until all grains were separated (Lipps, 1993). The samples were then sieved to remove particles smaller than 63 microns and placed into a Quincy Lab, Inc. oven set at 120°F (Lipps, 1993). Once completely dry, the sediment was analyzed under 15x magnification using a WILD Heerburgg microscope. Microfossils were manually sorted and glued onto a 1-inch by 2-inch numbered grid slide for further identification.
Geochemistry
Eighteen samples from ten jackets containing sediment and/or bone were analyzed for major, minor and trace element composition. Samples were prepped for analysis using the microwave-assisted acid digestion method of Ziegler and Murray (2007) followed by inductively coupled plasma-atomic emission spectroscopy (ICP-OES) in the ICP lab at the
Department of Geological Sciences at CSU Fullerton. First, the samples were powdered using an IKA© A11 basic lab grinder and placed into clean acetate vials. Next, approximately
0.05 grams of the powdered material was measured and placed into clean Teflon® reaction vessels. A pre-measured pipette with a disposable tip was used to place 6 milliliters (ml) of nitric acid, 2 ml of hydrochloric acid, and 2 ml of hydrofluoric acid into each vessel. Each vessel was then placed into a high pressure sleeve, sealed, and transferred to an Anton Paar Multiwave 3000 microwave digestion system. The temperature was increased to 160°C over 12 minutes, followed by an increase to 210°C over 8 minutes, where the temperature was held for a full 30 minutes. 26
27
The vessels were then cooled for about 30 minutes until reaching a temperature below 50°C. The vessels were immediately opened and 1.0 ml of 30% hydrogen peroxide (H2O2) and 10 ml of 5% boric acid (H3BO3) was added to each vessel using pre-measured pipette with disposable tips.
The vessels were resealed and placed back into the microwave. The vessels were heated a second time to 160°C over 8 minutes and held at a constant 160°C for an additional 7 minutes. The vessels were allowed to cool below 50°C over about 30 minutes, after which the solutions were decanted to 50 ml falcon tubes and diluted to a volume of about 50 ml with ultrapure water. The samples were then analyzed on a Perkin – Elmer Optima 7300 DV ICP-OES housed in the
Department of Geological Sciences at CSU Fullerton.
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CHAPTER 3
RESULTS
Bonebed of Origin
Ideally the bonebed or origin for each specimen should be known in order to understand the specific paleodepositional conditions that led to the formation of each of the three bonebeds at Bonita Canyon Planning Area 26. However, the bonebed of origin was only recorded for seven jackets in The Keith Companies (1998) mitigation report.
Furthermore, determination of the bonebed of origin for the remaining jackets was not possible due to the following discrepancies and lack of information:
(1) Collection Status: The Keith Companies (1998) mitigation report states that only
specimens considered of scientific value from the lower two bonebeds were
salvages. However, sixteen jackets were noted on the field maps to have been
collected from Bonebed 1.
(2) Law of Superposition: Approximately 24 grids contain multiple overlapping
specimens as seen on the reconstructed field map and in Figure 5. However,
indicative sedimentological features and stratigraphic thicknesses separating each
specimen are not noted in the mitigation report. Therefore, inference about the
bonebed of origin based on the law of superposition was impossible. Lastly, no
evidence indicates the bonebed of origin for girds containing a single specimen,
which is the majority of girds.
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(3) Jacket Number Chronology: The reasoning of the numbering system or
chronology of specimen removal is not described in The Keith Companies (1998)
mitigation report. Although the lower numbered jackets were likely removed first
(higher in section), and higher numbered jackets were removed later (lower in
section), specimen removal might have occurred in some other order.
(4) Bonebed Order: The Keith Companies (1998) mitigation report and John D.
Cooper’s stratigraphic column were in reversed order for the numbering of the
three bonebeds and their descriptions. Further confusing the situation is that the
Recovery Plan (The Keith Companies, 1998) only describes two bonebeds,
neither of which correlated with those described in The Keith Companies (1998).
(5) Stratigraphic Correlation: Correlation between John D. Cooper’s stratigraphic
descriptions (Figure 4a and b) and sedimentological descriptions from this study
were not possible due to a lack of detailed descriptions and/or unique
characteristics of the bonebed sedimentology.
Although the bonebed of origin could not be determined for each specimen, the field map reconstruction, John D. Cooper’s stratigraphic column, and descriptions in The Keith
Companies (1998) mitigation report were vital in determining the overall depositional history of Bonita Canyon Planning Area 26.
Taphonomy
Taphonomic features were individually rated on a scale of 1 to 5 for 27 skeletal elements collected from thirteen jackets (Appendix B). Quality of preservation values range between 3 and 4.5, with lower numbers indication a higher degree of preservation (Table 2).
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The results show two distinct degrees of preservation of the observed skeletal elements. Sixteen elements show a moderately high degree of preservation with values ranging from 2 to 3 (Figure 7a; Appendix D), whereas, eleven elements exhibit poor quality of preservation with values between 3.5 and 4.5 (Figure 7b; Appendix D). In addition, the poorly-preserved specimens are also so highly fragmented that no values can be assigned for abrasion or bioerosion (Appendix D).
Table 2. Taphonomic results, well preserved specimens highlighted in light gray. 1 Seen in thin section only. 2 Seen in jacket specimen only. NA = Not Available.
No evidence of remineralization or compaction was evident in the studied skeletal elements, however black coatings are found in sediment and on bone material observed from fine jackets and fine thin sections (Table 2). Irregular-shaped, black blotches (ranging from 1 mm to 1 cm in diameter) were observed on bone surfaces in jacketed specimens (Figure 8a), while thin sections collected from three jackets (001-4, 002-3, and 125-1) reveal a thin (1/4 mm thick) black veneers on bone surfaces (Figure 8b). Similar black blotches form concentric patterns (leisegang rings) in sediment surrounding bone in some jackets (Figures
8c and 8d). These black coatings are believed to be the result of iron sulfide mineral precipitation related to bacterial growth on the decomposing cetacean carcasses. 30
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Three samples (001-4, 125-1, and 204A-3) contain traces (<5%) of matrix within
Haversian canals, and one sample (002-3) contains hematite partially infilling (<5%) of
Haversian canals seen in thin section samples (Figure 9).
A
B
Figure 7. Photographs of fossil preservation, A) well preserved bone (119, note perpendicular fractures), and B) poorly preserved bone (176B).
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A 2 cm
B C 1 mm
1 mm
D 1 cm
Figure 8. Photographs of coatings, A) black blotches (circled) on bone surface (001), B) thin, black veneer on the bone surfaces in thin section (red arrows) and spheres in Haversian canals (circles) sample 002-3, plane polarized light, C) photomicrograph of black blotches in sediment (arrow); sample 176B-2, and D) concentric, discontinuous black blotches (leisegang bands) in sediment surrounding bone (172C; circled).
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A B
Figure 9. Photographs of matrix infilling in Haversian canals, traces (<5%) of matrix (circles) within Haversian canals in samples A) 001-4 and B) 125-1.
All of the observed specimens exhibit some amount of surface cracking, flaking and sawtooth fractures (Figure 10). The majority of observed specimens are also cut by perpendicular fractures that extend though bone and into the surrounding sediments (Figure
8a.). These fractures are clearly caused by post-depositional processes, possibly due to excavation and removal; thus the perpendicular fractures were not included when determining the fragmentation or overall quality of preservation ratings (Table 2).
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D B
A
2 cm
C
Figure 10. Photograph of fossil fragmentation, (142) exhibiting (A) surface cracking, (B) flaking, (C) sawtooth fractures, and (D) a perpendicular fracture.
Of the approximately 168 illustrated skeletal elements, the degree of articulation was determined for 71 elements from 28 jackets and estimated for an additional 84 elements form
60 jackets using the reconstructed field maps (Appendix C). Some elements were not fully exposed at the time of illustration, therefore the degree of articulation could not be identified for thirteen of the elements. Approximately 46% of the 168 skeletal elements were determined or estimated to be articulated or semi-articulated, 30% were associated, and 9% were disarticulated with 15% undermined (Figure 11; Appendix C).
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Figure 11. Pie graph of the degrees of articulation of cetacean bones from the Bonita Canyon bonebeds.
Paleocurrent Analysis
Analysis of azimuthal measurements collected from 99 elongate and articulated skeletal elements (Appendix C) were plotted on 180 rose diagrams, which show a strong unidirectional NE-SW preferred orientation of all measurements, which is interpreted as representing the dominant paleocurrent direction during deposition of the cetacean remains
(Figure 12a). Plotting measurements of elements specified to have originated from Bonebed
1 (per the field maps) (two jackets; five measurements) also shows a strong preferential NE-
SW orientation (Figure 12b). However, plotting the measurements of elements reported from
Bonebed 2 (five jackets; eight measurements) shows a more erratic distribution of orientations with a slight N-S preference (Figure 12c).
Since the bonebed of origin could not be determined for the remaining jackets,
Figures 12d through 12i show elements grouped by other characteristics, such as measurements of articulated elements (Figure 12d), fragmented bones (Figure 12e), all collected specimens (Figure 12f), and specimens not collected (Figure 12g), which all exhibit 35
36 a NE-SW preferred orientation similar to elements in Bonebed 1 (Figure 12b). However, elements discovered in the North Block (Figure 12h) show more erratic orientations compared to elements discovered in the South Block (Figure 12i), which exhibit a preferred
NE-SW unidirectional orientation.
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A B C
D E F
G H I
Figure 12. 180° Rose diagrams of azimuth orientation measurements collected from A) all specimens, B) specimens from Bonebed 1, C) specimens from Bonebed 2, D) articulated specimens, E) Bone Fragments, F) Collected Specimens, G) Specimens Not Collected H) Specimens Collected in the North Block, I) Specimens Collected in the South Block.
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Sedimentology
Sedimentological data was collected from fourteen open jackets. However, seven jackets (002, 119, 125, 142, 166, 176A, and 176B) contained little or no sediment above the level of bone and two jackets (155 and 172C) contained very little sediment around previously removed elements; therefore data was limited for these jackets (Appendix B).
Visual observations of fourteen jackets indicates two main types of sediment occur at
Bonita Canyon Planning Area 26. Twelve jackets contain light to dark gray to brownish gray siltstone with varying amounts of very fine to coarse grain sand, both as lenses and scattered grains. Iron oxide staining ranges from mottled to subparallel to bedding, and is often more abundant around the bones. The remaining two jackets (003A and 176A) contain light grayish brown to brownish gray, moderately to poorly-sorted silty sandstone with some scattered fine to medium angular to well-rounded gravel.
Nine of the fourteen jackets also contain silty sand to sandy lenses or layers with traces of gravel, and range from 0.127 cm to 20.32 cm wide and 0.27 cm to 5.08 cm thick.
No sandy lenses or layers are seen in three of the fourteen jackets, however, two jackets (155 and 172C) did not contain sufficient sediment for a complete description of the sediments surround bone.
Petrographic analysis of twelve thin sections collected from eight jackets confirms two general sediment types surrounding the bones (Appendix E). Nine samples consist of tuffaceous sandy silt (Appendix E), while three samples consist of moderately to poorly- sorted tuffaceous wacke (Appendix E). Grains of tuff appear in all samples, as angular and blocky clasts with varying sizes (Figure 13). In addition, the thin section samples exhibit varying amounts of iron oxide staining (Figure 8c and Figure 13a).
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A 1 mm B
1 mm
Figure 13. Photographs of grains of tuff (circled) in thin section, A) Gray Siltstone (142-2), and B) Tuffaceous Wacke (125-1).
Multiple burrows were observed in seven jackets (Appendix B and D), while no evidence of bioturbation is seen in six jackets and one jacket did not contain sufficient sediment to determine if bioturbation was present. All observed burrows occur as simple branching tubes with diameters ranging from 0.635 to 1.27 cm, and are identified as
Planolites based on the tubular, unlined nature of the burrows, as well as their oblique to subparallel orientation to bedding surfaces. All burrows observed begin below the level of bone, and extend to a maximum depth of 7.62 cm inches (204A) below the bone. The burrows are infilled with fine to coarse grained silty sand and are typically stained with iron oxide (Figure 13) and/or surrounded by concentric bands of iron oxide staining (Figure 14).
One jacket (199; Figure 15) contains lenticular and circular features approximately 1.27 cm diameter with no iron staining, however, they are infilled with fine to medium sand indicating these are most likely burrows. Only two of the six jackets contain burrows that are slightly lenticular in cross-section, likely due to compaction, while all other burrows are circular in cross-section.
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Figure 14. Photograph of burrows, jacket 176B showing two adjacent Planolites burrows below bone (circled).
Figure 15. Photograph of a cross-section with burrows, jacket 176B showing sand-filled Planolites burrows surrounded by concentric bands of iron staining (circled).
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Figure 16. Photograph of lenticular features in jacket 119. These sand-filled lenticular and circular features (circled) are approximately 1 cm in diameter with no iron staining and are also interpreted as Planolites burrows.
Microfossils
Six sediment samples were analyzed under magnification for foraminifera, which can provide indications of paleodepth at the time of deposition as well as biostratigraphic data.
No foraminifera were found in the six samples, however one sample did contain two microfossil fragments, which are likely sponge spicules (Figure 17) according to Dr. Ken
Finger of UC Berkeley, however, these do not provide useful paleoenvironmental information.
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5 mm
Figure 17. Photograph of microfossils, possibly sponge spicules, found during this study. Each grid measures 5 mm2.
Geochemistry
Eighteen sediment and bone samples collect from ten jackets were analyzed from iron, and phosphorus (Table 3). Results are presented as parts per million (ppm) and oxide percents (Table 3), as summarized below:
Barium (Ba ppm) ranges from 832 to 6412 ppm and averages 1870.91 ± 1421.79
ppm.
Iron (%Fe2O3) ranges from 1.73 to 7.67% with an average value of 3.38 ± 1.27%.
Phosphorus (%P2O5) ranges from 0.10 to 6.41% and averages 0.93 ± 1.34%
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Sample ID Location Type Ba ppm Fe ppm P ppm %Fe2O3 %P2O5 Average Shale Values 580 NA NA 6b 1a 001-1 Above Sed 1396 28150 6019 4.02 1.38 001-2 At Sed 968 21870 854.4 3.13 0.20 001-3 Below Sed 867 20870 690.7 2.98 0.16 001-3 Dup Below Sed 855 20900 700.3 2.99 0.16 002-1 Above Sed 875 17580 945.2 2.51 0.22 002-2 At Sed + Bone 2269 21860 9609 3.13 2.20 003-1 Below Sed 1793 25060 1704 3.58 0.39 003-2 At Sed 2396 15760 1110 2.25 0.25 111-1 Below Sed 832 16390 655.4 2.34 0.15 119-1 At Sed 5157 25220 2805 3.61 0.64 119-2 Below Sed 2830 43780 3158 6.26 0.72 142-1 Below Sed 2570 24390 5340 3.49 1.22 142-3 Below Sed 1459 21740 5082 3.11 1.16 166-1 At Sed 952 20790 1511 2.97 0.35 166-2 Below Sed 1124 20610 431.9 2.95 0.10 176B-1 At Sed + Bone 2396 31880 8071 4.56 1.85 176B-3 Below Sed 838 23160 447.2 3.31 0.10 176B-5 At Sed 6412 53660 27970 7.67 6.41 179A-1 Below Sed 1439 12070 216.2 1.73 0.05 179A-2 At Sed 867 15710 1176 2.25 0.27 204A-1 At Sed 1151 21040 2024 3.01 0.46 204A-2 Above Sed 2633 20980 9696 3.00 2.22 204A-5 Below Sed 952 19830 3146 2.84 0.72 Average 1870.91 23621.74 4059.23 3.38 0.93 Standard Deviation 1421.79 9093.54 5986.69 1.30 1.37
Table 3. Geochemical results, average shale values and major, minor and trace element results measured from sediment and sediment and bone samples from selected fossil jackets from Bonita Canyon. a Tribovillard et al. (2006); bYaalon (1961).
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CHAPTER 4
DISCUSSION
Taphonomy
The quality of fossil preservation and articulation is determined by biostratinomy and early diagenesis (Brett and Baird, 1986). Processes that degrade skeletal material, such as fragmentation and corrosion, occur after the removal of protective soft tissues as the result of prolonged exposure on the seafloor (Brett and Baird, 1986). Therefore, sedimentation rates at the time of deposition of a carcass on the seafloor determines the degree of preservation and articulation of skeletal material.
Results of this study of many well preserved and articulated specimens point to relatively rapid burial of the fossils contained within the Bonita Canyon bonebeds, which seems likely given the tectonic and sedimentologic history of the San Joaquin Hills during the middle Miocene (see below; Cooper and Sawlan, 2008). Differences in the degree of preservation and articulation between individual elements from Bonita Canyon Planning
Area 26 suggest variations in the rate of burial of the bones. Elements with a high to moderate degree of preservation and articulation (176A, 179A, and 204A; Table 2) were likely buried most rapidly, before connective and other soft tissues fully decomposed or were removed by scavengers, and before pre-diagenetic fragmentation and corrosion could occur.
Elements that were disarticulated or associated but have a high to moderate degree of preservation (199 and 143; Table 2), likely have more complex histories. Scavenging and/or
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45 transport of elements from a partially decomposed carcass would result in disarticulation, however, these elements lack evidence of corrosion, and therefore were also buried relatively rapidly before all soft tissue was removed. Elements that were semi-articulated or in close anatomical association while exhibiting a poor degree of preservation (125, 155, 166, 172C, and 178B; Table 2), were likely exposed for a longer time on the seafloor before final burial.
Pre-diagenenic fragmentation, such as surface cracking, flaking, and sawtooth fractures, and corrosion occur only after all soft tissue is removed, suggesting that poorly-preserved specimens passed through a significant portion of ecological (Mobile Scavenger) stage I.
Overall, the high degree of articulated or associated elements is indicative of little post- mortem transport of the bones, beyond possible reorientation of the bones by bottom currents
(see below), or the movement of articulated or associated bones within larger mass flows
(i.e., Bonebed 1, see below).
Diagenenic alteration, such as remineralization and compaction of bone material was not observed in the 27 skeletal elements analyzed during this study. However, the majority of observed specimens are cut by post-burial perpendicular fractures that extend through bone and into the surrounding sediments (Figure 8a). Although the timing of the perpendicular fracturing is unknown, it is possible fracturing occurred during excavation and removal of skeletal material from Bonita Canyon Planning Area 26.
Geochemistry
Geochemical results reveal that the sediment and bone material sampled are not particularly enriched in phosphate or iron, however barium is enriched when compared to values for average shale (Table 3). Average barium values are enriched compared to average shale (1870.91 ppm ±1421.79 ppm vs. 580 ppm for average shale, Wedepohl, 1971).
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Elevated barium levels are likely due to high primary productivity within the marine basin during deposition of the Bonita Canyon bonebeds (Dymond, et al., 1992), possibly providing a food source for various migrating cetacean species.
Average phosphate values are not enriched when compared to average shale (0.93 ±
1.34% vs. 0.16% for average shale; Table 3). However, seven samples are enriched (Table
3), probably due to the redistribution of phosphate from bone material into the sediment as the whale carcass decomposed, and pore waters became saturated with respect to phosphate.
Allison et al. (1991) describe iron sulfide precipitation associated with a recently deposited whale carcass (~3 years prior to the study). According to Allison et al. (1991), iron sulfide minerals are present as fine layers on inner surfaces of trabeculae, heavy black staining on bone surfaces, and as concentric layers in sediments surrounding bone. Allison et al. (1991) attribute iron precipitation to sulfate reduction within the trabeculae as well as below the sediment-water interface. Although iron concentrations (23621.7 ± 8893.6 ppm) from the Bonita Canyon bonebed material are below that of average shale (48,000 ppm;
Wedephol, 1991), similar black coatings to those documented by Allison et al. (1991) are observed on bone surfaces, in Haversian canals, and as leisegang rings around bone, and are identified as a combination of iron sulfide and iron oxide minerals. The presence of iron sulfide mineral (or presumably oxidized iron sulfide mineral in the form of iron oxides) within bone (e.g. Haversian canals), on bone surfaces, and in bands surrounding the bones provides evidence for anaerobic sulfate reduction, which occurred when oxygen was consumed and alternate metabolic pathways were employed to continue decay of the whale carcasses (Allison et al., 1991; Berner, 1981).
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Sedimentology
Sedimentological and petrographic analysis confirms two main types of sediment as described in John D. Cooper’s stratigraphic column and The Keith Companies (1998) mitigation report for Bonita Canyon Planning Area 26 (Figure 4), which shows an overall pattern of alternating layers of thin sandstone and gravels (5-2 cm thick) interbedded with thicker siltstone and mudstones intervals (20 cm- 1 m thick). The sand and gravel interbeds become progressively coarser-upwards, and are capped by a sandy pebble to boulder conglomerate lens that contains the uppermost bonebed, Bonebed 1 (The Keith Companies,
1998). The thick siltstone and mudstone units represent lower energy depositional periods with high rates of sedimentation that occurred continuously across a submarine fan to continental slope environment (Cooper and Sawlan, 2008). The relatively thin, coarse grained sand, gravel and pebble units represent pulses of increased energy, likely marine turbidity and debris flows, which appear to have aligned the bone, but did not transport them individually, based on the generally high degree of preservation and articulated or associated nature of the majority of skeletal elements (see below).
Angular grains of tuff were identified in all petrographic samples containing both coarse and fine grained matrix. The size and angularity of the tuff grains suggest a local volcanic source with deposition concomitant with the Bonita Canyon bonebeds.
The Paularino Member is often found intertonguing with the San Onofre Breccia in the San Joaquin Hills (Cooper and Sawlan, 2008). Clasts of glaucophane schist are described in John D. Cooper’s stratigraphic column from Bonebed 2 (Figure 4). However, no clasts of
Catalina Schist were found during this study, suggesting sediments were primarily derived
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48 from rocks eroded from the Santa Ana Mountains to the east, with occasional clasts derived from Catalina Schist to the west of Bonita Canyon Planning Area 26.
Paleocurrents
Azimuthal measurements collect from articulated and disarticulated skeletal elements at Bonita Canyon Planning Area 26 reveal a prominent NE0SW paleocurrent direction. This corresponds with previous paleocurrent data collected from the Topanga Formation in the
San Joaquin Hills (Blair, 1978) that demonstrates a dominant flow direction to the southwest in both proximal and distal portions of a submarine fan environment. Overall, the paleocurrent data from articulated and disarticulate skeletal elements suggest that the whale carcasses were oriented by currents just prior to deposition on the seafloor, and disarticulated elements were frequently reoriented by currents prior to burial.
Microfossils and Age
The Paularino Member of the Topanga Formation is characterized by its tuffaceous nature and Relizian to Luisian age microfossils (Raschke, 1984). Although no useful microfossils were collected during this project, the foraminifera Hermicristellaria beali, a marker for middle Miocene Relizian to Luisian age sediments, was identified from sediments collected during excavation of the Bonita Canyon bonebeds (The Keith Companies, 1998). In addition, angular grains of tuff are identified in all petrographic samples during this study, which further supports the assignment of the Bonita Canyon bonebeds to the Paularino
Member of the Topanga Formation (Raschke, 1984).
Depositional Model
High accommodation space created by the opening of the Los Angele Basin during the middle Miocene, coupled with eustacy and tectonic uplift inland, caused copious amounts
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49 of sediment to be deposited and redistributed by mass flows along the continental margin
(Cooper and Sawlan, 2008). In the ancestral San Joaquin Hills, Bonita Canyon Planning Area
26 was near the depocenter of Topanga Basin, which was on the edge of the rapid subsiding
Capistrano Embayment, which led to the development of a NE-SW trending submarine fan turbidite sequence preserved at the interbedded siltstone and sandstone units of the Paularino
Member at Bonita Canyon Planning Area 26 (Cooper and Sawlan, 2008; The Keith
Companies, 1998).
With the onset of a marine transgression during the middle Miocene, coastal upwelling within the Topanga Basin may have provided a food source for various migrating whale species similar to present day conditions. Upon death, currents within the basin transported whale carcasses to near the Bonita Canyon Planning Area 26 locality where they sand to the seafloor. The cause of death of the cetaceans within each bonebed at Bonita
Canyon Planning Area 26 was not likely due to a single mass die-off; rather each bonebed represent multiple mortality events where cetaceans died independently from separate causes, or, in the case of cluster skeletons, possibly in small groups. Although several small
Mysticete skeletons were described at Bonita Canyon Planning Area 26 (The Keith
Companies), their size relative to the large Mysticete skeletons discovered does not suggest these cetaceans died during infancy, therefore it is unlikely the Topanga Basin represents a calving ground.
Varying degrees of preservation, articulation, bioturbation, and iron coatings observed in each of the 14 jackets during this study suggest a complex and variable history for each of the bonebeds and among the individual whale carcasses.
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The lowermost bonebed, Bonebed 3 is contained within a massive siltstone unit indicative of low energy depositional environments. Although the mitigation report and field maps do not report which specimens originated from Bonebed 3, paleocurrent analysis of all specimens measured for this study suggest a predominantly NE-SW current direction throughout the depositional history of the study section (Figure 12a). Specimens discovered in Bonebed 3 are well preserved and highly articulated, suggesting very rapid burial during a time of high sedimentation. Four clustered Mysticete skeletons found within Bonebed 3 may also be the result of a single mass mortality event that affected individuals from a single pod, which were simultaneously deposited and rapidly buried. An additional large articulated
Mysticete skeleton most likely experienced bloat and float that led to detachment of the fluke and caudal vertebrae before the carcass sank to the seafloor and was rapidly buried. The dense concretionary silt enveloping specimens from Bonebed 3 was likely caused by mineral enrichment in surrounding sediments as the result of decomposition of soft tissues following burial. This suggests these specimens did not experience significant scavenging and therefore did not pass through ecological Stage I, further supporting rapid burial of these specimens immediately following deposition on the seafloor. Bonebed 3 represents a low energy depositional environment with high rates of sedimentation as a result of high accommodation space created by rapid tectonic subsidence and/or increased eustacy brought on by the progressive marine transgression during the early to middle Miocene. Deposition of Bonebed
3 likely predates formation of the submarine fan, and therefore represents deposition in an outer shelf to continental slope environment as previously documented (Cooper and Sawlan,
2008).
50
51
Bonebed 2 is described as a sandy siltstone that coarsens upwards to fine sand with sparse, floating coarse sand and gravel (The Keith Companies, 1998), and is indicative of a relatively low energy depositional environment with increasing depositional energy over time. Azimuthal measurements of specimens reported from Bonebed 2 show scattered fossil orientations with a weak N-S paleocurrent direction (Figure 12c). Specimens discovered in
Bonebed 2 are well preserved and semi-articulated to associated, suggesting these specimens may have experienced minor scavenging during ecological Stage I, however they underwent relatively rapidly burial before significant removal of soft tissue occurred. Elements discovered in close associated with articulated to semi-articulated components were likely disturbed by scavenging and/or bioturbation. Clustering of several small Mysticete skeletons described with similar taphonomic characteristics (The Keith Companies, 1998) suggest these individuals experienced similar histories from time of death to final burial; one plausible explanation for these clustered skeletons from one species is a mortality event that affected individuals from a single pod, which were then simultaneously deposited and rapidly buried. The increasing trend in depositional energy and weak N-W paleocurrent direction demonstrated in the data collected from Bonebed 2 are indicative of shifting depositional conditions that underwent an increase in energy over time, likely due to submarine fan progradation, possibly coupled with local tectonic subsidence that resulted in the net creation of accommodation space. Therefore, Bonebed 2 represents a period of low depositional energy with high rates of sedimentation where cetacean carcasses were rapidly buried soon after sinking but before significant scavenging or decomposition of soft tissues, resulting in semi-articulated and well preserved fossils.
51
52
Bonebed 1 is contained within a sandy pebble to boulder conglomerate lens surrounding by a massive sandy silt unit, which indicates a high energy depositional environment. Azimuthal measurements of specimens reported from Bonebed 1 indicate a strong NE-SW paleocurrent direction (Figure 12b). Specimens discovered in Bonebed 1 are mostly disarticulated and highly fragmented. However, only some elements exhibit
Evidence of abrasion while others, such as a vertebral column, remain articulated (The Keith
Companies, 1998), suggesting these specimens likely experienced significant scavenging during ecological Stage I and/or decomposition, however some soft and connective tissues remained intact at the time of final burial. Soft tissues protected the underlying bones from abrasion and helped maintain the integrity of parts of the skeleton, even under high energy depositional conditions. Therefore, Bonebed 1 is thought to represent a gravity flow deposited on a NE-SW trending submarine fan environment, where partially decomposed cetacean remains were transported and/or redeposited resulting in disarticulation and poor preservation.
Overall, accumulation of the Bonita Canyon bonebeds began during quiet depositional conditions in an outer shelf to continental slope environment, when Bonebed 3 was deposited. Depositional energy increased as the result of the development of a submarine fan, with Bonebed f2 deposited in the medial to distal portions of the fan. Progradation of the submarine fan led to increasing depositional energy, with Bonebed 1 deposited in a more proximal setting than Bonebed 2. High accommodation space created by deposition on the edge of the subsiding Capistrano Embayment coupled with a progressive marine transgression resulted in high net rates of sedimentation that persisted during deposition of the entire sequence that contains the Bonita Canyon bonebeds.
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CHAPTER 5
CONCLUSIONS
The taphonomic, sedimentologic, and geochemical results presented in this study were used in combination with descriptions in The Keith Companies (1998) mitigation report to reconstruct a paleodepositional history for three cetacean bonebeds from Bonita Canyon
Planning Area 26 in Orange County, California that were deposited during the Relizian to
Luisian age of the middle Miocene. Bonebed 1 primarily contains poorly preserved and disarticulated fossils, while fossils from Bonebed 2 and 3 are well preserved and articulated to associated. Most skeletal elements exhibit pre-diagenenic fragmentation (surface cracking, flaking, and sawtooth fractures), however no diagenenic remineralization or compaction of bone material was observed. Sediments surrounding bone are tuffaceous sandy silts and moderately to poorly-sorted tuffaceous wackes. Iron sulfide and iron oxide mineral precipitation in and on bone surfaces and as leisegang rings in sediment surrounding bone are observed. Iron stained Planolites burrows are noted below the level of bone in seven of the
14 jackets observed. Overall, elongate skeletal elements reveal a predominately NE-SW paleocurrent direction.
Based on the results of this study, the Bonita Canyon bonebeds do not represent a condensed concentration deposited during a period of low net rates of sedimentation, as proposed by The Keith Companies (1998); rather the bonebeds represent a composite concentration deposited in a low energy continental shelf environment during a period of
53
54 high sedimentation. Although Bonita Canyon Planning Area 26 was typically quiet, high energy turbidity and gravity flows periodically swept across the region as a prograding NE-
SW trending submarine fan advanced and led to an increase in depositional energy over time.
High net rates of sedimentation are the result of high accommodation space created by a progressive marine transgression (Cooper and Sawlan, 2008) coupled with local tectonic subsidence (Ingle, 1979) during the tumultuous conditions that existed within the California
Borderland during the middle Miocene.
Further research is needed to prepare the remaining jacketed specimens removed from Bonita Canyon Planning Area 26. Identification of the age, gender, and species of individual skeletons will allow for a better understanding of the potential causes of death and possible relationships of clustered and isolation specimens within each of the three bonebeds.
Future work will also help determine why whale fossils are so common within Bonita
Canyon Planning Area 26, to further define the paleodepositional history of the individual bonebeds, and better place the sediments of Bonita Canyon Planning Area 26 into the overall context of the history of Los Angeles Basin.
The conditions present in the Los Angeles Basin during the Miocene led to one of the most complete paleontological records known from this time period. Less is known about middle Miocene (Relizian to Luisian) age depositional conditions in southern California. The
Bonita Canyon cetacean bonebeds in the Paularino Member of the Topanga Formation not only represent a very rare class of deep marine fossil accumulations that have not been previously examined in great detail, they also represent an opportunity to learn more about the depositional conditions during the middle Miocene in southern California. This study provided insight into the taphonomic processes that led to the accumulation of multiple
54
55 cetacean bonebeds within a single stratigraphic unit, and provide the first known example of a composite concentration of cetacean remains.
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APPENDIX A
FIELD MAPS
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APPENDIX B
JACKET DATA SHEETS
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Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-00-001_____ Horizon: _Unknown____ Orientation: _NA____ No. of Elements: _3____
Prepared by: _Alyssa Beach____ Method: _Matrix Removal____ Date Prepared: _July-Aug, 2015___
Species: _Cetacea______Bone Type(s): _Rib Fragments______
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _None Seen______Rating: _1____
Fragmentation: _Large perpendicular fractures; Surface cracking and flaking______Rating: _3____
Remineralization: _None; Black coating on bone______Rating: _1____
Bioerosion: _None Seen______Rating: _1____
Stratigraphy Quality of Preservation Rating: _2.5___
Matrix (size, mineralogy, contacts, staining):_Silt, medium gray, little FeO2 staining (mostly mottling, some surrounding burrows), little to trace very fine to medium grained sand throughout; trace_____ subrounded, subparallel, fine to coarse sandy lens (2” wide x ¾” high), some bone fragments have__ black coating (surface and internally), pale yellow mottling throughout. ______
Sedimentary Structures (erosional surfaces, imbrication, grading):_Massive other than lenses______(described above).______
Bioturbation (type, location, and distribution of trace fossils):_FeO2 stained burrows, circular_(~1/4” –_½” diameter), directly beneath bone and oblique to apparent bedding planes.______
Photos: _0001-0004; 0017-0018; 0021-0022; 0038-0044; 0095-0151; 0203-0212; 0231-0242.______
Sample ID Date Notes GeoChem Microfossil Thin Section 001-1 7-2-15 Above Bone X 001-2 7-16-15 At Bone X X 001-3 7-28-15 Below Bone X 001-4 7-28-15 Bone X 001-5 8-31-15 Below Bone X 001-6 8-31-15 At Bone X
157
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-00-002___ Horizon: _Unknown____ Orientation: _NA_____ No. of Elements: _1_____
Prepared by: _Alyssa Beach_____ Method: _Matrix Removal______Date Prepared: _July, 2015____
Species: _Cetacea______Bone Type(s): _Unknown______
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _Not able to tell______Rating: _NA___
Fragmentation: _Extensive surface cracking and flaking______Rating: _4____
Remineralization: _None______Rating: _1____
Bioerosion: _Not able to tell______Rating: _NA__
Stratigraphy Quality of Preservation Rating: _2.5___
Matrix (size, mineralogy, contacts, staining):_Sandy Silt, medium gray, fine to medium grained sand,
subangular to subrounded, some massive FeO2 staining, quartz and feldspar grains, white specks.______
Sedimentary Structures (erosional surfaces, imbrication, grading): _Mostly massive.______
Bioturbation (type, location, and distribution of trace fossils): _None seen.______
Photos: _0005; 0030-0033; 0279-0291.______
Sample ID Date Notes GeoChem Microfossil Thin Section
002-1 7-16-15 Above Bone X
002-2 9-11-15 At Bone X
002-3 9-11-15 At Bone/Bone X
158
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-15-003_____ Horizon: _Unknown____ Orientation: _NA____ No. of Elements: _5____
Prepared by: _Ryo Delu_____ Method: _Matrix Removal_____ Date Prepared: _Sept-Oct, 2015____
Species: _Cetacea; Possibly Shark____ Bone Type(s): _Cetacean Rib; Mammalian Vertebrae (x2)____
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _None Seen______Rating: _1____
Fragmentation: _Extensive surface cracking/flaking; Perpendicular and sawtooth____ Rating: _3.5__
Remineralization: _None; Bones are stained with FeO2______Rating: _1____
Bioerosion: _Not able to tell______Rating: _NA___
Stratigraphy Quality of Preservation Rating: _3.5___
Matrix (size, mineralogy, contacts, staining):_Silty Sand, light grayish tan, abundant FeO2 staining,__ clay; large lenses of subrounded, very fine to medium grained sand; 1/2” -1” thick layer of silty sand, subrounded to rounded, very fine to coarse grained sand surrounded by FeO2 staining; few fine____ grained gravel, rounded to subrounded, one medium grained gravel, subrounded, above bone; bone covered in FeO2 staining.______
Sedimentary Structures (erosional surfaces, imbrication, grading): _Large lenses/layers of very fine_ to coarse grained sand and few fine to medium grained gravel surrounded by FeO2 staining.______
Bioturbation (type, location, and distribution of trace fossils): _None seen.______
Photos: _0381-0399; 0412-0441; 0452-0470.______
Sample ID Date Notes GeoChem Microfossil Thin Section
003-1 9-25-15 Below Bone X
003-2 9-25-15 At Bone X
159
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-97-111_____ Horizon: _Unknown____ Orientation: _NA____ No. of Elements: _0____
Prepared by: _Crystal Cortez______Method: _Matrix Removal___ Date Prepared: _Prior to 2015___
Species: _Unknown______Bone Type(s): _None observed______
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: ______Rating: _NA____
Fragmentation: ______Rating: _NA___
Remineralization: ______Rating: _NA___
Bioerosion: ______Rating: _NA___
Stratigraphy Quality of Preservation Rating: _NA___
Matrix (size, mineralogy, contacts, staining):_Silty Clay, gray, little very fine grained sand, little FeO2 staining in some areas.______
Sedimentary Structures (erosional surfaces, imbrication, grading): _Massive.______
Bioturbation (type, location, and distribution of trace fossils): _None Seen.______
Photos: _0405-0411.______
Sample ID Date Notes GeoChem Microfossil Thin Section
111-1 9-25-15 Below Bone X
160
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-97-119_____ Horizon: _Unknown____ Orientation: _266____ No. of Elements: _2___
Prepared by: Crystal Cortez, Ryo Delu__ Method: Matrix Removal__ Date Prepared: Prior to 2015__
Species: _Cetacea; Shark___ Bone Type(s): _Large Mandible; Shark Tooth (OCPC# 80007/80013)___
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _None Seen______Rating: _1____
Fragmentation: _Step (4) and perpendicular (7) fractures; Little surface flaking_____ Rating: _2____
Remineralization: _None; Black coating on bone______Rating: _1____
Bioerosion: _None Seen______Rating: _1____
Stratigraphy Quality of Preservation Rating: _2____
Matrix (size, mineralogy, contacts, staining):_Silt Clay, medium gray; some fine to medium grained__ sand, subangular to subrounded sandy lenses; some fine to medium grained sand infilled burrows__ ~1/2” in diameter; FeO2 staining throughout and around one lens; abundant FeO2 staining and little black coating on bone surfaces.______
Sedimentary Structures (erosional surfaces, imbrication, grading): _Layer of fine to coarse grained__ sand and fine grained gravel, both subangular to subrounded, directly below bone with dark FeO2__ staining. ______
Bioturbation (type, location, and distribution of trace fossils): _Round burrows ~1/2” diameter_____ infilled with fine to medium grained subrounded sand; no FeO2 staining.______
Photos: _0161-0292; 0213-0217; 0372-0380.______
Sample ID Date Notes GeoChem Microfossil Thin Section
119-1 8-12-15 At Bone X
119-2 8-12-15 Below Bone X
119-3 8-26-15 Below Bone X
161
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-97-125_____ Horizon: _Unknown____ Orientation: _NA____ No. of Elements: _1____
Prepared by: _Michelle Barboza___ Method: _Matrix Removal___ Date Prepared: _ Prior to 2015__
Species: _Unknown______Bone Type(s): _Unknown; Very little bone material______
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _ Not able to tell______Rating: _NA___
Fragmentation: _ Not able to tell______Rating: _NA___
Remineralization: _None______Rating: _1____
Bioerosion: _Not able to tell______Rating: _NA___
Stratigraphy Quality of Preservation Rating: _3.5__
Matrix (size, mineralogy, contacts, staining):_Silty Clay, gray, some very fine to fine grained sand.______
Sedimentary Structures (erosional surfaces, imbrication, grading): _Several ½” – 1” lenses filled with very fine to fine grained, rounded to subrounded sandy silt, trace coarse grained sand; one lens____ stained with FeO2, others had FeO2 staining near or partially surrounded the lens. ______
Bioturbation (type, location, and distribution of trace fossils): _At least one burrow, ½” in diameter, slightly oval, below bone, FeO2 staining, difficult to tell angle relative to bone; several other lenses_ may actually be burrows.______
Photos: _0350-0371. ______
Sample ID Date Notes GeoChem Microfossil Thin Section
001-1 9-22-15 Above Bone/Bone X
162
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-97-142_____ Horizon: _Unknown____ Orientation: _291___ No. of Elements: _1____
Prepared by: _Michelle Barboza___ Method: _Matrix Removal___ Date Prepared: _ Prior to 2015__
Species: _Cetacea______Bone Type(s): _Unknown (OCPC# 80016)______
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _Some pitting______Rating: _2.5__
Fragmentation: _Little surface cracking/flaking; Sawtooth, step & perpendicular____ Rating: _3____
Remineralization: _None______Rating: _1____
Bioerosion: _None Seen______Rating: _1____
Stratigraphy Quality of Preservation Rating: _2.5___
Matrix (size, mineralogy, contacts, staining):_Silt, gray, little fine to coarse grained sand, trace fine__ grained gravel throughout, subangular; FeO2 staining subparallel (along fractures) throughout; some sand lenses ~2.3” wide by ½” high, infilled with fine to medium grained sand, FeO2 staining on outer edges; trace FeO2 staining and black coating on bone surfaces.______
Sedimentary Structures (erosional surfaces, imbrication, grading): _Some sand lenses ~2.3” wide by ½” high, infilled with fine to medium grained sand, FeO2 staining on outer edges. ______
Bioturbation (type, location, and distribution of trace fossils): _None Seen. ______
Photos: _0019-0020; 0292-0340; 0471-0473. ______
Sample ID Date Notes GeoChem Microfossil Thin Section
142-1 7-6-15 Below Bone X
142-2 9-11-15 Below Bone X
142-3 9-11-15 Below Bone X
163
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-97-155____ Horizon: _Unknown____ Orientation: _241____ No. of Elements: _1____
Prepared by: _Unknown_____ Method: _Matrix Removal______Date Prepared: _ Prior to 2015____
Species: _Fish______Bone Type(s): _Vertebra; Very little bone material ______
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _Not able to tell______Rating: _NA__
Fragmentation: _Not able to tell______Rating: _NA___
Remineralization: _None______Rating: _1____
Bioerosion: _Not able to tell______Rating: _NA___
Stratigraphy Quality of Preservation Rating: _4.5___
Matrix (size, mineralogy, contacts, staining): Silty Clay, grayish tan, some very fine to coarse grained sand, FeO2 staining. ______
Sedimentary Structures (erosional surfaces, imbrication, grading): _Not enough sediment for a_____ complete description.______
Bioturbation (type, location, and distribution of trace fossils): _ Not enough sediment for a complete description.______
Photos: _None.______
Sample ID Date Notes GeoChem Microfossil Thin Section
164
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-97-166____ Horizon: _Unknown____ Orientation: _298____ No. of Elements: _1____
Prepared by: _Michelle Barboza___ Method: _Matrix Removal___ Date Prepared: _Jan-Feb, 2015__
Species: _Cetacea______Bone Type(s): _Rib?______
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _Not able to tell ______Rating: _NA___
Fragmentation: _Extensive surface flaking; Some sawtooth and perpendicular______Rating: _3.5__
Remineralization: _None______Rating: _1____
Bioerosion: _ Not able to tell______Rating: _NA___
Stratigraphy Quality of Preservation Rating: _4____
Matrix (size, mineralogy, contacts, staining):_Sandy silt, gray, very fine to medium grained sand, few coarse grained, rounded sand, trace fine, subrounded gravel; very light FeO2 staining throughout,__ some dark FeO2 staining; fine to coarse grained sand lenses with subangular to subrounded sand.______
Sedimentary Structures (erosional surfaces, imbrication, grading): _Coarse lens of silty sand,______medium to coarse grained sand, subrounded, trace fine to medium grained gravel, subangular,____ directly below bone (~1/4”).______
Bioturbation (type, location, and distribution of trace fossils): _Burrow below bone (~1/2” to ¼”____ diameter), infilled with fine to medium grained sand, subangular, FeO2 staining; FeO2 ring about ¼” surrounding bone; burrow are oblique to bone. ______
Photos: _0047-0071; 0152-0161; 0084-0094; 0271-0278. ______
Sample ID Date Notes GeoChem Microfossil Thin Section 166-1 7-27-15 At Bone X 166-2 7-27-15 Below Bone X X 166-3 9-1-15 Below Bone X
165
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-97-172C____ Horizon: _Unknown___ Orientation: _NA____ No. of Elements: _10___
Prepared by: _Unknown_____ Method: _Matrix Removal_____ Date Prepared: _Prior to 2015_____
Species: _Cetacea______Bone Type(s): _Rib Frags; Bulla Frags; Other Frags (OCPC# 80006)_____
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _Not able to tell______Rating: _NA___
Fragmentation: _Extensive surface cracking and flaking______Rating: _4.5___
Remineralization: _None; Black coating on bone______Rating: _1____
Bioerosion: _Not able to tell______Rating: _NA__
Stratigraphy Quality of Preservation Rating: _3.5___
Matrix (size, mineralogy, contacts, staining):_Silty Clay with some sand, gray, abundant FeO2______staining throughout; immediately below bone is ~2” layer of medium to coarse grained sandy clay,_ FeO2 staining; black coating around and on some bones, also heavily stained with FeO2.______
Sedimentary Structures (erosional surfaces, imbrication, grading): _ Not enough sediment for a____ complete description.______
Bioturbation (type, location, and distribution of trace fossils): _ Burrows several inches long, ~1/4”__ to ½” diameter, FeO2 staining, slightly flattened (removed from sediment, cannot tell location_____ relative to bone); some lenses (possibly burrows) infilled with very fine to coarse grained sand.______
Photos: _0486-0504. ______
Sample ID Date Notes GeoChem Microfossil Thin Section
166
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-97-176A____ Horizon: _Unknown___ Orientation: _225____ No. of Elements: _4____
Prepared by: _Unknown______Method: _Matrix Removal_____ Date Prepared: _Prior to 2015____
Species: _Cetacea______Bone Type(s): _Unknown______
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _None Seen______Rating: _1____
Fragmentation: _Several perpendicular fractures; Some surface cracking/flaking____ Rating: _2____
Remineralization: _None seen______Rating: _1____
Bioerosion: _None Seen______Rating: _1____
Stratigraphy Quality of Preservation Rating: _3____
Matrix (size, mineralogy, contacts, staining): _Silty sand, tannish gray, poorly sorted, very fine to___ coarse grained sand; layer of coarse grained sand to fine grained gravel immediately below bone;__ some large (coarse gravel to cobble sized) mudstone clasts with abundant FeO2 staining_(above and below bone).______
Sedimentary Structures (erosional surfaces, imbrication, grading): _Massive other than layers______(described above).______
Bioturbation (type, location, and distribution of trace fossils): _None seen. ______
Photos: _0264-0270. ______
Sample ID Date Notes GeoChem Microfossil Thin Section
176A-1 9-1-15 Below Bone X
167
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-97-176B_____ Horizon: _Unknown___ Orientation: _307___ No. of Elements: _1____
Prepared by: _Michelle Barboza, Alyssa Beach_ Method: Matrix Removal_ Date Prepared: 2014-15__
Species: _Cetacea______Bone Type(s): _Unknown______
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _Not able to tell______Rating: _NA___
Fragmentation: _Extensive sawtooth fractures throughout______Rating: _4.5__
Remineralization: _None; Black coating on bone______Rating: _1____
Bioerosion: _Not able to tell______Rating: _NA___
Stratigraphy Quality of Preservation Rating: _4.5___
Matrix (size, mineralogy, contacts, staining):_Silt, gray (lighter at top, darker at bottom), trace fine to coarse grained, subangular sand; lenses (some possibly burrows) with FeO2 concentric rings, infilled with fine to medium grained sand; fine laminations at bottom and middle of jacket; grains are_____ mostly quartz and feldspar; ~2” below bone is lens of FeO2 spots. ______
Sedimentary Structures (erosional surfaces, imbrication, grading): _None other than lenses______(described above).______
Bioturbation (type, location, and distribution of trace fossils): _Seven burrows infilled with FeO2___ stained sand/silty sand, flattened, ½” diameter, 2” long (1), 3” long (3), 4” long (3), all below bone,__ two directly below bone; concentric FeO2 rings surround burrows. ______
Photos: _0013-0016; 0023-0029; 0045-0046; 0218-0230. ______
Sample ID Date Notes GeoChem Microfossil Thin Section 176B-1 7-1-15 At Bone X 176B-2 8-28-15 At Bone X 176B-3 8-31-15 Below Bone X 176B-4 8-31-15 Below Bone X
168
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-97-179A____ Horizon: _Unknown___ Orientation: _275____ No. of Elements: _1____
Prepared by: _Michelle Barboza, Ryo Delu_ Method: Matrix Removal__ Date Prepared: Aug-?, 2015_
Species: _Cetacea______Bone Type(s): _Skull? (Not fully prepped at time of report)______
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _None Seen______Rating: _1____
Fragmentation: _Perpendicular & sawtooth; Extensive surface cracking/flaking______Rating: _2.5__
Remineralization: _None; trace of black coating on bone______Rating: _1____
Bioerosion: _None Seen______Rating: _1____
Stratigraphy Quality of Preservation Rating: _2.5___
Matrix (size, mineralogy, contacts, staining):_Clay, medium gray, some silt and fine to medium_____ grained sand interspersed almost evenly throughout, some sparse layers; little FeO2 staining; some_ yellowish gray clayey material surrounded by FeO2 staining; one area of clayey sand, subrounded,__ below bone ~1/2” (not touching); trace of localized black coating on bone surface, heavy FeO2_____ staining on bone surface. ______
Sedimentary Structures (erosional surfaces, imbrication, grading): _Massive other than sparse layers (described above). ______
Bioturbation (type, location, and distribution of trace fossils): _None seen. ______
Photos: _0400-0404; 0474-0485. ______
Sample ID Date Notes GeoChem Microfossil Thin Section
179A-1 9-25-15 Below Bone X
179A-2 9-25-15 At Bone X
169
Bonita Canyon Jacket Data Sheet
Jacket #: _PEL-97-204A___ Horizon: _Unknown___ Orientation: _186, 315___ No. of Elements: _4__
Prepared by: Michelle Barboza, Crystal Cortez_ Method: Matrix Removal Date Prepared: July-?, 2015
Species: _Cetacea______Bone Type(s): _Mandible; Bulla______
Taphonomy (Scale: 1 = none, 2 = minor, 3 = significant, 4 = highly, 5 = completely)
Abrasion: _None Seen______Rating: _1____
Fragmentation: _Four perpendicular fractures; Some surface cracking/flaking______Rating: _2____
Remineralization: _None; Some black coating on Bulla______Rating: _1____
Bioerosion: _None Seen______Rating: _1____
Stratigraphy Quality of Preservation Rating: _2.5___
Matrix (size, mineralogy, contacts, staining): Silty Clay, light gray, some sand, abundant FeO2______staining and yellowing throughout; several long (~6-8” wide, ½” thick) lenses/layers of silty sand,___ very fine to medium grained, subrounded, FeO2 staining below and in lens; ~2” thick layer______immediately below bone, medium to coarse sandy clay, subrounded to subangular, heavy FeO2____ staining; several bone have black coating/spots on surface, others have FeO2 staining internally.______
Sedimentary Structures (erosional surfaces, imbrication, grading): _Described above. ______
Bioturbation (type, location, and distribution of trace fossils): _Burrows ~2-3” below bone, ~1/2”___ diameter, 2.5-7” long, round, FeO2 staining, infilled with sandy silt, oblique to bone. ______
Photos: _0006-0012; 0034-0037; 0072-0083; 0256-0263; 0442-0451. ______
Sample ID Date Notes GeoChem Microfossil Thin Section
204A-1 7-1-15 At Bone X X 204A-2 7-1-15 Above Bone X X 204A-3 7-16-15 Bone X 204A-4 9-1-15 Below Bone X 204A-5 9-25-15 Below Bone X
170
APPENDIX C
TAPHONOMY MEASUREMENTS
Bonebed of Origin Black Staining Collection Azimuth Jacket ID Block Field Maps Report Thin Section Jacket Element Degree of Articulation Status Orientation 001 S? Yes Y Y Rib Fragments? Same as 224? NA 002 Unknown Yes Y N Unknown Unknown NA 003 Unknown Yes NA N Rib Fragments; Shark? Vert (x2) Unknown NA 101 NA Bagged No map Cetacea? Fragments No map NA 102 S Yes Rib Seciton Semi-Articulated? w/172? 208 103 S Yes Skeletal Elements Semi-Articulated? w/172? NA 104 N Boxed Misc Cetacea? fragments Associated? w/105 & 106? NA 105 N Boxed Vertebrae Associated? w/104 & 106? NA 106 N Yes Pectoral Girdle Elements Associated? w/104 & 105? 297 106 N Yes Unknown Associated? 295 107 N Boxed Dentary Fragments Semi-Articulated? w/179? NA 108 S Yes Rib Sections Semi-Articulated? w/172? NA 109 S Yes Odontocete? Skull (right side up) Semi-Articulated? w/172? 352 110 S Yes Rib Section Associated? w/111 & 112? 244 111 S Yes NA N Dentary Frag? Associated? w/110 & 112? NA 112 S Boxed Misc Cetacea? fragments Associated? w/110 & 111? 183 113 NA No No map Fragment, Cetacea? No map NA 114 N Yes Dentary Frag Associated? w/158? 227 115 S Yes Misc Mammalia fragments Associated? w/116? NA 116 S Yes Rib Sections and Fragments Associated w/125 320 116 S Yes Rib Sections and Fragments Associated w/125 287 117 S Yes Rib Section Associated? w/116? NA 118 S Yes Misc Cetacea? fragments Associated? w/116? NA 119 S Yes N Y Large whale Dentary/Shark tooth Associated? w/135? 266 120 N Yes Pectoral Girdle Semi-Articulated? w/179? NA 120 N Yes Pectoral Girdle Semi-Articulated? w/179? 209 121 S Yes Misc fragments Disarticulated? 210 122 S Yes Rib Sections Disarticulated? 219 123 S No Dentary Fragment? NA NA 124 S Yes Vertebrae Disarticulated? NA 125 S Yes Y N Vert Frag? Associated w/116 NA 126 NA No No map Fragment, Cetacea? No map NA 127 NA Bagged No map Fragment, Cetacea? No map NA 128 NA No No map Fragment, Cetacea? No map NA 129 NA Yes Cetacea Rib Frag; Shark? Vert Associated? NA 130 NA Boxed No map Fragment, Cetacea? No map NA 131 NA Boxed No map Fragment, Cetacea? No map NA 132 S No Dentary Fragment? Associated? w/133 229 132 S No Dentary Fragment? Associated? w/133 229
171 132 S No Dentary Fragment? Associated? w/133 263
133 S No Rib Section Associated? w/132 253
Bonebed of Origin Black Staining Collection Azimuth Jacket ID Block Field Maps Report Thin Section Jacket Element Degree of Articulation Status Orientation 134 NA No No map Fragment, Cetacea? No map NA 135 S Yes Shark? Vertebae Associated? w/119? NA 136 S Yes 2 Fragment, Cetacea? Disarticulated? NA 137 N No Fragments, Cetacea? Disarticulated? NA 138 S Yes Rib? NA 295 139 S Yes Dentary NA 322 140 S Yes Rib Section; Limb elements Associated? 240 140 S Yes Rib Section; Limb elements Associated? 244 141 S Yes Rib Section NA 247 142 S Yes Y N Dentary? or Rib? Disarticulated 291 143 S Yes 2 Scapula NA 189 143A S Yes 2 Vertebrae Articulated? NA 144 S Yes 2 Cetacea? Articulated? 246 144 S Yes 2 Cetacea? Articulated? 328 144 S Yes 2 Cetacea? Articulated? 236 144 S Yes 2 Cetacea? Articulated? 250 145 S Yes 2 Unknown Articulated? 187 145 S Yes 2 Unknown Articulated? 189 145A S Yes 2 Scapula, Vertebrae Articulated? NA 146 S Yes 2 Cetacea? Rib Section Articulated? 350 147 S Yes Rib Fragments, Vertebrae Associated? NA 148 S No Misc Mammalia fragments Associated? NA 149 S Yes Rib Section Associated? 233 150 S No Rib Fragments, Misc Fragments Associated w/151 NA 151 S Yes Cetacea? Rib Fragments Associated w/150 NA 152 S No Misc Mammalia fragments NA NA 153 NA No No map Fragment No map NA 154 S Boxed Rib Fragments Disarticulated 307 155 S Yes NA N Whale Rib Frag, Fish Vert? Associated? 241 156 S Yes Rib Section, Vertebrae NA 308 157 S Yes Mammalia fragments NA NA 158 S Yes 1 3 Lg whale, big map, Skull (right side up) Articulated 235 158 S Yes 1 3 Large whale, Section 1 Articulated NA 158 S Yes 1 3 Large whale, Section 2 Articulated NA 158 S Yes 1 3 Large whale, Section 3 Articulated NA 158 S Yes 1 3 Large whale, big map, Vert Col Articulated 232 158 S Yes 1 3 Large whale, Section 4 Articulated NA 158 S Yes 1 3 Large whale, section 5 Articulated NA 172 158 S Yes 1 3 Large whale, section 6 Articulated NA
Bonebed of Origin Black Staining Collection Azimuth Jacket ID Block Field Maps Report Thin Section Jacket Element Degree of Articulation Status Orientation 158 S Yes 1 3 Large whale, section 7 Articulated NA 159 S Yes Associated Ribs Semi-Articulated? 243 159 S Yes Associated Ribs Semi-Articulated? 247 159 S Yes Associated Ribs Semi-Articulated? 243 160 NA No No map Cetacea? Fragment No map NA 161 S No Dentary Fragment Associated? 235 162 S Yes Cetacea? Scapula frag Associated? w/158? NA 163 S No Rib Fragments Associated? w/158? 332 163 S No Rib Fragments Associated? w/158? 291 164 S? Yes Rib Fragments Associated 248 165 S? Yes Dentary Fragment Associated 246 166 S Yes N N Rib Section Associated 298 167 NA Yes Misc fragments Associated w/166 NA 168 NA Yes Rib Section, Fragments Associated w/166 NA 169 S Yes Rib Fragments Associated w/166 351 170 NA Yes Rib Section Associated w/166 NA 171 S? Yes Misc fragments, Cetacea? NA NA 172A S Yes Rib? or Dentary? Semi-articulated 199 172A S Yes Vert Semi-articulated 199 172B S Yes Pectoral girdle? Semi-articulated 249 172B S Yes Vert Semi-articulated 248 172B S Yes Rib Semi-articulated 255 172B S Yes Vert Coloumn Articulated 251 172B S Yes Vert Coloumn Articulated 246 172B S Yes Rib Semi-articulated 240 172B S Yes Rib Semi-articulated 336 172C S Yes NA Y Ribs and vertebrae Semi-articulated NA 173A S No Partial skeleton Semi-Articulated w/174? 213 173B S Yes Partial skeleton Semi-Articulated w/174? 183 173C S Yes Partial skeleton Semi-Articulated w/174? 240 173C S Yes Partial skeleton Semi-Articulated w/174? 233 173C S Yes Partial skeleton Semi-Articulated w/174? 233 173D S Yes Partial skeleton Semi-Articulated w/174? 190 173D S Yes Partial skeleton Semi-Articulated w/174? 350 173D S Yes Partial skeleton Semi-Articulated w/174? 351 173E S Yes Partial skeleton Semi-Articulated w/174? NA 174 S Yes Rib fragments Semi-Articulated w/173? 242 174 S Yes Rib fragments Semi-Articulated w/173? 242 174 S Yes Vertebral Column? Articulated? w/173? 239 175 NA No No map Large Bone Frag, Cetacea? No map NA 176-1 NA No Unknown ? Unrealted to 176A NA 173
Bonebed of Origin Black Staining Collection Azimuth Jacket ID Block Field Maps Report Thin Section Jacket Element Degree of Articulation Status Orientation 176A S Yes N N Unknown Semi-Articulated? 225 176B S Yes N N Unknown Semi-Articulated? 307 176C S Yes Unknown Semi-Articulated? 303 176D S Yes Unknown Semi-Articulated? NA 176E S Yes Unknown Semi-Articulated? 281 177 NA Boxed Unknown NA NA 178A N Yes 1 Unknown Semi-articulated NA 178B N Bagged 1 Vert Coloumn Articulated 243 178D1 N Yes 1 Unknown Semi-articulated 242 178D3B N Yes 1 Unknown Semi-articulated NA 178F N Yes 1 Unknown Semi-articulated 277 178G N Yes 1 Unknown Semi-articulated NA 178H N Yes 1 Unknown Semi-articulated NA 179A N Yes NA Y Skull (up side down) Articulated 275 179B N Yes Rib Semi-articulated 288 179B N Yes Rib Semi-articulated 282 179B N Yes Rib Semi-articulated 296 179B N Yes Vert Column, section B Semi-articulated 327 179B N Yes Vert Column, section A Articulated 337 180A N Yes Vertebrae Semi-articulated w/178? NA 180B N Yes Vertebrae Semi-articulated w/178? NA 180C N Yes Vertebrae Semi-articulated w/178? NA 183 S Yes Large Bone NA 247 184A N & S Yes Unknown Associated? 224 184B S Yes Unknown Associated? NA 189 N No Fragment Disarticulated NA 198 N Boxed Fragments Disarticulated NA 199 S No Fragments Disarticulated 231 200 N & S Yes Unknown Associated w/201 335 201 N Yes Unknown Associated w/200 208 204A S Yes Y Y Mandible? Earbones Semi-Articulated? 186 204A S Yes Y Y Mandible? Earbones Semi-Articulated? 315 204B S Yes Unknown Semi-Articulated? NA 205A S Boxed Unknown Semi-Articulated? 273 205B S Boxed Vertebrae? Semi-Articulated? NA 206 S Boxed Fragment Disarticulated NA 207 S No Fragment Disarticulated NA 208 S No Earbones, skull frags Semi-Articulated? w/218? NA 209 NA No No map Cetacea? Fragment No map NA 174 210 NA No No map Cetacea? Fragment No map NA
Bonebed of Origin Black Staining Collection Azimuth Jacket ID Block Field Maps Report Thin Section Jacket Element Degree of Articulation Status Orientation 211 S No Rib Section Disarticulated 250 212 S ? Associated Skull Elements Disarticulated? NA 213 S Yes Earbone; Ribs; misc bone Associated NA 214 NA Yes No map Cetacea? Fragment No map NA 215 S Yes Rib Section Associated? w/218? 269 215 S Yes Rib Section Associated? w/218? 192 216 S Yes Rib Section, Fragments Associated? w/218? NA 217A S No Rib Sections, Vert Frags Semi-Articulated? w/218? NA 217B S No Rib Sections, Vert Frags Semi-Articulated? w/218? 250 218A S Yes Earbone and fragments Semi-Articulated? w/217? NA 218B S Yes Earbone and fragments Semi-Articulated? w/217? 204 218B S Yes Earbone and fragments Semi-Articulated? w/217? 273 219 S No Skeletal Elements Semi-Articulated? w/217/18? NA 220 S No Rib and Associated Elements Associated 215 221 S No Vertebrae Disarticulated? NA 222 S Yes Rib Section Disarticulated? 227 223 S No Earbones; incomplete skull Associated? w/217/18? NA 224 S Yes Misc fragments NA NA 225 S Yes Misc fragments Disarticulated? NA 226 S Yes Dentary, associated ribs Associated? 208 226 S Yes Dentary, associated ribs Semi-Articulated? 225 227 S No Misc Mammalia fragments Associated? w/217/18? NA 228 S No Skull? Fragment Associated? w/217/18? NA
175
176
APPENDIX D
JACKET SPECIMEN PHOTOGRAPHS AND PHOTO LOG
177
Jacket ID Date Photo # (s) Description 001 6/22/2015 0001-0004 Jacket preparation, tools 002 6/25/2015 0005 Opening Jacket 204A 7/2/2015 0006-0008 Sediment sample (204A-1) adjacent to Bulla 204A 7/2/2015 0009-0012 Sediment sample (204A-2) above mandible 176B 7/2/2015 0013-0016 Sediment sample (176B-1) adjacent to bone 001 7/2/2015 0017-0018 Sediment sample (001-1) above bone 142 7/6/2015 0019-0020 Sediment sample (142-1) below bone 001 7/8/2015 0021-0022 Bone sample (001-4) for thin section 176B 7/16/2015 0023-0025 Cross-section view (wet) 176B 7/16/2015 0026-0029 Burrows under bone 002 7/16/2015 0039-0031 Sediment sample (002-1) above bone 002 7/16/2015 0032-0033 Cross-section view (wet) 204A 7/16/2015 0034-0037 Bone sample ( 204A-3) for thin section 001 7/27/2015 0038-0044 Bioturbation under bone (?) 176B 7/27/2015 0045-0046 Cross-section view (dry) 166 7/27/2015 0047-0054 Burrows under bone 166 7/27/2015 0055-0057 Sediment sample (166-1) adjacent to bone 166 7/27/2015 0058-0062 Sediment sample (166-2) below to bone 166 7/27/2015 0063-0068 Burrows under bone 166 7/27/2015 0069-0071 Large clasts 204A 7/27/2015 0072-0083 Burrows under bone 166 7/30/2015 0084-0088 Cross-section (dry) 166 7/30/2015 0089-0094 Cross-section (wet) 001 7/30/2015 0095-0107 Black material on bone 001 7/30/2015 0108-0113 Cross-section (dry) 001 7/30/2015 0114-0121 Cross-section (wet) 001 8/2/2015 0122-0130 Cross-section (dry) 001 8/2/2015 0131-0139 Cross-section (wet) 001 8/4/2015 0140-0144 Cross-section (dry) 001 8/4/2015 0145-0151 Cross-section (wet) 166 8/4/2015 0151-0160 Microfossil sample dissolution 119 8/12/2015 0161-0169 Sediment sample adjacent to bone 119 8/12/2015 0170-0177 Sediment sample below bone 119 8/13/2015 0178-0183 Cross-section (dry) 119 8/13/2015 0184-0190 Cross-section (wet) 119 8/13/2015 0191-0202 Coarse material under bone
178
Jacket ID Date Photo # (s) Description 001 7/28/2015 0203-0206 Sediment sample below bone 001 7/6/2015 0207-0212 Sediment sample at bone 119 8/26/2015 0213-0217 Thin Section sediment sample, below bone 176B 8/28/2015 0218-0220 Thin Section sediment sample, at bone 176B 8/31/2015 0221-0225 Sediment below bone 176B 8/31/2015 0226-0230 Sediment below bone for thin section 001 8/31/2015 0231-0237 Sediment below bone for thin section 001 8/31/2015 0238-0242 Sediment at bone for thin section Misc 8/31/2015 0243-0250 Thin section samples being coated w/epoxy Misc 8/31/2015 0251-0255 Sediment for microfossil, slides 204A 9/1/2015 0256-0263 Sediment below bone for thin section 176A 9/1/2015 0264-0270 Sediment below bone for thin section 166 9/1/2015 0271-0278 Sediment below bone for thin section 002 9/11/2015 0279-0284 Sediment at bone (002-2) 002 9/11/2015 0285-0291 Sediment with bone (002-3) for thin section 142 9/11/2015 0292-0300 Sediment below bone for thin section (142-2) 142 9/11/2015 0301-0310 Sediment below bone for thin section (142-3) 142 9/11/2015 0311-0340 Coarse lenses (x2, wet and dry) 166 9/11/2015 0341-0347 Microfossil sample through microscope Misc 9/25/2015 0348-0349 Microfossil sieve #230 125 9/25/2015 0350-0355 Cross-section (dry) 125 9/25/2015 0356-0366 Cross-section (wet) 125 9/25/2015 0367-0371 Sediment sample with bone for thin section 119 9/25/2015 0372-0380 Mandible OCPC#80013 003 9/25/2015 0381-0387 Sediment sample below bone 003 9/25/2015 0388-0392 Large clasts 003 9/25/2015 0393-0399 Sediment sample at bone 179A 9/25/2015 0400-0404 Sediment sample at bone 111 9/25/2015 0405-0411 Sediment sample below bone 003 10/23/2015 0412-0426 Vetebra (shark?) 003 10/23/2015 0427-0429 Cetacean Rib? 003 10/23/2015 0430-0441 Whole jacket, prepped 204A 9/25/2015 0442-0451 Sediment sample below bone 003 10/23/2015 0452-0470 Coarse matrix around cetacean rib 142 10/23/2015 0471-0473 Removed bone element 179A 10/23/2015 0474-0478 Cetacean skull 179A 10/23/2015 0479-0485 Matrix around skull 172C 10/23/2015 0486-0502 Cetecean bone fragments (removed) 172C 10/23/2015 0503-0504 burrows (removed)
179
Jacket 204A, photo 007
Jacket 204A, photo 009
180
Jacket 204A, photo 0011
Jacket 176B, photo 0015
181
Jacket 001, photo 0017
Jacket 142, photo 0019
182
Jacket 001, photo 0022
Jacket 176B, photo 0024
183
Jacket 002, photo 0031
Jacket 002, photo 0032
184
Jacket 204A, photo 0036
Jacket 001, photo 0038
185
Jacket 166, photo 0052
186
Jacket 166, photo 0071
Jacket 204A, photo 0073
187
Jacket 166, photo 0093
001, photo 0097
188
Jacket 001, photo 0119
Jacket 001, photo 0138
189
Jacket 001, photo 0148
Samples taken from Jacket 166, photo 0158
190
Jacket 119, photo 0176
Jacket 119, photo 0192
191
Jacket 001 and 176B, photo 0250
Jacket 176A, photo 0267
192
Jacket 176A, photo 0269
Jacket 166, photo 0275
193
Jacket 142, photo 0306
Jacket 125, photo 0365
194
Jacket 125, photo 0370
Jacket 003, photo 0391
195
Jacket 179A, photo 0403
Jacket 111, photo 0410
196
Jacket 003, photo 0424
197
Jacket 003, photo 0429
Jacket 003, photo 0431
198
Jacket 003, photo 0437
Jacket 204A, photo 0451
199
Jacket 003, photo 0452
Jacket 142, photo 0472
200
Jacket 179A, photo 0474
Jacket 179A, photo 0480
201
Jacket 172C, photo 0487
Jacket 172C, photo 0490
202
Jacket 172C, photo 0502
Jacket 172C, photo 0503
203
APPENDIX E
THIN SECTION PHOTOGRAPHS
204
001-4 in polarized light (pl).
001-4 in ppl.
205
001-4 in ppl.
001-4 in ppl.
206
001-5 in pl.
001-6 in pl.
207
002-3(X10 magnification) in pl.
002-3 in pl.
208
002-3 in pl.
119-3 in pl.
209
119-3 in pl.
125-1 in pl.
210
125-1 in pl.
125-1 in pl.
211
125-1 in pl.
125-1 in pl.
212
142-2 in pl.
166-3 in pl.
213
176A-1 in pl.
176A-1 in pl.
214
176B-2 in pl.
204A-3 in pl (x10).
215
204A-3 in pl (x10).
204A-3 in pl (x10).
216
204A-4 in pl.