SURFACE AND SUBSURFACE ANALYSIS OF THE MIDDLE JURASSIC EXETER SANDSTONE IN NORTHEASTERN NEW MEXICO by KEVIN BUGEL, B.S. A THESIS IN GEOLOGY

Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE

Approved

Accepted

May, 1991 ACKNOWLEDGEMENTS

I would like to express my appreciation to ...• ....., I J- ! ) , • v I Dr. George Asquith for his suggestion of the thesis topic

and for his assistance and support throughout the course of

this study. The assistance and suggestions of

Dr. Thomas M. Lehman and Dr. Alanzo D. Jacka were also

appreciated. I would like to thank New Mexico Bureau of

Mines and Mineral resources for their funding of the field

work and use of their geologic resources facility. The

financial assistance of the Adobe Chair for both field

expenses and film processing was also acknowledged. Also

greatly appreciated was the field assistance of Tom

Richardson and Jeff Over. I would like to thank Mike Gower

for his participation in the thin section preparation. I am

grateful to my parents Tom and Donna Bugel for their

unlimited support and for believing in me. I would also

like to thank the residents within the study area for their

interest and cooperation. Special thanks are extended to

the Oberg and Miera families for their hospitality and

friendship.

ii TABLE OF CONTENTS

Page . . ACKN'OWLEDGEMENTS • •••••••••••.••••••••••••••••.••... 11

ABSTRACT ...... •...... v .. LIST OF FIGURES ...... V11 CHAPTER

I. INTRODUCTION...... 1 Purpose of Study...... 1 Methods of Study...... 2 Location of Study Area...... 3 Physical Geography...... 3

II. STRATIGRAPHIC RELATIONSHIPS...... 7 General...... 7 Type section...... 13 Regional Stratigraphy...... 14 Regional Depositional Setting...... 16

III. SEDIMENTARY FACIES ANALYSIS...... 21 General...... 21 Fac1.es. 1...... 22 Characteristics...... 22 Depositional Systems...... 27 Facies 2...... 32 Characteristics...... 32 Depositional Systems...... 39 Facies 3 ...... 4 0 Characteristics...... 4 o Depositional Systems...... 41

IV. PETROLOGY...... 57 General...... 57 Mineral Composition And Texture..... 58 Gra1n. S1ze...... 62 Cements...... 6 6

iii Page

v. PALEO-WIND ANALYSIS. • • • • • • • • • • . . . . . • • • . . . 78 General ...... 78 Discussion ...... 78 VI. DEPOSITIONAL ENVIRONMENTS...... 83 General ...... 83 Lithostratigraphic Relationships .. . . 84 Exeter Geometry ...... 92

VII. SUMM.A.RY •••••••••••••••••••••••••••••••••• 97

REFERENCES ...... •...•.....•...... 100

APPENDICIES

APPENDIX A ...... •...... 108

APPENDIX B ••••••••••••••••••••••••••••••••••••• 174

APPENDIX C ••••••••••••••••••••••••••••••••••••• 184

APPENDIX D ••••••••••••••••••••••••••••••••••••• 192

iv ABSTRACT

The Middle Jurassic Exeter Sandstone in northeastern

New Mexico is a medium- to fine-grained, moderate to well sorted quartzose sandstone. This sandstone can be subdivided into three eolian facies: 1.) cross-stratified dune facies; 2.) horizontally stratified interdune and

extradune facies; and 3.) massive (bioturbated) interdune

and extradune facies. These three eolian facies are

complexly interbedded throughout the study area.

The cross-stratified dune facies consists of large

sets (up to 4.6 meters ) of tabular and trough cross­

strata with grainflow and grainfall laminations. The

horizontally stratified interdune and extradune facies

display horizontal to low angle (<10°) stratification

that commonly exhibit bimodal grain size distributions.

Similar bimodal grain size distributions have been

described in both ancient and modern interdune lag or reg

deposits. The massive (reworked) interdune and extradune

facies consist of burrowed and bioturbated sandstones

with minor wave ripples, soft sediment deformation, and

desiccation polygons. The association of these internal

features with the massive facies suggests an intermittent

interdune or extradune pond or playa depositional

environment. The three eolian facies of the Exeter Sandstone in

northeastern New Mexico display criteria similar to

v those described in the Permian White Rim Sandstone. An

erg margin depositional setting for the Exeter Sandstone

is also supported by regional paleo-wind studies on

Jurassic eolian transport systems.

Paleo-wind analysis of the Exeter Sandstone suggests

windflow toward the south-southwest and to the northeast

with a regional resultant vector of N.79° E. The large

variations are typical of arc spreads found in modern and

ancient eolian deposits of crescentic dunes. The absence

of readings to the northwest suggests that the paleo-wind

direction was from the northwest. This regional paleo­

wind assessment is in agreement with the mid-Jurassic

paleo-wind trends of other Jurassic eolian deposits.

Isopach maps of the Exeter reveal a series of

southeasterly trending isopach thicks and thins. This

geometry is interpreted to represent a series of sand

ridges (draa?) and depressions (interdraa corridors?)

which were influenced by pre-Exeter paleotopographic

features.

vi LIST OF FIGURES Figure

Page

1.1 Location of Study Area ••...•...... 4

1.2 Prominent Physiographic Features of Northeastern New Mexico ••...... 5

2.1 Schematic diagram of the mid-Jurassic system showing the underlying and overlying relationships .•...•...... 8

2.2 Digitized induction and compensated neutron density log illustrating the Jurassic subsurface stratigraphic relationships .... 9

2.3 Unconformable lower contact between the mid-Jurassic Exeter and the Upper Triassic DocJcum Group...... 10

2.4 Late Paleozoic Uplifts and Basins in New Mexico and Colorado ••...... •.•...... 17

2.5 Regional reference map of the major tectonic elements of northeastern New Mexico...... 18

3.1 Cross-stratification in Facies 1 ...... 23

3.2 Coarse-grained laminations ••..•..•...... 26

3.3 Scour and fill structure in Facies 1 ...... 28

3.4 Horizontal stratification in Facies 2 .... 33

3.5 Oscilation-ripples in float in the base of unit 2 (Facies 2) at Cimarron East (measured section 26) ...•...... 35

3.6 Barite lenses in unit 3 (Facies 2) at Gallegos South (measured section 2) .•..... 36

3.7 Clay laminations in Facies 2 ...... 37

3.8 Bioturbated sediments of Facies 3 ...... 42

vii Figure

Page

3.9 Bioturbated sediments in Facies 3 .•...... 44

3.10 Burrows in the bioturbated sediments in Facies 3 at Trujillo road cut (measured section 14) .•...... •...... •...... • 46

3.11 Disturbed bedding in Facies 3 ...... 48

3.12 Load structures at the contact between Facies 3 and the Triassic Dockum Group at the Cimarron East Section (measured section 26) .•..••.•....•••...••...... 49

3.13 Megapolygonal mud crack casts measuring 90 centimeters across at the Miera Ranch (measured section 8) • ...... • . . . . . • . 50

3.14 Probable water escape structures .•...... 51

3.15 Clay rip up clasts in Facies 3 at the basal contact with the Triassic Dockum Group at the Ray Ranch (measured section 10)...... 53

3.16 Discontinuous clay laminations in Facies 3 at the Miera Ranch (measured section 8)...... 54

4.1 Compositional classification of the Exeter Sandstone in northeastern New Mexico...... 59

4.2 Photomicrograph of a polycrystalline quartz grain (center) ...... •...... 60

4.3 Photomicrograph of twinned plagioclase feldspar grains and fine grained quartz grains...... 61

4.4 Rock fragments in the Exeter Sandstone .... 63 4.5 Photomicrograph illustrating bimodal grain size distributions in the Exeter Sandstone. • . • • ...... 65

viii Figure

Page 4.6 Characteristic bimodal grain size distributions in interdune deposits ....•.. 67 4.7 Photomicrograph of kaolinite cement filling primary intergranular pore space and displaying its characteristic "booklet" morphology ...... 69

4.8 Cutans in the Exeter Sandstone •...... 71 4.9 Photomicrograph displaying poikilotopic carbonate cement filling the intergrainular pore space ...... 73

4.10 Carbonate cements in the Exeter Sandstone. • • . • . . . . . • . • • . • • . . . . . • . . . • ...... 7 4

4.11 Photomicrograph of well developed quartz overgrowths. . • ...... 77

5.1 Paleo-wind pattern for the Exeter Sandstone in northeastern New Mexico ...... 79

5.2 Paleogeographic map for Middle Jurassic time depicting cross bed resultants .•..... 81

6.1 Schematic diagram and cross-sections of dune, interdune and extradune deposits .... 84

6.2 Cross-section A-A' illustrating the intertonguing relationships of Facies 1, 2, and 3 in the east-central part of the study area...... 86

6.3 Cross-section B-B' illustrating the intertonguing relationships of Facies 1, 2, and 3 from the eastern to the western part of the study area ...... 88

6.4 Cross-section C-C' illustrating the intertonguing relationships of Facies 1, and 2 in the southern part of the study area. • • • • • • . • • • . • . . • ...... • ...... 9 0

ix Figure

Page 6.5 Isopach map of the Middle Jurassic Exeter Sandstone in northeastern New Mexico (hand contoured) . . . . . • • . • • • • . . . • . • • . . . • • • • ...... 94 6.6 Isopach map of the Middle Jurassic Exeter Sandstone in northeastern New Mexico (contoured by computer program Surfer version 4.0 using the spline curve method) . . . . • • . . . . • ...... • ...... 95

X CHAPTER I INTRODUCTION

Purpose of study The purpose of this investigation is to interpret the depositional environment(s) of the mid-Jurassic Exeter Sandstone of northeastern New Mexico. As a part of this study, an effort was made to collect paleo-wind data from the mid-Jurassic Exeter Sandstone and compare it with the regional paleo-wind data of other workers. Also, subsurface data were obtained to determine the regional geometry of the Exeter Sandstone. There are two primary reasons for such an investigation. First, very little geologic work has been done on the Exeter in the northeastern New Mexico vicinity and there have been few published regional interpretations in which the Exeter has been included. Second, there are differing opinions regarding the depositional environment of the Exeter in New Mexico. Mankin (1958, 1972) interprets the Exeter Sandstone as an eolian depositional system, whereas Savela (1977), based on grain-size probability curves, suggested that the Exeter represents a marine tidal and beach-dune ridge deposit, part of which may have formed above sea level.

1 2

Jacka (1973) also suggested that the Exeter was , dominantly of marine origin. Others (Walker and

Middleton, 1979, and Freeman and Visher, 1975) have argued for a tidal shelf depositional environment for similar sandstones, now almost universally regarded as eolian in origin. However, the distinction between eolian and tidal sand wave deposits is often a difficult one to make (Eschner and Kocurek, 1986).

Methods of study

The methods of study include both outcrop and subsurface studies. The surface study included both the measurement and description of 27 stratigraphic sections

(see Appendix A for measured sections and locations) .

Also included in the outcrop study was the measurement of paleo-wind data, primary sedimentary structure analysis, and the description of depositional environments. Thin sections of the Exeter Sandstone were prepared to study the composition and grain size. The slides were stained to aid in the identification of potassium feldspar.

Point counting of 100 grains per slide allowed for the classification of samples according to Folk's (1980) classification of sedimentary rocks.

Subsurface data were obtained from the Well Log

Library at the New Mexico Bureau of Mines and Minerals, socorro, New Mexico. The 5 geophysical logs and 28 3 sample (drillers) logs were used to determine the thickness of the Exeter Sandstone (see Appendix D for locations). The overall geometry of the Exeter was contoured using both a spline curve (''best fit") computer program (Surfer version 4) and by the writer. Surface and subsurface thickness relationships (geometry), depositional environments, and stratigraphic relationships within the Exeter were then synthesized.

Location of Study Area

The study area is located in the northeastern corner of New Mexico (Figure 1.1). The approximate boundaries of the study area include the Texas-Oklahoma-New Mexico border (east), the Colorado-New Mexico border (north), the extreme eastern edge of the Sangre de Cristo

Mountains (west), and Interstate Highway 40 (south). The counties that make up the field area include Harding, San

Miguel, Union counties, and portions of Colfax,

Guadalupe, Mora, and Quay counties.

Physical Geography

Northeastern Mew Mexico is an extension of the southwestern portion of the Great Plains province, which extends eastward from the front of the Rocky Mountains as a gently eastward-sloping, relatively flat alluvial plain with a regional slope of approximately 2 1/2 degrees to the east (Figure 1.2). In contrast to the mountain chain 4

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LEGEND

0 MEASURED SECTION NEW MEXICO • SUBSURFACE POINT

Scale 10 Index Map :J .... ' '

Figure 1.1 Location of Study Area. 5

•,.

•·+------~------

aVAUI

Scale 10.. .-- -0 - 10- -zo- -so mil••

Figure 1.2 Prominent Physiographic Features of Northeastern New Mexico. After Mankin, 1958. 6 to the west, the area of investigation was subjected to little structural deformation. Minor normal faulting

(with local graben development) and isolated gentle folds constitute the visible structures.

The relatively flat and featureless uplands are bounded by sharp topographic breaks throughout the province. The essentially horizontal caprock which

supports rims and mesas throughout Northeastern New

Mexico consists of basalt or sandstone, underlain by non­ resistant shale and mudstone. The major dendritic and

largely ephemeral tributary drainage channels are

confined to interplateau valleys which commonly develop

into narrow steep-walled canyons and represent the

sculpting and excavation of the uplands throughout the

area. CHAPTER II

STRATIGRAPHIC RELATIONSHIPS

General

The Jurassic System is widely exposed in northeastern New Mexico, but exposures are limited for the most part to the major canyons dissecting the Las

Vegas Plateau and to the Canadian escarpment (Figure

1.2). The Jurassic strata are generally subdivided into four rock-stratigraphic units (Figure 2.1) including the

Exeter (Entrada) Sandstone, the Todilto Limestone, the

Bell Ranch Formation, and the Morrison Formation (Lucas and others, 1985b). The rock sequence consists predominantly of sandstone, siltstone, mudstone, and shale, with minor discontinuous beds of impure limestone

(Mankin, 1972). Figure 2.2 is a geophysical well log illustrating the subsurface stratigraphy of the Exeter

Sandstone, the underlying Triassic Dockum Group, and overlying Jurassic Morrison Formation.

The mid-Jurassic Exeter is underlain by Triassic redbeds of the Dockum Group (Figure 2.3a) throughout the study area. The contact is discomformable at most locations but in the Dry Cimarron River valley, the contact is an angular unconformity (Figure 2.3b). In the

7 8

SYSTEM SERIES STAGE GROUP FORMATION LITHOLOGY

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- - •• 0 :··. ------.._..::_-_~ 0• • ••• •• J0 ~· u Zz w ---- -(/) 0:: _J 0 ••• 0 ') ~<{ ~:...:...·.: (/) w z - -- "': <( a.. z- - _-_-_ -_ a.. ~~ I ~ --- a::- <{0 -_ -_ -_-_ :::> uz u I- ~--=--~--=------~---­-----

Figure 2.1 Schematic diagram of the mid-Jurassic system showing the underlying and overlying relationships. After Schaeffer and Patterson (1984; vertical scale is diagramatic). 9

-1150 SP 40 0 RIU4 300 PHI NEU 0

0 GR 200 0 RILO 300 PHI DEN 0 ·····························------

1300 i

::z=

'· ... '' ..,....,.._.,_, ... . :?:: ·, 400 ,. ,· Upper ·· .. Jurassic s- : :.. ;;~ Morrison r-- ) 3 Formation ~.... --...... _-- r-----(....,j 450 ~:------.::·.... ?ii;:::;;;.;~~;.,.·~lllll'---- ~--.. .·1 I .7::"::;... ""? s- I .~ --'- -=> ·, : '::c... -"' -~-- {,· ~ ~ - '- 500 ---·~.,.,.,- ,• ·: :0 !' Hiddle /' ' I Jurassic ' '• > ' --', ...... Exeter •'. .... - 550 .r;: _, ~' Sandstone ) \ ·I ,,), ,..,.''. (J-2 Unconformityt)___ :,_;_...... ,.i~ •. ' ' (_ 600 > I ..\ , } . ~- ::· I I --~"""· Upper 650 ; I Triassic -:.:·. ; I' - -___ ,.,. Dockum .. I I Group I I •:··-·:z;·:J ...... J 700 ..... >

I 750 !

Figure 2.2 Digitized induction and compensated neutron density log illustrating the Jurassic subsurface stratigraphic relationships. Reese and Jones, M.E. O'Connor No.1 (Point M; see Appendix D for well location). 10

Figure 2.3 Unconformable lower contact between the mid­ Jurassic Exeter and the Upper Triassic Dockum Group. a) Horizontal unconformity at Tucumcari Mountain (Tucumcari, New Mexico vicinity). 11

b) Angular unconformity at Battleship Mountain (Dry Cimarron River Valley vicinity, northeastern New Mexico). 12 majority of exposures, the Exeter is a cliff-forming unit and is easily identified from a distance both by its topographic expression and by the color contrast. The Exeter Sandstone is tan or white in color while the underlying Triassic Dockum Group and Upper Jurassic Morrison Formation are predominantly dark red mudstones. The disconformity and angular unconformity that separates the mid-Jurassic Exeter Sandstone from the Triassic Dockum Group has been dated as Middle Jurassic in age and termed the J-2 unconformity by Pippiringos and O'Sullivan (1978). This unconformity is indicative of both the tectonic uplift and subsequent erosion of the eastern Colorado Plateau and northeastern New Mexico area, prior to the deposition of the Exeter. Although paleontological evidence supporting a Jurassic age for the Exeter Sandstone is sparse, vertebrate fossils have been discovered in the overlying Morrison and Todilto Formations which support a Jurassic age for the Exeter Sandstone (Mankin, 1972; Lucas and others 1985a). The stratigraphic relationship between the Exeter Sandstone and overlying Morrison Formation described by Mankin (1958), combined with the datable fauna present in the Morrison of the Colorado Plateau and Oklahoma panhandle support a Late Jurassic age assignment for the Morrison and a mid-Jurassic age assignment for the underlying Exeter Sandstone. The stratigraphic 13 association of the Exeter Sandstone with the Morrison

Formation suggests that the deposition of the Exeter may have begun during Middle Jurassic and continued into Late

Jurassic time.

Lucas and others (1985a) also suggest that the

Jurassic age for the Exeter (Entrada) Sandstone is best supported by its stratigraphic relationships with the

"more securely dated" sediments and associated dinosaur

fauna of the Morrison. Imlay (1980) suggests that the

lower age limit for the Exeter (Entrada) of the Colorado

Plateau ranges from late Bathonian to late Callovian and most likely early to middle Callovian. Others have proposed an upper age limit for the Exeter (Entrada) of

early Callovian age based on a datable fish fauna from the Todilto Limestone (Lucas and others, 1985a). Mankin

(1972) states, however, that the precise age and

correlation of the Exeter is still open to debate.

Type Section

The Exeter Sandstone was first described by Lee

(1902) in the vicinity of the Exter post office. This

later became the Valley Post Office (now Johnson) in the dry Cimarron Valley of Union County, northeastern New

Mexico. Lee misspelled "Exter" and instead named the

sandstone Exeter. The type location of the Exeter

sandstone is in the sw 1/4; SE 1/4; of section 28, 14

T.32 N., R.35 E., on the western face of Shiprock butte

(Battleship Mountain of current usage).

The exact location of the Exter Post Office is not known. Because of some uncertainty in the location of

Lee's type section, Stovall (1943) designated as the type section the nearly vertical cliffs south of New Mexico

Highway 325 in section 32, T.35 N., R.32 E.

Regional Stratigraphy

The Exeter Sandstone is considered to be equivalent to the Entrada Sandstone of the Four Corners region, and probably equivalent to the Ocate sandstone (Bachman,

1953) of Mora and Colfax Counties (Wood and others,

1953). Bachman (1953) stated that the Ocate is probably correlative with the Entrada Sandstone of northwestern

New Mexico and may also be correlative with the Exeter

Sandstone of northeastern New Mexico and northwestern

Oklahoma.

Heaton (1939) measured and described a number of sections containing Jurassic rocks in the Rocky Mountain region and was able to demonstrate that the Entrada

Sandstone of Utah could be convincingly correlated eastward to the Front Range of Colorado and thence southward into northeastern New Mexico. He thus treated the Exeter Sandstone of the Dry Cimarron River valley as 15 an equivalent of the Entrada Sandstone. Heaton (1939) describes the Ocate sandstone of Mora County as follows:

A grey, medium to massive, somewhat cross-laminated sandstone about fifty feet thick.... Typically the sandstone crops out as a rounded ledge. It is usually composed of medium sized, well rounded, quartz grains that frequently have frosted surfaces. Ferruginous stains and calcite veins are common.

Lessard and Bejnar (1976) suggested that the Exeter

(Entrada) Sandstone could be divided into two members.

They suggest that the "Ocate member" is indicative of a lacustrine, subeolian setting. The upper "Exeter

(Entrada) member" represents an eolian component.

Baldwin and Muehlberger (1959) demonstrated the equivalence of Lee's (1902) Exeter Sandstone with the mid-Jurassic Entrada Sandstone, described by Gilluly and

Reeside (1928) in eastern Utah. Lucas and others (1985b) argue for the rejection of the name Exeter as a formation and redefine Lee's original Exeter Sandstone as the

Exeter member (upper 17.7 m) of the Entrada Sandstone.

Lucas and others (1985b) also reject further usage of the term Ocate (Bachman, 1953) because it occupies the same stratigraphic position as the Entrada (Exeter) Sandstone throughout east-central and northeastern New Mexico.

The writer agrees with Mankin (1958, 1972) whose investigations of the Exeter Sandstone of northeastern

New Mexico suggest that the Wingate? sandstone of 16 northwestern Quay County (Dobrovolny and others, 1946) and the Ocate sandstone (Bachman, 1953) of Mora County are part of the same lithesome as the Exeter sandstone.

Mankin (1972) states that the term "Exeter" was accredited to the sandstone unit throughout its aerial extent in northeastern New Mexico in recognition of nomenclatural priority (it precedes the term Entrada by

26 years) introduced by Lee (1902) and should therefore

remain in use for the district.

Regional Depositional Setting

A regional assessment of the Jurassic western margin

of the North American plate by Kocurek and Dott (1983)

suggests that it represented an Andean-type plate margin.

Subduction of the Farallon plate beneath the American

plate produced a continental volcanic arc system. The

Jurassic formations east of the Andean-type margin were deposited in a retro-arc basin. The marine units in the west thin eastward into restricted marine, tidal-flat, and eolian deposits (Kocurek and Dott, 1983).

According to Kocurek and Dott (1983), the Jurassic basin of the western United States was bounded by local remnant elements of the Ancestral Rockies to the east, and the Mogollon Highlands to the south . Mankin (1958) suggested that the Exeter Sandstone was influenced by the sierra Grande Uplift (Figures 2.4 and 2.5), a local relic 17

FRONT RANGE GEANTICLINE (I'~ "~ ~0"'~ +~ ~ "~ 7f~ "< )to -f+ ~ c ~c (<' ~Q ~PISHAPA (~ ~ ~"Cl UPLIFT ~ ~~~0 COLORADO ~ ,...______...... ---·------~-- N~W MEXICO

ROWE-MORA BASIN

I I TEXAS BASIN I I I

0 25 50 75 100 milea SCALE

Figure 2.4 Late Paleozoic Uplifts and Basins in New Mexico and Colorado. From King (1959). 18

\-- \ N1w Mutco [J I I I { I -J- Ratn01 h( 1 I l (_) I ~~ 1 f I ~ I 91• I /l TAOS I I ~ ~ ONION o • / .._o / ~ 'Okla. j { I fc 0 L f,A X . /l~.._ ...... -----Texas ... )_I ,_,...,. / 1 --1-tt•l' 1 "'Q , -----,__ I'< t __J DALLAM § ) u) / ' ~-l_ oALHA~( -----"""'~'BA Sl ~ : ;:'1 6° / \ j\ ttAR 01 NG .. . ·... I • --1 0 (. ;i-+r0RA I r· 10 ~ I1 HARTLEY ~-~j---!U--/-J---'\ r·Ri·v l/.. ···;m ' :;{! I/ \ \ 0~· --- ·---

j '-:--~- I 1 \ -t ' I ' ' I \,~JSAN MIGUEL 'r- __ _j I OLDHA ... ~-_j I ...... ------· - ' 0 1UCIII'YIC:.rl f------/ QUAY i---1'- i'\. I -~h...J ~~\~' ~cu -f.-----.0- ~ ' __ It • ... ,,. I _I~ \Jls•nt•Rou ~ •81"'~~ 1DEAF SMITH- TORRA~CE /\ I I --~- I PALO ouno BASIN I ff II ~· G ~ A 0 A L u p E ~- cuRRy ['- ,- ' I J/ I \ ,-- 'DE L ___ j PARMER I \-~~ ~ I BACA • ,. """"" M I \ t 4 t t I to-...... j t I ... • • . IH • • • ..•••.

Figure 2.5 Regional reference map of the major tectonic elements of northeastern New Mexico. From Roberts and Others (1976). 19 of the Ancestral Rockies, because the Exeter thins over the inferred location of this feature. He also infers that the adjacent Ancestral Rockies were likely sources of sediment for the Exeter Sandstone. Like other Jurassic deposits in the western United States, significant amounts of sediment supplied for the Exeter Sandstone were probably multicyclic and derived from the adjacent craton accompanied by reworking of sediments within the basin (Kocurek and Dott, 1983; Snoparsky, 1986). King (1959) and Baltz (1965) suggest that the major Pennsylvanian and Permian tectonic features in the northern New Mexico-southern Colorado region (Figure 2.4) include the San Luis Uplift (southern extension of the Uncompahgre Geanticline), the Wet Mountain-Apishapa Uplift (southeast extension of the Front Range Geanticline) the Sierra Grande Uplift, and the intervening Rowe-Mora Basin (southern extension of the Colorado basin into New Mexico). Baltz (1965) suggested that the Rowe-Mora Basin was connected at its southern end to the Tucumcari Basin (extension of the Palo Duro Basin in Texas; Figure 2.5). Permian, Upper Triassic, and Upper Jurassic sediments blanketed the northeastern New Mexico-southern Colorado region and buried the Late Paleozoic Sierra Grande, Apishapa, and San Luis uplifts (Baltz, 1965; McGookey and others, 1972). 20

Snoparsky (1986) conducted investigations regarding the provenance of the Exeter Sandstone in Cimarron County, Oklahoma and adjacent parts of Union County, New Mexico and concluded that the heavy- and light-mineral assemblages are indicative of multiple sources. The heavy mineral fraction and sedimentary rock fragments suggest a sedimentary "recycling" system (Snoparsky, 1986). The variability in quartz types and rock fragments throughout the Exeter, accompanied with diversities in texture and mineralogy support this multiple source hypothesis. CHAPTER III

SEDIMENTARY FACIES ANALYSIS

General

The Exeter Sandstone may be subdivided into three facies. The three facies observed in the study area include:

1. tabular and trough cross-stratified facies.

2. horizontally stratified facies.

3. massive (structurally indistinct) facies.

The three lithofacies exhibit complex vertical and lateral associations.

Eolian depositional systems are best recognized by their physical sedimentary structures and by the processes associated with the formation and migration of dunes and smaller eolian bedforms. The following features are associated with wind-derived deposits

(Bigarella, 1972; Collinson, 1978; Walker and Middleton,

1977; Ahlbrandt and Fryberger, 1982; Fryberger and others, 1983; Chan, 1989; Deynoux and others, 1990): (1) large-scale, high-angle cross-stratification (up to 35 m thick), which may commonly display tabular or trough morphologies; (2) high ripple indices (R.I.>15); (3) sedimentary structures related to the process of sand avalanching down the dune slipfaces (ie. grainflow

21 22 deposits); (4) minor sedimentary features, including raindrop imprints, vertebrate tracks, desiccation features, and the deformation of lee side laminae; (5) the intercalation of dune facies with interdune facies andjor poorly sorted lag deposits on erosional bounding surfaces; (6) frosting of the sand particles; and (7) characteristic light and heavy mineral segregations.

Facies 1

Characteristics

Tabular and trough cross-stratification are the primary sedimentary structures in the strata that comprise facies 1. Facies 1 ranges from 0 to 16.8 meters

in thickness and consists of friable to well cemented, moderate to well sorted, white, medium- to fine-grained

(0.3-0.125 mm), sandstone. These sandstones display sets

of large scale (set-thickness from 1.5 to 4.6 meters),

low- to high-angle (up to 32°), tabular cross­

stratification (Figure 3.1a). Lower set boundaries are

tangential. Some sandstones display sets of medium (set­

thickness from .3 to 1.5 meters) to large-scale, low- to

high-angle, convex-up, trough cross-stratification

(Figure 3.1b) with tangentional lower set boundaries (see

Appendix A). The internal features of the primary

sedimentary structures include coarse-grained laminations 23

Figure 3.1 Cross-stratification in Facies 1. a) Tabular cross-stratification at David Hill (measured section 3). Facies 1 appears in the middle of the section and is 12 meters thick. 24

b) Trough cross-stratification (Facies 1) at Gallegos North (measured section 4). 25

(inverse-graded grainflow tongues) and fine-grained laminations (grainfall deposits; Figures 3.2a and 3.2b).

Cut and fill structures are observed on first order bounding surfaces (Figures 3.3a and 3.3b).

Facies 1 is thickest in the area of Gallegos, New

Mexico (Harding County) where it attains a maximum thickness of 16.8 meters at Gallegos Ranch North.

Tabular and trough cross-stratification are also present in the north face of Tucumcari Mountain and in the

Palomas Hills. Facies 1 is also found in the western part of the study area near Las Vegas, New Mexico (see

Appendix A) . Snoparsky (1986) describes a similar facies in the

Exeter Sandstone of western Oklahoma. This facies attains a maximum thickness of 19.8 meters and exhibits large-scale, low- to high-angle "wedge-planar" (McKee and

Weir, 1953) or tabular cross-stratification.

Depositional Systems

The features that characterize Facies 1 support an eolian inland dune depositional setting. Sets of large- scale tabular cross-stratification are a product of . crescentic bedforms and are similar to cross-strata 1n both modern eolian environments and ancient sandstones that have been interpreted as eolian in origin 26

Figure 3.2 Coarse-grained laminations. a) Inverse­ graded grainflow tongues measuring .3 to 1.2 meters in width) and fine-grained cross-laminations (9rainfall deposits) in Facies 1 taken at Los Montoyas (measured section 16). 28

Figure 3.3 Scour and fill structures in Facies 1. a) at Cimarron East (measured section 26). Pencil for scale. 27

b) Grainflow deposits and grainfall deposits in Facies 1 at Los Montoyas (measured section 16). 29

b) at Miera Ranch (measured section 8). Hammer for scale. 30 (Gradzinski and Jerzykiewicz, 1974; Steidtmann, 1974;

Weber, 1979; McKee, 1979; Kocurek and others, 1981a;

Fryberger and others, 1983; Rubin and Hunter, 1983;

Ekdale and Picard, 1984; Chan, 1989). Coarse-grained

(inverse-graded grainflow tongues) and fine-grained cross-laminations (grainfall deposits; Figures 3.2a and

3.2b) are features commonly displayed in both modern and

ancient eolian dune settings (Kocurek and others, 1981a;

Fryberger and others, 1983). These are considered to be

important critera for the distinction between eolian and

subaqueous depositional environments (Kocurek and others, 1981a) .

Fine-grained laminations, coarse-grained

laminations, and inverse-graded bedding are indicative of sediment deposition commonly observed in modern eolian dunes. Fine-grained laminations are interpreted to be the result of sand grains settling out of suspension in the zone of flow separation lee of the dune crest. The coarse-grained laminations (grainflow tongues) and

inverse-graded beds are inferred to be grainflow

(avalanche) cross-strata which result from over steepening of dune lee slopes at the brink when the angle of repose exceeds 34 degrees (Hunter, 1977).

The segregation of fine and coarse particles in modern dunes is produced during avalanching where the coarser grains are held in the upper surface of the flow by dispersive pressure. Inverse grading may also be 31 produced when the coarse grainflow sediments overtake previously deposited fine- to very fine-grained grainfall deposits (Bagnold, 1954; Sallenger, 1979). Scour and fill structures occur on first order bounding surfaces in Facies 1 (Figures 3.3a and 3.3b). Scour and fill structures are interpreted to represent periods of erosion (deflation) or non-deposition (Kocurek, 1981b; Rubin and Hunter, 1983; Talbot, 1985). Similar structures are identified on the first order bounding surfaces of the Middle Jurassic Entrada Sandstone, Utah (Kocurek, 1981b) and suggest that the relief is the result of wind deflation andjor by water erosion. Grain size distribution and sorting observations also support an eolian dune depositional setting for Facies 1. The texture of Facies 1 is typical of both modern and ancient dune sands. The predominance of quartz and the dominantly well-sorted, subrounded, fine­ grained texture of Facies 1 resembles other ancient eolian sandstones including the De Chelly, Navajo, and Coconino (McKee, 1979) as well as many modern desert dune sand deposits (Ahlbrandt, 1979). The range in sorting (moderate to well sorted) and the range in grain size (medium- to fine-grained sand) support the deposition of Facies 1 within an inland dune environment (Ahlbrandt, 1979). 32

Facies 2 Characteristics Facies 2 ranges from 0 to 11 meters in thickness and is comprised of moderate to well indurated, poorly sorted, reddish-brown to tan, medium- to very fine­ grained sandstones. These sandstones display thinly- to thickly- bedded, horizontal and low-angle (<10°) stratification (see Appendix A). Facies 2 intertongues with Facies 1 and Facies 3 throughout the field area. Facies 2 is thickest at Palomas, New Mexico (Quay County) in the south-central part of the study area, where it attains a maximum thickness of 11 meters at Palomas Hills (measured section 21; see Appendix A). Facies 2 is characterized by thinly- to thickly­ bedded horizontal stratification and horizontal and low­ angle plane bed stratification (Figures 3.4a and 3.4b), wave-rippled surfaces with truncated ripple crests (Figures 3.5), discontinuous barite lenses (Figure 3.6), bimodal sorting (Figure 4.5), and clay laminae (Figures 3.7a and 3.7b). The sediments of Facies 2 are sub-angular to well rounded, possess a wide range in grain size and commonly exhibit bimodal sorting (Figure 4.5). 33

Figure 3.4 Horizontal stratification in Facies 2. a) at Davidson Ranch (measured section 22). Note the 3 foot mudstone intervals at the base and the middle of the exposure. 34

b) at Palomas Hills (measured section 21). Graduate students for scale. 35

Figure 3.5 Oscilation-ripples in float in the base of unit 2 (Facies 2) at Cimarron East (measured section 26). 36

Figure 3.6 Barite lenses in unit 3 (Facies 2) at Gallegos South (measured section 2). 37

Figure 3.7 Clay laminations in Facies 2. a) at San Jon section (above the scale; measured section 1). 38

b) at San Jon section (see hammer head; measured section 1). Note the divergence of the clay laminations to the right a~d their convergence to the left. 39

Depositional Systems The stratigraphic evidence suggests that two depositional sub-environments represent the horizontal stratified, non-dune facies including both interdune and extradune sand sheet environments . Friedman and Sanders (1978) indicate that deflation lag or reg deposits are common features of both modern interdune settings and inferred ancient eolian interdune deposits (Figures 3.6a and 3.6b). The exact depositional mechanisms for these sediments may include grains falling from suspension, grains retained as lag on reg surfaces, grains deposited under subaqueous conditions, and/or the intercalation of Facies 2 with Facies 1 (Fryberger and others, 1983). The presence of mudstone-beds (Figure 3·.4a) and thin discontinuous clay laminations (Figures 3.7a and 3.7b), celbar pods (Figure 3.6), and oscillation ripples with truncated ripple-crests (Figure 3.5) suggests that Facies 2 was in part deposited subaqueously. Lacustrine depositional settings are considered quite common within eolian depositional systems (Picard and High, 1981; Fouch and Dean, 1982). Chan (1989) described similar facies in the Permian White Rim Sandstone of southeastern Utah. The White Rim Sandstone deposits consist of horizontal laminations with both normal and inverse grading. Some of the laminations 40 may be grainfall deposits according to Hunter (1977). The presence of mud drapes is inferred to indicate periodic flooding.

Kocurek and Nielson (1986) characterize similar deposits as sand sheets and describe them as aerially extensive eolian sand deposits that lack dunes with slipfaces. Modern sand sheet deposits are commonly associated with warm climate sand seas and occur on both the up-wind and down-wind margins of dune fields and in interdune or draa corridors. Fryberger and others (1983) also suggest that sand sheets may form within the interior of a dune complex or independent of a dune field. They suggest that sand sheets represent a transitional component deposited between dune complexes, sabkha, or between eolian and extradune (non-eolian) facies.

Facies 3 Characteristics Massive Facies constitute Facies 3. The sediments of Facies 3 range from 0 to 22.6 meters in thickness and consist of moderate to well indurated, poorly sorted, reddish-brown to grayish-tan, medium- to very fine­ grained sandstones which are structurally indistinct or massive (see Appendix A). 41

Facies 3 intercalates with Facies 1 and Facies 2 throughout the field area (Figure 3.8a and 3.8b). Facies 3 is thickest 10 miles west of Roy, New Mexico (Harding County) where it attains a maximum thickness of 22.6 meters at the Ray Ranch. Features that are common to the massive or bioturbated sediments of Faces 3 include bedding that is horizontal and bioturbated, mottled and structurally indistinct or massive (Figures 3.9a and 3.9b). Both distinct and indistinct burrows (Figure 3.10), soft sediment deformation (Figures 3.11a and 3.11b), load features (Figure 3.12), desiccation features (megapolygon casts measuring 90 centimeters across; Figure 3.13), fluid escape structures? (Figure 3.14a and 3.14b), shale­ pebble rip up clasts (Figure 3.15), and shale laminations (Figure 3.16) are also present. The sediments of Facies 3 are sub-angular to well rounded and possess a wide range in grain size sorting.

Depositional Systems The features displayed in Facies 3 suggest a depositional setting comparable to that of Facies 2. With the exception of sediment mixing, the structures of both Facies 2 and 3 suggest deposition in two non-dune depositional environments including both interdune and extradune sand sheet environments. 42

Figure 3.8 Bioturbated deposits of Facies 3. a) at the Miera Ranch (measured section 8). Note the intertonguing relationships between Facies 3 (red) and Facies 1 (tan) "honeycomb" weathering profile of Facies 1. Bush in foreground is 1.5 meters high. 43

b) at Monument Point Section {measured section 19). Bioturbated sediments in Facies 3 are overlain by Facies 1. Note the truncated upper contact with Quaternary alluvium. Hammer for scale. 44

Figure 3.9 Bioturbated sediments in Facies 3. a) at the Miera Ranch. Fluid escape structures? occur throughout the unit. Clipboard for scale. 45

b) at Trujillo road cut (measured section 14). 46

Figure 3.10 Burrows in the bioturbated sediments in Facies 3 at Trujillo road cut (measured section 14). 47

Figure 3.11 Disturbed bedding in Facies 3. a) Soft sediment deformation features in Facies 3 at the Ray Ranch (measured section 10). 48

b) Deformed laminae in Facies 3 at Cimarron East section (measured section 26). 49

Figure 3.12 Load structures at the contact between Facies 3 and the Triassic Dockum Group at the Cimarron East section (measured section 26). 50

Figure 3.13 Megapolygonal mud crack casts measuring 90 centimeters across at the Miera Ranch (measured section 8). The casts are weathering out below a ledge and formed in a 7.6 centimeter thick mudstone bed. 51

Figure 3.14 Probable water escape structures. a) in Facies 3 at the Miera Ranch (measured section 8}. Lense cap for scale. 52

b) in Facies 3 at the Miera Ranch (measured section 8). Lense cap for scale. Note the liesegang rings. 53

Figure 3.15 Clay rip up clasts in Facies 3 at the basal contact with the Triassic Dockum Group at the Ray Ranch (measured section 10). 54

Figure 3.16 Discontinuous clay laminations in Facies 3 at the Miera Ranch (measured section 8). 55

The features of Facies 3 suggest that it accumulated in an environment subject to periodic flood events. The evidence which supports the existence of intermittent ponds and/or lakes includes, soft sediment deformation (Figures 3.11a and 3.11b), load structures and rip up clasts (Figures 3.12 and 3.15), mud crack casts and fluid escape structures? (Figures 3.13, 3.14a, and 3.14b), and discontinuous clay laminations (Figure 3.16). Clay laminations (Figure 3.16) and homogeneous, clay-rich sediment is common in Facies 3 throughout the field area. These features are commonly observed in similar ancient facies of both the Permian White Rim Sandstone of southeastern Utah and the mid-Jurassic Entrada Sandstone of the Four Corners Region (Chan, 1989; Kocurek, 1981b; Kocurek and Nielson, 1986). Modern eolian systems also display similar features associated with non-dune deposition (Fouch and Dean, 1982). Burrowing is a very common, if not ubiquitous, feature of eolian deposits. The most common bioturbating organisms in eolian environments are the arthropods. The various orders of arthropods, indigenous to eolian environments, have existed for at least 300 million years (Ahlbrandt, 1979). Distinct burrows are found near Trujillo, New Mexico at measured section 14 (Figure 3.10). Biogenic structures in modern eolian deposits are dominantly 56 produced by a variety of insects, arachnids, molluscs, amphibians, and small mammals (Ekdale and Picard, 1984). CHAPTER IV PETROLOGY

General Thin sections of 63 sandstone samples were analyzed using a petrographic microscope. Mineral composition, texture, and cements were evaluated to aid in the determination of the environment of deposition. Some of the more important parameters considered were grain morphology (grain size and shape), the mineralogical composition (quartz, feldspar, and rock fragments) and their condition (fresh or weathered), the type and percentage of the cementing material, and the percentage of porosity. The Exeter ranges from friable to moderately well­ cemented, medium to very-fine grained, angular to well­ rounded, moderate to well-sorted sandstone. The samples collected and thin sectioned were moderately to well cemented. The friable, poorly cemented units were described at the outcrop but not sampled. Visual observations of roundness were performed on all of the samples collected. The majority of the grains are subangular to well-rounded. This roundness criterion conforms with the roundness data of Mankin (1958).

57 58

Mineral Composition and Texture With the exception of a few samples which are classed as mature to supermature quartz arenites (more than 95% quartz and 5% or less feldspar and rock fragments; Folk, 1980; see Appendix C), the majority of the samples are classified as mature to supermature subarkose, sublitharenite, lithic arkose, and feldspathic litharenite sandstones (Figure 4.1). The Exeter Sandstone is moderate- to well-sorted and rounded to well-rounded. Textural differences exist between dune, interdune, and extradune deposits. These observations concur with the textural parameters described by Ahlbrandt (1979) for inland eolian environments.

Quartz Quartz is the most abundant mineral in each of the samples (Figure 4.2). The quartz grains are generally fine grained, and subangular to well rounded.

Feldspar The feldspar grains consist of varying amounts of potassium and plagioclase feldspar.(Figure 4.3). The feldspar grains display both fresh unaltered surfaces and severely abraded surfaces. The abraded, vacuolized, and corroded feldspar grains are well rounded. 59

QUARTZ

0 0

Feldspothlc Lithic Arkose Llthorenite Lltharenlte FELDSPARS

~ Facies 1 0 Facies 2

0 Facies 3

Figure 4.1 Compositional classiffcation of the Exeter sandstone in northeastern New Mexico. After Folk (1980). 60

Figure 4.2 Photomicrograph of a polycrystalline quartz grain (center). Bar scale is .25 mm. Cross-polarized light. Sample 5-3 from Facies 2. 61

Figure 4.3 Photomicrograph of twinned plagioclase feldspar grains and fine grained quartz grains. Bar scale is 1 mm. Cross-polarized light. Sample 17-1 from Facies 3. 62 Sedimentary Rock Fragments

The sedimentary rock fragments include well rounded

chert and large detrital carbonate grains (Figures 4.4a

and 4.4b). The presence of chert and carbonate grains

suggests a minor source area in chert-bearing carbonate rocks from interdunal, sabkha settings.

Mankin {1958) notes that carbonate and chert

fragments appear to be more abundant in the eastern portion of the study area. He suggests that this trend

supports the existence of a second contributing sedimentary source.

Grain Size

Many of the interdune and extradune (Facies 2) sandstones exhibit bimodal grain size distributions

(Figure 4.5). The presence of bimodal grain size distributions may be the result of incomplete sorting and may represent different methods of transportation and subsequent deposition. The finer particles were transported in suspension or by saltation and deposited as grainfall sediments. The coarser mode could be the result of transportation entirely by creep (traction).

Folk (1968) suggests that reworking by wind tends to winnow-out the particles of intermediate sand-size (<.5 mm) because they are more easily saltated and are deposited as dune sands. The remaining interdune lag 63

Figure 4.4 Rock fragments in the Exeter Sandstone. a) Photomicrograph of a large chert grain (center) and two smaller chert grains (upper and lower right) . Note the preserved primary intergranular porosity. Bar scale is 1 mm. Cross-polarized light. Sample 8-1 from Facies 3. 64

b) Photomicrograph of two large carbonate lithoclasts. Bar scale is 1 mm. Cross-polarized light. Sample 29-1 from Facies 3. 65

Figure 4.5 Photomicrograph illustrating bimodal grain size distributions in the Exeter Sandstone. Bar scale is 1 mm. Cross-polarized light. Sample 5-3 from Facies 2. 66 deposits on reg flats consist of particles too large to saltate and finer particles which pack within the void spaces of the lag to form cohesive pavements (Figures 4.6a and 4.6b). Deflation lags consist particles ranging in size from 0.5 mm to 2.0 mm. These interdune deposits commonly display strongly bimodal grain size distributions (Folk ,1968; Friedman and Sanders, 1978; Ahlbrandt and Fryberger, 1982; Fryberger and Others, 1979b). Mankin (1958) concluded that the sorting coefficients of the Exeter range from 0.23 to 0.65, indicative of a very well-sorted to moderately-sorted sand. These are also typical coefficients for both recent wind derived dune sands.

Cements Cements commonly observed include clay, carbonate,and quartz overgrowths. These cements were apparently formed during three diagenetic events.

Clay Cement Authigenic kaolinite is the most abundant of the pore-filling, clay cements (Figure 4.7). The occurrence of kaolinite is documented in both well cemented and poorly cemented samples. Clay coatings or "cutans" are common in many of the samples. Two types of cutans, argillans and 67

Figure 4.6 Characteristic bimodal grain size distributions in interdune deposits. a) Scanned image of a photomicrograph of a modern reg deposit collected in the Simpson Desert, Australia. Viewed through a binocular microscope. Plane light. From Folk (1968). 68

b) Scanned image of a photomicrograph of a sandstone inferred to be an ancient reg deposit in the Lander Sandstone (Ordovician), Wyoming, USA. Plane polarized light. From Folk (1968). 69

Figure 4.7 Photomicrograph of kaolinite cement fill i ng primary intergranular pore space and displaying its characteristic "booklet" morphology. Bar scale is .25 mm. Cross-polarized light. Sample 28-3 from Facies 2. 70 ferriargillans, were identified. The orientation of the clay platlets in the coatings are parallel to the grain surfaces. The coatings are not continuous around individual grains (Figures 4.8a and 4.8b). Walker (1979) provides conclusive evidence of cutan formation through his SEM investigations of modern eolian deposits of western Libya. He suggests that these yellowish hydrated iron oxide coatings are is derived from airborne (suspended) dust which is mechanically infiltrated into the sand through meteoric groundwater percolation.

Carbonate Cements The carbonate cements include both poikilotopic, anhedral calcite and euhedral dolomite. The samples well cemented with calcite commonly exhibit poikilotopic texture (Figure 4.9). Poikilotopic calcite commonly occurs in the well cemented, resistant sandstones and displays a ''knobby" texture on the weathered outcrop surfaces. Dolomite varieties include both subhedral corroded dolomite and euhedral zoned types (Figures 4.10a and 4.10b). Dolomite cement in places embays quartz and feldspar grains. Dolomite cements occur in both well and poorly cemented sandstones. 71

Figure 4.8 cutans in the Exeter Sandstone. a) Photomicrograph of corroded (discontinuous) argillans and poorly developed quartz overgrowths in a well rounded sandstone. Note the preserved primary intergranular porosity. Bar scale is .25 mm. Cross-polarized light. Sample 5-3 from Facies 2. 72

b) Photomicrograph of ferriargillans (reddish-brown rims) and poorly developed quartz overgrowths on quartz grains. Note the preferential cementation of scalenehedral calcite cement on the carbonate grains. Bar scale is .25 mm. Plane-polarized light. Sample 4-2 from Facies 1. 73

Figure 4.9 Photomicrograph displaying poikilotopic carbonate cement filling the intergranular pore space. Crystals are optically continuous up to 1 mm. Bar scale is 1 mm. Cross-polarized light. Sample 17-1 from Facies 3. 74

Figure 4.10 Carbonate cements in the Exeter Sandstone. a) Photomicrograph of zoned rhombohedral dolomite cement in the intergranular pore space of a well rounded sandstone. Bar scale is 1 mm. Cross-polarized light. Sample 5-3 from Facies 2. 75

b) Photomicrograph of large dolomite rhomboherdron filling the intergranular pore space of a well rounded sandstone. Bar scale is 1 mm. Cross-polarized light. Sample 28-3 from Facies 2. 76

Quartz Overgrowths Quartz overgrowths fill the primary pore space and reduce the primary porosity. Quartz overgrowths commonly have distinct boundaries and are well developed in samples which contain low percentages of clay cement. ''Dust" lines mark the contact between the grains and overgrowths and precede the development of overgrowths (Figure 4.11). Feldspar overgrowths are extremely scarce and very difficult to discern due to the obscuring tendency of the potassium feldspar stain. 77

Figure 4.11 Photomicrograph of well developed quartz overgrowths. Note the interlocking appearance and absence of intergranular pore space. Bar scale is 1 mm. Cross-polarized light. Facies 2. CHAPTER V

PALEO-WIND ANALYSIS

General

Paleo-wind data were collected from medium- to large-scale sets of tabular and trough cross­ stratification in Facies 1. Ninety-three unidirectional paleo-wind measurements including bearings of trough set axes (trend and dip pairs) and dip directions of cross­ bedded surfaces. The paleo-wind rose diagrams were constructed using the computer program "Vector Rose" by

Zippi (1988) and all readings are grouped into 20 degree azimuth classes (see Appendix B for rose diagrams).

Discussion

The paleo-wind orientation data for Facies 1 are compatible with an eolian depositional environment.

Individual data sets commonly exhibit high variability

(Figure 5.1). The high regional variability of cross­ strata orientations in Facies 1, combined with the occurrence of medium- to large-scale trough cross-strata suggests their formation by crescentic dunes. The arc spread and distribution of the cross-stratification in

Facies 1 are similar to those in the Permian Coconino, the Permian De Chelly, and the Triassic/Jurassic(?)

78 79

•- ··-·· IO~· 104" !: '93" 57 )··-··"--··-··-··-··-··-··-··-··-··-·--·L-··-··-··-··-··-··-·· .-··-··-··1·37" I I ~ J._J' II \ COLFAX UNION .') ( ')

. ·-·-·-·· ' M R A .. \ H A. R o 1N G l-.--·-·-·-·-·lr ' 0 ~ L••.

l - I I Ii .""'-· "'· . __. I 'v·-·---·-·------·-·-·-·\ I I \., ) : .r-·-·-·-·-·~ i \ ... ',· .i /..\ i .

REGIONAl PlOT \ . I ! ~---~ . SAN Ml GU EL r-·-·-"' r ______. ______...... ·1---·--~t a uA v

I - J GUADALUPE I \ 1-35" r·-·-·-·_; ! j I I I •

LEGEND

0 MEASURED SECTION

NEW MEXICO A SUBSURFACE POINT

Scale 'P Index Map ! .... ' Figure 5.1 Paleo-wind pattern for the Exeter Sandstone in northeastern New Mexico. See Figure 1.1 for rose locations. See Appendix B for statistics. 80

Navajo Sandstones described by McKee (1979). cross­

stratification types in these ancient eolian deposits

resemble those produced by the crescentic (barchan or

barchanoid) dunes common to modern eolian settings.

Modern crescentic (barchanoid) dunes often exhibit

considerable directional variability (arc spreads); for

example at White Sands National Monument, New Mexico

(McKee, 1966), the Namib Desert Coast, South Africa

(Fryberger, 1979a), and the Cherchen Desert, China

(Fryberger, 1979a). The directional variability of

modern crescentic dunes is attributed to both the strong

curvature of dune slipfaces and the daily or seasonal

varying directions and intensities of the wind.

The regional vector resultant (N.79° E.) for the

Exeter in the study area is in agreement with the paleo­

wind studies of Middle Jurassic eolianites of Snoparsky

(1986) and Peterson (1988) for northeastern New Mexico

(Figure 5.2). Kocurek and Dott (1983) suggest that

western North America occupied the latitudinal range of

northeasterly trade winds (Figure 5.2).

Paleo-wind data obtained by the writer and by previous workers (Snoparsky, 1986) for the mid-Jurassic

Exeter Sandstone in northeastern New Mexico indicate that the mean sand transport direction throughout the study area was quite variable during mid-Jurassic time (Figure

5.1). However, the dominant direction ranged from the 81

• low hlllaf?l- or- 1""'\ lowlanclal?l

Pacific ""' ,.... ;Y -?--?- Ocean Sundance Seaway

-1 ,.... r'\ I I /,..._ VolcanlcaC?I r­ ?/Highlanda or ,.... J low hllla ...... ~" /7 '- ", lowlanda ~ ... ~ ...... - '-..~ ~ \ .. ?··. .. ?. , ., ""''' ..... ·· __., -.. ""' ,...:J

' ...

lowland a .·?·· .., ..... ·····

lOll Ml ~~..c-....L_, •. -, I I J 100 200 300 400 SOO kM A I

Figure 5.2 Paleogeographic map for Middle Jurassic time depicting cross bed resultants. From Peterson (1988). 82 south-southwest to the north-northeast suggesting a paleo-wind direction from the northwest for the study area. The paleo-wind variation in Facies 1 may also be attributed to minor deflections around local topographic features or bedforms. The actual distribution of the dip directions within the cross-stratified units may be polymodal. Because as many as 25 measurements may be needed to accurately define bimodal and polymodal distributions with high confidence, more measurements may be needed for more detailed analysis of the cross­ stratified units (Potter and Pettijohn, 1977). CHAPTER VI

DEPOSITIONAL ENVIRONMENTS

General

Previous studies have identified the Exeter as an

eolian sandstone (Mankin, 1958, 1972; Snoparsky, 1986).

Local fluvial and lacustrine deposits have been

identified within the Exeter of the Oklahoma-northeastern New Mexico (Snoparsky, 1986).

Mankin (1958, 1972) suggests that the Exeter of the

study area "was deposited as a dune-sand in an interior

basin with southeasterly-migrating dunes" and was

associated with "small playa lake development".

This study also supports an eolian depositional

environment for the Exeter Sandstone. The presence of

the three eolian facies:

1. Cross-stratified dune deposits (Facies 1).

2. Horizontal-stratified interdune and extradune deposits (Facies 2).

3. Massive bioturbated interdune and extradune deposits (Facies 3). indicates that the Exeter was deposited in a variety of complex eolian sub-environments. The aerial association of the three Exeter facies resembles the model proposed by Fryberger and others (1979a; Figure 6.1).

83 84

INTERDUNE

LOW-ANGLE EOLIAN

crou-beddlng graded laminae small current rlpplea with clay-drope on top climbing laminations WINO water laid gravel eroplonal boundl~ horizontally laminated sand sur ace acour and fill horilontally laminated sana croaa- bedding ahalt laminations horl~ontally I aminated sand FLUVIAL-EOLIAN EOLIAN

Figure 6.1 Schematic diagram-and cross-sections of dune, interdune, and extradune deposits. After Fryberger, Ahlbrandt, and Andrews (1979b). 85

Lithostratigraphic Relationships

Correlation of the three lithofacies from the

southeast to north-central part of the study area

(Figure 6.2) suggests a transition from extradune sand

sheet deposition (Facies 2) to a dune field depositional

settings (Facies 1). The central region of the cross­

section contains interdune deposits (Facies 2 and

Facies 3) overlying the cross-stratified dune deposits (Facies 1).

The facies correlation from the southeast to the

northwest (Figure 6.3) displays transitions from

extradune sand sheet depositional environments (Facies 2)

to interdune lacustrine depositional environments (Facies

2 and Facies 3) through the central region of the field

area, and then changing to dune field depositional

settings (Facies 1) in the west-central region. Mankin

(1958, 1972) and Trauger (1972) have inferred that the

absence of the dune facies in the central region of the study area indicates that there existed a pre-Exeter topographic high through the region.

The facies associations from the southeast to the southwest part of the study area (Figure 6.4) reveal intertonguing of marginal extradune sand sheet deposits

(Facies 2) and dune deposits (Facies 1). 86 Figure 6.2 Cross-section A-A' illustrating the intertonguing relationships of Facies 1, 2, and 3 in the east-central part of the study area. --

•· JIEUUUO aECTia. u •· 'IUCiaiiCUI ....,... 111 ...... QUAY CGUWft • IIDI ...-JCD ...-- ..

II[W I ---.._ I: I ...... _ ft. ,_. I J r--..__•1 ' ' 1 lndnUap ~aarTl-. ~ ..... -UIG _.,, •Dt llalCO REUU'IlED aECrta. , II&ASVIli:D RCTIOII ' ~ED 8&CTI- I DAV'IDIULL IIJCWELL IWial IIJDA aAIIC::. -UIG a.Mn, ftV ll!:l

~...:TI-l BA8Uili:D ·IIC'I"'- J ~ ...... MIIDIK C'aUW'ft • ... .XI CO

1

Facies 2 Facies 2 Facies 1 Facies 1

A I ~ c --=-- -~--;,.~ ~ ~- ... -- - ~ =1- ·-r ~ I -1 ...... _I \ A

Q) ...J 88 Figure 6.3 Cross-section B-B' illustrating the intertonguing relationships of Facies 1, 2, and 3 from the eastern to the western part of the study area. ~ IUCTII* 2l

'IVCUICMI ~~· -- QUAY c:uu.ft, IIDI IIIli I CO •

--..

IIEUVIlED IIC:rll* 16 1 Ulll IIIIII'TOYAI

IAII IUGUEL C0UJrn, IIEV IIDICO

IIEASUaal UCTIOII l IIEASUilED &ICTIOII 1!1 L\11 .1011 CAifOII ~ AGUA QUAY COOfll]'l, IIDf IIICI:lCO SAM NIGUEl. COUirrY, JIEV MDI CO ~ &IICTio. liO 11U.SU11a1 &IICTII* 14 PAlLO -.rotA QIAII'I' ,..,.ILLO I,UI IUGUJ:L COVIITY, L\11 IIIGVU. CIDUII'n, IIIII JII:XICD

III&AIUIIDI IICnOII t JIV.SuaED UCTIOII U 1

uco~ uu&AJ~~~

~IIIG cowrn, IIIII IIIli ICO ' IAII lltC:UU. CIDUII'n, JIEV IIICI:lCO Facies 2 ,~Facies Y> ~~! J --F"acies 3 ':-'}: ""> -~;~, Facies 1 B 1 ~------~ L ~-:'--~==;:;;._;;;.bOor> Facies 2 H ------5J,..' .J B

·~~i.;

(X) \0 90 Figure 6.4 Cross-section c-C' illustrating the intertonguing relationships of Facies 1, and 2 in the southern part of the study area. f!USI.IUD Rn'JO. 21

PIU.OfiAI Ill~ lltAIUUD ACTIO. U QUAY C0U1rn, IIIII ICEIII CO 'I'\IC\JitCAaJ IIOUWT AJ •

QUAY COGift, .Elf IIEirlCD

Facies 1

•· Facies~ 3 ···' ~ \ Jlt:ASURED SECTION n ...-- .. DASUitED RCTJO. 1) 11A11DU IWICII IFacies 1 ~RCTJO.l'r QUAY COUirn, CUDIVO IUU.

CIUAIIoU.Uft c:a.n, - IIDlCD

Facies 2

Facies 2 Facies 2

.:~ ·-r . ·., l l>_l ~ ,-.•-.;! 1:-:•J C ---r:-r rT --1 ·.·.4 c \·==·­:-:-;-...... ·

\0 ..... 92

The complex intercalations of the three eolian facies (Figures 6.2, 6.3, and 6.4) is typical of erg margin settings as described by Chan (1989). Table 6.1 is a list of 16 of the 25 criteria used by Chan (1989) to differentiate eolian erg margin sub-environments in the Permian White Rim Sandstone of southeastern utah. The Middle Jurassic paleogeographic map from Peterson (1988; Figure 5.2) also places northeastern New Mexico in an erg margin depositional setting.

Exeter Geometry Isopach maps of the Exeter were constructed by hand and with a computer using the spline curve ("best fit") method in Surfer version 4. The program produces a three-dimensional curved surface which is "fit" to the data values in the grid cell. The nodal values are derived from X, Y, and Z data which are entered into the grid node from a base map using a digitizing board. Computer maps can be used to help substantiate andjor support the more interpretive hand contoured maps. However, the program will extrapolate through areas that are lacking data, so caution must be used in interpretation. The Exeter Sandstone displays considerable variation in thickness throughout the study area (Figures 6.5 and 6.6). These variations are both a reflection of the 93

Table 6.1 Summary of features of the Exeter Sandstone of northeastern New Mexico that are similar to features in the Permian White Rim Sandstone of South East Utah. Modified after Chan (1989).

Features and characteristics Exeter Abundance

Sheet sand Facies (Exeter Facies 2) Horizontal and low-angle (<10°) stratification Common of fine- to medium-grained (0.125-0.5 mm) sand alternating with coarse-grained (0.5-1.2mm) sand lags Grainfall (?)/plane bed deposits Rare Root traces (?)/bioturbation Rare Mud drapes over water-laid ripples Rare Eolian Dune Facies (Exeter facies 1) High-angle (up to 32°)cross-strata in sets up Common to 10 m thick Tabular and trough sets Common Avalanche tongues/Grain flow strata Present Grainfall strata Rare Barchanoid dune forms (1-4 m high) with Present cresent shaped geometries Interdune Facies (Exeter Facies 2) Thin, wavy, horizontal strata (0.125-0.25 mm Common sand} Reworked Facies (Exeter Facies 3) Fluid escape structures? Rare Massive sandstone Common Horizontal planar stratification Common Wave ripples Rare Small polygon and megapolygon sandstone Present structures Disturbed and Mottled bedding (burrowed or Common rooted}? 94

'Q CD ~ \ } 1 ) \ Contour Interval• 20 feet Scale 10 0 .... 10 tO

LEGEND

~ WEASUREO 8ECTION ~ MORRISON FM. OVERLYING .. ~ ...... ~ THE DOCKUM GROUP • SUBSURFACE POINT

Figure 6.5 Isopach map of the Middle Jurassic Exeter sandstone in northeastern New Mexico (hand contoured). Contour interval is 20 feet.

' 95

Triassic Subcro

Contour Interval • 20 fill Scale •t ! .... 10

LEGEND

l14uM., Ci) MEASURED SECTION ~ MORRISON FM. OVERLYING L:_j THE DOCKUM GROUP • SUBSURFACE POINT

Figure 6.6 Isopach map of the Middle Jurassic Exeter Sandstone in northeastern New Mexico (contoured by computer program Surfer version 4.0 using the spline curve method). Contour interval is 20 feet. 96 associated depositional environments andfor the presence of pre-Exeter topographic relief. The lack of Exeter

Sandstone deposits in the southeast portion of the study area however, is the result of post-Exeter erosion on the west flank of the Bravo Dome (Figure 6.5).

The isopach maps define a broad centrally located region lacking or exhibiting a thin section of the Exeter

Sandstone. Mankin (1958, 1972) and Trauger (1972) have suggested that this feature represents a region of pre­

Exeter positive topographic relief because the Exeter thins over the region.

A comparison of Figures 6.5 and 6.6 indicates that both maps have a faint north-northwest trend of isopach thicks and thins. Prehaps this geometry represents a series of paleo-sand ridges (?draa) and valleys

(?interdraa corridors) whose geometry was modified by pre-Exeter paleotopograph highs. CHAPTER VII

SUMMARY

The mid-Jurassic Exeter Sandstone of northeastern

New Mexico maybe differentiated into three distinct eolian lithofacies. Facies 1 ranges from o to 16.8 meters thick. It consists of moderate to well sorted, medium- to fine-grained sandstone with sets of large­ scale (1.5 to 4.6 meters), tabular and trough cross­ strata analogous to that observed in modern cresentic dune complexes. The primary sedimentary structures and and grain size characteristics of Facies 1 indicate that it represents an inland dune depositional setting.

Facies 2 ranges from 0 to 11 meters thick and consists of thinnly- to thickly-bedded horizontally stratified,subangular to well rounded sandstone that commonly exhibits bimodal grain size distributions.

Bimodal grian size distributions have been described in modern and ancient eolian interdune and extradune deposits. These deposits intertongue with Facies 1 and

Facies 3 throughout the study area. The features of

Facies 2 suggest that it represents both an interdune and extradune depositional setting which experienced periods of intermittent flooding.

Facies 3 ranges from 0 to 22.6 meters thick and is characterized by medium- to very fine-grained sandstone

97 98 with bioturbated, mottled, and structurally indistinct to massive bedding with wave ripples and desiccation. The internal features of Facies 3 suggest that it represents both interdune and extradune depositional settings which were periodically flooded and reworked by organisms. The three eolian facies:

1. Cross-stratified dune deposits {Facies 1).

2. Horizontal-stratified interdune and extradune deposits {Facies 2).

3. Massive interdune and extradune deposits {Facies 3).

indicate that the Exeter was deposited in several eolian environments. The aerial association of the three facies resembles the model proposed by Fryberger and others

{1979a). This model depicts a dominant eolian depositional environment with interdune plane-bed deposits occuring between the dune deposits and extradune reworked deposits occurring on the margins of the system.

Of the 25 criteria used by Chan {1989) to distinguish erg margin eolian deposits, 16 were noted in the Exeter

Sandstone.

The Middle Jurassic Exeter Sandstone of northeastern

New Mexico is a poorly to moderately well cemented, medium to very-fine grained, angular to well rounded, well sorted sandstone. Exeter samples are classified as quartzarenites, subarkoses, sublitharenites, and 99 feldspathic litharenites. The cements observed in the

Exeter include clay, carbonate, and quartz overgrowths.

The paleo-wind data collected from Facies 1 agree with an eolian depositional environment. The variability exhibited by the data is inferred to reflect both the morphology of the bed forms andjor the deflection of the wind around topographic features. The regional paleo­ wind vector for the Exeter (N.79° E.) is in agreement with paleo-wind studies of the Middle Jurassic eolianites conducted by Snoparsky (1986) and Peterson (1988) for northeastern New Mexico.

The Exeter Sandstone displays considerable variation in thickness throughout northeastern New Mexico. The

Exeter geometry defines a faint north-northwest trend which is interpreted to represent a series of paleo-sand ridges and depressions that were modified by pre-Exeter paleotopographic highs. REFERENCES

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Kocurek, G., and Dott, R.H., Jr., 1981a. Distinctions and uses of stratification types in the intrpretation of eolian sand: Journal of Sedimentary Petrology, v. 51, No. 2, p. 579-595.

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APPENDIX A

STRATIGRAPHIC COLUMNS, DESCRIPTIONS, AND SAMPLE LOCATIONS 108 Legend

Tabular Cross-Stratification

Trough Cross-Stratification

Horizontal Stratification

Covered Interval

-~:.- .:·· .... :· ;. .... ····-··· .. ·······• Bioturbation ·~:·.. ·<:~::.:::.~ ;.:::. :·.

Ripples

Burrows

Barite Lenses frrrj Mud Crack Casts

. . . . Sandstone D. . -- Shale D - - ~ Limestone . Alluvium

Jm UPPER JURASSIC MORRISON FORMATION

Je MIDDLE JURASSIC EXETER FORMATION

UPPER TRIASSIC DOCKUM GROUP

* Weathering profiles are not drawn to scale and are exaggerated to show recessive and resistant lithologies. 109 MEASURED SECTION 1

SAN JON

QUAY COUNTY, NEW MEXICO

NE 1/4; SW 1/4; Sec. 20; T.9 N.; R.34 E.

Jm

Vertical Scale 40- 12-

Je 30- 9-

20- 6-

10- 3- "Rd o- o- feet meters 110 MEASURED SECTION 1

SAN JON

QUAY COUNTY, NEW MEXICO

NE 1/4; SW 1/4; Sec. 20; T.9 N.; R.34 E.

Unit No. Description Thickness in meters

3. Horizontally stratified, medium-bedded, poorly sorted, friable, tan, very fine­ grained sandstone. Discontinuous, very thin, gray clay laminations randomly through unit 3. Gradual, recessive contact with Upper Jurassic Morrison Formation. 6.40

2. Massive, recessive, poorly sorted, friable, tan, very fine-grained sandstone. Prominent, discontinuous, very thin, gray clay laminations. 1.83

1. Horizontally stratified, indistinct, medium­ bedded, well indurated, resistant, poorly sorted, reddish-tan, very fine-grained, sandstone. Upper 3 feet contains wave ripples and indistinct burrows. Shale­ pebble rip up clasts above lower recessive (distinct) contact with Triassic Dockum Group. 4.57

total 12.80 111 MEASURED SECTION 2

GALLEGOS SOUTH

HARDING COUNTY, NEW MEXICO

SW 1/4; Sec 22; T.16 N.; R.30 E.

Jm

Vertical Scale .· .. ·:·.·: . ·.... : ~ ·.. 40- 12- .. . . ·... :. I ',I o ... '· '• ...... , ...... 30- 9- . . , Je '• Unit 2 ·'·: : ..·.:: ...... 20- 6- ·· ...... ~·. : ... .·. ·:· ·;.·.. 10- 3-

o- o- feet meters 112 MEASURED SECTION 2

GALLEGOS SOUTH

HARDING COUNTY, NEW MEXICO

SW 1/4; Sec 22; T.16 N.; R.30 E.

Unit No. Description Thickness in meters 3. Thinly-bedded, well cemented, white, fine­ grained, sandstone, overlain by a massive, recessive, friable, reddish-brown, silty sandstone, succeeded by a wave-rippled, well cemented, resistant, white, fine­ grained sandstone with celbar rosettes. Recessive Upper contact with Upper Jurassic Bell Ranch formation. 2.75 2. Massive, structureless, friable, recessive, partially covered, poorly sorted, tan, fine-grained, quartz sandstone. 8.40 1. Mottled, resistant, white, very fine­ grained, sandstone interbedded with reddish-tan, friable, fine-grained, silty sandstone. Wavy contact with the Triassic Dockum Group. .85

total 12.00 113 MEASURED SECTION 3

DAVID HILL

HARDING COUNTY, NEW MEXICO

SW 1/4; SE 1/4; Sec 13 T.18 N.; R.29 E.

Jm

· . ...:__~..; ..... ~~

-·--r--. .. . ---~··. -~~-~~--~·... ..:~~~~ ---:_--;·--:.--~ ...

Je Vertical Scale 40- 12.

Unit 2 30- 9-

20- 6-

Unit I 10- 3- "fid 0· 0· feet meters 114 MEASURED SECTION 3

DAVID HILL

HARDING COUNTY, NEW MEXICO

SW 1/4; SE 1/4; Sec 13 T.18 N.; R.29 E.

Unit No. Description Thickness in meters 3. Horizontally stratified, medium-bedded, well indurated, resistant, white, fine- grained sandstone. Overlain by recessive shales and sandstones of the Upper Jurassic Bell Ranch formation. 7.07

2. Large-scale, high-angle, tabular cross­ stratified, well cemented, resistant, well sorted, white, fine-grained quartz sandstone. Cross-bed cossets are 10 to 15 feet apart. Inverse graded coarse grain segregations in the cross­ stratification (grainflow tongues). 11.95

1. Thinly-laminated, resistant, greyish­ white, fine-grained quartz sandstone. Lower contact with Triassic Dockum Group partially covered. 1.01

total 20.03

·- 115 MEASURED SECTION 4

GALLEGOS NORTH

HARDING COUNTY, NEW MEXICO

NE 1/4; NE 1/4 Sec 9; T.16 N.; R.30 E.

Jm

Je Vertical Scale 40- 12·

Unit I

30- 9-

20- 6-

10- 3-

"Rd o­ a­ feet meters 116 MEASURED SECTION 4

GALLEGOS NORTH

HARDING COUNTY, NEW MEXICO

NE 1/4; NE 1/4 Sec 9; T.16 N.; R.30 E.

Unit No. Description Thickness in meters 2. Horizontally stratified, medium-bedded, clay-rich, homogenized, indistinctly bioturbated, poorly sorted, red, fine­ grained, sandstone. Upper contact with the Upper Jurassic Bell Ranch formation is gradual. 7.32

1. Large-scale, low- and high-angle, trough cross-stratified, light brown, fine­ grained, moderately to well sorted, quartz sandstones. Inverse graded coarse grain segregations in the cross-stratification (grainflow tongues) . Alternating coarse and fine grained ripples on second order bounding surfaces. Lower contact with the Triassic Dockum group recessive and distinct. 16.76

total 24.08 117 MEASURED SECTION 5

LIBBY RANCH EAST

HARDING COUNTY, NEW MEXICO

NE 1/4; SW 1/4; Sec 17; T.19 N.; R.Jl E.

Jm Vertical Scale Unlt4 40- 12-

Unlt3 30- 9-

Unlt2 Je

20- 6- Unit I

10- 3- "Rd o- o- feet meters 118 MEASURED SECTION 5

LIBBY RANCH EAST

HARDING COUNTY, NEW MEXICO

NE 1/4; SW 1/4; Sec 17; T.19 N.; R.31 E.

Unit No. Description Thickness in meters 4. Horizontally stratified, finely-bedded, well indurated, resistant, white, fine-grained, sandstone. Overlain by recessive shales and sandstones of the Upper Jurassic Bell Ranch formation. 1.77

3. Medium-scale, low-angle, trough cross­ stratified, white, fine-grained sandstone. Covered recessive interval between units 2 and 3. 9.01 2. Horizontally stratified, thinly-bedded, well indurated, resistant, white, fine-grained, sandstone. wave ripples appear on bedding planes. .98 1. Medium-scale, high-angle, tabular cross­ stratified, resistant, well sorted, white, fine-grained sandstone. Lower contact with Triassic Dockum Group partially covered. 4.45

total 16.21 119 MEASURED SECTION 6

LIBBY RANCH WEST

HARDING COUNTY, NEW MEXICO

SE/SW 1/4; Sec 1; T.19 N.; R.JO E.

Vertical Scale 40- 12-

Jm 30- 9-

20- 6- Je Unit I ?-. 10- 3- Rd o- o- feet meters 120 MEASURED SECTION 6

LIBBY RANCH WEST

HARDING COUNTY, NEW MEXICO

SE/SW 1/4; Sec 1; T.l9 N.; R.30 E.

Unit No. Description Thickness in meters

2. Horizontally stratified, finely-bedded, recessive, clay-rich, red, fine-grained sandstone. Upper portion is clay-rich, homogenized, indistinctly bioturbated, poorly sorted, red, fine-grained, sandstone. 2.38

1. Fan horizontally-stratified, medium- to finely-bedded, very low-angle, white, fine-grained sandstone. Rippled bedding planes and "honeycomb" weathering profile in upper portion of unit. Lower contact with Triassic Dockum Group covered. 3.29

total 5.67 121 MEASURED SECTION 7

MICHELL RANCH

HARDING COUNTY, NEW MEXICO

SE 1/4; NW 1/4; Sec 16; T.19 N.; R.29 E.

Jm

Unit 4

Unit 2 Vertical Scale Je 40- 12-

30· 9-

Unit I 20- I·

10- 3-

0- a­ feet meters 122 MEASURED SECTION 7

MICHELL RANCH

HARDING COUNTY, NEW MEXICO

SE 1/4; NW 1/4; Sec 16; T.19 N.; R.29 E.

Unit No. Description Thickness in meters

3 & 4 Interbedded horizontal to indidstictly bioturbated and medium-scale, moderate­ angle, trough cross-stratified, well sorted, grey, fine-grained, sandstones Recessive grey shale break at contact between umits 2 and 3. Upper contact with the Upper Jurassic Bell Ranch formation is gradual. 6.04

2. Horizontally stratified, finely-bedded, recessive, clay-rich, red, fine-grained sandstone. Upper portion is clay-rich, homogenized, indistinctly bioturbated, red, poorly sorted, fine-grained sandstone. 3.51

1. Large-scale, high-angle, tabular cross­ stratified, well cemented, resistant, well sorted, white, fine-grained, quartz sandstone. Cross-bed cossets are 10 feet apart. A horizontal-stratified, thinly-bedded, clay-rich sandstone underlies the cross-bedded sets. The basal contact with the Triassic Dockum Group is recessive and distinct. 8.69

total 18.24 123 MEASURED SECTION 8

MIERA RANCH

HARDING COUNTY, NEW MEXICO

SE 1/4; Sec 27; T.21 N.; R.30 E.

Unit 4

Unit 3

Vertical Seale Je 40- 12- Unit 2

30- 9-

20- ·- Unit I

10- 3-

0· a­ feet meters 124 MEASURED SECTION 8

MIERA RANCH

HARDING COUNTY, NEW MEXICO

SE 1/4; Sec 27; T.21 N.; R.30 E.

Unit No. Description Thickness in meters 4. Massive, well indurated, brownish-tan, fine-grained sandstone. Random occurrence of ?diagenetic cylindrical structures. Contact with Upper Jurassic Bell Ranch formation truncated. 1.22

3. Horizontally stratified, medium- to thinly­ bedded, indistinct, mottled, clay-rich, homogenized, indistinctly bioturbated, reddish-pink to tan, very fine-grained, clay-rich sandstone. Clay drapes and ?diagenetic cylendrical structures occur randomly throughout. 8.69

2. Large-scale, high-angle, tabular cross­ stratified, well cemented, resistant, well sorted, white, fine-grained, quartz sandstone. Cross-bed cossets are 10 to 12 feet apart. Inverse gradded coarse grain segregations (grainflow tongues) in the cross-stratification present. Scalped cross-bedding (scour and fill) viewed in lower portion of unit 2. Honeycomb weathering profile. 4.24

1. Horizontally stratified, indistinct, medium­ bedded, clay-rich, homogenized, indistinctly bioturbated, poorly sorted, red, fine-grained, sorted sandstone. Mud polygons measuring up to 26 inches across in recessive mid-section of unit 1. Mottled nodular appearance. Contact with Triassic Dockum Group recessive and very distinct. 6.77

total 20.92 125 MEASURED SECTION 9

KIDD RANCH

HARDING COUNTY, NEW MEXICO

NW 1/4; SW 1/4; Sec 14; T.18 N.; R.26 E.

Vertical Scale 40- 12-

30- 9-

Jm 20- 6-

Je 10- 3- "Ad o- o- feet meters 126 MEASURED SECTION 9

KIDD RANCH

HARDING COUNTY, NEW MEXICO

NW 1/4; SW 1/4; Sec 14; T.18 N.; R.26 E.

Unit No. Description Thickness in meters

1. Interbedded horizontal and scalped, high-angle, tabular, cross-stratified (scour and fill), resistant, well sorted, reddish-tan, fine-grained sandstones. Honeycomb weathering profile. Lower contact with Triassic Dockum Group recessive. Upper contact with Upper Jurassic Bell Ranch formation recessive and distinct. 2.77

total 2.77 127 MEASURED SECTION 10

RAY RANCH

HARDING COUNTY, NEW MEXICO

SW 1/4; NE 1/4; Sec 35; T.20 N.; R.24 E.

Jm

Vertical Scale Je 40- 12-

-~.,.,··- --·--·- •...... -- -· -·:~~~~::. ···'.\ -···· - 30- ...,.,,.__-····· -- 9- Unit I

20- 6-

10- 3-

"'Rd o­ 0- feet meters 128 MEASURED SECTION 10

RAY RANCH

HARDING COUNTY, NEW MEXICO

SW 1/4; NE 1/4; Sec 35; T.20 N.; R.24 E.

Unit No. Description Thickness in meters 2. Horizontally stratified, medium-bedded (indistinct), well indurated to friable, yellowish- brown, fine-grained sandstone. Minor inner-beds of silty sandstones and shales. Bedding planes are horizontal but structurally indistinct. Upper contact with the Upper Jurassic Morrison Formation is partially covered. 9.75 1. Horizontal stratified, medium-bedded (indistinct), well indurated, yellowish­ brown, fine-grained sandstone. Thin shale laminations appearing in between bedding planes. Soft sediment deformation occurring in the lower portion of unit 1. Clay drapes over wave ripples and load features in first eleven feet of unit 1. Lower contact with the Triassic Dockum Group partially covered. 12.8

total 22.55 129 MEASURED SECTION 11

BELL RANCH NORTH

SAN MIGUEL COUNTY, NEW MEXICO

35°, 38', 00" Latitude; 104°, 2', 30" Longitude

Vertical Scale 40- 12-

30- 9- Jm

20- 6-

Unit I Je

10- 3- Rd o- o- feet meters 130 MEASURED SECTION 11

BELL RANCH NORTH

SAN MIGUEL COUNTY, NEW MEXICO

35°, 38', OO" Latitude; 104°, 2', 30" Longitude

Unit No. Description Thickness in meters 1. Horizontally stratified, medium-bedded, well sorted, friable, tan, fine-grained sandstone. Bedding planes alternate from resistant to recessive in profile. Resistant planes are structurally indistinct. Recessive planes are thinly bedded. Lower contact with the Triassic Dockum Group well defined. Upper contact with the recessive shales and sandstones of the Upper Jurassic Bell Ranch formation is gradual. 3.05

total 3.05 131 MEASURED SECTION 12

BELL RANCH SOUTH

SAN MIGUEL COUNTY, NEW MEXICO

11 35°, 27', 00 , Latitude; 104°, 04', 30" Longitude

Vertical Scale 40- 12-

30- 9-

Jm 20- 6-

Je 10- 3- "Rd o- o- feet meters 132 MEASURED SECTION 12

BELL RANCH SOUTH

SAN MIGUEL COUNTY, NEW MEXICO

35°, 27', 00", Latitude; 104°, 04', 30" Longitude

Unit No. Description Thickness in meters

1. Thinly-bedded, well cemented, wave-rippled, white, fine-grained sandstone. Resistant celbar rosette pods appearing in the upper portion of unit 1. Lower contact with the Triassic Dockum Group well defined. Upper contact with the recessive shales and sandstones of the Upper Jurassic Bell Ranch formation is gradual. 1.68

total 1.68 133 MEASURED SECTION 13

RANDAL RANCH

QUAY COUNTY, NEW MEXICO

SW 1/4; NE 1/4; Sec 17; T.9 N.; R.27 E.

Jm

Vertical Scale 40- 12·

Je 30- 9-

20- 6- Unit I

10- 3- id 0· 0· feet meters 134 MEASURED SECTION 13

RANDAL RANCH

QUAY COUNTY, NEW MEXICO

SW 1/4; NE 1/4; Sec 17; T.9 N.; R.27 E.

Unit No. Description Thickness in meters

2. Interbedded horizontal and medium-scale, moderate-angle, trough cross-stratified, well sorted ,light brown, fine-grained sandstones. Upper contact with the Upper Jurassic Morrison Formation is recessive. 9.94

1. Horizontally stratified, indistinct, medium-bedded, well indurated, resistant, poorly sorted, reddish-tan, very fine­ grained, quartz sandstone. Shale-pebble rip up clasts above lower (distinct) recessive contact with Triassic Dockum Group. 4.94

total 14.88 135 MEASURED SECTION 14

TURJILLO

SAN MIGUEL COUNTY, NEW MEXICO

NW 1/4; NW 1/4; Sec 23; T.15 N.; R.24 E.

Jm

~,.._,. :..:··.:.: Unit2 ::--~. .::~~ --:--=-.-.. :;· .- ·.

--~· ·.·---~-·-. Vertical Scale 40- 12-

30- 9-

20- 6-

10- 3-

o- o- feet meters 136 MEASURED SECTION 14

TRUJILLO

SAN MIGUEL COUNTY, NEW MEXICO

NW 1/4; NW 1/4; Sec 23; T.15 N.; R.24 E.

Unit No. Description Thickness in meters

2. Horizontally stratified, medium-bedded (indistinct), well indurated, brownish­ tan, fine-grained sandstone. Recessive shale laminations in between bedding plane contacts. Contact with Upper Jurassic Morrison Formation gradational and recessive. 2.29

1. Horizontally stratified, mottled, indistinctlly bioturbated, slightly friable, well sorted, greyish-brown, fine-grained sandstone. Random burrows appearing in upper portion of unit 1. 11.13

total 13.42 137 MEASURED SECTION 15

CANON DEL AGUA SAN MIGUEL COUNTY, NEW MEXICO 35°, 29', OO" Latitude; 105°, 03', 45" Longitude

Jm

Unit4 --a-·­ ·•&'"" ·-·

Vertical Scale 40- 12· Je

Unit2 30- 9-

20· 8-

Unit I

10- 3· "Rd o- 0· feet meters 138 MEASURED SECTION 15 CANON DEL AGUA

SAN MIGUEL COUNTY, NEW MEXICO

35°, 29', OO" Latitude; 105°, 03', 45" Longitude

Unit No. Description Thickness in meters 4. Horizontally stratified, medium-bedded (indistinct), well indurated, brownish­ tan, fine-grained sandstone. Contact with Upper Jurassic Morrison Formation gradational and recessive. 2.16 3. Interbedded horizontal and medium-scale, moderate-angle, trough cross-stratified, well sorted, grey, fine-grained sandstone. 4.57 2. Large-scale, low-angle, trough cross­ stratified, moderately to well sorted, white, fine-grained quartz sandstone. Cross-bed cossets are 3 feet apart. Large-scale, high-angle, tabular cross­ stratified, well cemented, resistant, well sorted, white, fine-grained, quartz sandstone in upper portion unit 2. 6.40

1. Large-scale, high-angle, tabular, cross­ stratified, well cemented, resistant, well sorted, white, fine-grained quartz sandstone. Cross-bed cossets are 6 feet apart. Lower contact Triassic Dockum Group is partially covered. 3.67

total 16.80 139 MEASURED SECTION 16

LOS MONTOYAS

SAN MIGUEL COUNTY, NEW MEXICO

35°, 25', 30 11 Latitude; 105°, 12', 30 11 Longitude

...... Jm

Unlt4

Unit 3

Je Vertical Scale 40- 12·

Unit2

30. 9- <:...... , ..··. '

20- 6- Unit I

10- 3-

0· 0- feet meters 140 MEASURED SECTION 16 LOS MONTOYAS

SAN MIGUEL COUNTY, NEW MEXICO

35°, 25', 30" Latitude; 105°, 12', 30" Longitude

Unit No. Description Thickness in meters 4. Horizontally stratified, thinly bedded, recessive, light grey, fine-grained sandstone. Recessive shale zone (2 inches thick) on the contact between unit 3 and 4. Abrupt contact with the Upper Jurassic Todilto Limestone. 1.46 3. Medium-scale, high-angle, trough cross­ stratified, well sorted, fine-grained, quartz sandstone. Cross-bed cossets 4 feet apart. Unit 3 is partially covered occluded by jointing and fracturing. 15.70 2. Horizontally stratified, indistinct, tan, fine-grained, sandstone. Bedding occluded by jointing and fracturing. 4.12 1. Large-scale, high-angle, tabular, cross­ stratified, well cemented, resistant, well sorted, greyish-white, fine-grained, feldspathic sandstone. Bedding planes are indistinct. Inverse graded grain segregations in the cross-stratification (grainflow tongues) . Lower contact Triassic Dockum Group is recessive. 6.80

total 28.08 141 MEASURED SECTION 17

CUERVO HILL

GUADALUPE COUNTY, NEW MEXICO 35°, 07', 40" Latitude; 107°, 30', 25 11 Longitude

Jm

Vertical Scale 40- 12-

Je 30- 9-

20- 6-

10- 3-

Rd o- o- feet meters 142 MEASURED SECTION 17

CUERVO HILL

GUADALUPE COUNTY, NEW MEXICO

35°, 07', 40" Latitude; 107°, 30', 25" Longitude

Unit No. Description Thickness in meters 5. Horizontal stratified, thinly bedded, partially covered, very friable, yellow, fine-grained, sandstone. Upper contact with Upper Jurassic Morrison Formation is gradual and partially covered (indistinct). 1.46 4. Medium-scale, low-angle, trough cross­ stratified, greyish-yellow, friable, fine-grained sandstone. 3.05

3. Horizontal stratified, medium to thickly bedded, well indurated, reddish-grey, fine-grained sandstone. Scalped bedding surfaces (scour and fill) throughout unit 3. 3.60

2. Large-scale, low-angle, tabular cross­ stratified, well cemented, resistant, well sorted, tan, fine-grained quartz sandstone. 2.59

1. Horizontal stratified, mottled, slightly friable, well sorted, indistinctly bioturbated, greyish-tan, very fine­ grained sandstone. Lower contact with Triassic Dockum Group is recessive and distinct. 1.34

total 12.04 143 MEASURED SECTION 18

T-4 RANCH

SAN MIGUEL COUNTY, NEW MEXICO

35°, 19', 00 11 Latitude; 104°, 11', 30 11 Longitude

Vertical Scale 40- 12- Jm

30- 9- - ·- : .... ~- ·, ... :...:,.·. ·-~::·.- ... : ·.· .. .,- ..... -· -...... - .·,·.: ._ .... ~ ~ . " -·: -·· ·"· .•.,-... -· -·,··· - Je Unit I .· .-;. ·.~·· ·:· ·:·. 20- 6- .~~ ::~... ~: ~·... :::·

~~6~f 10- 3------

o- o- feet meters 144 MEASURED SECTION 18

T-4 RANCH

SAN MIGUEL COUNTY, NEW MEXICO

35°, 19', 00" Latitude; 104°, 11', 30" Longitude

Unit No. Description Thickness in meters 2. Horizontal stratified, finely bedded, fine­ grained sandstone. Rippled surface on contact between units 1 and 2. Upper contact with Upper Jurassic Morrison Formation recessive and distinct. .95

1. Horizontal stratified, medium-bedded (indistinct), mottled, slightly friable, well sorted, indistinctly bioturbated, reddish-brown, very fine-grained sandstone. Lower contact with Triassic Dockum Group is recessive and distinct. 6.07

total 7.02 145 MEASURED SECTION 19

MONUMENT POINT

SAN MIGUEL COUNTY, NEW MEXICO

35°, 19', 30 11 Latitude; 104°, OO', 00" Longitude

Vertical Scale 40- 12- Qal

30- 9-

Je 20- 6-

Unit I

10- 3- 'Rd

0· o- feet meters 146 MEASURED SECTION 19

MONUMENT POINT

SAN MIGUEL COUNTY, NEW MEXICO

35°, 19', 30" Latitude; 104°, 00', OO" Longitude

Unit No. Description Thickness in meters

2. Large-scale, low-angle, trough cross­ stratified, reddish-brown, friable, well­ sorted, fine-grained sandstone. Upper contact truncated and distinct with Quaternary alluvium. 3.08

1. Medium-scale, low-angle, trough cross­ stratified, reddish-brown, indistinctly bioturbated, friable, fine-grained sandstone. Lower contact with Triassic Dockum Group distinct (grey shale). 3.93

total 7.01 147 MEASURED SECTION 20

PABLO MONTOYA GRANT

SAN MIGUEL COUNTY, NEW MEXICO

35°, 15', 00" Latitude; 103°, 50', 00 11 Longitude

Vertical Scale 40- 12-

Jm

Unit 2 30- 9-

.~:~;;/.: :{(..;:\·: J e ·.:... ·· ·· ... · ·.• 20- 6- Unit I ·.:-:::_:~-..:·>_?·.:.· ,\.••.

10- 3-

o- o- feet meters 148 MEASURED SECTION 20

PABLO MONTOYA GRANT

SAN MIGUEL COUNTY, NEW MEXICO

35°, 15', OO" Latitude; 103°, 50', OO" Longitude

Unit No. Description Thickness in meters

2. Medium-scale, low-angle, trough cross­ stratified, reddish-brown, friable, flaggy, well sorted, fine-grained sandstone. Upper contact recessive and distinct with the Upper Jurassic Morrison Formation. 1.98

1. Horizontal stratified, medium-bedded (indistinct), mottled, slightly friable, well sorted, indistinctly bioturbated, reddish-brown, very fine-grained sandstone. Lower contact with Triassic Dockum Group is recessive and distinct. 5.03

total 7.01 149 MEASURED SECTION 21

PALOMAS HILLS

QUAY COUNTY, NEW MEXICO

NE 1/4; SW 1/4; Sec 17; T.10 N.; R.28 E.

Je

Jm

Unit I

_-;~·-- Vertical Scale •.•.. or:. •.•:, .. :. 40- . :_ .. .4-~:- 12- .... ···: ,_ .....-- -.- ----···--·· • J ..... , '• I ~:.%~-=~--- Unit 4 ···· :~::.. . -· , ...... 30- 9· --- --. - -- ,.;...., -~

20- 6-

Unit 3 10- 3-

------0· 0- -- - feet meters 150 MEASURED SECTION 21 PALOMAS HILLS

QUAY COUNTY, NEW MEXICO

NE 1/4; SW 1/4; Sec 17; T.10 N.; R.28 E.

Unit No. Description Thickness in meters 6. Horizontal stratified, thinly bedded, recessive, friable, tan sandstone. Upper contact recessive and distinct with the Upper Jurassic Morrison Formation. 3.29 5. Medium-scale, high-angle, trough cross­ stratified, moderately resistant, friable, well sorted, white, fine-grained sandstone. Course-grained, resistant, asymmetrical ripple laminations on the first order bounding surfaces. 3.11 4. Massive, indistinct, slightly friable, reddish-tan sandstone. 7.47 3. Horizontal stratified, indistinct, thin to medium bedded, recessive, very friable, white, fine-grained sandstone. wave ripple laminations preserved in mid and upper portions of unit 3. 4.02

2. Medium-scale, trough cross-stratified, friable, pinkish-white, very fine-grained sandstone. Topsets are truncated. 2.38 1. Horizontal stratified, indistinct, medium­ bedded, well indurated, resistant, reddish­ tan, poorly sorted, very fine-grained, quartz sandstones interbedded with massive, recessive, poorly sorted, tan, very fine-grained sandstones. Shale­ pebble rip up clasts above lower (distinct) recessive, bulbous contact with Triassic Dockum Group. 31.09

total 51.36 MEASURED SECTION 22 151

DAVIDSON RANCH

QUAY COUNTY, NEW MEXICO

NE 1/4; SE 1/4; Sec 16; T.B N.; R.29 E.

Jm

... ·......

-.-.. -··· .· ~

. . .···.. , - -··;~;':

.... ·. ·.. -.:~~-· -. - . - -. Unit I Je Vertical Scale ... _.... 40- 12- - --.-:··· ;i:;;. :... . -·- ~

30- 9- ·... :_ .. ·... :~...... ·--- ... ·...... "',.·. . -. _ . .

20- 6-

10. 3-

"'Rd o- o- feet meters 152 MEASURED SECTION 22

DAVIDSON RANCH

QUAY COUNTY, NEW MEXICO

NE 1/4; SE 1/4; Sec 16; T.8 N.; R.29 E.

Unit No. Description Thickness in meters

1. Horizontally stratified to massive, medium-bedded, well indurated, poorly sorted, very fine-grained sandstones with interbedded recessive red/grey shale breaks 3 feet thick. Lower contact with Triassic Dockum Group is recessive and distinct. Upper contact recessive and distinct with the Upper Jurassic Morrison Formation. Recessive Morrison Formation partially covered with oyster shales in float. 22.86

total 22.86 153 MEASURED SECTION 23

TUCUMCARI MOUNTAIN

QUAY COUNTY, NEW MEXICO

NW 1/4; SW 1/4; Sec 31; T.11 N.; R.31 E.

Jm

U\lt4

Je

Unit I Vertical Scale ·.: .. "~ 40- 12-

30- 9- .. -· - --· .. -·- . -, - . .. -· r •. --· ......

4-· : ..... ~ 20- -6- Unit 2

··- ·:· ·t -· . '"':' .

10- 3-

id o­ 0- feet meters 154 MEASURED SECTION 23

TUCUMCARI MOUNTAIN

QUAY COUNTY, NEW MEXICO

NW 1/4; SW 1/4; Sec 31; T.11 N.; R.31 E.

Unit No. Description Thickness in meters

4. Horizontal stratified, medium to thinly bedded, friable, tan, fine-grained sandstone. Upper contact with Upper Jurassic Morrison Formation recessive and distinct. 5.33

3. Large-scale, high-angle, tabular cross­ stratified, slighty friable, well sorted, white, fine-grained quartz sandstone. Truncated top-sets and foresets. Inverse graded grain segregations in the cross­ stratification {grain flow tongues) . Lower contact with unit 2 marked by very friable, recessive, massive, white sandstone. 7.62

2. Indistinct, large-scale, high-angle, tabular cross-stratified, very friable, tan sandstones interbedded with flat­ lying, indistinct, thin to medium bedded, recessive, very friable, white sandstones. Lower contact with unit 1 marked by very friable, recessive, massive, white sandstone. wave ripple laminations preserved in upper portion of unit 2. 11.98 155 TUCUMCARI MOUNTAIN

QUAY COUNTY, NEW MEXICO

NW 1/4; SW 1/4; Sec 31; T.11 N.; R.31 E.

Unit No. Description Thickness in meters

1. Indistinct, flat-lying, medium-bedded, well indurated and resistant, reddish­ tan, poorly sorted, very fine-grained quartz sandstones interbedded with massive, recessive, poorly sorted, tan, very fine-grained sandstones. Indistinct, large-scale, high-angle, tabular cross­ stratified, friable, white sandstone in upper portion of unit 1. Distinct, recessive, contact with brick red shales of the Triassic Dockum Group. 23.84

total 48.77 156 MEASURED SECTION 24

OCATE

MORA COUNTY, NEW MEXICO

NW 1/4; NW 1/4; Sec 2; T.22 N.; R.18 E.

Jm

Unit 2

Je Vertical Scale 40- 12-

Unit I

30- 9-

20- 6-

10- 3-

o­ 0- feet meters 157 MEASURED SECTION 24

OCATE

MORA COUNTY, NEW MEXICO

NW 1/4; NW 1/4; Sec 2; T.22 N.; R.18 E.

Unit No. Description Thickness in meters

2. Massive, friable, recessive, reddish-tan, silty sandstone. Upper portion of unit contains scalped, high-angle, tabular cross-stratified,truncated (scour and fill), resistant, reddish-tan, well sorted, fine-grained sandstone. Upper contact with Upper Jurassic Morrison Formation is recessive and partially covered. 4.72

1. Medium- to large-scale, moderate- to high­ angle, trough cross-stratified, pale white, fine-grained sandstone. Upper contact with unit 2 is marked by pustular wave-rippled surface. Lower contact with Triassic Dockum Group is covered (inferred). 15.85

total 20.57 158 MEASURED SECTION 25

TURKEY MOUNTAINS

MORA COUNTY, NEW MEXICO

35°, 56', 00 11 Latitude; 104°, 52', 30 11 Longitude

Jm

Vertical Scale Unit 2 40- 12-

30- 9- Je Unit I 20- 6-

10- 3-

o- o- feet meters 159 MEASURED SECTION 25

TURKEY MOUNTAINS

MORA COUNTY, NEW MEXICO

56', OO" Latitude; 104°, 52', 30" Longitude

Unit No. Description Thickness in meters 2. Medium-scale (scalped), high-angle, tabular cross-stratified (scour and fill), resistant, reddish-tan, well sorted, fine-grained sandstone. Wave ripples present in lower portion of unit 2. Upper contact with Upper Jurassic Morrison Formation is recessive and partially covered. 2.59

1. Medium- to large-scale, moderate- to high­ angle, trough cross-stratified, pale white fine-grained sandstone. Upper contact with unit 2 is recessive and covered. Lower contact with Triassic Dockum Group is covered (inferred). 8.02

total 10.61 160 MEASURED SECTION 26

CIMARRON EAST

UNION COUNTY, NEW MEXICO

NE 1/4; SE 1/4; Sec 33; T.32 N.; R.35 E.

Jm

·:· ·.-, -· .. ..- . . .. .

. . . .

. . ----...... ------

.• . Je Unit 2 · . Vertical Scale 40- 12-

30- 9-

20- 6-

10- 3-

---·-- ·------~·· ·-·--·--. . a­ a­ feet meters 161 MEASURED SECTION 26

CIMARRON EAST

UNION COUNTY, NEW MEXICO

NE 1/4; SE 1/4; Sec 33; T.32 N.; R.35 E.

Unit No. Description Thickness in meters 3. Horizontal stratified, thickly-bedded, indistinct, mottled, bioturbated, homogenous, fine-grained, tan sandstones interbedded with silty green-grey shales. Top of unit 3 is capped by well cemented resistant light brown sandstone. Overlain by recessive shales and sandstones of the Upper Triassic Morrison Formation. 12.19

2. Horizontal stratified, recessive, friable, flaggy, wave ripple laminated, very fine- grained, silty sandstone. 1.68 1. Horizontal stratified, indistinct, medium­ to thickly-bedded, mottled, red, fine­ grained sandstone. Upper portion of unit 1 contains medium- to large-scale, moderate- to high-angle, trough cross­ stratified, white, fine-grained sandstone. Lower contact with Triassic Dockum Group is angular and disconformable. 10.67 35.0

total 24.54 162 MEASURED SECTION 27

CIMARRON WEST

UNION COUNTY, NEW MEXICO

SE 1/4: Sec 27; T.32 N.; R.33 E.

Jm

Vertical Scale 40- 12-

30- 9- ·· .. Je

Unit I 20- 6-

.· . --· ···- ...... - ... ,\,,:'"'. . : ..• ... ·.-.. ,. .. _:.:1, - ··- 10- 3- id o- o- feet meters 163 MEASURED SECTION 27

CIMARRON WEST

UNION COUNTY, NEW MEXICO

SE 1/4; Sec 27; T.32 N.; R.33 E.

Unit No. Description Thickness in meters 3. Horizontal stratified, medium-bedded, well indurated, resistant, white, fine-grained sandstones. Upper contact distinct with recessive shales and sandstones of the Upper Triassic Morrison Formation. 1.83 2. Large-scale, high-angle, tabular cross­ stratified, well cemented, resistant, well sorted, white, fine-grained quartz sandstone. Inverse graded grain segregations in the cross-stratification (grainflow tongues). 1.52

1. Horizontal stratified, indistinct, medium­ to thickly-bedded, mottled, red sandstones interbedded with medium- to large-scale, moderate- to high-angle, indistinct trough cross-stratified, pale white, fine-grained sandstones. Lower contact with Triassic Dockum Group is recessive and distinct. 9.14

total 12.49 164 MEASURED SECTION 28

CIMARRON N0.1

UNION COUNTY, NEW MEXICO

NW 1/4; NE 1/4; Sec 7; T.31 N.; R.32 E.

Description Thickness in meters

The Upper Jurassic Morrison Formation overlies the Triassic Dockum Group. No Exeter present. 0.0 165 MEASURED SECTION 29

CIMARRON N0.2

UNION COUNTY, NEW MEXICO

NW 1/4; SW 1/4; Sec 15; T.31 N.; R.31 E.

Description Thickness in meters

The Upper Jurassic Morrison Formation overlies the Triassic Dockum Group. No Exeter present. 0.0 166 MEASURED SECTION 30

SABINOSO

SAN MIGUEL COUNTY, NEW MEXICO

SE 1/4; SW 1/4; Sec 21; T.17 N.; R.24 E.

Description Thickness in meters

The Upper Jurassic Bell Ranch formation overlyes the Triassic Dockum Group. No Exeter present. 0.0 167

SAMPLE LOCATION TABLE REFER TO FIGURE 1 FOR LOCATIONS OF MEASURED SECTIONS ------SECTION SAMPLE NUMBER NUMBER ------LOCATION 1 1-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

1 1-2 Unit 1. Collected 1.5 meters up from basal contact with unit 1 and the Triassic Dockum Group.

1 1-3 Unit 1. Collected .6 meters down from contact between units 1 and 2.

2 2-1 Unit 3. Collected .6 meters up from contact between units 3 and 2.

3 3-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

3 3-2 Unit 2. Collected 3.1 meters up from contact between units 1 and 2.

3 3-3 Unit 3. Collected .6 meters down from contact beteen unit 3 and the Upper Jurassic Bell Ranch formation.

4 4-2 Unit 1. Collected 7.6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

4 4-3 Unit 2. Collected .6 meters down from contact between unit 2 and the Upper Jurassic Bell Ranch formation.

5 5-2 Unit 2. Collected 1.2 meters down from contact between units 1 and 2.

5 5-3 Unit 4. Collected .6 meters down from contact between unit 4 and the Upper Jurassic Bell Ranch formation. 168

SAMPLE LOCATION TABLE REFER TO FIGURE 1 FOR LOCATIONS OF MEASURED SECTIONS ------SECTION SAMPLE NUMBER NUMBER LOCATION ------

6 6-2 Unit 2. Collected .6 meters up from contact between units 1 and 2.

7 7-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

7 7-2 Unit 2. Collected .25 meters up from contact between units 1 and 2.

8 8-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

8 8-3 Unit 3. Collected .6 meters down from contact between unit 3 and 4

9 9-1 Unit 1. Collected 1.5 meters up from basal contact with unit 1 and the Triassic Dockum Group.

10 27-1 Unit 1. Collected 1.5 meters up from basal contact with unit 1 and the Triassic Dockum Group.

10 27-2 Unit 1. Collected 12.2 meters up from contact with unit 1 and the Triassic Dockum Group.

10 27-3 Unit 3. Collected .6 meters down from contact between unit 2 and the Upper Jurassic Morrison Formation.

13 14-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

13 14-2 Unit 2. Collected 3.7 meters up from contact between units 1 and 2. 169

SAMPLE LOCATION TABLE REFER TO FIGURE 1 FOR LOCATIONS OF MEASURED SECTIONS ------SECTION SAMPLE NUMBER NUMBER LOCATION ------

13 14-3 Unit 3. Collected .6 meters down from contact between unit 2 and the Upper Jurassic Morrison Formation.

14 15-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

14 15-2 Unit 1. Collected 5.8 meters down from contact between units 1 and 2.

14 15-3 Unit 2. Collected .2 meters down from contact between unit 2 and the Upper Jurassic Morrison Formation.

15 16-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

15 16-2 Unit 3. Collected .6 meters up from contact between units 2 and 3.

15 16-3 Unit 4. Collected .6 meters down from contact between unit 4 and the Upper Jurassic Morrison Formation.

16 17-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

16 17-2 Unit 3. Collected .6 meters up from contact between units 2 and 3.

16 17-3 Unit 4. Collected .6 meters up from contact between units 3 and 4.

17 18-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group. 170

SAMPLE LOCATION TABLE REFER TO FIGURE 1 FOR LOCATIONS OF MEASURED SECTIONS ------SECTION SAMPLE NUMBER NUMBER LOCATION ------17 18-2 Unit 3. Collected .6 meters up from contact between units 2 and 3.

17 18-3 Unit 4. Collected .6 meters down from contact between unit 4 and the Upper Jurassic Morrison Formation.

18 19-2 Unit 1. Collected 1.5 meters down from contact between units 1 and 2.

19 20-1 Unit 1. Collected 2.4 meters up from basal contact with unit 1 and the Triassic Dockum Group.

20 21-1 Unit 1. Collected 4.6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

20 21-2 Unit 1. Collected .6 meters down from contact between units 1 and 2.

20 21-3 Unit 2. Collected .6 meters down from contact between unit 2 and the Upper Jurassic Bell Ranch formation .

21 22-1 Unit 2. Collected . 6 meters up from contact between units 1 and 2 •

21 22-2 Unit 4. Collected . 6 meters up from contact between units 3 and 4 .

. 6 meters down from 21 22-3 Unit 6. Collected contact between unit 6 and the Upper Jurassic Morrison Formation.

22 23-1 Unit 1. Collected 3.2 meters down from contact between unit 1 and the Upper Jurassic Morrison Formation. 171

SAMPLE LOCATION TABLE REFER TO FIGURE 1 FOR LOCATIONS OF MEASURED SECTIONS ------SECTION SAMPLE NUMBER NUMBER LOCATION ------

22 23-1A Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

22 23-2 Unit 1. Collected in red, recessive, shaly-sand 9.6 meters up from contact with unit 1 and the Triassic Dockum Group.

22 23-3 Unit 1. Collected .6 meters down from contact between unit 1 and the Upper Jurassic Morrison Formation.

23 24-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

23 24-2 Unit 3. Collected .9 meters up from contact between units 2 and 3.

24 25-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

24 25-2 Unit 1. Collected on the rippled surface between units 1 and 2.

24 25-3 Unit 2. Collected 1.1 meters down from contact between unit 2 and the Upper Jurassic Morrison Formation.

25 26-2 Unit 1. Collected 3.4 meters up from contact with unit 1 and the Triassic Dockum Group.

25 26-3 Unit 2. Collected .6 meters down from contact between unit 2 and the Upper Jurassic Morrison Formation. 172

SAMPLE LOCATION TABLE REFER TO FIGURE 1 FOR LOCATIONS OF MEASURED SECTIONS ------SECTION SAMPLE NUMBER NUMBER ------LOCATION

26 28-1 Unit 1. Collected 1.8 meters up from basal contact with unit 1 and the Triassic Dockum Group.

26 28-2 Unit 3. Collected .92 meters up from contact between units 2 and 3.

26 28-3 Unit 3. Collected .6 meters down from contact between unit 3 and the Upper Jurassic Morrison Formation.

27 29-1 Unit 1. Collected .6 meters up from basal contact with unit 1 and the Triassic Dockum Group.

27 29-2 Unit 3. Collected .6 meters up from contact between units 2 and 3.

27 29-3 Unit 3. Collected .6 meters down from contact between unit 3 and the Upper Jurassic Morrison Formation. 173

APPENDIX B

PALEO-WIND DATA 174

EXPLAINATION OF STATISTICAL VARIABLES (Zippi, 1988) N = Number of observations contained in the data set.

Class Interval = the data is grouged into "classes" of your c h o1ce. ('1e. 5,0 10,0 15, 20,0 25,0 or 30 0 ). The frequency of occurrence of observations within a class interval is plotted on the rose diagram. This grouping only affects the diagrammatical output not the statistics.

Max = maximum class frequency or the maximum number of observations to fall into a single class.

Max % = maximum class frequency as a percentage of the total number of observations, or maximum % of observations to into a single class. [(Max/N)*100].

Mode = the class interval with the maximum number of observations. This is not mathematical determination of the mode.

Mean = resultant vector or mean vector. X = arctan (w/v), where w = 1/n 0 sin(Ai) and v = 1/N 0 cos(Ai)' and where (Ai) =observations (i = 1 toN).

Ang. Dev = standard angular deviation. s 0 = [-2loge(1- So}J/l, where S0 = 1- Rand 1 = 1 for un1directional data and 1 = 2 for bidirectional data. For small s 0 , the formula for standard devi?~ion angular deviation reduces to: s 0 = [2(1- R) ] •

r mean vector length or t5om the origin in = dis~an~e 1 polar cooridates. r = (w +v ) / ' r = R/N.

R - magnitude ~r l~ngth of the resultant vector. R = (V2+w ) 1 / , where W = 0 sin (Ai) and V = 0 cos (Ai)· L - magnitude or length of resultant vector in percent. L = (R/N) * 100.

Rayleigh t~st z = Rayleigh's test of randomness. z = R /N. This test is used to decide if the distribution of the population from which the observations were made is uniform unimodal. 2 2 F(test) = sufs0 , where su = variance of a uniform distribution and s 0 = ther sample variance. 175

N Unid1rectional 6 Stat 1st tcs N= 20 4.8 Class 1nterva1= 20· 3.6 Max= 6

2.4 Max%= 30~ Mode= 160. 1.2 Mean= 161.9. Ang. Dev.= 37. t• r= .8105 R= 16.216 L= 81.079% Rayletgh test z= 13. 145 F

N I Unidirectional Stat1st1cs N= 22 Class Interval= 20· Max= 5 r--·tax%= 22.75% Mode= 40. Mean= 45• Ang. Dev.= 61. r= .567 R= 12.4755 L= 56.706~ Rayleigh test z= 7.07 F

N I Unfdtrectfonal 17 Stat1st1cs N= 17 5.6 Class 1nterval= 20· 4.2 Max= 7 2.8 Max%= 41.2% Mode= 220· 1.4 Mean- 232.55 • Ang. Dev.= 57.ss· r= .603 R= 10.258 L= 60.341% Rayle1gh test ./ z= 6.185 F= 7.91 d.f.• 16 In denominator for data file named: clipboard data GALLEGOS NORTH 178

N Untdtrect tonal 3 Stat1stfcs

2.4 N= 11 C1 ass 1n t erv a 1= 2 0 • Max= 3 Max%= 27.25~ Mode= 240. Mean= 224.3. Ang. Dev.= 72.os· r= .453 R= 4.985 L= 45.318% Rayletgh test z= 2.255 f(test)= 5.05 d.f.• 10 In denominator

ror data rile named: clipboard dala LAS VEGAS 179

N I Un1direct1ona1 4 Stat1st1cs N= 17 Class 1nterval = 20· Max= 4 Max%= 23.55% Mode= 120· Mean= 69.75 • Ang. Dev.= 70. 15· r= .472 R= 8.03 L= 47.235% Ray1e1gh test z= 3.79 F

N I Unfdfrect fona I Stat 1st 1cs N= 6 Class 1nterva 1= 20· Max= 3 Max~= so~ Mode= 20· Mean= 1a.s· Ang. Dev.= 18. 1s· r= .951 R= 5.706 L= 95.1 ~ Rayle1gh test z= 5.425 F(test)= 79.62 d.f.• 5 In denominator

for data file named: clipboard data OCATE & TURKEY MT.S 181

Unidirect ion a 1 Stat1st1cs N= 13 2.4 Class 1nterva 1= 20· Max= 3 Max%= 23.1% Mode= tao· Mean= 155.05 • Ang. Dev.= 65.9. r= .516 R= 6.709 L= 51.607% Rayleigh test z= 3.46 F(test)= 6.04 dJ.• 12 In denominator

for data nte named: clipboard data TUCUMCARI 182

N I Un\d\rgct\onal Stat 1st 1CS N= 93 Class 1nterval= 20· Max= 11 Max%= 1 1.85% Mode= 40· - Mean= 79.5. Ang. Dev.= 115.65. r= .13 R= 12. 122 L= 13.034% Rayletgh test z= 1.58 F(test>= 1.96 d.f.• 92 In denominator for data Ole named: clipboard data REGIONAL PLOT 183

APPENDIX C

PERCENTAGE COMPOSITION AND "QFR" DATA 184

Explanation of Headers

QUARTZ: Includes straight extinction, undulatory, polycrystaline, and stretched quartz varieties.

FELDSPAR: Includes both potassium feldspar and plagioclase feldspar.

ROCK FRAGMENTS: Includes chert and carbonate grains.

CEMENTS: Includes carbonate (calcite and dolomite), clay, and quartz overgrowths.

POROSITY: Includes primary and secondary porosity. PERCENTAGE COMPOSITION REFER TO FIGURE 1 FOR LOCATIONS OF MEASURED SECTIONS AND APPENDIX I FOR MEASURED SECTIONS, DESCRIPTIONS, AND SAMPLE LOCATIONS. ------[ <------% ------> ] SECTION SAMPLE QUARTZ FELDSPAR llOC~ CEKEKTS POllOSITY NUMBER NUMBER FRAGKEITS QUARTZ CARB. CLAY OVERGROWTHS ------

1 1-1 51 9 8 5 12 9 6 1 1-2 45 22 14 12 0 5 2 1 1-3 55 20 7 7 0 9 2

2 2-1 64 7 16 7 0 6 0

3 3-1 56 10 12 3 12 5 2 3 3-2 61 7 8 0 11 6 7 3 3-3 58 13 7 4 5 9 4

4 4-2 53 8 8 3 >1 12 15 4 4-3 48 16 11 3 7 10 5

5 5-2 55 5 9 9 9 8 5 5 5-3 41 12 20 8 7 11 2

6 6-2 50 6 14 7 10 11 2

7 7-1 44 23 13 6 >1 9 5 7-2 49 9 14 8 4 7 9 ....., 7 ()) U1 PERCENTAGE COMPOSITION REFER TO FIGURE 1 FOR LOCATIONS OF MEASURED SECTIONS AND APPENDIX I FOR MEASURED SECTIONS, DESCRIPTIONS, AND SAMPLE LOCATIONS. ------[ <------% ------> 1 SECTION SAMPLE QUARTZ FELDSPAR ROC I: CEKEKTS POROSITY NUMBER NUMBER FRAGMENTS QUARTZ CARB. CLAY OVERGROWTHS

8 8-1 45 10 14 5 6 8 12 8 8-3 58 4 6 4 3 14 11

9 9-1 60 2 11 7 8 6 6

10 27-1 53 6 10 27 2 0 2 10 27-2 64 >1 6 11 8 3 8 10 27-3 61 >1 4 19 8 2 6 10 27-4 55 8 7 26 >1 3 >1

13 14-1 46 13 12 3 5 6 15 13 14-2 55 5 15 7 3 6 9 13 14-3 49 9 15 9 >1 7 11

14 15-1 55 2 14 3 8 10 8 14 15-2 61 >1 6 2 7 13 11 14 15-3 54 0 12 10 7 10 7 15 16-1 51 5 15 2 2 15 10 15 16-2 60 2 8 7 >1 18 5 15 16-3 55 2 17 3 0 18 5

~ Q) 0\ PERCENTAGE COMPOSITION REFER TO FIGURE 1 FOR LOCATIONS OF MEASURED SECTIONS AND APPENDIX I FOR MEASURED SECTIONS, DESCRIPTIONS, AND SAMPLE LOCATIONS. ------[ <------% ------> ] SECTION SAMPLE QUAKTZ FELDSPAK KOC~ CEMENTS POKOSITY NUMBER NUMBER FKAGMEKTS QUARTZ CARB. CLAY OVERGROWTHS ------

16 17-1 59 7 9 14 0 10 0 16 17-2 56 5 13 5 1 20 1 16 17-3 60 9 10 5 3 9 4

17 18-1 40 17 10 3 2 16 12 17 18-2 47 16 12 0 0 16 9 17 18-3 47 13 13 0 >1 18 9

18 19-2 49 7 8 3 0 14 19

19 20-1 52 4 12 5 0 16 11

20 21-1 so 8 12 0 0 14 16 20 21-2 so 6 11 4 1 11 17 20 21-3 49 10 11 >1 0 11 19 21 22-1 61 9 4 4 0 5 17 21 22-2 52 6 13 0 19 0 10 21 22-3 65 7 6 0 0 2 20

~ (X) ...J PERCENTAGE COMPOSITION REFER TO FIGURE 1 FOR LOCATIONS OF MEASURED SECTIONS AND APPENDIX I FOR MEASURED SECTIONS, DESCRIPTIONS, AND SAMPLE LOCATIONS. ------[ <------% ------> ] SECTION SAMPLE QUAKTZ FELDSPAK KOC~ CEMEITS POKOSITY NUMBER NUMBER FRAGKEITS QUARTZ CARB. CLAY OVERGROWTHS ------~------

22 23-1 43 8 11 35 0 0 3 22 23-lA 53 10 12 25 0 0 >1 22 23-2 46 10 6 38 0 0 0 22 23-3 47 10 6 37 0 0 2

23 24-1 48 11 10 19 6 >1 6 23 24-2 60 6 8 1 0 7 18 24 25-1 54 >1 6 22 4 9 5 24 25-2 70 0 4 21 0 3 2 24 25-3 54 4 5 22 13 2 0 25 26-2 70 0 5 1 3 19 2 25 26-3 66 0 4 0 4 18 8

26 28-1 47 9 11 25 0 6 2 26 28-2 46 5 13 15 6 3 12 26 28-3 51 5 7 22 9 0 6

27 29-1 so 4 8 20 11 0 7 27 29-2 51 8 5 20 7 3 6 8 9 18 14 >1 9 ~ 27 29-3 42 0) 0) 189

Q-F-R DATA REFER TO FIGURE 1 FOR LOCATIONS OF MEASURED SECTIONS AND APPENDIX I FOR MEASURED SECTIONS, DESCRIPTIONS, AND SAMPLE LOCATIONS. ------[ <------% ------> ] SECTION SAMPLE QUARTZ FELDSPAR ROCK NUMBER NUMBER FRAGMENTS ------1 1-1 75 14 11 1 1-2 53 29 18 1 1-3 66 25 9

2 2-1 73 8 19

3 3-1 71 14 15 3 3-2 80 9 11 3 3-3 74 17 9

4 4-2 77 11 12 4 4-3 64 21 15

5 5-2 79 8 13 5 5-3 56 17 27

6 6-2 71 9 11

7 7-1 54 29 17 7 7-2 68 12 20

8 8-1 66 14 20 8 8-3 86 6 8

9 9-1 85 3 12

10 27-1 76 9 5 10 27-2 89 2 9 10 27-3 94 0 6 10 27-4 78 12 10

13 14-1 66 18 16 13 14-2 73 7 20 13 14-3 68 12 20

14 15-1 79 3 18 14 15-2 89 2 9 14 15-3 82 0 18 190 ------[ <------% ------> ] SECTION SAMPLE QUARTZ FELDSPAR ROC It NUMBER NUMBER FRAGMENTS ------15 16-1 72 7 21 15 16-2 86 3 11 15 16-3 73 3 24

16 17-1 79 10 11 16 17-2 76 7 17 16 17-3 76 11 13

17 18-1 60 25 15 17 18-2 63 20 17 17 18-3 65 18 17

18 19-2 76 11 13

19 20-1 77 6 17

20 21-1 73 12 15 20 21-2 75 8 17 20 21-3 70 15 15

21 22-1 82 12 6 21 22-2 72 8 20 21 22-3 83 9 8

22 23-1 69 13 18 22 23-1A 72 12 16 22 23-2 75 16 9 22 23-3 75 16 9 14 23 24-1 70 16 11 23 24-2 81 8 10 24 25-1 89 1 5 24 25-2 95 0 8 24 25-3 86 6

26-2 93 0 7 25 6 25 26-3 94 0 16 26 28-1 70 14 21 26 28-2 72 7 11 26 28-3 81 8 191 ------[ <------% ------> ] SECTION SAMPLE QUARTZ FELDSPAR ROCK NUMBER NUMBER FRAGMENTS ------

27 29-1 80 7 13 27 29-2 80 11 7 27 29-3 72 13 15 192

APPENDIX D

SUBSURFACE DATA LOCATIONS

& EXETER THICKNESS 193

DRILLERS LOGS

Point Name T. I R. I Sec. Thickness

A Emma Hunker No. 1 16, 17, 36 20.44 m.

B Leatherwood-Reed No.2 16, 17, 15 19.80 m.

c Lula Gamdrel 20, 26, 24 10.07 m.

D Lloyd Gambrel 20, 26, 26 19.80 m.

E Conchas Dev. No.1 17, 211 34 18.30 m.

F w. s. Ranch No.1 26, 20, 01 27.50 m.

G Sauble No.2 26, 24, 01 22.27 m.

H Sauble p & A 27, 24, 35 15.30 m.

I Maxwell Land Grant No. 28, 22, 11 18.30 m.

J Continental No.4 29, 22, 17 33.25 m.

K Moore No.1 29, 24, 10 19.80 m.

L Witt No.1 29, 35, 13 22.30 m. 194

DRILLERS LOGS

Point Name T. I R. I sec. Thickness

R J.B. Leiser Clayton #5 26 I 351 34 6.10 m.

s Oil Expl Irwin #1 211 361 29 6.10 m.

T Nunn Wallace #1 201 361 30 3.05 m.

u Gruemmers Gruemmer #2 291 291 03 15.30 m.

v Freeman Smith #1 291 321 22 5.50 m.

w Noxsey Jones #1 261 321 27 6.10 m.

X Nerndon Mock #1 271 361 25 13.12 m.

y Galbreath Britt #1 241 301 14 12.80 m.

z Continental FLB #1 241 36, 02 15.30 m.

AA Dillard State #1 231 331 02 4.27 m.

BB Nunn Nopson #1 231 351 26 3.05 m. 195

GEOPHYSICAL LOGS

Point Name T. I R. I sec. Thickness

M Reese & Jones 16, 19, 30 24.40 m.

N Sanford Estate Et Al. No.1 20, 22, 27 17.80 m.

0 BDCDGU No. 2033-151G 20, 33, 15 11.60 m.

p Triggs No.1 15, 28, 02 6.10 m.

Q Mobil-1Y R.S. Coon ET AL. 20, 23, 22 45.80 m.