Geology of the Pennsylvanian and Permian

Cutler Group and Permian Kaibab Limestone

in the Paradox Basin, Southeastern Utah and

Southwestern Colorado

By Steven M. Condon

EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

A.C. Huffman, Jr., Project Coordinator

U.S. GEOLOGICAL SURVEY BULLETIN 2000–P

A multidisciplinary approach to research studies of

sedimentary rocks and their constituents and the

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1997
For sale by U.S. Geological Survey, Information Services

Box 25286, Federal Center

Denver, CO 80225

Any use of trade, product, or firm names in this publication is for descriptive purposes only and

does not imply endorsement by the U.S. Government

Library of Congress Cataloging-in-Publication Data

U.S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY

Gordon P. Eaton, Director

Condon, , Steven M.

Geology of the Pennsylvanian and Permian Cutler Group and Permian Kiabab Limestone in the Paradox Basin, southeastern Utah and southwestern Colorado / by Steven M. 

Condon.

p. cm. — (Evolution of sedimentary basins—Paradox Basin ; P)

(U.S. Geological Survey bulletin ; 2000)

Includes bibliographical references.

Supt. of Docs. no.: I 19.3:2000–P

1. Geology, Stratigraphic—Pennsylvanian. 2. Geology, Stratigraphic—Permian. 

3. Cutler Group. I. Title. II. Series. III. Series: Evolution of sedimentary basins—Paradox Basin ; ch. P.

QE75.B9 no. 2000–P

[QE673] 

557.3 s—dc21

[551′.7′52′09792] 97–9764 

 CIP
III

CONTENTS

Abstract ........................................................................................................................... P1

Introduction ..................................................................................................................... 1

Geographic and Structural Setting .......................................................................... 1

Previous Studies and Nomenclature ....................................................................... 2

Methods................................................................................................................... 5

Data ................................................................................................................. 5

Contour Maps.................................................................................................. 5

Stratigraphy ..................................................................................................................... 6

Underlying Rocks ................................................................................................... 7

Honaker Trail Formation ................................................................................ 7

Rico Formation and Elephant Canyon Formation .......................................... 11

Cutler Group ........................................................................................................... 12

Cutler Formation, Undivided .......................................................................... 12

Lower Cutler Beds .......................................................................................... 13

Contacts................................................................................................... 13

Lithology and Depositional Environments ............................................. 13

Correlations............................................................................................. 18

Age .......................................................................................................... 20

Cedar Mesa Sandstone .................................................................................... 20

Organ Rock Formation.................................................................................... 23

White Rim Sandstone...................................................................................... 23

De Chelly Sandstone....................................................................................... 25

Kaibab Limestone ................................................................................................... 27

Overlying Rocks ..................................................................................................... 27

Paleogeography............................................................................................................... 28

References Cited ............................................................................................................. 32

Appendix 1. Drill holes used as control points for maps and cross sections .................. 39

Appendix 2. Measured sections used as control points for maps and cross sections ..... 44

FIGURES

1. Map showing geographic features of Paradox Basin and adjacent areas.................................................................. P3

2. Map showing structural elements of Paradox Basin and adjacent areas................................................................... 4

3. Cross sections showing stratigraphic relationships and nomenclature used in Paradox Basin................................. 8

4. Cross section of rocks at Pennsylvanian-Permian boundary..................................................................................... 10

 5–7. Photographs showing:

 5. Undivided Cutler Formation at Indian Creek....................................................................................................... 14

 6. Honaker Trail Formation, lower Cutler beds, and upper part of Cutler Formation at Shafer dome .................... 14

 7. Honaker Trail Formation, lower Cutler beds, and Cedar Mesa Sandstone at the confluence of the Green and 

Colorado Rivers.................................................................................................................................................... 15

8. Well log showing the lower part of the Moenkopi Formation, Organ Rock Formation, Cedar Mesa Sandstone,

lower Cutler beds, and the upper part of the Honaker Trail Formation at Elk Ridge................................................ 16

9–10. Photographs showing:

9. Honaker Trail Formation, lower Cutler beds, and Cedar Mesa Sandstone near Mexican Hat, Utah .................. 17

10. Petrified wood in lower Cutler beds..................................................................................................................... 17

 11. North-south cross section showing correlation of lower Cutler beds and Cedar Mesa Sandstone ........................... 19
IV CONTENTS

12–14. Photographs showing:

12. Interbedded sandstone, silty sandstone, and siltstone of the Cedar Mesa Sandstone near the confluence

of the Green and Colorado Rivers ........................................................................................................................ 22 

13. Cedar Mesa Sandstone and lower Cutler beds in Gypsum Canyon ..................................................................... 22

14. Organ Rock Formation near Hite, Utah ............................................................................................................... 24

15. Well log showing lower part of the Moenkopi Formation, Kaibab Limestone, White Rim Sandstone, 

Organ Rock Formation, and the top of the Cedar Mesa Sandstone in the Henry Basin ............................................ 25

16–18. Photographs showing:

16. White Rim Sandstone, Organ Rock Formation, and top of Cedar Mesa Sandstone in Elaterite Basin ............... 26

17. Tar seep in White Rim Sandstone in Elaterite Basin............................................................................................ 27

18. De Chelly Sandstone at Monument Valley........................................................................................................... 28

19. Well log showing the lower part of the Chinle Formation, De Chelly Sandstone, Organ Rock Formation, 

and the top of the Cedar Mesa Sandstone in northeastern Arizona........................................................................... 29

20. Late Paleozoic structural elements in the Southwestern United States ..................................................................... 30

 21. Paleogeography of the Paradox Basin in Early Permian (Wolfcampian) time .......................................................... 31

22. Paleogeography of the Paradox Basin in Early to Late Permian (Leonardian to Guadalupian) time ....................... 32

PLATES

1. Map of Paradox Basin and adjacent areas showing locations of drill holes and outcrops used for this study, 

 and lines of section shown in figures 3, 4, and 11

2. Map of Paradox Basin and adjacent areas showing structure contours drawn on the base of the Cutler Group or 

Formation

3–9. Maps of Paradox Basin and adjacent areas showing thickness of:

3. Pennsylvanian and Permian Cutler Group or Formation

4. Pennsylvanian and Permian lower Cutler beds

5. Permian Cedar Mesa Sandstone 

6. Permian Organ Rock Formation

7. Permian White Rim Sandstone

8. Permian De Chelly Sandstone

9. Permian Kaibab Limestone
P1

Geology of the Pennsylvanian and Permian Cutler Group 

and Permian Kaibab Limestone in the Paradox Basin, 

Southeastern Utah and Southwestern Colorado

By Steven M. Condon

ABSTRACT

The Cutler Formation is composed of thick, arkosic,

alluvial sandstones shed southwestward from the

Uncompahgre highlands into the Paradox Basin. Salt tectonism played an important role in deposition of the Cutler

in some areas. In the northeast part of the basin, more than

8,000 ft, and as much as 15,000 ft, of arkose was trapped

between rising salt anticlines—this arkose is thin to absent

over the crests of some anticlines. In the western and southern parts of the basin, the Cutler is recognized as a Group

consisting of, in ascending order: the lower Cutler beds,

Cedar Mesa Sandstone, Organ Rock Formation, White Rim

Sandstone, and De Chelly Sandstone. The aggregate thickness of these formations is less than 2,000 ft. The formations

of the Cutler Group were deposited in a complex system of

alluvial, eolian, and marine environments characterized by

abrupt vertical and lateral lithologic changes. The basal Cutler is Pennsylvanian in age, but the bulk of the Group was

deposited during the Permian. The Cutler is conformably

underlain by the Pennsylvanian Hermosa Group across most

of the basin. It is overlain unconformably by the Permian

Kaibab Limestone in the western part of the Paradox Basin.

The Cutler or Kaibab are overlain unconformably by the Triassic Moenkopi or Chinle Formations.

INTRODUCTION

This study was funded as a part of the U.S. Geological

Survey’s Evolution of Sedimentary Basins Program. The

Paradox Basin, located in southeastern Utah and southwestern Colorado, was the subject of a multidisciplinary stratigraphic, sedimentologic, geochemical, and structural

investigation. In this report, I describe the regional geology

of the Pennsylvanian and Permian Cutler Group and Kaibab

Limestone in the Paradox Basin, based mainly on the study

of geophysical well logs and outcrop data.

To many people, the canyon country of southeastern

Utah and northern Arizona epitomizes the Permian of the

Southwestern United States. The canyons and mesas of Canyonlands National Park and the spires and monoliths of

Monument Valley are associated with Permian rocks, the

Cutler Group in particular. Some reports, such as Wengerd

and Matheny (1958) and Baars (1962), have previously demonstrated that the lower part of the Cutler is, however, Pennsylvanian, and this report describes rocks at the Systemic

boundary in some detail. In parts of the Paradox Basin, the

position of the basal contact of the Cutler is controversial.

Once regarded as an unconformable Systemic boundary, it

now is interpreted by some as gradational, and the position

of the Pennsylvanian-Permian boundary is also questioned.

The correlation of younger Permian rocks has been relatively

more straightforward; there is, however, substantial disagreement concerning the depositional environments of

some units. The arguments are summarized in this report.

Acknowledgments.—Jean Dillinger digitized the base

maps used for the maps presented here. Critical reviews by

J.E. Huntoon and J.D. Stanesco were of great help in improving the manuscript. Discussions of Pennsylvanian, Permian,

and Triassic rocks with J.A. Campbell, R.F. Dubiel, K.J.

Franczyk, A.C. Huffman, Jr., J.E. Huntoon, and J.D.

Stanesco were very helpful in my gaining an understanding

of those units.

GEOGRAPHIC AND STRUCTURAL SETTING

The Paradox Basin is an oval area in southeastern Utah

and southwestern Colorado that, for this study, is defined by

the maximum extent of halite and potash salts in the Middle

Pennsylvanian Paradox Formation (fig. 1, pl. 1). Using this

definition, the basin has a maximum northwest-southeast

length of about 190 mi, and a northeast-southwest width of

about 95 mi. The Paradox Basin, as thus recognized, is in the

central part of the Colorado Plateau. The shape of the basin

was modified and obscured by later tectonic events, primarily the Laramide orogeny. Today, the basin has been dissected in places by uplift of the Colorado Plateau and by

downcutting of the Colorado River and its tributaries. The

basin is primarily a Pennsylvanian feature that accumulated
P2 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

thick deposits of carbonate, halite, potash, sandstone, and

arkose in response to tectonic downwarping and simultaneous uplift along its northeastern border. In this report, I

focus on the Pennsylvanian and Permian stratigraphic units

that overlie the salt, even though the depositional limits of

those units do not correspond to the limit of salt. The name

“Paradox Formation” originated with Baker and others

(1933) for exposures of the unit in Paradox Valley, Montrose

County, Colorado. The valley and town of Paradox were

probably named because the Dolores River cuts through the

south valley wall, runs transversely across the valley at right

angles to the northwest trend of the valley, and exits through

the north valley wall. The relation of the river to the valley is

thus, seemingly, a paradox (Hite and Buckner, 1981).

The basin is bordered on the northeast by the

Uncompahgre Plateau, a broad anticline cored by Precambrian rocks and faulted along its southwestern side (fig. 2).

The east side of the basin is bounded by the San Juan dome,

an area that is covered, in part, by Tertiary volcanic rocks. In

the Needle Mountains, a prominent feature of the southern

San Juan dome, Precambrian rocks are widely exposed. The

southeast end of the basin is defined by the northeast-trending Hogback monocline that extends southwestward from

the Durango, Colo., area through northwestern New Mexico.

The southern and southwestern border of the Paradox Basin

is rather poorly defined topographically, extending northwestward from Four Corners (the junction of Utah, Colorado, New Mexico, and Arizona) across the Monument

upwarp to the Henry Basin. The northwest side is bounded by

the San Rafael Swell, and the far northern end of the basin

merges with the southern end of the Uinta Basin.

Structural and topographic features of the Paradox

Basin are very diverse. The northern part of the basin has

been termed the “Paradox fold and fault belt” (Kelley,

1958b). This area consists of a series of roughly parallel,

northwest-trending faults, anticlines, and synclines. The

northeastern part of this division is most complexly folded,

and salt from the Paradox Formation has risen diapirically to

the surface. Dissolution of salt in the center of some anticlines in this region has caused down-faulting and the formation of grabens along the anticlinal crests. Rocks as old as

Pennsylvanian are exposed in the cores of some of the anticlines, and remnants of Cretaceous rocks are present in some

synclines and in collapsed blocks within some anticlines. The

southwestern part of the fold and fault belt is also faulted and

folded but lacks the complex piercement structures of the

northeastern part.

South of the fold and fault belt are the Blanding Basin

and the Four Corners platform (fig. 2). The Blanding Basin

is a generally undeformed area in which Jurassic and Cretaceous rocks are at the surface. The Four Corners platform is

a structurally high bench capped by Cretaceous rocks that

separates the Paradox and San Juan Basins. The Hogback

monocline defines the southeast side of the Four Corners

platform.

The extreme southwestern part of the Paradox Basin is

coincident with the Monument upwarp. This area consists of

deep canyons and high mesas that provide the setting for part

of Canyonlands National Park, Natural Bridges National

Monument, and other recreation and cultural-resource areas.

The upwarp trends generally north and is a broad anticline. It

is bounded on the east by the steeply dipping Comb Ridge

monocline and merges to the west with the Henry Basin

across the White Canyon slope. A northeast-trending anticline along the Colorado River is an extension of the Monument upwarp that projects into the fold and fault belt.

Permian and some Pennsylvanian rocks are widely exposed

on the upwarp and along the river.

Adding to the picturesque qualities of the Paradox Basin

are intrusive rocks of the La Sal, Abajo, and Sleeping Ute

Mountains that lie within the basin, and intrusive centers

such as the Henry, Carrizo, La Plata, Rico, and San Miguel

Mountains in surrounding areas. These intrusive rocks are

Late Cretaceous to Tertiary in age, and their emplacement

deformed the enclosing sedimentary rocks into broad domes.

The current structural configuration of the basin and

surrounding area is shown on plate 2, a structure contour map

drawn on the base of the Cutler Group or Formation. This

horizon was chosen because the data set for the horizon is the

most complete for any stratigraphic unit discussed in this

report. Older stratigraphic units are generally less suitable

because of the fewer wells that penetrated those units, and

younger stratigraphic units are commonly eroded and incomplete, making them less useful for a structure contour map.

Plate 2 shows, in circled numbers clockwise from upper

left (1) the high area of the San Rafael Swell, (2) the high area

of the Uncompahgre Plateau, flanked on its southwest by the

deepest part of the Paradox Basin, (3) McElmo dome west of

Cortez, Colo., (4) the low area of the San Juan Basin in northwestern New Mexico, (5) the high area of the northern Defiance Plateau in northeastern Arizona, (6) the high area of the

Monument upwarp in southeastern Utah, and (7) the low area

of the Henry Basin. The sharp flexure of Comb Ridge monocline is clearly evident on the eastern side of the Monument

upwarp. Also evident is the structural nose that extends

northeastward from the northern end of the Monument

upwarp along the Colorado River into the fold and fault belt.

Northwest-trending contours in the northeastern part of the

basin are evidence of the salt anticlines in the fold and fault

belt. Because of the relatively widely spaced control points,

offsets on faults are not shown on this map.

PREVIOUS STUDIES AND NOMENCLATURE

The remoteness and inaccessibility of much of the Paradox Basin served to isolate it from the scrutiny of geologists

until the latter half of the 19th century. Powell’s historic voyages down the Green and Colorado Rivers were the first

detailed accounts of the area (Powell, 1875). The Henry
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P3

Mountains, just west of the basin, were the last major mountains discovered in the American West.

Whitman Cross and his associates studied the rocks of

the San Juan Mountains of southwestern Colorado at the

beginning of the 20th century and were among the first to

describe the Permian rocks outcropping in that area. The

Cutler Formation was named by Cross and others (1905) for

exposures along Cutler Creek, 4 mi north of Ouray, Colo. It

was considered provisionally Permian in age due to a lack of

fossils. The Rico Formation was named by Cross and Spencer (1900) and was considered Pennsylvanian and Permian

in age. The Rico was thought to represent beds transitional

between the largely marine Hermosa Formation or Group

below and the continental Cutler Formation above.

Figure 1. Map showing geographic features of the Paradox Basin and adjacent areas. AC, Arch Canyon; DC, Dark Canyon; GC,

Gypsum Canyon; IS, Island in the Sky district of Canyonlands National Park. Circled numbers refer to other figures in this report that

are photographs of outcrops or that indicate locations of well logs.
P4 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

Interest in the water, mineral, and oil and gas resources

of southeastern Utah prompted more geologic studies during

the early 20th century. Baker and Reeside (1929) defined the

units of the Cutler in southeastern Utah and introduced

names that are still in use today. In their terminology, the

Cutler Formation included, from bottom to top, the Halgaito

tongue, Cedar Mesa Sandstone member, Organ Rock tongue,

De Chelly Sandstone member, White Rim Sandstone

member, and Hoskinnini tongue. The Rico Formation was

also recognized in southeastern Utah and was considered

Permian in age. Key reports from this period include Longwell and others (1923), Baker and others (1927, 1936), Gilluly and Reeside (1928), Baker and Reeside (1929), Gilluly

(1929), Baker (1933, 1936, 1946), Dane (1935), Gregory

(1938), and McKnight (1940). These studies were directed

mainly toward mapping the surface rocks and structures

Figure 2. Map showing structural elements of the Paradox Basin and adjacent areas. Dashed lines indicate transitional or indefinite

boundaries between elements. PVA, Paradox Valley anticline; CCA, Cane Creek anticline; SD, Shafer dome. Modified from Kelley (1958a,

1958b).

2a
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P5

because of the paucity of deep drilling in the basin at that

time. They did provide the basic geologic framework of the

basin, which has been refined by subsequent geologic

studies.

One of the oldest oil fields in Utah was discovered in

1908 at Mexican Hat (Lauth, 1978); wildcat drilling took

place in many areas of the basin through the mid-1950’s.

Discovery of the giant field at Aneth, southeast of Bluff,

Utah, in 1956 (Matheny, 1978) accelerated deep drilling in

the basin. Wengerd and Strickland (1954) and Wengerd and

Matheny (1958) used the newly drilled deep wells to integrate the geology of Pennsylvanian and Permian units

throughout the Four Corners area. Wengerd and Matheny

(1958) raised the Cutler to Group rank and, additionally,

included what they called the “Rico transitional facies” in

the Cutler. The Rico was thought to be of both Pennsylvanian and Permian age.

Baars (1962) presented regional correlations of Permian units of the southern Colorado Plateau. He used most

of the terminology introduced by Baker and Reeside (1929)

and modified by Wengerd and Matheny (1958) for the Cutler. Baars differed from previous workers mainly in his

rejection of the concept of the Rico as a transitional unit

between Pennsylvanian and Permian strata. On the basis of

field studies by Shell Oil Co. in the 1950’s, Baars (1962) recognized a regional unconformity between the Hermosa

Group and the Cutler Group. In addition, he formally named

the Elephant Canyon Formation for a succession of Permian

(Wolfcampian) carbonates in the northwestern part of the

Paradox Basin. The Elephant Canyon was described as grading laterally into the Halgaito Formation and interfingering

with the overlying Cedar Mesa Sandstone. Baars (1962)

defined the Elephant Canyon as entirely Permian in age, but

he recognized that the base of the undivided Cutler along the

Uncompahgre front was likely Pennsylvanian.

This system of nomenclature was widely accepted and

used until Loope (1984), Loope and others (1990), and Sanderson and Verville (1990) questioned the presence of an

unconformity beneath the Elephant Canyon. Furthermore,

some strata in the Elephant Canyon that were considered

Permian in age by Baars (1962, 1987) were interpreted as

Pennsylvanian (Missourian and Virgilian) by Sanderson and

Verville (1990). Loope (1984) and Loope and others (1990)

recommended abandonment of the name “Elephant Canyon

Formation.” They assigned the lower part of the Elephant

Canyon to the underlying Hermosa Group and renamed the

upper part the “lower Cutler beds.” The Hermosa was considered Pennsylvanian and the lower Cutler beds Permian. In

this report, I present regional cross sections wherein I show

my correlations of this problematic interval in the subsurface

of the Paradox Basin.

Due to the exceptional exposures of the Cutler in the

Canyonlands area of southeastern Utah, there are many theses and reports dealing with this stratigraphic interval. Many

of these reports are cited below in discussions of individual

rock units. Of particular note is Lohman (1974), whose

report includes many color photographs of rocks in Canyonlands National Park. Additional data are summarized in

Dubiel, Huntoon, Condon, and Stanesco (1996) and Dubiel,

Huntoon, Stanesco, and others (1996).

METHODS

DATA

The main sources of data for this study are geophysical

logs from wells drilled throughout the Paradox Basin and

surrounding areas (Appendix 1). A collection of paper logs

was purchased and was used as the basis for the correlations

and maps presented here. Types of logs include gamma-ray,

neutron, spontaneous potential, resistivity, conductivity, and

interval transit time (sonic). A total of 202 well logs were

used for this study.

Supplementing the geophysical logs were sample logs

from the American Stratigraphic Company (AMSTRAT).

These sample logs were used to match specific lithologies to

the geophysical log responses. The logs were invaluable in

working out correlations of the lower part of the Cutler

Group.

A third major source of data was a database of petroleum exploration wells, compiled by Rocky Mountain Geological Databases, Inc., which is mainly concerned with

Pennsylvanian and older stratigraphic units. This database

provided a consistent top for the Hermosa Group.

Other sources of data were reports concerning Permian

rocks in the Paradox Basin area. Surface rocks have been

studied previously by other geologists, and thus lithologies

and thicknesses of outcropping units in areas not visited by

the author were available (Appendix 2). Data were collected

from descriptions of 97 outcrop areas. Published isopach

maps and cross sections of subsurface units were also consulted to see how other geologists portrayed the units.

I examined outcrops of Permian and adjacent rocks

throughout the Paradox Basin. Localities visited included

much of Canyonlands National Park, the adjacent Glen Canyon National Recreation area, the San Rafael Swell, the

Monument upwarp and the canyon of the San Juan River, the

area of salt anticlines in the northeastern part of the basin,

and the Permian outcrops that flank the Needle Mountains in

southwestern Colorado.

CONTOUR MAPS

The isopach and structure maps compiled for this report

were constructed using a program called Interactive Surface

Modeling (ISM), formerly marketed by Dynamic Graphics,

Inc. A base map was digitized to provide a geographic base
P6 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

for the other maps, and then individual files containing location and thickness data were gridded and contoured. Several

figures in this report show log curves with picks of geologic

units. These picks were made by me and are the data that

were compiled into the isopach and structure maps. The projection of the maps is Lambert conformal conic based on

standard parallels 33° and 45°.

Computer contouring is, by its nature, an averaging process that is dependent on two factors: (1) the quality of the

data input into the program and (2) the method used to calculate the contours. The quality of the input data is itself made

up of several factors, including, but not limited to, (1) the

number of control points used, (2) the distribution of the control points, (3) the number of stratigraphic units penetrated

by each well, and (4) the accuracy of picks made by the

investigator.

The detail shown by the isopach maps would have been

greater if more logs had been used; however, budget and time

constraints limited the data set to the selected subset of wells.

Because of this, the maps and cross sections provide an overview of the geology of the basin rather than a detailed analysis of local areas. The area of salt anticlines, in the

northeastern part of the basin, is especially complex, both

structurally and stratigraphically.

The methods used for computer contouring vary

according to the program used. In the ISM program used for

this study, a grid is first constructed that is the basis for the

contour lines. A grid defines a surface in three-dimensional

space that is calculated from the input scattered-data (x, y, z)

coordinates. The area shown on the maps was divided into a

grid matrix of 300 rows and 300 columns. This is equivalent

to a grid spacing in the x direction (longitude) of about 0.75

miles and a grid spacing of about 0.9 miles in the y direction

(latitude).

Each grid node (intersection points between grid lines)

is calculated in two steps: (1) initial estimation of grid node

values and (2) biharmonic iterations using scattered-data

feedback. The initial estimate is made by dividing the twodimensional x, y space into octants centered on each grid

node (Dynamic Graphics, Inc., 1988). Scattered-data points

are selected within each octant depending on their distribution. Nearby points are used first within each octant, and the

program will not search past two points in adjacent octants to

calculate an empty octant; however, if no data are near a grid

node, the program will search to the edge of the data set to

find data. Once the points are selected, they are averaged

using an inverse distance algorithm in which weighting is

dependent on the angular distribution of the points.

After this initial estimate is made, ISM uses a biharmonic cubic spline function to fit a minimum tension surface

to the grid nodes. To ensure that the minimum tension surface honors the scattered data as accurately as possible, a

scattered-data feedback procedure is used to keep grid nodes

tied to neighboring scattered data. In this study, as many as

eight scattered-data points that fall within one-half cell of a

grid node were used in this feedback procedure.

Once the minimum tension grid surface is calculated,

ISM can use the grid to construct contour maps, cross sections, and perspective views of surfaces. It is essential to

keep in mind that the final products are calculated from the

grid values, not from the scattered data. Thus, there is some

degree of averaging of the original data when constructing

the contour maps.

The point of this discussion of techniques, and the relevance to the present study, is to illustrate that the contour

maps presented herein were constructed using a consistent

set of procedures that result in repeatable results. This

method differs from hand-contouring methods because in the

latter techniques the geologist commonly contours using a

set of ill-defined and inconsistently applied procedures that

introduce biases according to the individual’s intent. This is

not to say that a hand-contoured map is any less accurate than

a computer-generated map. An individual’s knowledge of an

area is essential to the successful portrayal of a unit that is

present in the subsurface and that is only known at scattered

control points.

One of the shortcomings of computer-generated contour

maps is that in areas of widely spaced control points, the

importance of some data values may be exaggerated. For

example, pinch-outs of units are not located precisely

because of the distance between control points that define the

pinch-outs. Rather than disregarding computer-generated

maps as useless and going back to the “old-fashioned method

of eyeballing,” the limitations of computer maps need to be

recognized and taken into consideration in any analysis of the

data.

STRATIGRAPHY

In this report, the Cutler Group is considered to consist

of the following lithostratigraphic units (fig. 3): (1) a lower

Cutler unit that includes part of the Elephant Canyon Formation of Baars (1962), the “lower Cutler beds” of Loope and

others (1990), the Rico Formation of some reports, and the

Halgaito Formation, (2) the Cedar Mesa Sandstone, (3) the

Organ Rock Formation, (4) the White Rim Sandstone, and

(5) the De Chelly Sandstone. Where the Cutler cannot be

subdivided, it is recognized as the Cutler Formation, undivided. The Permian Kaibab Limestone, also known locally as

the Black Box Dolomite, overlies the Cutler on the far west

side of the Paradox Basin and is discussed in the context of

Permian stratigraphy and paleogeography. The names “Rico

Formation” and “Elephant Canyon Formation” have been

championed by some and vilified by others and are not used

as formal rock-stratigraphic terms in this report. I discuss

past usage of the units in this report and explain why I do not

use them.
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P7

Figures 3A–3D are cross sections that show the stratigraphic relationships and nomenclature for the rock units

discussed in this report. The cross sections were constructed

by compiling data from the isopach maps of each stratigraphic unit along the lines of section. Exceptions are in

areas of pinch-outs of units, such as the White Rim Sandstone or De Chelly Sandstone, where the isopach maps may

exaggerate by a few miles the lateral extent of the units due

to widely spaced control points.

Disputes over correlations of the Cutler in the Paradox

Basin have been caused by: (1) the complexity of the Cutler

depositional system and (2) an inconsistent use of stratigraphic names. In any given location, a vertical change in

lithology is readily observable; in many instances, vertical

interbedding between stratigraphic units can also be

observed. Lateral facies changes are characteristic of almost

all the units of the Cutler, and this has been especially troublesome in the study of basal Cutler strata. Although exposures along the Colorado River have aided study of the

Cutler, a covered interval between the Hite, Utah, area and

the Mexican Hat, Utah, area has led to correlation problems.

There are also few outcrops of the Cutler in most of the eastern two-thirds of the basin, between the Colorado River and

Monument upwarp on the west and the Uncompahgre Plateau and Needle Mountains on the east.

Disagreement about characteristics of the Hermosa and

Cutler in the Paradox Basin has also led to divergent use of

stratigraphic terms. One example is at Cane Creek anticline

and Shafer dome in the northern part of the basin (fig. 2).

McKnight (1940) stated that there are approximately

150–300 ft of Hermosa exposed, which are overlain by 585

ft of Rico Formation. Conversely, Baars (1971) did not recognize any Hermosa at those localities and assigned the

whole succession to the Elephant Canyon Formation.

Another example is in the southern part of the basin along the

San Juan River. Baker (1936) picked the contact between the

Hermosa and the Rico at a change from massive limestones

below to thinner limestones and red beds above, but O’Sullivan (1965) picked the contact approximately 100 ft higher

in the section on other lithologic criteria. Baars (1962)

assigned the entire section to the Hermosa. These are but two

examples of people using different names for the same

strata; similar examples could be cited for many other places

in the basin. The converse, using the same name for different

strata without explicitly saying so, has also been done and

has led to miscorrelations and confusion.

UNDERLYING ROCKS

HONAKER TRAIL FORMATION

In most of the Paradox Basin, the Pennsylvanian

Honaker Trail Formation of the Hermosa Group, or the Hermosa Formation, undivided, underlies the Cutler Group. The

exceptions are along the northeastern margin of the basin

where the Cutler overlies Proterozoic rocks and west of the

basin, on the San Rafael Swell, where the Cutler locally

overlies Mississippian rocks. The datum used in this report

for the top of the Honaker Trail in the subsurface was generally that picked on AMSTRAT logs or by Rocky Mountain

Geological Databases, Inc. (RMGD). The upper part of the

Honaker Trail is characterized by thick limestone beds associated with varying amounts of sandstone and shale. The

amount and composition of interbedded sandstones changes

from place to place in the Paradox Basin, depending on the

distance from the Uncompahgre highlands and the environments of deposition in which the sandstones were deposited.

It is unlikely that there is a single limestone that extends

throughout the basin that could be used as a datum for the top

of the Honaker Trail. Limestones have been observed to thin,

grade into sandstone and shale, or otherwise change facies

laterally in some exposures. Atchley and Loope (1993)

showed that depositional cycles in the Honaker Trail along

the southwestern basin margin cannot be traced to the north.

The limited control points in some areas of the basin make it

impossible to accurately trace individual limestone beds

from one well to another. There is usually a marked lithologic break at the top of the Honaker Trail, however, and that

is the basis for the pick between the Hermosa and Cutler.

Examples of this pick are shown on figure 4.

Reports by Dane (1935), Cater (1970), Franczyk

(1992), and Franczyk and others (1995) summarized the

lithology of the upper part of the Hermosa along the northeast margin of the basin, the areas closest to the Uncompahgre highlands. Limestone beds are gray to yellowish gray,

dense, medium to thick bedded, and fossiliferous. Common

fossils are brachiopods, pelecypods, echinoids, corals, gastropods, and fusilinids. Chert concretions are present in some

limestone beds. In general, sandstone beds of the upper Hermosa in this area are gray, yellowish gray, and tan; conglomeratic to fine grained; subarkosic to arkosic; and thick

bedded. The shale beds in the upper Hermosa are generally

gray, green, and tan, as opposed to red shale beds in the Cutler, and are evenly bedded. Neither Dane (1935) nor

Franczyk (1992) and Franczyk and others (1995) recognized

strata that could be assigned to the Rico Formation, and

Cater (1970) could not identify a Rico Formation in most of

his study area. The Cutler overlies the Hermosa or Proterozoic rocks in the areas discussed by those authors. Farther

southwest in the Paradox Basin, the lithology of the Honaker

Trail changes somewhat. It has been described in those areas

by Baker (1933, 1936, 1946), McKnight (1940), Wengerd

and Matheny (1958), Lewis and Campbell (1965), O’Sullivan (1965), Melton (1972), Loope (1984, 1985), Loope and

others (1990), Sanderson and Verville (1990), and Atchley

and Loope (1993) among others.

From Cane Creek anticline to the confluence of the

Green and Colorado Rivers (hereafter called the
P8 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

Figure 3 (above and facing page). Cross sections showing stratigraphic relationships and nomenclature used in the Paradox

Basin. Locations of the cross sections are shown on plate 1. Datum is the basal Triassic unconformity. Cross sections were constructed by compiling thickness data from isopach maps along indicated lines of section. The number and position of limestone

beds in the lower Cutler beds is schematic. A, Uncompahgre uplift to San Rafael Swell; B, Uncompahgre uplift to Henry Basin;

C, Uncompahgre uplift to Monument upwarp; D, Uncompahgre uplift to San Juan Basin.
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P9
Figure 4. Cross section showing well logs of section at the Pennsylvanian-Permian boundary from near the San Rafael Swell to the Utah-Colorado State is shown on plate 1. Numbers above well logs correspond to those on plate 1 and in Appendix 1. All logs are gamma ray-neutron. Uppermost Virgilian into red beds of typical Cutler lithology. Pccm, Cedar Mesa Sandstone; Pch, Halgaito Formation; Pec, Elephant Canyon Formation. The numbers at the top tion are picks from the Rocky Mountain Geological Databases, Inc., database.
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P11

Confluence), the Honaker Trail is composed of thick beds of

sandstone, limestone, and shale. McKnight (1940, p. 22)

reported that sandstone and arkose make up 49 percent of the

formation, limestone 31 percent, and shale 20 percent at a

location on the Colorado River just upstream from the Confluence. Sandstone beds are as thick as 75 ft, limestone beds

are as thick as 40 ft, and shale beds are as thick as 20 ft. Sandstone is white, gray, greenish, or reddish; fine to medium

grained; and commonly cross-bedded. Limestone is gray,

dense, fossiliferous, and contains chert nodules in some

beds. Shale is mainly gray to green, although some beds are

reddish. Shale beds are commonly calcareous and contain

marine fossils in some places.

Some of the best exposures of the Honaker Trail Formation are along the Colorado River just south of the Confluence (Baker, 1946). In this area, the Honaker Trail is

composed mainly of interbedded limestone and sandstone in

nearly equal amounts and a small percentage of shale. Limestone occurs in beds as thick as about 45 ft and is light to dark

gray, dense, cherty, and fossiliferous. Sandstone is in beds as

thick as about 50 ft and is light to dark gray, greenish gray,

tan, and salmon; fine to medium grained; and cross-bedded.

Loope (1984, 1985) interpreted the sandstones in the upper

part of the Honaker Trail Formation in this area as eolian in

origin. The sandstones have medium- to large-scale crossbeds and transport directions to the southeast (Loope, 1984).

Atchley and Loope (1993) indicated that eolian sandstones

make up about 50 percent or more of the Honaker Trail from

the Confluence area southward to Elk Ridge.

Honaker Trail exposures near Elk Ridge were described

by Lewis and Campbell (1965). In that area, the interbedded

lithologies of limestone, sandstone, and shale persist. Limestone beds are gray, dense, cherty, fossiliferous, and are as

thick as 60 ft. Sandstone beds are commonly light gray, calcareous, and as thick as 30 ft. Shale beds are gray, thin bedded, calcareous, and as thick as 15 ft. Lewis and Campbell

(1965, p. B8) noted that the upper Hermosa is gray and the

overlying Rico Formation is red, although Murphy (1987)

described red siltstone in the upper Hermosa at Dark Canyon.

The southernmost exposures of the Honaker Trail are in

the canyon of the San Juan River, near Mexican Hat, Utah

(fig. 1). This area has been described by Woodruff (1912),

Miser (1925), Baker (1936), Wengerd and Matheny (1958),

Wengerd (1963, 1973), O’Sullivan (1965), and Goldhammer

and others (1991). Access to the Hermosa is relatively easy

in this area because a trail leads from the rim of the canyon

down to the San Juan River. Although this is the type area for

the Honaker Trail Formation (Wengerd and Matheny, 1958),

some have argued that the name should not have been

applied here (Hite and Buckner, 1981). Evaporite rocks of

the underlying Paradox Formation pinch out before reaching

Honaker Trail, so the basal contact of the Honaker Trail Formation is arbitrary at this locality.

In contrast to areas north of Elk Ridge, the Honaker

Trail Formation along the San Juan River has relatively little

sandstone and proportionately more limestone and shale. In

a section on the San Juan River, H.D. Miser measured 840.5

ft of the Honaker Trail (Baker, 1936). Of this thickness, less

than 5 percent is sandstone, 55 percent is limestone, and 40

percent is shale or covered interval. As in areas to the north,

limestone beds here are thick, gray, massive, cherty, and fossiliferous. Shale beds are also thick and are mainly gray and

calcareous. The few sandstone beds are gray to yellow, calcareous, fine grained, and cross-bedded. Baker (1936) noted

that, although the contact of the Hermosa with the overlying

Rico is gradational, the massive, somber-colored limestone

and sandstone of the Hermosa contrasts strongly with the

thin-bedded, reddish-colored rocks of the Rico.

RICO FORMATION AND ELEPHANT CANYON 

FORMATION

The term “Rico Formation” originated with Cross and

Spencer (1900) for exposures near Rico, Colo. (fig. 1). The

Rico was envisioned as a unit transitional between the Hermosa, below, and the Cutler (at that time considered part of

the Dolores Formation), above. As such, it contained both

marine limestones and continental clastic red beds. A faunal

change from dominantly brachiopods in the Hermosa to

dominantly pelecypods in the Rico was used as a distinguishing criterion. The upper contact of the Rico was

vaguely defined as being the highest occurrence of Rico fossils; the Cutler is unfossiliferous. The Rico was considered

Permian(?) in age by Cross and Howe (1905).

The term “Rico Formation” was first used in southeastern Utah by Prommel (1923), who was then followed by

Baker and others (1927). Baker and Reeside (1929) correlated the Rico throughout the Paradox Basin, and the term

became commonly used in the region through the reports of

Baker (1933, 1936, 1946) and McKnight (1940). In all of

these reports, the Rico was considered to be Permian in age,

determined on the basis of marine fossils, and was thought to

represent beds transitional between the Hermosa and Cutler.

Baars (1962) vigorously objected to the concept of a

transitional unit between the Hermosa and the Cutler. His

objections were mainly based on (1) an interpreted unconformity between the Hermosa and Cutler in much of the region

and (2) the fact that beds assigned to the Rico are time transgressive, becoming younger to the west. In its place, Baars

(1962) introduced the name “Elephant Canyon Formation,”

which was defined as the sequence of Permian (Wolfcampian) carbonates present only in the northwestern part of the

Paradox Basin. Key points in the definition of the Elephant

Canyon are (1) that it overlies the Systemic boundary

between the Pennsylvanian and the Permian and (2) this

boundary was interpreted as an unconformity. As thus

defined, the Elephant Canyon was a chronostratigraphic
P12 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

unit, not a lithostratigraphic unit, because rocks of the underlying Hermosa Group have a lithology similar to that of the

lower part of the Elephant Canyon.

Although Baars’ (1962) intent was to simplify the

nomenclature and refine paleogeographic interpretations,

many reports continued to use a mix of the terms “Rico Formation” and “Elephant Canyon Formation.” For example

Wengerd (1973, p. 134) showed both units as present, with

the Elephant Canyon overlying the Rico; Molenaar (1975, p.

142) only showed the Elephant Canyon; Campbell (1979, p.

15) used both terms interchangeably; Loope (1984) used

only the Rico Formation; and Campbell (1987, p. 93) used

only the Elephant Canyon Formation.

There is some indication that the Elephant Canyon was

used in ways other than how Baars (1962) had defined it. For

instance, a geologic map of Canyonlands National Park,

including the type area for the Elephant Canyon, shows

300–400 ft of Honaker Trail Formation underlying the Elephant Canyon near the mouth of Elephant Creek (Huntoon

and others, 1982). Baars’ original definition of the unit

(Baars 1962, p. 176) stated that only 55 ft of Honaker Trail

Formation is exposed above river level at that locality.

Huntoon and others (1982) showed about 400–500 ft of Elephant Canyon at the Confluence, whereas Baars (1975)

stated that there is about 1,000 ft of Elephant Canyon there.

Loope (1984), Loope and others (1990), and Sanderson

and Verville (1990) asserted that they could find no evidence

of an unconformity at the base of Baars’ (1962) Elephant

Canyon and thus disputed the concept of the Elephant Canyon Formation. Initially, Loope (1984) reverted to the

nomenclature of McKnight (1940) and Baker (1946) by

using the term “Rico Formation” for strata between the Hermosa and Cutler. Eventually, Loope and others (1990)

acknowledged that the term “Rico Formation” might be inappropriate and used an interim name “lower Cutler beds” for

that interval. Field checking of these strata by A.C. Huffman,

Jr. and me in nearby Big Springs Canyon revealed that the

base of Loope and others’ (1990) lower Cutler beds corresponds to the base of the Elephant Canyon as mapped by

Huntoon and others (1982).

Condon (1992), Huffman and Condon (1993), and Condon and Huffman (1994) recognized the Rico Formation in

the San Juan Basin. The unit had been previously identified

as such by Wengerd and Matheny (1958) and can be traced

through much of the basin in the subsurface. In comparing

the southeast end of figure 4 (of this report) and cross section

F-F′ of Condon and Huffman (1994), it is apparent that the

top of our Rico Formation in the San Juan Basin corresponds

to the top of the Honaker Trail Formation as recognized here

in the Paradox Basin. On the basis of the correlations presented herein, it now seems that the unit recognized as Rico

in the San Juan Basin underlies the Rico of the Mexican Hat,

Confluence, and Shafer dome areas of southeastern Utah.

The Rico, as recognized by Huffman and Condon (1993) in

the San Juan Basin, is probably entirely Pennsylvanian in

age.

Because of the varied past usage of the term “Rico Formation” and the disputed status of the Elephant Canyon

Formation, I use neither term as a formal name in this report.

I continue to use the term “lower Cutler beds” in the sense of

Loope and others (1990). As defined, it is a lithostratigraphic

unit lying above the Hermosa Group and below or adjacent

to the Cedar Mesa Sandstone. As demonstrated below, this

unit consists partially of the Elephant Canyon Formation of

Baars (1962), the “Rico Formation” of some authors, and the

Halgaito Formation, depending on the location in the basin.

The lower Cutler beds, as used by me, includes both Pennsylvanian and Permian strata, based on fusilinid identifications

presented in Loope and others (1990) and Sanderson and

Verville (1990).

CUTLER GROUP

CUTLER FORMATION, UNDIVIDED

Along the southwestern margin of the Uncompahgre

plateau, the Cutler is not divided into members or formations.

It consists of a heterogeneous sequence of arkosic conglomerate and lesser amounts of arkosic sandstone, siltstone, and

mudstone. Detailed stratigraphic and sedimentological studies of the Cutler in the northeastern part of the Paradox Basin

include those by Baker (1933), Dane (1935), McKnight

(1940), Baars (1962), Cater (1970), Rascoe and Baars

(1972), Werner (1974), Mack (1977), Campbell (1979, 1980,

1981), Campbell and Steele-Mallory (1979), and Mack and

Rasmussen (1984). Paleontological studies were summarized by Lewis and Vaughn (1965) and Baird (1965).

As a whole, the formation is dark red, purple, and

maroon, although some beds are gray to greenish. Conglomerates are poorly sorted; material ranges from sand size to

boulders as large as 25 ft (Schultz, 1984). Trough cross-bedding and horizontal bedding are present in some of the sandstone beds, and ripple marks are present in some of the finer

grained rocks. There are few sedimentary structures in the

coarsest conglomerates, but clasts are graded both normally

and inversely, and some pebbles display imbrication dipping

to the northeast. Pebbles, cobbles, and boulders within the

Cutler are derived from nearby Proterozoic rocks (Werner,

1974). In the Gateway, Colo., area, debris flow and proximal-braided-stream deposits have been described (Campbell,

1980; Mack and Rasmussen, 1984; Schultz, 1984). This area

and two others along the Uncompahgre front were interpreted as alluvial fans (Campbell, 1980).

Clastics of the Cutler Formation, undivided, become

finer grained southward and westward from the Uncompahgre front (Baker, 1933; Dane, 1935; Cater, 1970). Campbell

(1979, 1980) interpreted this as a change from a proximal
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P13

braided facies in the northeast to meandering stream systems

farther to the southwest within an alluvial fan depositional

system. In the central and southwestern parts of the Paradox

Basin, the Cutler can be divided into individual formations

within the Cutler Group (Baars, 1962). Baker (1933, 1946),

McKnight (1940), Langford and Chan (1988, 1989), and

Stanesco and Campbell (1989) described the gradation of the

undivided Cutler into the Cutler Group. The gradation does

not occur along a sharp boundary but rather occurs over a

distance of many miles. Figure 5 shows the Cutler Formation

along Indian Creek, east of the Confluence, which is in the

zone of gradation. Various plates in this report show the

areas over which the constituent formations of the Cutler

Group can be recognized.

Plate 3 is an isopach map showing the general thickness

of the Cutler Formation or Group in the Paradox Basin. The

range in thicknesses used for this map is from 0 to 8,165 ft,

although Baars (1975) mentioned that at least 15,000 ft of

Cutler had been drilled in the basin in one well. Figures

3A–3D show a direct correspondence between the fold and

fault belt and deposition of the Cutler. Within the salt anticline region, the Cutler is undivided and consists of alluvial,

arkosic rocks. Outside this area, the Cutler can be divided

into formations on the basis of lithology and depositional

environments. The salt anticline area seems to have acted as

a trapping mechanism for fluvial sediments being shed from

the Uncompahgre highlands. The true distribution of thick

and thin areas is much more complex than can be shown here

because of widely spaced control points. Rising salt anticlines caused the Cutler to both thicken markedly in the adjacent synclines and to thin over the tops of the anticlines. In

some places within the fold and fault belt, the Cutler is

absent on the tops of some anticlines. Cross sections in Cater

(1970) show the thickness variations of the Cutler in the Paradox Valley area.

LOWER CUTLER BEDS

CONTACTS

Basal arkoses of the Cutler Formation become finer

grained to the southwest of the Uncompahgre Plateau and

eventually merge into units that have been called Rico Formation, Elephant Canyon Formation, lower Cutler beds, or

Halgaito Formation in different parts of the basin or by different geologists. This interval has been the subject of more

debate concerning correlations than any other unit in the

Cutler, so the bottom and top contacts, as used in this report,

need to be clearly defined.

In the Cane Creek anticline and Shafer dome areas in

the northern part of the basin, I pick the top of the Hermosa

at the same horizon as McKnight (1940) and Lohman (1974,

p. 52), which is at the top of massive white to gray limestone

and sandstone beds (fig. 6). The interbedded limestone,

sandstone, and reddish mudstone beds above the Hermosa

have been previously assigned to the Rico (McKnight, 1940)

or to the Elephant Canyon (Baars, 1971). The top of the

lower Cutler beds is at the top of the Shafer limestone,1

which forms a bench on either side of the river in this area. 

The contact I recognize between the Hermosa and

lower Cutler at the confluence of the Green and Colorado

Rivers (fig. 7) is the same as McKnight (1940) and Loope

and others (1990). The pick is at the change from massive

gray and white limestone and sandstone beds to red hues of

the lower Cutler. There is an increase in arkosic beds in the

lower Cutler and a decrease in the amount of limestone in

this area. The top of the lower Cutler beds is at the base of

the overlying Cedar Mesa Sandstone. Baars (1962) placed

all but the lower 55 ft of strata between the river and the

Cedar Mesa in the Elephant Canyon. McKnight (1940) considered the lower Cutler beds to be the Rico Formation.

The stratigraphic relationships observed at the Confluence continue southward through outcrops exposed along

the Colorado River. I observed these outcrops by raft

through Cataract Canyon and from the canyon rim at Gypsum Canyon and Dark Canyon (fig. 1). At Gypsum Canyon,

limestone beds of the lower Cutler beds are interbedded with

sandstone of the overlying Cedar Mesa Sandstone. This

interbedding at the outcrop is also evident in many of the

well logs in the area.

Between Dark Canyon and Mexican Hat, Utah, there is

a gap in outcrops of the strata underlying the Cedar Mesa

Sandstone of nearly 50 mi. A well approximately half way

between those areas shows the log characteristics of this

interval (fig. 8). The logs shown in figure 4 also show the

character of the lower Cutler in the subsurface of the basin.

In the canyon of the San Juan River, I agree with Baker

(1936) in placing the top of the Hermosa at the top of the

massive limestone and sandstone sequence. Overlying thinner bedded strata, which contain reddish sandstone and siltstone in addition to minor limestone, are included in the

lower Cutler beds. The lower Cutler includes all strata to the

base of the Cedar Mesa Sandstone in this area (fig. 9), which

includes beds previously assigned to the Rico and Halgaito

Formations

LITHOLOGY AND DEPOSITIONAL ENVIRONMENTS

In most of the basin, strata above the Hermosa and

below the Cedar Mesa Sandstone or equivalent rocks are

1 The Shafer limestone is not a formal stratigraphic unit recognized by

the U.S. Geological Survey. Its name was attributed by McKnight (1940)

to H.W.C. Prommel, a geologist who was active in stratigraphic and structural studies in the Moab area in the 1920’s. The name was used by Prommel and Crum (1927) and was subsequently used by the U.S. Geological

Survey in various Bulletins concerned with this area. The Shafer was used

by McKnight (1940) as a marker bed for the top of the Rico Formation in

the area he mapped between the Green and Colorado Rivers. The Shafer is

noteworthy today because the northeastern access roads leading into Canyonlands National Park are built on this resistant unit.
P14 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

Figure 5. Undivided Cutler Formation at Indian Creek, east of the confluence of the Green and

Colorado Rivers; person for scale in center of photo. In this area, Cutler fluvial strata are interbedded

with eolian strata. Purple fluvial strata are composed of coarse-grained channel arkose and mudstone

overbank material. This facies forms the lower part of the massive cliff just above the road. Orange

eolian strata are finer grained and form the middle part of these cliffs. Some eolian strata have been

bioturbated and are massive, but high-angle cross-beds are visible in some beds.

Figure 6. Honaker Trail Formation, lower Cutler beds, and upper part of Cutler Formation at Shafer

dome. Top of Honaker Trail is at top of bench above Colorado River. Top of lower Cutler beds is at

top of Shafer limestone (arrows). Interbedded fluvial and eolian strata of the Cutler Formation form

cliff above the lower Cutler beds. Mesozoic units form cliff in the background. Thickness of lower

Cutler beds here is approximately 580 ft.
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P15

Figure 7. Honaker Trail Formation, lower Cutler beds, and Cedar Mesa Sandstone at the confluence of the Green and Colorado Rivers. View is to the north; Green River is on the left flowing toward

viewer. Contact between the Honaker Trail and the lower Cutler is marked by change from gray and

white beds to red beds (arrow). Cedar Mesa Sandstone forms the cliffs at the top of the exposure.

Lower Cutler beds are approximately 600 ft thick here.

a mix of quartzose sandstone and arkose, minor conglomerate, mudstone, siltstone, and limestone (fig. 4).

This package grades northwestward into a carbonatedominated succession that overlies the Hermosa and

underlies the Organ Rock Formation or White Rim Sandstone (fig. 3A). Plate 4 shows the distribution and thickness of these beds as recognized in this report.

Outcrops of the lower Cutler beds in the Cane Creek

anticline and Shafer dome areas in the north-central part of

the basin are dominated by quartz sandstone and arkose.

Sandstone beds are dark red, orange, and pinkish to light

greenish gray, fine to coarse grained, and cross-bedded.

Many of the sandstone beds have been interpreted as eolian

deposits (Terrell, 1972). Arkose is dark red, maroon, and

purple, fine to coarse grained, cross-bedded, and contains

pebbles and cobbles at the base of some beds. Arkose beds

commonly display scour-and-fill structures and have erosive

bases. Terrell (1972) noted a 60-ft conifer log in an arkose

channel at Cane Creek anticline; similar petrified wood is

present in the core of Shafer dome (fig. 10). The coarse grain

size, sedimentary structures, and association with channels

indicates deposition of the arkose in fluvial channels and

related environments. Red, brown, and green siltstone or

mudstone is also commonly interbedded with sandstone or

arkose.

Limestone beds are gray, cherty, and fossiliferous.

Limestone beds are most abundant near the top and base of

the interval, and the middle part is dominated by quartz sandstone and arkose. The Shafer limestone at the top of the lower

Cutler beds forms a broad bench over much of this area, but

pinches out on the northeastern flank of Cane Creek anticline.

Terrell (1972) interpreted the beds of the lower Cutler in

the north-central part of the basin as deposits of a delta system in an arid region. His model consisted of fluvial channels

draining the Uncompahgre highlands to the northeast and

flowing southwestward through eolian dune fields to an

open-marine sea. The interbedding of arkose, sandstone, and

limestone were interpreted to represent the complex shifting

of fluvial channels, dune fields, and delta lobes across the

area. This interpretation was supported by Tidwell (1988),

who discovered a thin coal seam and a flora representative of

swampy conditions in this same area.

From the Confluence to Dark Canyon, the lower Cutler

beds are characterized by the same mix of quartz sandstone,

arkose, and limestone that is present at Cane Creek anticline

and Shafer dome (Baker, 1946; Lewis and Campbell, 1965;

Loope, 1984). Loope (1984) pointed out that much of the

sandstone in the lower Cutler is fine to medium grained and

cross-bedded in medium- to large-scale sets. The transport

direction of these sandstones was to the southeast. Loope

(1984) interpreted these sandstone beds as eolian in origin.

Other sandstone beds are flat-bedded, fine to coarse grained,

and contain vertebrate trackways in places (Loope, 1984).
P16 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

Kocurek and Nielson (1986) interpreted these strata as eolian

sand sheets. Arkose beds in the Cataract Canyon area are

generally confined to the lower part of the section (Baker,

1946; Loope, 1984) and are finer grained than correlative

beds to the northeast in the Moab area. These arkose beds

seem to indicate renewed uplift of the Uncompahgre highland, possibly accompanied by a wetter climate and a

resulting pulse of arkosic sediment into the basin.

Limestones are both gray, thick bedded, cherty, and fossiliferous and thin bedded and sandy to argillaceous. Limestones

are again concentrated at the top and base of the lower Cutler

in this area; the middle part is mainly red beds. A limestone

bed at the top of the interval, northeast of the Confluence,

was observed to be cross-bedded. This, or a similar bed, was

interpreted as a migrating sand wave (Loope, 1984) or a tidal

channel (Kocurek and Nielson, 1986). One limestone bed at

the top of the lower Cutler beds pinches out to the northeast

in outcrops along the Colorado River (McKnight, 1940).

Other limestones appear higher in the section northwestward

from the Confluence area (fig. 4). Mudstone and siltstone

beds are present, but poorly exposed, in the lower Cutler

beds. Desiccation cracks, adhesion ripples, possible paleosols, and leaf fragments in mudstone and siltstone beds suggest deposition in lacustrine or tidal-flat environments

(Loope, 1984; Kocurek and Nielson, 1986).

In the San Juan River canyon, the lower Cutler beds

(previously included in the Rico Formation) consist of silty

sandstone and siltstone interbedded with limestone and mudstone. Sandstone is white, gray, and red, silty, very fine

grained, and cross-bedded. Siltstone is reddish brown, calcareous, and slope forming. The siltstone gives this part of

the section its characteristic reddish hue. O’Sullivan (1965)

noted that the siltstone beds are very similar to those in overlying strata he mapped as the Halgaito Formation. Limestone

beds are gray to brown, sandy, fossiliferous, and form laterally persistent ledges along the canyon walls (fig. 9). Some

of the sandstone beds are also calcareous and form ledges

similar to the limestone beds.

This part of the section consists of several progradational-transgressive cycles in which continental red beds are

sharply overlain by transgressive marine limestones. The lateral continuity of strata, general lack of channel deposits,

and homogeneity of the red bed units indicates deposition in

a low-relief area near the sea but not in an area influenced by

prograding delta lobes. Murphy (1987) interpreted the red

siltstones of this interval as loess deposits.

At the surface in the San Juan River area, the upper part

of the lower Cutler beds (previously included in the Halgaito

Formation) is brick red and consists mainly of interbedded

very fine grained silty sandstone and sandy siltstone. Some

sandier or more calcareous beds weather to ledges, but as a

whole the unit forms a slope below the Cedar Mesa Sandstone (fig. 9). A few thin, gray, nodular limestone beds that

pinch and swell along strike are present near the base of the

unit. Some thin fluvial channels contain limestone pebble

conglomerates, and paleosols are present throughout the section. Vaughn (1973) summarized the vertebrate fauna in

these strata and stated that the vertebrate fossils are confined

to stream-channel deposits. The fauna includes abundant

fresh-water sharks, rhipidistian crossopterygian fish,

actinopterygian fish, lungfish, amphibians, and primitive

Figure 8. Well log showing the lower part of the Moenkopi Formation, Organ Rock Formation, Cedar Mesa Sandstone, lower Cutler beds, and the upper part of the Honaker Trail Formation at Elk

Ridge. Well is number 94 (plate 1 and Appendix 1). Log curves are

gamma ray on the left and interval transit time on the right. Note the

blocky nature of the Cedar Mesa Sandstone that contrasts with interbedded limestone, mudstone, and sandstone of the lower Cutler

beds. Massive limestone and sandstone beds mark the top of the Honaker Trail. Vertical scale is in feet.
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P17

Figure 10. Stump of petrified wood from lower Cutler beds near the Colorado River in the center

of Shafer dome; Brunton compass in center of photograph for scale. Other wood is encased in arkosic

channel sandstone bed in background. Channel sandstone is just above contact with the Honaker Trail

Formation. Terrell (1972) described a similar “conifer” log from the nearby Cane Creek anticline in

beds at the same stratigraphic position.

Figure 9. Honaker Trail Formation, lower Cutler beds, and Cedar Mesa Sandstone at

Johns Canyon, west of Mexican Hat, Utah. Top of Honaker Trail forms the lower ledges at

the base of the exposure. Top of Rico Formation is at top of double ledge in center of photograph. Halgaito Formation forms slope at base of Cedar Mesa cliffs in background and is

about 465 ft thick here. Cedar Mesa is of variable thickness due to erosion but averages

about 700 ft in this area.
P18 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

reptiles. The flora of this interval includes Calamites,

arborescent lycopods, and seed ferns (Vaughn, 1973).

Gregory (1938, p. 41) noted the similarity of the strata

previously mapped as Rico and Halgaito and stated, “Except

for the fossils and the larger numbers of persistent limestone

beds in the Rico there is little to distinguish that formation

from the overlying Cutler. Both are Permian red beds, both

are dominantly calcareous, irregularly bedded, more or less

arkosic sandstones with considerable range in texture. Were

it not for established usage the Rico and the lowest Cutler

(Halgaito member) might be combined in one formation....”

It is for this reason that I combine the two units into the lower

Cutler beds in this report.

The underlying Honaker Trail Formation of the San

Juan River area was deposited as a combination of deep- and

shallow-water marine carbonates interbedded with coastalplain siltstones and sandstones (Atchley and Loope, 1993).

The lower Cutler of this area reflects deposition in these

same environments. The overall progradational sequence of

the lower Cutler is marked by several marine transgressions

in its lower part (Rico), whereas the upper part (Halgaito) is

entirely continental. Murphy (1987) proposed an eolian origin for many of the red beds of the Rico and Halgaito in the

San Juan River area. Her proposed model is that the red beds

are, in large part, loess that was deposited downwind from

eolian strata of the upper Hermosa Group and Cedar Mesa

Sandstone. Several lines of evidence were used to support an

interpretation of loess rather than supratidal deposits for the

red siltstone. These included (1) the grain size of the siltstone

is typical for loess deposits, (2) detrital dolomite rhombs are

largely unabraded, (3) laminated to massive siltstone beds

are the most common lithofacies, and this lithofacies lacks

bedforms related to subaqueous deposition, (4) paleosols,

characterized by rhizoliths and carbonate nodules, are common throughout the red-bed sequence, and (5) chaotic or disrupted bedding, which would have been caused by

precipitation of halite or gypsum in a supratidal environment,

is absent in the red beds. Interbedded limestone-pebble conglomerates were deposited in streams flowing through the

loess deposits. Johnson (1989) described a contemporaneous

depositional system in the Pennsylvanian to Permian Maroon

Formation in the Eagle Basin, on the north side of the

Uncompahgre uplift, that may be similar to that of the lower

Cutler in this area. The paleontological data cited by Vaughn

(1973) suggests a drying trend through the Cutler of this area,

but the fauna and flora of the Halgaito indicate wetter conditions than those that followed in the upper Cutler.

CORRELATIONS

Baars (1962, 1987) stated that the Elephant Canyon Formation (lower Cutler beds of this report) grades southward

from Cataract Canyon into the Cedar Mesa Sandstone and

Halgaito Formation. An issue not addressed, however, is the

relationship of strata mapped as Rico in Cataract Canyon

(Lewis and Campbell, 1965) to the Rico of the San Juan

River canyon area. Baars (1962, p. 172) assigned the San

Juan River Rico to the Hermosa, thus recognizing a simple

gradation of the Elephant Canyon into the Halgaito.

Examination of strata in both places and at other localities on the Monument upwarp has led me to somewhat different conclusions. In comparing lithologies, thicknesses, and

the relationship of the lower Cutler to the Cedar Mesa Sandstone, I believe that the Rico of the San Juan River area correlates with the lower Cutler of Dark Canyon, Cataract

Canyon, and Arch Canyon, which is just west of Bluff, Utah.

The Halgaito grades northward into the Cedar Mesa, or may

have been locally eroded, and is equivalent to a portion of the

lower Cutler beds in areas north and west of the Confluence

where the Cedar Mesa grades laterally into these beds (Baars,

1987). The Halgaito is absent in Arch, Dark, and Gypsum

Canyons and over a large part of the Monument upwarp in

the subsurface. Gregory (1938) noted local erosion and conglomerates at the base of the Cedar Mesa Sandstone in sections he examined in the Monument upwarp area, suggesting

an unconformable relationship. My stratigraphic studies support the idea of a local unconformity there, indicating that the

upwarp may have been a positive feature during or shortly

after deposition of the Halgaito. These relationships are

shown in figure 11. On the basis of these correlations, the

Halgaito is included in the lower Cutler beds as used in this

report.

This idea is not without precedent. Although they were

working with limited outcrops and no subsurface data, Baker

and Reeside (1929, p. 1423) showed a northward gradation

of the Halgaito into the Cedar Mesa Sandstone. Plates 4 and

5 show this relationship in plan view. On plate 4, the lower

Cutler is thick in the San Juan River area, thins northward

over the Monument upwarp, and thickens again northwest of

the Colorado River. Plate 5 shows the thickest area of Cedar

Mesa Sandstone in the Hite area where the lower Cutler is

thin. Baars (1962, p. 169) noted that the Halgaito also grades

into the Cedar Mesa west of the Monument upwarp.

In the subsurface, the lower Cutler beds (Halgaito and

Rico) can be traced eastward from the Mexican Hat area as a

distinct unit above the Hermosa and below the Cedar Mesa

Sandstone and equivalent beds (pl. 4). Thick limestones of

the Rico eventually grade into red beds, in a manner similar

to that shown on figure 4. This gradation to red beds occurs

at about the Utah-Colorado State line. However, an important characteristic of the red bed interval in southwestern

Colorado, northwestern New Mexico, and northeastern

Arizona is the presence of abundant thin limestone beds. This

interval was mapped as Halgaito Formation by Huffman and

Condon (1993). In southwestern Colorado, the limestone

beds pinch out in the easternmost wells, but, in New Mexico,

limestone beds are abundant in the wells along the San Juan
Figure 11. North-south-oriented cross section extending from the General Petroleum 45-5-G well, just east of the San Rafael Swell, to outcrops alon

Mexican Hat, Utah. Location of the cross section is shown on plate 1; well numbers and outcrop number above well logs correspond to numbers on pl2. Relationships show that the Halgaito Formation grades laterally into the lower part of the Cedar Mesa Sandstone north of the San Juan River. The Cutler beds northwest of the confluence of the Green and Colorado Rivers. Lower Cutler beds include strata previously included in the Rico Formation oin the north and Rico Formation or Halgaito Formation in the south. The numbers at the top of the Hermosa Group are top measured depths from the 
P20 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

River northwest of Farmington. The southernmost well in the

New Mexico data set is the only one in this area that does not

contain limestone beds. Several of the holes in northeastern

Arizona also contain limestone beds in the lower Cutler interval, suggesting a southeast-oriented depression in the Four

Corners area in which limestones, probably of pedogenic origin, accumulated. This area also remained low during the

subsequent deposition of the gypsiferous facies of the Cedar

Mesa Sandstone.

Southwest and west of the Paradox Basin the lower Cutler grades into the Pakoon Limestone or Oquirrh Group,

respectively (Johnson and others, 1992). These rocks were

deposited in a variety of shallow- to deep-marine environments and do not show evidence of being affected by the Cutler depositional system that was tied to the Uncompahgre

highlands.

AGE

Sanderson and Verville (1990) demonstrated, and Baars

(1991) agreed, that the lower part of Baars’ (1962) Elephant

Canyon Formation is Virgilian in age. The General Petroleum 45-5-G well that was the subject of Sanderson and Verville’s (1990) study is shown on figure 4 (well no. 22). Note

that on figure 4 some strata assigned to the Elephant Canyon

by Baars (1987) in this well are included in the Honaker Trail

Formation in this report. The pick for the Honaker Trail in

this and adjacent wells is based on data from the Rocky

Mountain Geological Databases data set. As shown on figure

4, the lower part of the lower Cutler beds is Virgilian in age

and the upper part is Wolfcampian. The Virgilian carbonates

can be traced to the southeast to a point just southeast of the

Colorado River, where they grade into red beds. Southeast of

this pinch-out, strata of the lower Cutler and the Cutler Formation, undivided, are also Virgilian and Wolfcampian in

age, but the thickness of Virgilian strata is uncertain because

of a lack of marine fossil-bearing limestones. Data from

Franczyk and others (1995) suggest that the base of the Cutler is probably Missourian, and possibly as old as Desmoinsian, along the Uncompahgre Plateau. The PennsylvanianPermian boundary is also shown on figure 11, which extends

from the General Petroleum 45-5-G well southward to the

San Juan River. The correlations suggest that the boundary is

within strata traditionally assigned to the Rico in the San

Juan River area.

Deposition of the lower Cutler beds in the Paradox

Basin records the filling of the basin in the Late Pennsylvanian to Early Permian. This process proceeded from east to

west and north to south, with clastic rocks derived from the

Uncompahgre highlands displacing marine waters. Intermittent transgressive pulses deposited marine limestones within

a mainly red-bed sequence. A marine embayment persisted

in the northwest part of the basin through most or all of the

Wolfcampian, and red beds of the lower Cutler grade into

this marine sequence. The lobate pattern of thick and thin

areas of much of the lower Cutler (pl. 4) supports an interpretation of deposition on shifting delta depocenters. Strata of

the Halgaito Formation, which was only recognized in outcrop in a small area of southeastern Utah, may be more

closely related to eolian processes.

CEDAR MESA SANDSTONE

The Cedar Mesa Sandstone is a thick, largely eolian

sandstone that was named for a mesa adjoining the San Juan

River in the Mexican Hat, Utah, area (fig. 9). The Cedar

Mesa is exposed over extensive areas in the southwestern

Paradox Basin along the Colorado River and on the Monument upwarp. It grades northeastward into the undivided

Cutler Formation and northwestward into carbonates of the

lower Cutler (Elephant Canyon of Baars, 1987). Southeast of

the Monument upwarp, the Cedar Mesa undergoes a facies

change to interbedded sandstone, shale and siltstone, limestone, and anhydrite or gypsum. This facies was correlated

southeastward into the San Juan Basin by Huffman and Condon (1993). Southwestward, the Cedar Mesa grades into the

Esplanade Sandstone, which in turn grades westward into the

Pakoon Limestone and Queantoweap Sandstone (Blakey,

1979, 1990). The Cedar Mesa is thickest in the southwest

part of the study area, where it is 1,330 ft thick in one well; it

is 1,000 ft thick or thicker in a large area just west of the

Monument upwarp (pl. 5). Due to gradation of one unit into

the other, the Cedar Mesa is thickest where the lower Cutler

beds are thin. The Cedar Mesa has been discussed in reports

by Baker (1936, 1946), Sears (1956), Mullens (1960), Baars

(1962), Witkind and Thaden (1963), Lewis and Campbell

(1965), O’Sullivan (1965), Chamberlain and Baer (1973),

Mack (1977), Loope (1984, 1985), Langford and Chan

(1988, 1989, 1993), Stanesco and Campbell (1989), and

Lockley and Madsen (1993).

The Cedar Mesa Sandstone consists of several interbedded lithofacies that vary in abundance geographically. The

main lithology is light gray to yellowish gray, fine- to coarsegrained, cross-bedded and flat-bedded, quartzose sandstone.

Cross-bedded cosets display small- to large-scale trough and

tabular-planar cross-bedding. The size of cross-bed sets and

the grain size of the sandstone decreases from northwest to

southeast (Langford and Chan, 1993), and sand-sized marine

fossil fragments decrease from west to east (Stanesco and

Campbell, 1989). Eolian transport directions, interpreted

from foreset dip orientations, are mainly to the southeast

(Mack, 1977; Loope, 1984; Stanesco and Campbell, 1989).

Inversely graded laminae, sand-flow toes, contorted strata,

and rhizolith zones are components of the cross-bedded

sandstone (Loope, 1984; Stanesco and Campbell, 1989).

Flat-bedded cosets consist of thinly bedded, horizontal

to low-angle laminae and small-scale trough sets. A related

facies consists of mottled and bioturbated sandstones that
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P21

display poor stratification and nodules of limestone. These

were interpreted as paleosols by Loope (1980) and Stanesco

and Campbell (1989). Figure 8 shows the characteristic geophysical log response of the Cedar Mesa sandstone facies.

In some areas, siltstone or mudstone beds are common

features of the Cedar Mesa (fig. 12). Siltstone and mudstone

occur mainly around the periphery of the thickest area of

Cedar Mesa (pl. 5). Some siltstone and mudstone beds are

associated with fluvial strata of the undivided Cutler that

interfinger with the Cedar Mesa along its northeast boundary. Other siltstone and mudstone beds are thin and lenticular

and grade laterally into cross-bedded or flat-bedded eolian

strata. Root casts and mud cracks are present in these beds,

which were deposited in interdune areas.

Limestone beds are also associated with the Cedar

Mesa in some areas. In the Gypsum Canyon area, marine

limestone beds of the lower Cutler are interbedded with

sandstones of the Cedar Mesa at a gradational contact (fig.

13). This type of gradational contact is common in the area

northeast of Comb Wash and north of the San Juan River in

the subsurface of the Paradox Basin (pl. 5). In this area,

placement of the contact is somewhat arbitrary and depends

on the proportions of sandstone, siltstone or shale, and limestone. Intervals consisting of mainly sandstone and a few

limestones were included in the Cedar Mesa. In wells having

relatively little sandstone and abundant limestone, the lithofacies were assigned to the lower Cutler.

Other limestone beds are present within the main body

of the Cedar Mesa and are associated with siltstone or mudstone and flat-bedded sandstone beds. These limestones are

sandy, thin, and lenticular. One limestone bed that I examined on the Monument upwarp was overlain by thick paleosols. The depositional setting of these limestone beds

suggests deposition in interdune ponds.

Common features of the Cedar Mesa are laterally extensive bedding-plane surfaces that separate cross-bed cosets

and flat-bedded sand-sheet strata or paleosols (figs. 9, 12).

These surfaces have been related to deflation by wind to the

ground-water table (Stokes, 1968; Loope, 1985) or to flooding by adjacent streams (Langford and Chan, 1988, 1993).

Some surfaces can be traced for many miles along the outcrop.

The interpreted environment of deposition of the Cedar

Mesa has been the subject of much discussion. Baker’s

(1946) initial interpretation of it as an eolian deposit was

questioned by Baars (1962), who favored a marine origin.

Features such as low- to moderate-angle cross-bedding, thin,

horizontal sandstone beds, nature of ripple marks, numerous

horizontal bedding planes, and occurrence of shale and limestone beds suggested a marginal marine to beach or “littoral”

environment to Baars (1962). This interpretation was supported, in part, by Mack (1977, 1978, 1979), but Mack recognized a significant eolian component in the upper part of

the Cedar Mesa. Campbell (1979) and Campbell and SteeleMallory (1979) also recognized marine and eolian rocks in

strata equivalent to the Cedar Mesa. Chamberlain and Baer

(1973) reported on Thalassinid decapod burrows from

uppermost beds of the Cedar Mesa that are considered indicators of a marine environment.

On the basis of wind-ripple stratification, numerous

rhizolith zones, consistent transport orientations, lack of

marine macrofossils, and the presence of vertebrate trackways, Loope (1981, 1984) interpreted virtually all the crossbedded sandstone facies of the Cedar Mesa as eolian.

Loope’s arguments have been supported by Campbell

(1986), Chan and Langford (1987), Langford and Kamola

(1987), Blakey and others (1988), Langford and Chan (1988,

1989, 1993), Stanesco and Campbell (1989), and Langford

and others (1990), who discussed the Cedar Mesa as an

eolian deposit. Lockley and Madsen (1993) reported additional examples of vertebrate trackways in the Cedar Mesa

that support a nonmarine interpretation.

These recent studies have documented eolian sedimentary features in the Cedar Mesa that make it likely that much

of the formation is eolian in origin. However, on the edges of

the dune field, other depositional environments exerted a

greater influence. The Cedar Mesa grades northwestward

into carbonate-bearing beds of the lower Cutler, and the percentage of marine fossil fragments in the Cedar Mesa

increases northwestward. The source of these fossil fragments and quartz sand was most likely carbonate and siliciclastic beds that were exposed during drops in sea level or

that were moved onshore during storm events. Chan and

Kocurek (1988) discussed mechanisms of sediment transport

in marine-influenced eolian depositional systems. Strong

north-northwesterly winds (Peterson, 1988; Parrish and

Peterson, 1988) moved the sediments southeastward.

The northeast side of the Cedar Mesa erg was influenced by fluvial systems draining westward and southwestward from the Uncompahgre highlands. There is a broad

northwest-oriented zone of interbedded fluvial and eolian

rocks that extends from about the Confluence to the Shafer

dome area; isolated eolian deposits are present even farther

to the northeast. Fluvial deposits and processes of fluvialeolian interactions have been discussed by Mack (1977),

Langford and Chan (1988, 1989), and Stanesco and Campbell (1989). Repeated flooding of the edge of the dune field

created numerous horizontal bedding planes (“flood surfaces”), wet interdunes, and channel and flood-plain

deposits.

Southeast of the Monument upwarp, the Cedar Mesa

undergoes an abrupt facies change to thin eolian sandstone

beds, light pink to gray shale beds, thin limestone beds, and

massive gypsum or anhydrite (Sears, 1956; O’Sullivan,

1965; Stanesco and Campbell, 1989). This facies was

recognized by Baars (1962), but was considered to be part of

an undifferentiated lower Cutler interval. Huffman and Condon (1993) and Condon and Huffman (1994) correlated the

Cedar Mesa and its equivalent gypsiferous facies southeastward into the San Juan Basin on the basis of geophysical log
P22 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

Figure 12. Interbedded sandstone, silty sandstone, and siltstone of the Cedar Mesa Sandstone just

south of the confluence of the Green and Colorado Rivers. Light-colored sandstone is eolian; dark

silty sandstone and siltstone were deposited in both eolian and fluvial environments. Thin limestone

at base of exposure (in the trees) is the top limestone of the lower Cutler beds.

Figure 13. Cedar Mesa Sandstone (at top) and lower Cutler beds in Gypsum Canyon, just east of

the Colorado River. Note transition zone at top of lower cliff where limestone beds are interbedded

with light-colored Cedar Mesa beds. This is an example of the Cedar Mesa grading northward into

the lower Cutler beds sequence. This relationship is shown diagrammatically on figure 11.
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P23

responses. The unit is mappable as a discrete unit over much

of the northwestern San Juan Basin. Stanesco and Campbell

(1989) interpreted this facies as a coastal sabkha on the basis

of sulfur-, carbon-, and oxygen-isotope analyses of gypsum

and limestone samples. The gypsiferous facies thins southeastward (pl. 5) as a result of gradation into the lower Cutler

beds (pl. 4), in a manner similar to that shown diagrammatically on figure 11. This relationship suggests that there may

have been a connection to a marine environment around the

south margin of the main Cedar Mesa erg.

ORGAN ROCK FORMATION

The Organ Rock Formation is a red bed unit of the Cutler that is similar in many respects to the lower Cutler beds.

It crops out around the edges of the Monument upwarp, in

canyons incising Elk Ridge, and in a narrow band along the

Colorado River, mainly below the Confluence. In some

places in Monument Valley and near the Confluence, outliers of Organ Rock form monuments and spires. The Organ

Rock is conformable with the underlying Cedar Mesa Sandstone and the overlying White Rim and De Chelly Sandstones where those units are present. Where the White Rim

or De Chelly are absent, the Organ Rock is overlain unconformably by the Moenkopi or Chinle Formations. The northernmost outcrops of the unit on the east side of the Colorado

River were originally referred to as the “Bogus tongue” of

the Cutler by Baker (1933).

Aside from the descriptive reports of Baker (1933,

1936, 1946), Gregory (1938), Sears (1956), Mullens (1960),

Witkind and Thaden (1963), Lewis and Campbell (1965),

and O’Sullivan (1965), there have been few studies of the

Organ Rock. Baars (1962) mapped the Organ Rock in the

subsurface and discussed its regional correlations. Stanesco

and Dubiel (1992); Dubiel, Huntoon, Condon, and Stanesco

(1996); and Dubiel, Huntoon, Stanesco, and others (1996)

reported on preliminary work concerning environments of

deposition of the Organ Rock.

The Organ Rock is composed of reddish-brown to lightred, sandy siltstone; silty sandstone; mudstone; and limestone-nodule conglomerate. Alternating resistant and nonresistant beds give the formation a horizontally banded

appearance (fig. 14). The geophysical log response of the

Organ Rock contrasts with the underlying Cedar Mesa

Sandstone (fig. 8) and the overlying White Rim Sandstone

(fig. 15). In many exposures, the lower part of the Organ

Rock is less sandy than the upper part and forms a broad

slope at the base of overlying cliffs. Exposures of this lower

part near Hite, Utah, contain sandy beds of clay-chip

conglomerate. Most strata in the lower part display few sedimentary structures, although ripple marks were observed in

some units. Root structures, raindrop impressions, adhesion

ripples, cut-and-fill structures, low-angle cross-beds, and

mud cracks are also present in some areas (J.E. Huntoon,

written commun., 1995). The Organ Rock intertongues

northeastward with purple arkose beds of the undivided Cutler (figs. 3A–3D). In the Paradox Basin, the Organ Rock

ranges from 0 to 830 ft thick (pl. 6). Thickest areas are in

southwestern Colorado and in the southeastern corner of

Utah. Thinnest areas are (1) just east of Hite, and (2) on the

San Rafael Swell where the Organ Rock pinches out

between the White Rim Sandstone and the lower Cutler beds

(fig. 3A). Abrupt changes in thickness along the Utah-Arizona State line may result from intertonging with either the

Cedar Mesa or De Chelly Sandstones. Although difficult to

document, internal unconformities may also account for

thinning of the Organ Rock in some areas.

The Organ Rock was deposited in a variety of depositional environments. Stanesco and Dubiel (1992) noted

mainly fluvial strata and some eolian strata in the Monument

Valley area northwest of Kayenta, Ariz., and southwest of

Mexican Hat, Utah. In the northern area of exposures, near

the Confluence, Stanesco and Dubiel (1992) interpreted the

Organ Rock as dominantly eolian. In the Hite area, a thick,

salmon-colored eolian bed is present at about the middle of

the Organ Rock (fig. 14). This unit displays small- to largescale, moderate- to high-angle cross-beds. The top of this

unit is highly bioturbated by plant rhizoliths similar to those

described from the Cedar Mesa Sandstone by Loope (1984,

1988).

Plant and animal remains have been recovered from the

Organ Rock, mainly in the Monument Valley area, and also

from areas north of the San Juan River. Most fossils have

been recovered from fluvial channel and associated overbank deposits. Mamay and Breed (1970) described ferns,

pteridosperms, and a possible conifer from a siltstone bed in

Monument Valley. The vertebrate fauna includes fish,

amphibians, and reptiles, similar to the assemblage present

in the Halgaito, but it lacks evidence of freshwater sharks or

rhipidistian fish (Vaughn, 1973). Upward changes in fauna

and flora from the Halgaito to the Organ Rock were interpreted by Vaughn (1973) to indicate increasingly arid conditions.

WHITE RIM SANDSTONE

The White Rim Sandstone is a largely eolian blanket

sandstone that is present mainly west of the Colorado River

(pl. 7) and is an easily identifiable unit on geophysical logs

(fig. 15). It forms a highly visible white band along canyon

rims; overlying strata are commonly weathered back from

the rims, leaving a broad bench on top of the White Rim

(fig. 16). The White Rim can be observed to thin to an erosional pinch-out in outcrops west of Moab, at Dead Horse
P24 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

Figure 14. Organ Rock Formation just east of Hite, Utah. Light-colored sandstone at road level is

the Cedar Mesa Sandstone. The White Rim Sandstone forms a light-colored cliff near the top of the

outcrop. The Moenkopi Formation is at the top of the cliff. The lower part of the Organ Rock is finer

grained than the upper part and weathers to a slope. The light sandstone in the middle of the Organ

Rock is an eolian bed containing calcareous rhizoliths on its upper surface.

Point, and east of Hite, in White Canyon. It is also absent

along part of the outcrop just southwest of the Confluence.

It is conformably underlain by the Organ Rock Formation

or the undivided Cutler Formation except in the northwestern part of the study area (fig. 3A), where carbonates of the

lower Cutler beds underlie it (Baars, 1987). In some places,

the Permian Kaibab Limestone conformably overlies or

grades into the White Rim; where the Kaibab is absent, the

Lower to Middle Triassic Moenkopi Formation unconformably overlies the White Rim.

Many detailed stratigraphic and sedimentologic studies have been conducted on the White Rim, beginning with

Emery (1918), Gilluly and Reeside (1928), Gilluly (1929),

McKnight (1940), and Baker (1946). Other studies include

Baars (1962), Baars and Seager (1970), Irwin (1971,

1976), Orgill (1971), Mitchell (1985), Huntoon and Chan

(1987), Steele (1987), Kamola and Chan (1988), and Chan

(1989). Studies relating to the Permian-Triassic unconformity in the Paradox Basin include those by Ochs and Chan

(1990) and Huntoon and others (1994).

In typical exposures, the White Rim consists of cliffforming, grayish-white to white, fine- to coarse-grained

sandstone displaying large-scale, high-angle cross-beds and

flat beds. A major component of the White Rim is an eolian

dune facies (Huntoon and Chan, 1987; Steele, 1987; Kamola

and Chan, 1988; Chan, 1989). This facies displays highangle cross-beds, high-index wind-ripple laminae, grainflow

and grainfall strata, and inversely graded laminae, which

together are indicative of an eolian environment. Transport

directions were to the southeast (Steele, 1987) and southsouthwest (Kamola and Chan, 1988).

Associated with the dune facies, and most fully developed at the base of the formation in the Island in the Sky district of Canyonlands, is a flat-bedded sandstone that contains

algal laminations, wind-ripple strata and small-scale crossbeds, bioturbated intervals, breccia layers, adhesion ripples,

and desiccation polygons (McKnight, 1940; Steele, 1987;

Chan, 1989). This interval was interpreted as a sand sheet or

sabkha deposit that was deposited prior to and downwind of

the main dune field of the White Rim erg (Chan, 1989). Other

thinner flat-bedded intervals are present within the dune

facies.

In the Elaterite Basin area, west-southwest of the Confluence, and in parts of the San Rafael Swell, the upper part

of the White Rim has a veneer of reworked strata. In Elaterite

Basin, this unit consists of 2 to 16 ft of very fine grained to

fine-grained sandstone displaying small, low-angle crossbeds, symmetrical ripple marks, fluid escape structures, ripup clasts of the lower dune facies, chert pebbles, and large

polygonal structures (Baars and Seager, 1970; Huntoon and

Chan, 1987). In the San Rafael Swell, a similar sequence is

5–35 ft thick and is a mix of poorly cemented sandstone and

siltstone beds interbedded with calcareous siltstone, mudstone, and carbonate beds. Ophiomorpha burrows were

noted in this area (Orgill, 1971). Orgill (1971) documented

onlapping relations of the overlying and partially equivalent
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P25

Kaibab Limestone with the White Rim, and Huntoon and

Chan (1987) described wave-cut terraces on the flanks of a

dune, indicating that there is preserved dune topography at

the upper surface of the White Rim. Baars and Seager (1970)

interpreted all of the White Rim as a marine deposit, but subsequent studies indicate that only the upper reworked part

has a marine origin. A similar reworked facies was described

by Davidson (1967) in the Circle Cliffs area southwest of the

Paradox Basin.

West of the Paradox Basin, the White Rim is interbedded with the Kaibab Limestone and displays abundant deformation features such as convolute bedding, microfaulting,

brecciation, and sandstone dikes (Kamola and Chan, 1988).

Concentrations of Thalassinoides and Chondrites burrows,

indicating subaqueous (possibly marine) conditions, are

present in some interbeds. Kamola and Chan interpreted the

White Rim as a coastal dune field that was intermittently

flooded by marine water. Steele (1987) reported glauconite

throughout the White Rim, which supports this

interpretation.

Although the White Rim thickens on the west side of

the study area (pl. 7), it thins farther to the west and south

(Mitchell, 1985). Irwin (1971, 1976) indicated that lower

part of the White Rim is an eastern equivalent of the marine

Toroweap Formation of northern Arizona. Rawson and

Turner-Peterson (1979) described the facies relationships of

the Toroweap. The upper, reworked, part of the White Rim

was correlated by Irwin (1971, 1976) with the Gamma member (basal part) of the Kaibab Limestone.

The White Rim has attracted interest as an economic

unit because of accumulations of hydrocarbons. The Elaterite Basin, in particular, has concentrations of tar sands that

seep tar in the heat of summer (fig. 17). The dune topography

preserved at the top of the White Rim is important because

hydrocarbons were trapped in these high areas below the

finer grained Moenkopi Formation.

DE CHELLY SANDSTONE

The De Chelly Sandstone is a massive-weathering,

cross-bedded eolian sandstone that is only present in the

southern part of the Paradox Basin (pl. 8). The De Chelly

crops out in Monument Valley, where it forms the upper

cliffs of the monuments (fig. 18), and along the western and

eastern margins of the Monument upwarp. Figure 19 shows

the log response of the De Chelly in the subsurface. It was

named for exposures in Canyon de Chelly, which is at the

southern margin of the study area, east of Chinle (pl. 8).

Descriptions of the De Chelly are in Baker (1936), Gregory

(1938), Sears (1956), Strobell (1956), Mullens (1960), Read

and Wanek (1961), Baars (1962), Witkind and Thaden

(1963), O’Sullivan (1965), Peirce (1967), Irwin (1971), and

Stanesco (1991).

As typically exposed, the De Chelly consists of pinkishbrown, light-orange, tan, and gray, very fine grained to

medium-grained, bimodally sorted, quartz sandstone. Many

of the quartz grains are coated with red iron oxide, giving the

formation its red hue. Some beds are silty, which gives the

formation a banded appearance in some exposures. Vaughn

(1973) noted the presence of abundant vertebrate trackways

in the De Chelly; this contrasts with the White Rim Sandstone, which, despite having been extensively studied, does

not have any reported trackways.

The De Chelly conformably overlies the Organ Rock

Formation and has been divided into two or more parts

(Read and Wanek, 1961; Peirce, 1967; Stanesco, 1991).

The lower part contains small- to large-scale, high-angle

cross-beds, parallel- and wavy-bedded sandstone, and

minor mud-draped, ripple-laminated sandstone (Stanesco,

1991). Paleocurrents were mainly to the southeast in the

lower part of the De Chelly (Read and Wanek, 1961;

Stanesco, 1991). The upper part contains mainly small- to

large-scale cross-beds that display dip vectors mainly to

the southwest (Read and Wanek, 1961; Stanesco, 1991).

Figure 15. Well log showing the lower part of the Moenkopi

Formation, Kaibab Limestone, White Rim Sandstone, Organ Rock

Formation, and the top of the Cedar Mesa Sandstone in the Henry

Basin on the west side of the study area. Well is number 85, plate

1 and Appendix 1. Log curves are gamma ray on the left and neutron on the right. Vertical scale is in feet.
P26 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

The De Chelly attains a maximum thickness of 750 ft

in the study area, increasing from north to south (pl. 8).

Pinch-outs, caused by erosional truncation, have been

noted in outcrop at the San Juan River (Baker, 1936; Mullens, 1960) and along Comb Wash (Sears, 1956; O’Sullivan, 1965). In addition to exposures on the Monument

upwarp and in Canyon de Chelly, the De Chelly crops out

in the Carrizo Mountains (Strobell, 1956) within the study

area. The De Chelly is unconformably overlain by either

the Moenkopi or Chinle Formations and grades northeastward into the undivided Cutler Formation. South of the

study area, the De Chelly and equivalent rocks are overlain

by the Permian San Andres Limestone, which may be

time-equivalent to the Kaibab Limestone (Baars, 1979;

Blakey, 1990). Blakey and Knepp (1989) and Blakey

(1990) indicated that the De Chelly grades southwestward

into the Coconino Sandstone and Schnebly Hill Formation

in Arizona.

Stanesco (1991) studied the relationships of cross-bedded and flat-bedded facies of the De Chelly on the Defiance

uplift and determined that it was deposited in eolian-dune,

sand-sheet, sabkha, and mud-flat environments. From Canyon de Chelly northward, the lower part of the De Chelly is

composed dominantly of large dunes of the central eolian

erg; southward on the Defiance uplift, sand sheets, sabkha,

and mud-flat environments dominate. The upper De Chelly

is composed mainly of large dunes deposited in the central

erg. A tongue of the Supai Formation, consisting of sabkha

and mud-flat deposits, divides the upper and lower parts just

south of the study area. Alternating facies indicate at least 12

transgressive-regressive cycles within the De Chelly

(Stanesco, 1991).

Irwin (1971) and Blakey (1979) suggested that the De

Chelly was related to sedimentation in the QuemadoCuchillo or Holbrook Basins in west-central New Mexico or

east-central Arizona, and the stratigraphic and facies relationships noted by Stanesco (1991) bear this out. The De

Chelly erg was built up by southwest- and southeast-blowing

winds and was influenced by intermittent marine transgressions from the south.

Because of their stratigraphic position above the Organ

Rock Formation, the De Chelly and White Rim Sandstones

have commonly been assumed to be of the same age (Baars,

1962). However, Blakey and Knepp (1989) and Blakey

(1990) interpreted the De Chelly as equivalent to the

Coconino Sandstone, and Irwin (1971) correlated the White

Rim with the younger Toroweap and Kaibab formations. If

this age disparity is correct, this suggests that there must be

currently unrecognized unconformities within the Organ

Rock or between the White Rim and the Organ Rock that are

not present in the southern part of the area where the De

Chelly crops out.

Figure 16. White Rim Sandstone, Organ Rock Formation, and top of Cedar Mesa Sandstone just

southwest of the confluence of the Green and Colorado Rivers. The White Rim forms a broad bench

and cliff at the top of the Organ Rock. The Cedar Mesa Sandstone undergoes a visible facies change

here from interbedded light sandstone and dark siltstone beds in foreground to red beds in the

distance.
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P27

KAIBAB LIMESTONE

The Kaibab Limestone is only present as a thin veneer

of limestone and dolomite in the western part of the

Paradox Basin (pl. 9). It is irregularly distributed at the surface and in the subsurface, due to both onlapping relationships with the underlying White Rim Sandstone and to

erosion at the pre-Triassic unconformity at its top. The

Kaibab does not crop out anywhere within the Paradox

Basin; scattered outcrops are exposed on the San Rafael

Swell. As such, the unit has not received much study in the

areas pertinent to this report. Studies of the unit include

those by Gilluly and Reeside (1928), Gilluly (1929), Baker

(1946), Davidson (1967), Irwin (1971, 1976), Orgill

(1971), Kiser (1976), and Mitchell (1985). Welsh and others (1979) proposed the name “Black Box Dolomite” as a

replacement for the Kaibab in part of the area discussed in

this report. This name was also used by Sprinkel (1994),

but not by Franczyk (1991).

In the San Rafael Swell, the Kaibab consists of gray,

buff, brown, and yellowish-brown dolomite and

interbedded limestone. The carbonate beds are commonly

sandy, vuggy, and very fossiliferous, including coquina

beds (Gilluly, 1929). Geodes lined with quartz and calcite

crystals and containing dead oil residues are common features. Where present on the east side of the swell, the

Kaibab forms dip slopes where the overlying Moenkopi

Formation has been stripped away. Baker (1946) noted a

west-to-east gradation of the Kaibab into the White Rim

Sandstone, with the upper parts of the Kaibab extending

farthest to the east. In the study area, the Kaibab ranges

from 0 to 140 ft thick (pl. 9).

The Kaibab is also present in the Circle Cliffs uplift

area (fig. 2) where it consists of thinly bedded, light-yellow

dolomite. In that area, Davidson (1967) noted oolites; thin

layers of green, glauconitic sandstone; and abundant moldic

porosity. Geodes and stringers of bedded chert, and gray

chert nodules are also present in that area. The upper part of

the White Rim Sandstone there contains thin beds of fossiliferous dolomite, indicating a transgressive marine environment transitional to the Kaibab.

Irwin (1971, 1976) interpreted the Kaibab of this area as

a shallow marine shelf deposit that represents the time of

maximum eastward transgression of the Kaibab sea. Orgill

(1971) thought that the Kaibab of the San Rafael Swell was

deposited in a shallow, narrow marine embayment on a surface having marked topography. Orgill (1971) documented

onlapping relationships of Kaibab carbonate beds onto

knolls of White Rim Sandstone. He interpreted interbedded

sandstone beds in the Kaibab as resulting from reworking of

White Rim sandstones. Irwin (1971, 1976) and Kiser (1976)

noted that there are petroleum shows in wells penetrating the

Kaibab throughout the Colorado Plateau, making it a potentially important economic unit.

OVERLYING ROCKS

Triassic rocks unconformably overlie the Kaibab Limestone or the Cutler throughout the Paradox Basin. In most of

southeastern Utah, the Moenkopi Formation is the basal Triassic unit. The lowest member of the Moenkopi, the Hoskinnini, was originally considered as the upper part of the Cutler

by Baker and Reeside (1929). In most of the Colorado part

of the basin, the Chinle Formation or correlative Dolores

Formation overlies the Cutler. In many parts of the western

Paradox Basin, the unconformity is marked by a chert-pebble conglomerate (Gilluly and Reeside, 1928; Baker, 1946;

Thaden and others, 1964). This conglomerate fills channels

cut into the top of the underlying Permian strata. Huntoon

and others (1994) measured cross-bedding in the conglomerate and determined that flow was to the east from an area

centered in the Circle Cliffs uplift area. This flow was in

marked contrast to the west- and northwest-dipping

paleoslope prevalent during Cutler time and during later

Figure 17. Tar seep from the White Rim Sandstone in Elaterite

Basin, southwest of the confluence of the Green and Colorado
P28 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

deposition of the upper part of the Moenkopi and the Chinle

Formations.

PALEOGEOGRAPHY

The Cutler Group records the filling of the depositional basin that had first developed in the Middle Pennsylvanian. Deposition during the Pennsylvanian had been

largely restricted to the area of the Paradox Basin, which

was bounded on the northeast by the Uncompahgre uplift,

on the south by the Zuni-Defiance uplift and Kaibab arch,

and on the west by the Emery uplift or Piute platform (fig.

20). During the Early Permian the southern and western

bounding structures had less effect, and sedimentation in

the Paradox Basin had more direct interaction with shelf

areas to the south and west.

The driving mechanisms for late Paleozoic deformation in the area of the Paradox Basin are not well constrained and were discussed in detail by Johnson and

others (1992) and Huffman and Condon (1993). To summarize, Early Permian sedimentation in the Paradox Basin

was dominated by the influence of the Uncompahgre highland, which was a westward-directed thrust block on the

northeast side of the basin (fig. 20). White and Jacobson

(1983) and Heyman (1983) identified many faults bounding the southwestern side of the Uncompahgre uplift, ranging from high-angle normal to high-angle reverse faults.

Frahme and Vaughn (1983) estimated at least 6 mi of horizontal and 20,000 ft of vertical displacement on one of

these faults.

The Uncompahgre highland itself is probably a result

of northwestward-directed compression, possibly

expressed as strike-slip movement, on a continental scale

(Stevenson and Baars, 1986). Compression is thought to

have resulted from collision of the Gondwana plate and a

northern plate (fig. 20), variously called Euramerica, Laurasia, or Laurentia (Ross and Ross, 1986; Johnson and others, 1992; Huffman and Condon, 1993). Johnson and

others (1992) also suggested that the geometry of the

Uncompahgre uplift may have been influenced by a leftlateral transform fault that may have bounded the western

continental margin.

Within this structural framework, clastics were shed

from the Uncompahgre highland westward into the Paradox

Basin since the Middle Pennsylvanian (Wengerd and

Matheny, 1958; Franczyk and others, 1995). Sedimentation

seems to have been continuous in that area throughout deposition of the Hermosa and Cutler, making the pick between

units indefinite in places. Due to abundant arkosic clastics

in the Hermosa Group, the composition of clastic rocks cannot be used as a criteria for separating the units. Franczyk

(1992) and Franczyk and others (1995) noted that the

boundary between the Hermosa and Cutler is gradational in

the Durango, Colo., area. They placed the contact at the top

of the highest carbonate bed of probable marine origin,

which is also at the color change from gray and green beds

to red beds. The youngest Hermosa strata in that area are

Desmoinsian in age, suggesting that the age of the Cutler is

Figure 18. De Chelly Sandstone underlain by the Organ Rock Formation and overlain by the

Moenkopi Formation at Monument Valley.
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P29

no younger than Missourian, and possibly Desmoinsian,

there.

In much of the central Paradox Basin, the contact

between the Hermosa and Cutler is also made at the highest

marine carbonate bed (fig. 4). However, along the western

side of the basin, marine carbonates formerly included in

the Rico Formation or Elephant Canyon Formation interfinger with red beds and are included in the lower part of the

Cutler. These strata range in age from Virgilian to Wolfcampian (Baars, 1962, 1991; Sanderson and Verville,

1990). Initiation of Cutler deposition thus possibly began as

early as Middle Pennsylvanian (Desmoinsian) in alluvial

fans and debris flows along the margin of the Uncompahgre

highlands. These alluvial sediments graded westward into

marine strata of Virgilian and Wolfcampian age in northern

Arizona and central Utah in marginal marine to deltaic

environments.

Figure 21 shows the paleogeography of the Paradox

Basin in Early Permian (Wolfcampian) time. At this time,

the basin was situated just north of the Equator and was

rotated as much as 45° clockwise from its present position. Prevailing winds blew from northeast to southwest

(present-day coordinates), but there was a significant

southeastward component (Parrish and Peterson, 1988;

Peterson, 1988), possibly caused by an eddy effect around

the north end of the Uncompahgre highlands. Streams still

drained the Uncompahgre, flowing to the west-northwest

and southwest, while Wolfcampian carbonates and clastics were being deposited off the northwestern end of the

Paradox Basin. A large coastal dune field (Cedar Mesa

Sandstone) was deposited just downwind of the carbonates; significant amounts of marine fossil clasts in the

Cedar Mesa indicate that the source of much of the sand

must have been exposed carbonate and clastic beds during lowstands of the sea. Some of the clastics were

undoubtedly derived from streams flowing from the

Uncompahgre highland into the sea, but another source

may have been marine sand moved southward from the

Wyoming shelf (Baars, 1962; Johnson and others, 1992).

Fluvial-eolian interactions occurred along the northeastern edge of the Cedar Mesa erg, and distal streams partially fed a large sabkha in the Four Corners area. Strong

unidirectional winds moved sand from northwest to southeast; the area around Mexican Hat, Utah, may have been

the site of loess deposition downwind from the main erg.

The morphology of dunes in the Cedar Mesa indicates

transverse to barchan dune forms. The main mass of the

Cedar Mesa Sandstone was deposited just to the west of

the Monument upwarp; the abrupt facies change to thin

clastic, gypsum, and limestone beds deposited in a sabkha

occurs on the east flank of the upwarp. This relationship

suggests that the Monument upwarp was a slight topographic high during deposition of the Cedar Mesa and that

the Four Corners area was a topographic low. A low in

this area had persisted since deposition of the lower Cutler beds (Halgaito Formation), shown by numerous limestone beds within the red bed sequence.

Figure 22 shows a paleogeographic reconstruction in

Leonardian to Guadalupian time for the Paradox Basin. The

Uncompahgre highlands were still high enough to shed

alluvial arkosic sediment to the west, southwest, and south.

In the northwestern part of the study area, first the Toroweap and later the Kaibab seas interfingered eastward with

the coastal White Rim Sandstone erg. Wind transport directions in the White Rim are similar to those of the Cedar

Mesa, mainly to the southeast. In the southern part of the

area, the slightly older De Chelly erg also developed. Stratigraphic relationships indicate that a marine environment

existed south of the De Chelly erg, in eastern Arizona and

west-central New Mexico. Although the lower De Chelly

also displays wind transport to the southeast, the upper part

of the unit was deposited by winds blowing more to the

southwest.

In an area on the west flank of the Monument

upwarp in the west-central part of the Paradox Basin, the

White Rim and De Chelly are absent and the Organ Rock

Figure 19. Well log showing the lower part of the Chinle Formation, De Chelly Sandstone, Organ Rock Formation, and the top

of the Cedar Mesa Sandstone on the northwest flank of the Defiance uplift, northeastern Arizona. Well is number 134, plate 1 and

Appendix 1. Log curves are gamma ray on the left and interval

transit time on the right. Vertical scale is in feet.
P30 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

is relatively thin (pl. 6, 7, 8). This suggests that the

upwarp may have still been an active structure during

deposition of the Organ Rock and possibly during

deposition of the White Rim and De Chelly. Two factors

have combined to conceal stratigraphic relations between

the White Rim and De Chelly in this area: (1) post-depositional erosion has removed both units over the crest of the

Monument upwarp, and (2) there has been little or no

Figure 20. Late Paleozoic structural elements in the southwestern United States. Modified from Huffman and Condon (1993).
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P31

drilling between Hite and the San Juan River. Irwin

(1971, p. 1989) interpreted strata in the Skelly Oil Co.

Nokai Dome 1 well as representing the De Chelly

overlain by White Rim and thus believed that the two

units are not correlatives. No other well data has become

available in the time since that interpretation. Until more

wells are drilled between Hite and the San Juan River, the

question can not be resolved conclusively.

At the close of the Permian, the Uncompahgre uplift

had been worn down to the point that it was no longer a

sediment source. The site of the Paradox Basin underwent erosion or nondepostion during the remainder of the

Guadalupian and Ochoan and into the Early Triassic. A

short-lived orogeny just to the west of the Paradox Basin

caused a temporary change in paleoslope to the east and

deposition of fluvial conglomerate in channels cut into the

upper surface of Cutler strata in places. Later in the TriasFigure 21. Paleogeography of the Paradox Basin area in Early Permian (Wolfcampian) time. Sources include Mack (1977), Campbell
P32 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

sic, the Uncompahgre again became established as a sediment source for part of the Moenkopi, Dolores, and

Chinle Formations and a westward paleoslope was again

established.

REFERENCES CITED

Atchley, S.C., and Loope, D.B., 1993, Low-stand aeolian influence

on stratigraphic completeness; upper member of the Hermosa

Formation (latest Carboniferous), southeast Utah, USA, in Pye,

K., and Lancaster, N., eds., Aeolian Sediments, Ancient and

Modern: Special Publication 16 of the International Association of Sedimentologists, p. 127–149.

Baars, D.L., 1962, Permian System of Colorado Plateau: American

Association of Petroleum Geologists Bulletin, v. 46, no. 2, p.

149–218.

———1971, River log, in Baars, D.L., and Molenaar, C.M., eds.,

Geology of Canyonlands and Cataract Canyon: Four Corners

Geological Society Field Conference, 6th, p. 61–87.

———1975, The Permian System of Canyonlands Country, in Fassett, J.E., ed., Canyonlands Country: Four Corners Geological

Society Field Conference, 8th, p. 123–127.

Figure 22. Paleogeography of the Paradox Basin area in Early to Late Permian (Leonardian to Guadalupian) time. Sources include

Steele (1987), Chan (1989), and Stanesco (1991). Paleolatitude (15° N.) from Scotese and McKerrow (1990).
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P33

———1979, The Permian System, in Baars, D.L., ed., Permianland: Four Corners Geological Society Field Conference, 9th,

p. 1–6.

———1987, Paleozoic rocks of Canyonlands country, in Campbell, J.A., ed., Geology of Cataract Canyon and Vicinity: Four

Corners Geological Society Field Conference, 10th, p. 11–16.

———1991, The Elephant Canyon Formation—For the last time:

Mountain Geologist, v. 28, no. 1, p. 1–2.

Baars, D.L., and Seager, W.R., 1970, Stratigraphic control of petroleum in White Rim Sandstone (Permian) in and near Canyonlands National Park, Utah: American Association of Petroleum

Geologists Bulletin, v. 54, no. 5, p. 709–718.

Baird, Donald, 1965, Footprints from the Cutler Formation: U.S.

Geological Survey Professional Paper 503–C, p. 47–50.

Baker, A.A., 1933, Geology and oil possibilities of the Moab district, Grand and San Juan Counties, Utah: U.S. Geological Survey Bulletin 841, 95 p.

———1936, Geology of the Monument Valley–Navajo Mountain

region, San Juan County, Utah: U.S. Geological Survey Bulletin 865, 106 p.

———1946, Geology of the Green River Desert–Cataract Canyon

region, Emery, Wayne, and Garfield Counties, Utah: U.S. Geological Survey Bulletin 951, 121 p.

Baker, A.A., Dane, C.H., and Reeside, J.B., Jr., 1933, Paradox formation of eastern Utah and western Colorado: American Association of Petroleum Geologists Bulletin, v. 17, no. 8, p.

963–980.

———1936, Correlation of the Jurassic formations of parts of

Utah, Arizona, New Mexico, and Colorado: U.S. Geological

Survey Professional Paper 183, 66 p.

Baker, A.A., Dobbin, C.E., McKnight, E.T., and Reeside, J.B., Jr.,

1927, Notes on the stratigraphy of the Moab region, Utah:

American Association of Petroleum Geologists Bulletin, v. 11,

no. 8, p. 785–808.

Baker, A.A., and Reeside, J.B., Jr., 1929, Correlation of the Permian of southern Utah, northern Arizona, northwestern New

Mexico, and southwestern Colorado: American Association of

Petroleum Geologists Bulletin, v. 13, no. 11, p. 1413–1448.

Blakey, R.C., 1979, Lower Permian stratigraphy of the southern

Colorado Plateau, in Baars, D.L., ed., Permianland: Four Corners Geological Society Field Conference, 9th, p. 115–129.

———1990, Stratigraphy and geologic history of Pennsylvanian

and Permian rocks, Mogollon Rim region, central Arizona and

vicinity: Geological Society of America Bulletin, v. 102, no. 9,

p. 1189–1217.

Blakey, R.C., and Knepp, Rex, 1989, Pennsylvanian and Permian

geology of Arizona, in Jenney, J.P., and Reynolds, S.J., eds.,

Geologic Evolution of Arizona: Tucson, Arizona, Geological

Society Digest 17, p. 313–347.

Blakey, R.C., Peterson, Fred, and Kocurek, Gary, 1988, Synthesis

of late Paleozoic and Mesozoic eolian deposits of the Western

Interior of the United States, in Kocurek, Gary, ed., Late Paleozoic and Mesozoic Eolian Deposits of the Western Interior of

the United States: Sedimentary Geology, v. 56, p. 3–125.

Campbell, J.A., 1979, Lower Permian depositional system, northern Uncompahgre basin, in Baars, D.L., ed., Permianland: Four

Corners Geological Society Field Conference, 9th, p. 13–21.

———1980, Lower Permian depositional systems and Wolfcampian paleogeography, Uncompahgre basin, eastern Utah and

southwestern Colorado, in Fouch, T.D., and Magathan, E.R.,

eds., Paleozoic Paleogeography of the West-Central United

States: Society of Economic Paleontologists and Mineralogists, Rocky Mountain Section, p. 327–340.

———1981, Uranium mineralization and depositional facies in the

Permian rocks of the northern Paradox Basin, Utah and Colorado, in Weigand, D.L., ed., Geology of the Paradox Basin:

Rocky Mountain Association of Geologists, p. 187–194.

———1986, The origin of first-order bounding surfaces in eolian

sequences [abs.], in Sediments Down Under: 12th International

Sedimentological Congress, Canberra, Australia, 1986, p. 52.

———1987, Stratigraphy and depositional facies; Elephant Canyon Formation, in Campbell, J.A., ed., Geology of Cataract

Canyon and Vicinity: Four Corners Geological Society Field

Conference, 10th, p. 91–98.

Campbell, J.A., and Steele-Mallory, B.A., 1979, Uranium in the

Cutler Formation, Lisbon Valley, Utah, in Baars, D.L., ed.,

Permianland: Four Corners Geological Society Field Conference, 9th, p. 23–32.

Cater, F.W., Jr., 1970, Geology of the salt anticline region in southwestern Colorado: U.S. Geological Survey Professional Paper

637, 80 p.

Chamberlain, C.K, and Baer, J.L., 1973, Ophiomorpha and a new

Thalassinid burrow from the Permian of Utah: Brigham Young

University Geology Studies, v. 20, part 1, p. 79–94.

Chan, M.A., 1989, Erg margin of the Permian White Rim Sandstone, SE Utah: Sedimentology, v. 36, p. 235–251.

Chan, M.A., and Kocurek, Gary, 1988, Complexities in eolian and

marine interactions; Processes and eustatic controls on erg

development, in Kocurek, Gary, ed., Late Paleozoic and Mesozoic Eolian Deposits of the Western Interior of the United

States: Sedimentary Geology, v. 56, p. 283–300.

Chan, M.A., and Langford, R.P., 1987, Discrimination of eustatic

and climatic events on eolian deposition, Permian Cutler

Group, southeastern Utah [abs.]: Geological Society of America, Abstracts with Programs, v. 19, no. 7, p. 617.

Condon, S.M., 1992, Geologic framework of pre-Cretaceous rocks

in the Southern Ute Indian Reservation and adjacent areas,

southwestern Colorado and northwestern New Mexico: U.S.

Geological Survey Professional Paper 1505–A, 56 p.

Condon, S.M., and Huffman, A.C., Jr., 1994, Northwest-southeastoriented stratigraphic cross sections of Jurassic through Paleozoic rocks, San Juan Basin and vicinity, Utah, Colorado, Arizona, and New Mexico: U.S. Geological Survey Oil and Gas

Investigations Chart OC–142.

Cooley, M.E., 1965, Stratigraphic sections and records of springs in

the Glen Canyon region of Utah and Arizona: Northern Arizona Society of Science and Art, Glen Canyon Series No. 6, 140

p.

Cross, Whitman, and Howe, Ernest, 1905, Red beds of southwestern Colorado and their correlation: Geological Society of

America Bulletin, v. 16, p. 447–498.

Cross, Whitman, Howe, Ernest, and Ransome, F.L., 1905, Silverton

folio: U.S. Geological Survey Atlas, Folio 120, 40 p.

Cross, Whitman, and Spencer, A.C., 1900, Geology of the Rico

Mountains, Colorado: U.S. Geological Survey 21st Annual

Report, pt. 2, p. 7–165.

Dane, C.H., 1935, Geology of the Salt Valley anticline and adjacent

areas, Grand County, Utah: U.S. Geological Survey Bulletin

863, 179 p.
P34 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

Davidson, E.S., 1967, Geology of the Circle Cliffs area, Garfield

and Kane Counties, Utah: U.S. Geological Survey Bulletin

1229, 140 p.

Dubiel, R.F., Huntoon, J.E., Condon, S.M., and Stanesco, J.D.,

1996, Permian deposystems, paleogeography, and paleoclimate of the Paradox Basin and vicinity, in Longman, M.W.,

and Sonnenfeld, M.D., eds., Paleozoic Systems of the Rocky

Mountain Region: Denver, Rocky Mountain Section-SEPM

(Society of Sedimentary Geology), p. 427–443.

Dubiel, R.F., Huntoon, J.E., Stanesco, J.D., Condon, S.M., and

Mickelson, Debra, 1996, Permian-Triassic depositional systems, paleogeography, paleoclimate, and hydrocarbon resources in Canyonlands, Utah, in Thompson, R.A., Hudson, M.R.,

and Pillmore, C.L., eds., Geologic Excursions to the Rocky

Mountians and Beyond, Field Trip Guidebook for the 1996

Annual Meeting, Geological Society of America, Denver, Colorado: Colorado Geological Survey, Special Publication 44

(CD-ROM), 23 p.

Dynamic Graphics, Inc., 1988, Interactive Surface Modeling, user’s

guide: Berkeley, California.

Emery, W.B., 1918, The Green River Desert section, Utah: American Journal of Science, 4th series, v. 46, no. 274, p. 551–577.

Finnell, T.L., Franks, P.C., and Hubbard, H.A., 1963, Geology, ore

deposits, and exploratory drilling in the Deer Flat area, White

Canyon district, San Juan County, Utah: U.S. Geological Survey Bulletin 1132, 114 p.

Frahme, Claudia, and Vaughn, E.B., 1983, Paleozoic geology and

seismic stratigraphy of the northern Uncompahgre front, Grand

County, Utah, in Lowell, J.D., and Gries, Robbie, eds., Rocky

Mountain Foreland Basins and Uplifts: Rocky Mountain Association of Geologists Field Conference, 1983, p. 201–211.

Franczyk, K.J., 1991, Stratigraphic and time-stratigraphic cross sections of Phanerozoic rocks along line C-C¢, Uinta and Piceance

Basin area, southern Uinta Mountains to northern Henry Mountains, Utah: U.S. Geological Survey Miscellaneous Investigations Series Map I–2184–C.

———1992, Measured section of the Pennsylvanian Hermosa

Group near Hermosa, Colorado: U.S. Geological Survey OpenFile Report 92-689, 5 p.

Franczyk, K.J., Clark, Germaine, Brew, D.C., and Pitman, J.K.,

1995, Chart showing lithology, mineralogy, and paleontology

of the Pennsylvanian Hermosa Group at Hermosa Mountain,

La Plata County, Colorado: U.S. Geological Survey Miscellaneous Investigations Map I–2555.

Gilluly, James, 1929, Geology and oil and gas prospects of part of

the San Rafael Swell, Utah: U.S. Geological Survey Bulletin

806–C, p. 69–130.

Gilluly, James, and Reeside, J.B., Jr., 1928, Sedimentary rocks of

the San Rafael Swell and some adjacent areas in eastern Utah:

U.S. Geological Survey Professional Paper 150–D, 110 p.

Goldhammer, R.K., Oswald, E.J., and Dunn, P.A., 1991, The hierarchy of stratigraphic forcing; an example from Middle Pennsylvanian shelf carbonates of the Paradox Basin, in Franseen,

E.K., and others, eds., Sedimentary Modeling; Computer Simulations and Methods for Improved Parameter Definition: Kansas Geological Survey, Bulletin 233, p. 361–413.

Gregory, H.E., 1938, The San Juan country: U.S. Geological Survey

Professional Paper 188, 123 p.

Heyman, O.G., 1983, Distribution and structural geometry of faults

and folds along the northwestern Uncompahgre uplift, western

Colorado and eastern Utah, in Averett, W.R., ed., Northern Paradox Basin—Uncompahgre Uplift: Grand Junction Geological

Society Field Conference, 1983, p. 45–57.

Hite, R.J., and Buckner, D.H., 1981, Stratigraphic correlations,

facies concepts, and cyclicity in Pennsylvanian rocks of the

Paradox Basin, in Weigand, D.L., ed., Geology of the Paradox

Basin: Rocky Mountain Association of Geologists, p. 147–159.

Huffman, A.C., Jr., and Condon, S.M., 1993, Stratigraphy, structure, and paleogeography of Pennsylvanian and Permian rocks,

San Juan Basin and adjacent areas, Utah, Colorado, Arizona,

and New Mexico: U.S. Geological Survey Bulletin 1808–O, 44

p.

Hunt, C.B., and others, 1953, Geology and geography of the Henry

Mountains region, Utah: U.S. Geological Survey Professional

paper 228, 234 p.

Huntoon, J.E., and Chan, M.A., 1987, Marine origin of paleotopographic relief on eolian White Rim Sandstone (Permian), Elaterite Basin, Utah: American Association of Petroleum

Geologists Bulletin, v. 71, no. 9, p. 1035–1045.

Huntoon, J.E., Dubiel, R.F., and Stanesco, J.D., 1994, Tectonic

influence on development of the Permian-Triassic unconformity and basal Triassic strata, Paradox Basin, southeastern Utah,

in Caputo, M.V., Peterson, J.A., and Franczyk, K.J., eds.,

Mesozoic Systems of the Rocky Mountain Region, USA: Society of Economic Paleontologists and Mineralogists (Society of

Sedimentary Geology), Rocky Mountain Section, p. 109–131.

Huntoon, P.W., Billingsley, G.H., Jr., and Breed, W.J., 1982, Geologic map of Canyonlands National Park and vicinity, Utah:

The Canyonlands Natural History Association, scale 1:62,000.

Irwin, C.D., 1971, Stratigraphic analysis of Upper Permian and

Lower Triassic strata in southern Utah: American Association

of Petroleum Geologists Bulletin v. 55, no. 11, p. 1976–2007.

———1976, Permian and Lower Triassic reservoir rocks of central

Utah, in Hill, J.G., ed., Symposium on Geology of the Cordilleran Hingeline: Rocky Mountain Association of Geologists

Field Conference, 1976, p. 193–202.

Johnson, S.Y., 1989, Significance of loessite in the Maroon Formation (Middle Pennsylvanian to Lower Permian), Eagle Basin,

northwest Colorado: Journal of Sedimentary Petrology, v. 59,

no. 5, p. 782–791.

Johnson, S.Y., Chan, M.A., and Konopka, E.A., 1992, Pennsylvanian and Early Permian paleogeography of the Unita-Piceance

Basin region, northwestern Colorado and northeastern Utah:

U.S. Geological Survey Bulletin 1787–CC, 35 p.

Kamola, D.L., and Chan, M.A., 1988, Coastal dune facies, Permian

Cutler Formation (White Rim Sandstone), Capitol Reef National Park area, southern Utah, in Kocurek, Gary, ed., Late Paleozoic and Mesozoic Eolian Deposits of the Western Interior of

the United States: Sedimentary Geology, v. 56, p. 341–356.

Kelley, V.C., 1958a, Tectonics of the Black Mesa region of Arizona, in Anderson, R.Y, and Harshbarger, J.W., eds., Guidebook

of the Black Mesa Basin, Northeastern Arizona: New Mexico

Geological Society Field Conference, 9th, p. 137–144.

———1958b, Tectonics of the region of the Paradox Basin, in Sanborn, A.F., ed., Guidebook to the Geology of the Paradox

Basin: Intermountain Association of Petroleum Geologists

Field Conference, 9th, p. 31–38.

Kiser, L.C., 1976, Stratigraphy and petroleum potential of the Permian Kaibab Beta Member, east-central Utah, in Hill, J.G., ed.,

Symposium on the Geology of the Cordilleran Hingeline:
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P35

Rocky Mountain Association of Geologists Field Conference,

1976, p. 161–172.

Kocurek, Gary, and Nielson, Jamie, 1986, Conditions favourable

for the formation of warm-climate aeolian sand sheets: Sedimentology, v. 33, p. 795–816.

Langford, R.P., and Chan, M.A., 1988, Flood surfaces and deflation

surfaces within the Cutler Formation and Cedar Mesa Sandstone (Permian), southeastern Utah: Geological Society of

America Bulletin, v. 100, p. 1541–1549.

———1989, Fluvial-aeolian interactions; Part II, ancient systems:

Sedimentology, v. 36, p. 1037–1051.

———1993, Downwind changes within an ancient dune sea, Permian Cedar Mesa Sandstone, southeast Utah, in Pye, K., and

Lancaster, N., eds., Aeolian Sediments, Ancient and Modern:

Special Publication 16 of the International Association of Sedimentologists, p. 109–126.

Langford, R.P., Chan, M.A., and Weis, Michelle, 1990, Changes in

depositional features of the Permian Cedar Mesa Sandstone,

Utah, implications for inferring growth and migration of ergs

[abs.]: Geological Society of America, Abstracts with Programs, v. 22, no. 7, p. A359.

Langford, R.P, and Kamola, D.L., 1987, Coarse- and mediumgrained wind ripples and avalanches in modern and ancient

eolian dunes [abs.]: Geological Society of America, Abstracts

with Programs, v. 19, no. 7, p. 739.

Lauth, R.E., 1978, Mexican Hat, in Fassett, J.E., ed., Oil and Gas

Fields of the Four Corners Area, Volume 2: Four Corners Geological Society, p. 682–687.

Lewis, G.E., and Vaughn, P.P., 1965, Early Permian vertebrates

from the Cutler Formation of the Placerville area, Colorado:

U.S. Geological Survey Professional Paper 503–C, p. 1–46.

Lewis, R.Q., Sr., and Campbell, R.H., 1965, Geology and uranium

deposits of Elk Ridge and vicinity, San Juan County, Utah:

U.S. Geological Survey Professional Paper 474–B, 65 p.

Lockley, M.G., and Madsen, J.H., Jr., 1993, Early Permian vertebrate trackways from the Cedar Mesa Sandstone of eastern

Utah; evidence of predator-prey interaction: Ichnos, v. 2, p.

147–153.

Lohman, S.W., 1974, The geologic story of Canyonlands National

Park: U.S. Geological Survey Bulletin 1327, 126 p.

Longwell, C.R., Miser, H.D., Moore, R.C., Bryan, Kirk, and Paige,

Sidney, 1923, Rock formations in the Colorado Plateau of

southeastern Utah and northern Arizona: U.S. Geological Survey Professional Paper 132–A, 23 p.

Loope, D.B., 1980, Evidence for soil-forming episodes during deposition of the Permian Cedar Mesa Sandstone of Utah [abs.]:

Geological Society of America, Abstracts with Programs, v.

12, no. 6, p. 278.

———1981, Products and processes of ancient arid coastline; lower Cutler Group (Permian), southeastern Utah [abs.]: American

Association of Petroleum Geologists Bulletin, v. 65, no. 5, p.

950.

———1984, Eolian origin of upper Paleozoic sandstones, southeastern Utah: Journal of Sedimentary Petrology, v. 54, no. 2, p.

563–580.

———1985, Episodic deposition and preservation of eolian sands;

a late Paleozoic example from southeastern Utah: Geology, v.

13, p. 73–76.

———1988, Rhizoliths in ancient eolianites, in Kocurek, Gary,

ed., Late Paleozoic and Mesozoic Eolian Deposits of the Western Interior of the United States: Sedimentary Geology, v. 56,

p. 301–314.

Loope, D.B., Sanderson, G.A., and Verville, G.J., 1990, Abandonment of the name Elephant Canyon Formation in southeastern

Utah: Physical and temporal implications: Mountain Geologist, v. 27, no. 4, p. 119–130.

Mack, G.H., 1977, Depositional environments of the Cutler-Cedar

Mesa facies transition (Permian) near Moab, Utah: Mountain

Geologist, v. 14, no. 2, p. 53–68.

———1978, The survivability of labile light-mineral grains in fluvial, aeolian, and littoral marine environments; the Permian

Cutler and Cedar Mesa formations, Moab, Utah: Sedimentology, v. 25, p. 587–604.

———1979, Littoral marine depositional model for the Cedar

Mesa Sandstone (Permian), Canyonlands National Park, Utah,

in Baars, D.L., ed., Permianland: Four Corners Geological

Society Field Conference, 9th, p. 33–37.

Mack, G.H., and Rasmussen, K.A., 1984, Alluvial-fan sedimentation of the Cutler Formation (Permo-Pennsylvanian) near

Gateway, Colorado: Geological Society of America Bulletin,

v. 95, no. 1, p. 109–116.

Mamay, S.H., and Breed, W.J., 1970, Early Permian plants from the

Cutler Formation in Monument Valley, Utah: U.S. Geological

Survey Professional Paper 700–B, p. 109–117.

Matheny, M.L., 1978, A history of the petroleum industry in the

Four Corners area, in Fassett, J.E., ed., Oil and Gas Fields of

the Four Corners Area, Volume 1: Four Corners Geological

Society, p. 17–24.

McKnight, E.T., 1940, Geology of area between Green and Colorado Rivers, Grand and San Juan Counties, Utah: U.S. Geological Survey Bulletin 908, 147 p.

Melton, R.A., 1972, Paleoecology and paleoenvironment of the

upper Honaker Trail Formation near Moab, Utah: Brigham

Young University Geology Studies, v. 19, part 2, p. 45–88.

Miser, H.D., 1925, Geologic structure of the San Juan Canyon and

adjacent country, Utah: U.S. Geological Survey Bulletin

751–D, p. 115–155.

Mitchell, G.C., 1985, The Permian-Triassic stratigraphy of the

northwest Paradox Basin area, Emery, Garfield, and Wayne

Counties, Utah: Mountain Geologist, v. 22, no. 4, p. 149–166.

Molenaar, C.M., 1975, Nomenclature chart of the Canyonlands and

adjacent areas, in Fassett, J.E., ed., Canyonlands Country: Four

Corners Geological Society Field Conference, 8th, p. 142.

Mullens, T.E., 1960, Geology of the Clay Hills area, San Juan

County, Utah: U.S. Geological Survey Bulletin 1087–H, p.

259–336.

Murphy, Kathleen, 1987, Eolian origin of upper Paleozoic red siltstones at Mexican Hat and Dark Canyon, southeastern Utah:

Lincoln, University of Nebraska, M.S. thesis, 127 p.

Ochs, Steffen, and Chan, M.A., 1990, Petrology, sedimentology

and stratigraphic implications of Black Dragon Member of the

Triassic Moenkopi Formation, San Rafael Swell, Utah: Mountain Geologist, v. 27, no. 1, p. 1–18.

Orgill, J.R., 1971, The Permian-Triassic unconformity and its relationship to the Moenkopi, Kaibab, and White Rim formations

in and near the San Rafael Swell, Utah: Brigham Young University Geology Studies, v. 18, pt. 3, 131–178.
P36 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

O’Sullivan, R.B., 1965, Geology of the Cedar Mesa–Boundary

Butte area, San Juan County, Utah: U.S. Geological Survey

Bulletin 1186, 128 p.

Parrish, J.T., and Peterson, Fred, 1988, Wind directions predicted

from global circulation models and wind directions determined

from eolian sandstones of the Western United States—A comparison, in Kocurek, Gary, ed., Late Paleozoic and Mesozoic

Eolian Deposits of the Western Interior of the United States:

Sedimentary Geology, v. 56, p. 261–282.

Peirce, H.W., 1967, Permian stratigraphy of the Defiance plateau,

Arizona, in Trauger, F.D., ed., Guidebook of Defiance-ZuniMt. Taylor region, Arizona and New Mexico: New Mexico

Geological Society Field Conference, 18th, p. 57–62.

Peterson, Fred, 1988, Pennsylvanian to Jurassic eolian transportation systems in the western United States, in Kocurek, Gary,

ed., Late Paleozoic and Mesozoic Eolian Deposits of the

Western Interior of the United States: Sedimentary Geology, v.

56, p. 207–260.

Powell, J.W., 1875, Exploration of the Colorado River of the West

and its tributaries explored in 1869, 1870, 1871, and 1872:

Washington, D.C., Government Printing Office, 291 p.

Prommel, H.W.C., 1923, Geology and structure of portions of

Grand and San Juan Counties, Utah: American Association of

Petroleum Geologists Bulletin, v. 7, p. 384–399.

Prommel, H.W.C., and Crum, H.E., 1927, Structural history of parts

of southeastern Utah from interpretations of geologic sections:

American Association of Petroleum Geologists Bulletin, v. 11,

no. 8, p. 809–820.

Rascoe, Bailey, Jr., and Baars, D.L., 1972, Permian System, in Mallory, W.W., ed., Geologic Atlas of the Rocky Mountain

Region: Denver, Rocky Mountain Association of Geologists, p.

143–165.

Rawson, R.R., and Turner-Peterson, C.E., 1979, Marine-carbonate,

sabkha, and eolian facies transitions within the Permian Toroweap Formation, northern Arizona, in Baars, D.L., ed., Permianland: Four Corners Geological Society Field Conference,

9th, p. 87–99.

Read, C.B., and Wanek, A.A., 1961, Stratigraphy of outcropping

Permian rocks in parts of northeastern Arizona and adjacent

areas: U.S. Geological Survey Professional Paper 374–H, 10 p.

Ross, C.A., and Ross, J.R.P., 1986, Paleozoic paleotectonics and

sedimentation in Arizona and New Mexico, in Peterson, J.A.,

ed., Paleotectonics and Sedimentation in the Rocky Mountain

Region, United States: American Association of Petroleum

Geologists, Memoir 41, p. 653–668.

Sanderson, G.A., and Verville, G.J., 1990, Fusilinid zonation of the

General Petroleum No. 45-5-G core, Emery County, Utah:

Mountain Geologist, v. 27, no. 4, p. 131–136.

Schultz, A.W., 1984, Subaerial debris-flow deposition in the upper

Paleozoic Cutler Formation, western Colorado: Journal of Sedimentary Petrology, v. 54, no. 3, p. 759–772.

Scotese, C.R., and McKerrow, W.S., 1990, Revised world maps and

introduction, in McKerrow, W.S., and Scotese, C.R., eds.,

Palaeozoic Palaeogeography and Biogeography: Geological

Society Memoir 12, p. 1–21.

Sears, J.D., 1956, Geology of Comb Ridge and vicinity north of San

Juan River, San Juan County, Utah: U.S. Geological Survey

Bulletin 1021–E, p. 167–207.

Shoemaker, E.M., and Newman, W.L., 1959, Moenkopi Formation

(Triassic? and Triassic) in salt anticline region, Colorado and

Utah: American Association of Petroleum Geologists Bulletin,

v. 43, no. 8, p. 1835–1851.

Sprinkel, D.A., 1994, Stratigraphic and time-stratigraphic cross sections: A north-south transect from near the Uinta Mountain axis

across the Basin and Range transition zone to the western margin of the San Rafael Swell, Utah: U.S. Geological Survey Miscellaneous Investigations Map I–2184–D.

Stanesco, J.D., 1991, Sedimentology and cyclicity in the Lower Permian De Chelly Sandstone on the Defiance Plateau; eastern

Arizona: Mountain Geologist, v. 28, no. 4, p. 1–11.

Stanesco, J.D., and Campbell, J.A., 1989, Eolian and noneolian

facies of the Lower Permian Cedar Mesa Sandstone Member of

the Cutler Formation, southeastern Utah: U.S. Geological Survey Bulletin 1808–F, 13 p.

Stanesco, J.D., and Dubiel, R.F., 1992, Fluvial and eolian facies of

the Organ Rock Shale Member of the Cutler Formation, southeastern Utah [abs.]: Geological Society of America, Abstracts

with Programs, v. 24, no. 6, p. 64.

Steele, B.A., 1987, Depositional environments of the White Rim

Sandstone Member of the Permian Cutler Formation, Canyonlands National Park, Utah: U.S. Geological Survey Bulletin

1592, 20 p.

Stevenson, G.M., and Baars, D.L., 1986, The Paradox; a pull-apart

basin of Pennsylvanian age, in Peterson, J.A., ed.,

Paleotectonics and Sedimentation in the Rocky Mountain

Region, United States: American Association of Petroleum

Geologists Memoir 41, p. 513–539.

Stewart, J.H., Poole, F.G., and Wilson, R.F., 1972, Stratigraphy and

origin of the Triassic Moenkopi Formation and related strata in

the Colorado Plateau region: U.S. Geological Survey Professional Paper 691, 195 p.

Stokes, W.L., 1968, Multiple parallel-truncation bedding

planes—A feature of wind-deposited sandstone formations:

Journal of Sedimentary Petrology, v. 38, p. 510–515.

Strobell, J.D., Jr., 1956, Geology of the Carrizo Mountains area in

northeastern Arizona and northwestern New Mexico: U.S.

Geological Survey Oil and Gas Investigations Map OM–160,

scale 1:48,000.

Terrell, F.M., 1972, Lateral facies and paleoecology of Permian

Elephant Canyon Formation, Grand County, Utah: Brigham

Young University Geology Studies, v. 19, part 2, p. 3–44.

Thaden, R.E., Trites, A.F., Jr., and Finnell, T.L., 1964, Geology and

ore deposits of the White Canyon area, San Juan and Garfield

Counties, Utah: U.S. Geological Survey Bulletin 1125, 166 p.

Tidwell, W.D., 1988, A new Upper Pennsylvanian or Lower Permian flora from southeastern Utah: Brigham Young University

Geology Studies, v. 35, p. 33–56.

Vaughn, P.P., 1973, Vertebrates from the Cutler Group of Monument Valley and vicinity, in James, H.L., ed., Guidebook of

Monument Valley and Vicinity, Arizona and Utah: New Mexico Geological Society Field Conference, 24th, p. 99–105.

Welsh, J.E., Stokes, W.L., and Wardlaw, B.R., 1979, Regional

stratigraphic relationships of the Permian “Kaibab” or Black

Box Dolomite of the Emery High, central Utah, in Baars, D.L.,

ed., Permianland: Four Corners Geological Society Field Conference, 9th, p. 143–149.

Wengerd, S.A., 1963, Stratigraphic section at Honaker Trail, San

Juan Canyon, San Juan County, Utah, in Bass, R.O., ed., Shelf

Carbonates of the Paradox Basin; a Symposium: Four Corners

Geological Society Field Conference, 4th, p. 235–243.
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P37

———1973, Regional stratigraphic control of the search for Pennsylvanian petroleum, southern Monument upwarp, southeastern Utah, in James, H.L., ed., Guidebook of Monument Valley

and Vicinity, Arizona and Utah: New Mexico Geological

Society Field Conference, 24th, p. 122–138.

Wengerd, S.A., and Matheny, M.L., 1958, Pennsylvanian system of

Four Corners region: American Association of Petroleum

Geologists Bulletin, v. 42, no. 9, p. 2048–2106.

Wengerd, S.A., and Strickland, J.W., 1954, Pennsylvanian stratigraphy of Paradox salt basin, Four Corners region, Colorado and

Utah: American Association of Petroleum Geologists Bulletin,

v. 38, no. 10, p. 2157–2199.

Werner, W.G., 1974, Petrology of the Cutler Formation (Pennsylvanian-Permian) near Gateway, Colorado, and Fisher Towers,

Utah: Journal of Sedimentary Petrology, v. 44, no. 2, p.

292–298.

White, M.A., and Jacobson, M.I., 1983, Structures associated with

the southwest margin of the ancestral Uncompahgre uplift, in

Averett, W.R., ed., Northern Paradox Basin—Uncompahgre

Uplift: Grand Junction Geological Society Field Conference,

1983, p. 33–39.

Witkind, I.J., and Thaden, R.E., 1963, Geology and uranium-vanadium deposits of the Monument Valley area, Apache and

Navajo Counties, Arizona: U.S. Geological Survey Bulletin

1103, 171 p.

Woodruff, E.G., 1912, Geology of the San Juan oil field: U.S. Geological Survey Bulletin 471–A, p. 76–104.

Published in the Central Region, Denver, Colorado

Manuscript approved for publication February 12, 1997

Edited by Richard W. Scott, Jr.

Graphics by Steven M. Condon and Richard P. Walker

Cartography, plates 1–7, by William E. Sowers and

Springfield & Springfield

Photocomposition by Norma J. Maes
P38 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN

APPENDIXES
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P39
P40 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P41
P42 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P43
P44 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN
GEOLOGY OF THE CUTLER GROUP AND KAIBAB LIMESTONE, PARADOX BASIN, SE. UTAH AND SW. COLO. P45
P46 EVOLUTION OF SEDIMENTARY BASINS—PARADOX BASIN