Ground-Water Row and Migration of Hydrocarbons 

to the Lower Permian White Rim Sandstone, 

Tar Sand Triangle, Southeastern Utah

U.S. GEOLOGICAL SURVEY BULLETIN 200Q-J
Cover. View south toward the LaSal Mountains along the Colorado River between 

Cisco and Moab, Utah. Fisher Towers in center is composed of Permian Cutler Formation 

and capped by Triassic Moenkopi Formation. The prominent mesa at left center is capped 

by Jurassic Kayenta Formation and Wingate Sandstone and underlain by slope-forming 

Triassic Chinle and Moenkopi Formations. The Chinle-Moenkopi contact is marked by a 

thin white ledge-forming gritstone. The valley between Fisher Towers and Fisher Mesa in 

the background is part of Richardson Mesa, part of Professor Valley. Photograph by Omer 

B. Raup, U.S. Geological Survey.
Ground-Water Flow and Migration of Hydrocarbons 

to the Lower Permian White Rim Sandstone, 

Tar Sand Triangle, Southeastern Utah

By Richard F. Sanford

EVOLUTION OF SEDIMENTARY BASINS PARADOX BASIN 

A.C. Huffman, Jr., Project Coordinator

U.S. GEOLOGICAL SURVEY BULLETIN 2000-J

A multidisciplinary approach to research studies of 

sedimentary rocks and their constituents and the 

evolution of sedimentary basins, both ancient and modem

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1995
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

Gordon P. Eaton, Director

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

Sanford, Richard F.

Ground-water flow and migration of hydrocarbons to the Lower Permian White Rim 

Sandstone, Tar Sand Triangle, southeastern Utah / by Richard F. Sanford.

p. cm. (Evolution of sedimentary basins Paradox Basin ; J) (U.S. Geological 

Survey bulletin; 2000)

Includes bibliographical references (p. -)

Supt.ofDocs.no.: I 19.2:B2000J

1. Groundwater flow Utah. 2. Petroleum Migration Utah. 3. White Rim 

Sandstone (Utah) I. Title. II. Series. III. Series: U.S. Geological Survey bulletin; 

2000.

QE75.B9 no. 2000-J 

[GB 1197.7] 

557.3 s dc20

[553.2'8'09792 95-11114

CIP
CONTENTS

Abstract........................................................................................................................... Jl

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

Paleotopographic History............................................................................................... 2

Ground-Water Flow History........................................................................................... 7

Pennsylvanian-Permian Aquifers................................................................................... 14

Hydrocarbon Source Rocks............................................................................................ 16

Diagenetic Evidence for Hydrocarbon Migration.......................................................... 18

Evaluation of Hydrocarbon Sources............................................................................... 19

Summary and Conclusions............................................................................................. 21

References Cited............................................................................................................. 22

FIGURES

1-12. Maps showing paleogeography during:

1. Deposition of the Torrey Member of the Lower Triassic Moenkopi Formation.......................................... J4

2. Deposition of the Shinarump Member of the Upper Triassic Chinle Formation......................................... 4

3. Deposition of the Lower Jurassic Wingate Sandstone ................................................................................. 5

4. Deposition of the Lower Jurassic Kayenta Formation................................................................................. 5

5. Deposition of the lower part of the Middle Jurassic Page Sandstone and Carmel Formations.................... 6

6. Deposition of the lower part of the Salt Wash and Bluff Sandstone Members of the

Upper Jurassic Morrison Formation............................................................................................................. 6

7. Early Cenomanian Neogastroplites americanus faunal zone and deposition of parts of the

Dakota Sandstone, Mowry Shale, and Cedar Mountain Formations ........................................................... 7

8. Middle Coniacian Inoceramus deformis faunal zone and deposition of part of the Mancos Shale............. 7

9. Late late Campanian Exiteloceras jenneyi faunal zone and deposition of part of the Tuscher and

Fairer Formations......................................................................................................................................... 8

10. Early Maastrichtian Baculites reesidei faunal zone and deposition of part of the

Hunter Canyon Formation............................................................................................................................ 8

11. Early Eocene and deposition of parts of the Wasatch and Green River Formations and

Flagstaff Limestone...................................................................................................................................... 9

12. Latest Eocene and (or) early Oligocene and deposition of the Duchesne River Formation ........................ 9

13-15. Maps showing:

13. Grid used for analysis of hydrology of the Canyonlands area..................................................................... 10

14. Pennsylvanian and Permian aquifers in Utah and adjacent States ............................................................... 15

15. Potential source rocks in Utah and adjacent States for various time periods............................................... 17

16. Schematic diagram showing distribution of red and bleached Permian rocks in the Canyonlands area

and inferred flow directions of organic-acid-bearing ground water...................................................................... 19

TABLES

1. Stratigraphic and paleohydrologic data on post-White Rim Sandstone units...................................................... J3

2. Hydraulic properties of units in Canyonlands area ............................................................................................... 11

III

Ground-Water Flow and Migration of Hydrocarbons

to the Lower Permian White Rim Sandstone,

Tar Sand Triangle, Southeastern Utah

By Richard F. Sanford1

ABSTRACT

The Lower Permian White Rim Sandstone in the Tar 

Sand Triangle of southeastern Utah contains an estimated 

12.5-16 billion barrels of heavy oil. Despite the large size of 

the deposit, the source of its oil is unknown. This paper systematically discusses source rocks for this petroleum from 

the standpoint of hydrocarbon abundance and maturity and 

ground-water flow history. Ground-water flow through the 

White Rim Sandstone was governed by six periods, each 

characterized by distinct paleotopographic conditions and 

directions of horizontal flow. Analysis of the transmissivity 

and thickness of the hydrostratigraphic units indicates that 

flow was mainly horizontal and had no major vertical component. Long-range transport of petroleum through Pennsylvanian and Permian sandstone aquifers that were 

hydrologically continuous with the White Rim was possible 

until Late Cretaceous to Paleocene Sevier thrusting. After 

thrusting, long-range migration would have been impeded or 

diverted by the thrust faults. Ten potential source-rock units 

are identified in the area. Some are unfavorable because they 

lack sufficient organic matter to account for the hydrocarbons in the Tar Sand Triangle. Others, particularly those in 

northern Utah, are unfavorable because ground water never 

flowed in the required direction. Sources to the southwest 

and southeast are hydrologically favorable. The Paradox 

Formation of the Hermosa Group is hydrologically favorable, but the pattern of bleaching of the Cutler Group redbeds and the eastward thinning of the White Rim are 

unfavorable. The Chainman Shale and other formations in 

Nevada are consistent with east- and northeast-flowing 

ground water, but migration across the thrust belt is problematic. The most likely source is the Late Proterozoic Chuar 

Group in west-central Utah. It is compatible with eastward 

and northeastward ground-water flow, with bleaching of the 

Permian aquifers, and with continuous sandstone aquifers 

east of the thrust belt, and it probably has sufficient mature 

organic matter to account for the oil in the Tar Sand Triangle.

J U.S. Geological Survey, MS 905, Denver, Colorado 80225.

INTRODUCTION

The Tar Sand Triangle in the Canyonlands area of 

southeastern Utah contains the largest accumulation of 

heavy oil ("tar") in the United States (Demaison, 1977). 

Most of the oil is in the Lower Permian White Rim Sandstone of the Cutler Group, but a small portion is in the Cedar 

Mesa Sandstone of the Cutler Group (Campbell and Ritzma, 

1979). Heavy oil in place is estimated at 12.5-16 billion barrels (Campbell and Ritzma, 1979). The White Rim consists 

of sandstone erg deposits modified by coastal marine processes (Steele, 1987; Chan and Kocurek, 1988; Chan, 1989). 

The tar is in a classic stratigraphic trap formed by pinchout 

to the southeast of the White Rim Sandstone against the 

Monument uplift (Baars and S eager, 1970). Oil is concentrated in zones of particularly thick sandstone that have been 

variously interpreted as offshore marine bars (Baars and Seager, 1970) and as eolian dunes modified by marine processes 

(Huntoon and Chan, 1987; Tubbs, 1989). Proposed sources 

for the oil include the Lower Permian Kaibab Formation and 

the Lower Triassic Sinbad Limestone Member of the Moenkopi Formation (Baars and Seager, 1970) and the Lower Permian Phosphoria Formation (Demaison, 1977). No study to 

date has systematically surveyed and evaluated all the possible hydrocarbon source rocks, and no study has considered 

petroleum migration in terms of paleohydrologic evolution.

This paper systematically examines petroleum source 

rocks from the standpoint of hydrocarbon abundance and 

maturity and ground-water flow history. Ground-water flow 

history is reconstructed from paleoenvironmental data, and 

periods of similar ground-water flow directions are identified. Transmissivities of the hydrostratigraphic units in the 

Canyonlands area are examined to identify local vertical 

flow directions. Pennsylvanian and Permian aquifers in Utah 

and adjacent States are identified to determine the feasibility 

of long-distance horizontal transport. Potential hydrocarbon 

source rocks are described with particular attention to quantity, maturation level, and timing of maturation. The bleaching of rocks in the Canyonlands area is used to indicate the 

flow of organic-acid-bearing ground water. Finally, all these

Jl
J2 EVOLUTION OF SEDIMENTARY BASINS PARADOX BASIN

factors are integrated to select a preferred hydrocarbon 

source rock.

It is assumed that paleo-ground-water flow was in the 

direction of paleo-surface-water flow. This is a good approximation for modern systems. Anisotropy of hydraulic conductivity potentially would make ground-water flow deviate 

from surface-water flow, but generally this effect is small, 

and data to compute this effect in the Colorado Plateau are 

unavailable. In addition, it is assumed that oil migrated in the 

direction of paleo-ground-water flow in the horizontal plane. 

Both oil and water are subject to the same pressure field, so 

horizontal flow directions should be similar; however, the 

rate of flow may vary because of the different viscosities, 

and, in the vertical direction, buoyancy causes oil to rise relative to water (Hubbert, 1953). Despite the expected differences in flow rate and vertical flow direction, the horizontal 

flow direction is the main constraint for identification of oil 

source rocks for the Tar Sand Triangle, and it should be predictable from the horizontal ground-water flow directions.

Acknowledgments. Discussions with Tony Bryant, 

Paula Hansley, Jackie Huntoon, Art Geldon, Ben Law, Vito 

Nuccio, and Jim Palacas improved this paper, which was 

reviewed by Vito Nuccio and Jim Palacas.

PALEOTOPOGRAPHIC HISTORY

The critical control on ground-water flow in a mature 

uplifted basin is topographic slope (Kreitler, 1989; Garven 

and others, 1993). Topographic slope provides the major 

driving force for large-scale regional ground-water flow. 

This study assumes that ground-water flow parallels the 

regional topographic gradient. The direction of 

ground-water flow is inferred from sediment current directions, provenance of source materials, and location of known 

uplifts.

Ground-water flow through the White Rim Sandstone 

was governed by six periods, each characterized by distinct 

paleotopographic conditions (table 1).

1. From the end of Late Permian White Rim deposition (256 Ma) to the end of the Middle to Late Jurassic J5 

unconformity (155 Ma) was a long period of time (99 m.y.) 

during which gradients were low and topographic slopes, 

and thus ground-water flow, were dominantly northwestward, locally southwestward, and rarely eastward. Local 

ground-water flow was important, particularly processes 

such as mixing of sea water with discharging ground water, 

evaporation in coastal sabkhas, and evaporative pumping 

that typify low-gradient coastal zones in arid environments. 

The low slopes and arid environment would have resulted in 

limited regional ground-water flow. Deposition and compaction during this period was slow. The mean deposition rate 

was a maximum of 0.011 mm/yr (37 ft/m.y.) for the entire 

period including major unconformities but averaged 

0.03-0.09 mm/yr (100-300 ft/m.y.) during depositional

periods. Ground water consisted of trapped sea water, hypersaline brine, and, locally, fresh water.

The Permian-Trias sic unconformity at the top of the 

White Rim Sandstone is marked by conglomerate-filled 

channels that indicate a western source (Huntoon, 1992). 

Thus, the first ground water in the White Rim flowed eastward during at least part of the time of the unconformity. The 

dominant direction of flow, however, was westward off the 

Uncompahgre uplift. Some of the marine pore water in the 

White Rim Sandstone may have been flushed out by fresh 

water at this time.

The Lower and Middle(?) Triassic Moenkopi Formation was deposited on an almost flat coastal plain of a sea that 

encroached from the northwest (fig. 1) (Stewart and others, 

1972; Ochs and Chan, 1990; Blakey and others, 1993). 

Sea-level changes, sediment supply, and climatic changes 

led to four transgressive-regressive cycles (Blakey and others, 1993). Numerous depositional environments are recognized from offshore marine to alluvial fan, but the dominant 

environments are nearshore marine. Ground water flowed 

dominantly northwestward toward the sea, but southwestward flow off the Uncompahgre uplift was important in the 

eastern part of the area. Fluvial environments would have 

favored recharge of fresh ground water. An unconformity 

marks a period of erosion between the Moenkopi and Upper 

Triassic Chinle Formations. Because both formations are 

dominated by a northwest slope, flow during the erosional 

period probably also was northwest.

The Chinle Formation consists of fluvial and lacustrine 

clastic sediments deposited in six depositional cycles (Stewart and others, 1972; Blakey and Gubitosa, 1983). Inferred 

ground-water flow was dominantly to the northwest but 

included tributary southwestward flow off the Uncompahgre 

uplift (fig. 2). The fluvial environments suggest higher slope 

than that of the Moenkopi. Paleoclimate reconstruction suggests a monsoonal climate (Dubiel and others, 1991), and 

thus major seasonal recharge of fresh ground water.

The Lower Jurassic Glen Canyon Group is composed of 

eolian and fluvial sediments. The eolian Wingate Sandstone 

unconformably overlies the Chinle. Erg-margin deposits 

southwest of the Canyonlands area indicate continuation of 

the dominant northwestward gradient (fig. 3) (Clemmensen 

and others, 1989). The gradient in the Canyonlands area may 

have been southwestward, similar to the gradient of the overlying Kayenta Formation. The fluvial Kayenta Formation 

indicates a westward flow direction (fig. 4) (Molenaar, 1971; 

Peterson, 1988) that is probably due to rejuvenation of the 

Uncompahgre uplift. Recharge of fresh ground water would 

have taken place during Kayenta deposition. The eolian 

Navajo Sandstone represents a major sand sea. 

Ground-water flow directions are unknown, but continuation 

of previous trends would suggest northwest and southwest 

flow directions.

The Middle Jurassic San Rafael Group is composed of 

dominantly marine clastic sediments and lesser eolian
GROUND-WATER FLOW AND MIGRATION OF HYDROCARBONS J3

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115° 113°

EVOLUTION OF SEDIMENTARY BASINS PARADOX BASIN

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109°

39C

37 C

NEVADA^ n_UIAH

1 T i

100 200 KILOMETERS 

I

Figure 1. Paleogeography during deposition of the Torrey 

Member of the Lower Triassic-Moenkopi Formation. Triangle indicates location of Tar Sand Triangle; arrows indicate direction of 

stream and inferred ground-water flow. Modified from Blakey 

(1974).

deposits (Molenaar, 1971). The marine Carmel, Curtis, and 

Summerville Formations indicate hydrostatic ground-water 

conditions (fig. 5). The dominantly eolian Entrada Sandstone represents erg and sabkha deposits. Hydraulic gradients during deposition of the San Rafael Group were the 

lowest since deposition of the Moenkopi. Sea water probably 

displaced fresh ground water introduced during fluvial episodes. The J5 unconformity represents the last stage of this 

period dominated by low gradients and northwest-southwest 

ground-water flow.

2. From the beginning of deposition of the Upper 

Jurassic Morrison Formation (155 Ma) through deposition of 

the middle to upper Cenomanian Dakota Sandstone (93.5 

Ma) was a period (60 m.y.) characterized by moderate gradients and ground-water flow toward the northeast. Fluvial 

deposition and erosional periods favored recharge of fresh 

water and flushing of sea water and hypersaline brine.

The Morrison Formation in the Canyonlands area consists of a lower fluvial sandstone and an upper overbank and 

lacustrine mudstone (Craig and others, 1955; Tyler and 

Ethridge, 1983; Turner and Fishman, 1991). Current 

directions indicate northeastward and eastward flow of 

ground water (fig. 6). Highland areas of the Elko uplift

39°

37°

_______ IDAHO _ _

NEVADA""! UTAH

Figure 2. Paleogeography during deposition of the Shinarump 

Member of the Upper Triassic Chinle Formation. Triangle indicates location of Tar Sand Triangle; arrows indicate direction of 

stream and inferred ground-water flow. Modified from Dubiel 

(1989).

(Thorman and others, 1991) were the source of ground-water 

recharge. Mixing of fresh water and underlying saline water 

in the shallow subsurface is indicated by uranium-vanadium 

deposits (Northrop and Goldhaber, 1990; Sanford, 1992).

Unconformably overlying the Morrison Formation are 

the Cedar Mountain and Burro Canyon Formations, which 

consist of fluvial sandstones shed from the Sevier highlands. 

The Cedar Mountain Formation, west of the Colorado River, 

exhibits eastward flow directions, whereas the Burro Canyon 

Formation, east the Colorado River, exhibits northerly and 

easterly flow directions (Craig, 1981).

Transgressive shoreline deposits of the Dakota Sandstone (Franczyk and others, 1992) mark the end of this 

period of dominantly northeastward flow (fig. 7). 

Fresh-water swamp and nearshore marine environments in 

the Dakota suggest discharge of fresh ground water and 

interaction with sea water typical of coastal regions.

3. The upper Cenomanian to Campanian Mancos 

Shale (93.5-76.6 Ma) was deposited in a shallow inland seaway (fig. 8). Because the Mancos and younger strata have 

been eroded from the Canyonlands area, reconstruction of 

ground-water flow requires interpolation from exposures to 

the north, south, and west. During this period, ground water
43°

115°

GROUND-WATER FLOW AND MIGRATION OF HYDROCARBONS

113° 111° 109° 115° 113°

J5

109°

41° -

39°

IDAHO

NEVADA UTAH

WYOMING

43C

100 200 KILOMETERS

Figure 3. Paleogeography during deposition of the Lower Jurassic Wingate Sandstone. Triangle indicates location of Tar Sand 

Triangle; arrows indicate direction of stream and inferred 

ground-water flow. Modified from Clemmensen and others (1989).

in sedimentary rocks below the Mancos was under hydrostatic conditions. Compaction of sub-Mancos sediments 

would have caused minor upward and outward flow, but 

compaction probably was minimal because of the abundance 

of sandstone in the section. The rapid deposition rate and the 

low permeability of Mancos sediments could have allowed 

overpressures to build up in the Mancos (Sanford, 1990). 

Pore water may have escaped downward into the Dakota as 

well as upward. The direction of compaction-driven flow 

can be estimated from isopachs of Upper Cretaceous rocks 

(fig. 8). If compaction-driven flow is mainly outward from 

the thickest part of a section, then it was mainly eastward and 

southeastward in the study area.

The Castlegate Sandstone represents a regressive 

period between the main body of the Mancos and the Buck 

Tongue of the Mancos. The Castlegate grades from fluvial to 

nearshore-marine sandstone (Fouch and others, 1983) and 

was probably mostly marine in the Canyonlands area. 

Ground-water flow was eastward. Hydraulic gradients 

would have been low, and ground water included both discharging fresh water and sea water. Owing to the low gradient, regional flow deeper in the section would have been 

minimal.

4. Regressive marine, coastal plain, and alluvial plain 

environments dominated in the late Campanian (Fouch and

41°

39C

37°

____ IDAHO 

NEVADA "1 UTAH

1 Eolian.. .

 '-.:' ^'"^ WYOMING^

./ Mixed [ / 

I continental

jAlluvial 'r ~K~^1 

1 plain

I 

f

100 200 KILOMETERS

Figure 4. Paleogeography during deposition of the Lower Jurassic Kayenta Formation. Triangle indicates location of Tar Sand 

Triangle; arrows indicate direction of stream and inferred 

ground-water flow. Modified from Peterson (1988).

others, 1983; Franczyk and others, 1990) from 79.4 to 74 

Ma. Fluvial deposits indicate eastward ground-water flow. 

This period was the second major period of topographically 

driven ground-water flow (the first being during Late 

Jurasssic-Early Cretaceous time).

The Sego Sandstone represents a microtidal barrier-island coastline environment (Franczyk and others, 

1990). Gradients were near zero, and almost hydrostatic conditions prevailed. The Neslen Formation represents deposition in a meander plain by streams flowing northeast to 

southeast (Franczyk and others, 1990). Gradients were low, 

and the regional flow was generally eastward.

5. In the period from middle late Campanian to late 

Miocene (74-10 Ma), gradients were low to moderate, and 

flow was generally northward. Current directions changed 

from easterly in early late Campanian to northeasterly and 

northerly in late late Campanian time (fig. 9) (Franczyk and 

others, 1992).

The Fairer and Tuscher Formations represent meandering and braided river systems (Franczyk and others, 1990). 

Northeastward and northward current directions were probably influenced by uplift of the San Rafael Swell (Franczyk 

and others, 1990). Inferred topographically driven 

ground-water flow rates probably were moderate; 

northeasterly flow dominated during much of Fairer and
J6

115'

EVOLUTION OF SEDIMENTARY BASINS PARADOX BASIN

111° 109° 115° 113° 109°

37'

Figure 5. Paleogeography during deposition of the lower part 

of the Middle Jurassic Page Sandstone and Carmel Formations. 

Triangle indicates location of Tar Sand Triangle. Modified from 

Peterson(1988).

Tuscher, deposition, and northward flow dominated late in 

the deposition.

In the Canyonlands area Maastrichtian through middle 

Eocene time was characterized by slight uplift, low relief, 

and probably nondeposition (figs. 10, 11) (Franczyk and others, 1990). During deposition of the lower to middle Eocene 

part of the Wasatch Formation to the north, sediments were 

transported north to northwest between the San Rafael uplift 

and the Uncompahgre uplift (Franczyk and others, 1990). 

Inferred ground-water flow was moderate and directed 

northward to northwestward.

Little is known of the period from late Eocene to early 

Miocene (40-10 Ma). The northward drainage (fig. 12) must 

have reversed prior to cutting of the Grand Canyon, but the 

timing of the reversal is unknown. Southwest of the study 

area in Arizona, deposits as young as 20-18 Ma indicate 

northward drainage (Lucchitta, 1972). Deposits at the mouth 

of the Colorado River indicate that the river did not exist 

before 10.6 Ma (Lucchitta, 1972). Tectonic activity and lava 

flows from the upper Colorado also support a 10-Ma age for 

initiation of Colorado River downcutting (Larson and others, 

1975). Thus, sometime between 20 and 10 Ma drainage 

changed from north to southwest. Meanders of the Colorado

37° -

Figure 6. Paleogeography during deposition of the lower part of 

the Salt Wash and Bluff Sandstone Members of the Upper Jurassic 

Morrison Formation. Triangle indicates location of Tar Sand Triangle; arrows indicate direction of stream and inferred 

ground-water flow. Modified from Peterson (1988).

River indicate a low to moderate slope on the erosion surface 

prior to major downcutting. Ground-water flow is inferred to 

have been northward prior to 20 Ma and to have gradually 

changed to southwestward by 10 Ma.

6. The last distinctive phase in the topographic history 

was uplift of the Colorado Plateau and downcutting by the 

Colorado River (10 Ma to present) (Lucchitta, 1972; Larson 

and others, 1975). For the first time, large-scale erosion 

allowed many units to be drained of ground water. The 

regional flow system was broken up into local flow systems 

at least down to river level, which locally corresponds to the 

top of the Paradox Formation in the Canyonlands area. 

Ground water began to flow toward the Colorado River, 

westward in the east part of the area, southward in the north 

part of the area, and eastward in the west part of the area. 

Fresh ground water replaced some saline pore water. The 

high topographic gradients induced large ground-water flows 

that were limited by available recharge.

In summary, there were six distinctive periods of 

ground-water flow in the study area. (1) From Late Permian 

to Middle Jurassic (256-155 Ma), ground water flowed 

northwest with tributary flow southwest off the Uncompahgre uplift and some eastward flow immediately following the
GROUND-WATER FLOW AND MIGRATION OF HYDROCARBONS J7

43C

115° 113° 111° 109°

37C

-_,_

NEVADA /\UTAH

I__ __ WYOMING

Figure 7. Paleogeography during the early Cenomanian Neogastroplites americanus faunal zone and deposition of parts of the 

Dakota Sandstone, Mowry Shale, and Cedar Mountain Formations. Triangle indicates location of Tar Sand Triangle; arrows indicate direction of stream and inferred ground-water flow. 

Modified from Franczyk and others (1992).

43°

113° 111° 109°

37° -

Figure 8. Paleogeography during the middle Coniacian Inoceramus deformis faunal zone and deposition of part of the Mancos 

Shale. Contours show thickness of Upper Cretaceous rocks (in 

thousands of feet), and open arrows show inferred direction of 

compaction-driven ground-water flow. Triangle indicates location of Tar Sand Triangle; arrow indicates direction of stream and 

inferred ground-water flow. Modified from Franczyk and others 

(1992).

Permian-Triassic unconformity. (2) From Late Jurassic to 

middle to late Cenomanian (155-93.5 Ma), ground water 

flowed northeast from the Elko and Sevier highlands. (3) 

From late Cenomanian to Campanian (93.5-76.6 Ma), the 

Mancos Shale was deposited, and conditions were almost 

hydrostatic. (4) During late Campanian (79.4-74 Ma), 

ground water flowed eastward from the Sevier highlands. (5) 

From middle late Campanian to late Miocene (74-10 Ma), 

flow was northward toward the Uinta Basin. (6) From late 

Miocene (10 Ma) to the present, flow was generally southwestward, but dissection by the Colorado River resulted in 

highly localized flows.

GROUND-WATER FLOW HISTORY

Knowing the topographic history and assuming that 

topographically driven ground-water flow parallels the topographic gradient and the surface-water direction, one can 

evaluate the effect of transmissivity variations along the flow

path in the Canyonlands area. Specifically, it is necessary to 

determine the extent of vertical flow upward or downward 

because vertical flow affects the migration and trapping of 

petroleum. A semiquantitative analysis was performed using 

reconstructed topographic slopes, measured thicknesses, and 

hydraulic conductivities. As a first approximation, other factors being the same, decreasing transmissivity favors upward 

flow and discharge, and increasing transmissivity favors 

downward flow and recharge. Other factors affect 

ground-water flow, but there is little o r no data on them. For 

example, changes in topographic slope affect flow, but accurate values of paleoslope are usually unavailable. Thus, only 

changes in transmissivity are considered here. Thicknesses 

of units are reasonably well known, but hydraulic conductivities are more uncertain. Uncertainty results from two 

sources. First, measured hydraulic conductivities are highly 

variable. Variations of two orders of magnitude are common. 

Given the scarcity of measurements, systematic variations 

are difficult to ascertain. Average values for many units may 

mask real variations. Second, modern hydraulic conductivi-
J8

115° 113°

EVOLUTION OF SEDIMENTARY BASINS PARADOX BASIN

109° 115° 113° 111° 109°

43°

37° -

Figure 9. Paleogeography during the late late Campanian Exiteloceras jenneyi faunal zone and deposition of part of the Tuscher 

and Farrer Formations. Triangle indicates location of Tar Sand 

Triangle; arrows indicate direction of stream and inferred 

ground-water flow. Modified from Franczyk and others (1992).

ties probably have changed from those in the past. Compaction, fracturing, dissolution, and cementation have changed 

the permeability by unknown amounts.

To judge the significance of these uncertainties I analyzed the hydraulic history using three sets of data: (1) total 

thickness of the stratigraphic section, (2) thickness of aquifers, and (3) transmissivities of the stratigraphic section. 

Using thickness removes the effect of hydraulic conductivity. This approach has the advantages of removing the effect 

of uncertainty in hydraulic conductivity and relying only on 

the relatively well known thicknesses. The drawback is that 

it ignores real, but uncertain, variations in hydraulic conductivity. Another approximation is to consider the thickness of 

aquifers only. This approach emphasizes the main 

water-conducting units and may be a closer approximation to 

actual transmissivities than thickness of the entire sedimentary package, but it avoids the uncertainties of modern, measured hydraulic conductivities. Finally, using modern 

transmissivities calculated from thicknesses and measured 

hydraulic conductivities is the best approximation to past 

transmissivities, assuming there has been no change in 

hydraulic conductivity with time. The distribution of 

hydraulic conductivity is reasonably well known for major

41°

39C

37C

 IDAHO __

NEVADA ; "UTAH" Marine

mud 

Marine sand

WYOMING

r

nter Canyor 

formation

Iz

£|i R'2 

O I m

? a .HO

o

100 200 KILOMETERS

Figure 10. Paleogeography during the early Maastrichtian Baculites reesidei faunal zone and deposition of part of the Hunter 

Canyon Formation. Triangle indicates location of Tar Sand Triangle; arrows indicate direction of stream and inferred ground-water 

flow. Modified from Franczyk and others (1992).

aquifers: the Madison-Redwall, Cutler-Maroon, and 

Weber-De Chelly (Geldon, in press).

The discrepancy between the three approaches approximates the error caused by uncertainty in past hydraulic 

conductivities. If the three approaches yield the same result, 

the result is more reliable than if the three approaches 

disagree.

The study area used for this semiquantitative analysis is 

within lat 37°30'-38030' N. and long 109°-111° W. (fig. 13). 

The area was divided into 16 cells, 4 per side, for data digitizing, contouring, and calculation. Hydraulic data, listed in 

table 2, are shown in groups of 16 values corresponding to 

the 16 cells. The five columns in table 2 are (1) thickness of 

the individual unit, (2) transmissivity of the individual unit, 

(3) cumulative thickness up from the base of the section, (4) 

cumulative thickness of aquifers only from the base of the 

section, and (5) cumulative transmissivity from the base of 

the section. Principal sources of stratigraphic and hydrologic 

data are compilations by Geldon (in press) for Paleozoic 

rocks and by Freethey and Cordy (1991) for Mesozoic rocks. 

Thickness and hydraulic conductivity for hydrostratigraphic 

units were gridded from contour maps for areas where data 

are sufficient. For the deeper units, from the Cambrian 

Flathead-Tapeats aquifer to the Triassic Chinle-Moenkopi
43°

115° 113°

GROUND-WATER FLOW AND MIGRATION OF HYDROCARBONS

111° 109° 115° 113°

J9

111°

41° -

39C

37°

_ NEVADA UTAH

WYQMTNG_

in

o

Flagstaff 

Limestone

XX XX

.4-

1

8 I

III

lO

100 200 KILOMETERS

Figure 11. Paleogeography during the early Eocene and deposition of parts of the Wasatch and Green River Formations and 

Flagstaff Limestone. Triangle indicates location of Tar Sand Triangle; arrows indicate direction of stream and inferred 

ground-water flow. Modified from Franczyk and others (1992).

37° -

Figure 12. Paleogeography during the latest Eocene and (or) 

early Oligocene and deposition of the Duchesne River Formation. 

Triangle indicates location of Tar Sand Triangle; arrows indicate 

direction of stream and inferred ground-water flow. Modified 

from Franczyk and others (1992).

confining unit, isopach data are available for most of the 

study area. From the Lower Jurassic Navajo-Nugget aquifer 

to the Upper Cretaceous Dakota aquifer, the units have been 

eroded in places within the study area, and the missing data 

are supplied by interpolation. For the Upper Cretaceous 

Mesaverde aquifer and the Upper Cretaceous Mancos confining unit, both of which are eroded from the study area, 

average values of thickness and hydraulic conductivity are 

calculated from the nearest locations at which they are 

present. For major Paleozoic aquifers, hydraulic conductivity has been contoured for the entire study area (Geldon, in 

press). For less important aquifers and for confining units, a 

constant hydraulic conductivity was used and was the 

median of the values in and near the study area. For Mesozoic aquifers (Freethey and Cordy, 1991), transmissivity has 

been contoured over the study area, and hydraulic conductivity was calculated from these values. For Mesozoic confining units, mean hydraulic conductivities are from figure 40 

of Freethey and Cordy (1991). Where data are missing, permeability in air (figure 32 of Freethey and Cordy, 1991) was 

converted to hydraulic conductivity by multiplying by the 

factor 0.003 m/day/mD (0.01 ft/day/mD). This factor is the

mean of the hydraulic conductivity to permeability ratio for 

those units for which both hydraulic conductivity and permeability are available.

Hydraulic properties of the section below the Permian 

White Rim Sandstone are controlled by three groups of 

hydrostratigraphic units: the lower Paleozoic section from the 

Cambrian Flathead-Tapeats aquifer to the Upper Mississippian to Middle Pennsylvanian Belden-Molas confining unit, 

the Lower Mississippian to Middle Pennsylvanian Paradox 

confining unit, and the Lower Pennsylvanian to Lower Permian Cutler-Maroon aquifer. Deposition of the lower Paleozoic section established the initial distribution of thickness, 

which increased regularly across the study area from southeast to northwest. The Upper Devonian to lower Upper Mississippian Madison-Redwall aquifer (consisting of the 

Mississippian Leadville Limestone in the study area) within 

this section provided most of the transmissivity. Transmissivity in the Leadville Limestone varies by two orders of magnitude in the Canyonlands area, from about IxlO"6 to 2x10^ 

m2/s (1-200 ft2/day, Geldon, in press). One highly transmissive area is in the White Canyon-Gypsum Canyon area 

southeast of the Colorado River, and another is west of the
J10 EVOLUTION OF SEDIMENTARY BASINS PARADOX BASIN

11 TOO1

110°00' 109°00'

Figure 13. Grid used for analysis of the hydrology of the Canyonlands area. Triangle indicates location of Tar Sand Triangle.

Dirty Devil River northwest of the Colorado River. The complexity of the transmissivity distribution and the magnitude 

of the variations makes difficult any generalizations for the 

area as a whole.

The Paradox Formation superimposed an irregular 

thickness distribution on the preexisting relatively regular 

distribution in that it added a "ridge" of thick sediments 

across the north-central part of the study area. Thickness 

decreased both north and south from this ridge. This feature 

subsequently dominated the entire section.

Deposition of the Lower Permian Cutler Group added a 

wedge of sediment that thinned from the Uncompahgre uplift 

in the northeast to the southwest. The most transmissive zone 

forms a "ridge" trending northeast across the study area. 

Transmissivity values range from about SxlO"6 to IxlOr4 

m2/s (3-100 ft2/day, Geldon, in press).

At the end of deposition of the White Rim Sandstone 

total thickness of the section up through the White Rim 

Sandstone varied from about 1,600 to 2,300 m (5,200-7,500 

ft), aquifer thickness from about 1,100 to 1,500 m 

(3,600-4,900 ft), and cumulative transmissivity from about 

5xlO~5 to 5x10^ m2/s (table 2). The section thins both north 

and south from the Paradox-controlled north-central thick 

area. Aquifer thickness increases to the north and east from 

the southeastern corner. Transmissivity decreases south and 

east from the northwestern corner and decreases east, west, 

and north from a south-central transmissive zone. The discrepancies among the three approaches indicate that the 

uncertainties equal the natural variations in magnitude. 

Whether ground-water flow was southwestward off the 

Uncompahgre uplift, westward off the Monument uplift, or

eastward off a local high, both upward and downward flow 

probably occurred locally in various parts of the study area.

At the end of deposition of the Upper Triassic Chinle 

Formation, total thickness of the section varied from about 

1,900 to 2,400 m (6,200-7,900 ft), aquifer thickness from 

about 1,100 to 1,500 m (3,600^,900 ft), and cumulative 

transmissivity from 3x10^ to IxlO"3 m2/s (table 2). Thickness distribution is similar to that at the end of deposition of 

the White Rim Sandstone. Total thickness decreases north 

and south from a north-central thick area. Aquifer thickness 

is the same as at the end of deposition of the White Rim 

Sandstone. Transmissivity decreases from the southwest 

toward the northeast and varies considerably within the area. 

As indicated by fluvial sandstones in the Lower and Middle(?) Triassic Moenkopi Formation and Upper Triassic 

Chinle Formation, ground-water flow was dominantly northwestward. Vertical flow based on variations in total thickness and aquifer thickness suggests recharge followed by 

discharge along the northwestward flow path. Vertical flow 

based on transmissivity suggests more variable recharge and 

discharge but slight net discharge. Again, the discrepancies 

among the three approaches indicate uncertainties having 

similar magnitude as the natural variations. For northwestward ground-water flow during deposition of the overlying 

Lower Jurassic Wingate Sandstone, the transmissivity suggests slight discharge; however, the total thickness is 

constant.

At the end of deposition of the Lower Jurassic Navajo 

Sandstone, total thickness of the section varied from about 

2,150 to 2,800 m (7,100-9,200 ft), aquifer thickness from 

about 1,350 to 1,900 m (4,400-6,200 ft), and transmissivity 

from 6x10^ to 2xlO~3 m2/s (table 2). Thickness distribution 

is essentially similar to that in the two periods previously discussed. Aquifer thickness decreases from the southwestern 

corner northward and especially eastward. Transmissivity 

decreases strongly from the northwestern corner to the southeastern corner. The gradient of decreasing transmissivity 

thus changed from northward and northeastward at the end of 

Chinle deposition to southeastward at the end of Navajo deposition. This change is mostly due to the thickness of the 

Navajo Sandstone, which thins dramatically from west to 

east (Jobin, 1962). During the period of marine, sabkha, and 

eolian deposition that followed deposition of the Navajo, 

topographic gradients were slight to nil and recharge was 

low. Ground-water flow was probably dominated by shoreline-related processes such as evaporation, sea-water refluxing, and density-driven convection. Regional flow in aerially 

exposed areas was probably toward the sea that invaded from 

the northwest. Although the total thickness variation is 

slight, increasing transmissivity in this direction suggests 

that ground water recharged into the Navajo-Nugget aquifer.

At the end of deposition of the Middle Jurassic Carmel 

Formation, total thickness of the section varied from about 

2,200 to 2,800 m (7,200-9,200 ft) and transmissivity from 

9.5x10^ to 2.6xlO~3 m2/s (table 2). Aquifer thickness
GROUND-WATER FLOW AND MIGRATION OF HYDROCARBONS 111

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Table 2. Hydraulic properties of units in Canyonlands area Continued.

Thickness (meters) Transmissivity of unit (m2/sec) Total thickness (meters) Aquifer thickness (meters)

Cum

NAVAJO-NUGGET AQUIFER

396 366 366 335 

427 396 396 335 

396 335 335 274 

396 335 335 305

1.61E-03 3.23E-04 1.08E-03 5.38E-04 

1.61E-03 3.23E-04 5.38E-04 4.30E-04 

1.40E-03 3.23E-04 3.23E-04 1.08E-04 

6.45E-04 3.23E-04 1.08E-04 8.60E-05

2,374 2,432 2,432 2,292 

2,713 2,768 2,615 2,768 

2,536 2,451 2,390 2,152 

2,384 2,384 2,384 2,289

1,631 1,664 1,664 1,609 

1,920 1,829 1,829 1,579 

1,798 1,597 1,597 1,347 

1,750 1,579 1,579 1,402

2.27E-03 

2.30E-03 

2.00E-03 

1.20E-03 

L,tiirNL.ii.-Jvujj<<rNJVuri uuiNfirNirsti umi

274 305 305 152 

305 305 152 152 

305 305 244 244 

274 305 305 274

4.84E-04 5.38E-04 5.38E-04 2.69E-04 

5.38E-04 5.38E-04 2.69E-04 2.69E^04 

5.38E-04 5.38E-04 4.30E-04 4.30E-04 

4.84E-04 5.38E-04 5.38E-04 4.84E-04

1,978 2,067 2,067 1,957 

2,286 2,371 2,219 2,432 

2,140 2,115 2,054 1,878 

1,987 2,048 2,048 1,984

6.58E-04 

6.85E-04 

6.01E-04 

5.50E-04 

WEBER-DE CHELLY AQUIFER

244 152 152 61 

152 61 61 30 

134 61 61 61 

104 61 61 61

1.08E-04 5.38E-07 8.60E-05 1.08E-05 

1.08E-05 1.08E-06 1.08E-04 8.60E-06 

1.08E-06 1.08E-04 1.08E-04 5.38E-06 

5.38E-06 2.15E-05 1.08E-04 3.23E-06

1,704 1,762 1,762 1,804 

1,981 2,067 2,067 2,280 

1,835 1,811 1,811 1,634 

1,713 1,743 1,743 1,710

1,234 1,298 1,298 1,274 

1,494 1,433 1,433 1,244 

1,402 1,262 1,262 1,073 

1,353 1,244 1,244 1,097

1.74E-04 

1.47E-04 

6.31E-05 

6.60E-05 

CUTLER-MAROON AQUIFER

244 671 671 823 

610 792 792 762 

701 762 762 640 

792 762 762 701

3.23E-06 1.08E-05 8.60E-05 1.08E-05 

2.15E-05 8.60E-05 1.08E-04 8.60E-06 

5.38E-05 1.08E-04 1.08E-04 1.08E-05 

5.38E-05 1.08E-04 5.38E-05 3.23E-05

1,460 1,609 1,609 1,743 

1,829 2,006 2,006 2,249 

1,701 1,750 1,750 1,573 

1,609 1,682 1,682 1,649

991 1,146 1,146 1,213 

1,341 1,372 1,372 1,213 

1,268 1,201 1,201 1,012 

1,250 1,183 1,183 1,036

6.67E-05 

1.36E-04 

6.20E-05 

6.06E-05 

PARADOX-EAGLE VALLEY CONFINING UNIT

122 152 152 305 

61 305 305 762 

91 213 213 366 

61 213 213 366

4.30E-06 5.38E-06 1.08E-05 3.23E-05 

2.15E-06 1.08E-05 2.69E-05 5.38E-05 

3.23E-06 7.53E-06 1.29E-05 2.15E-05 

2.15E-06 7.53E-06 1.29E-05 1.94E-05

1,216 939 939 920 

1,219 1,213 1,213 1,487 

1,000 988 988 933 

817 920 920 948

6.35E-05 

1.15E-04 

8.27E-06 

6.85E-06 

BELDEN-MOLAS CONFINING UNIT

152 55 55 12 

183 67 67 61 

152 122 122 55 

152 128 128 91

2.69E-06 9.68E-07 2.15E-07 5.38E-09 

3.23E-06 1.18E-06 1.08E-06 2.15E-07 

2.69E-06 2.15E-06 9.68E-07 5.38E-07 

2.69E-06 2.26E-06 1.61E-06 7.53E-07

1,094 786 786 616 

1,158 908 908 725 

908 774 774 567 

756 707 707 582

5.92E-05 

1.13E-04 

5.05E-06 

4.70E-06 

MADISON-REDWALL AQUIFER

320 244 244 213 

305 250 250 183 

274 244 244 189 

250 232 232 189

5.38E-05 2.15E-06 2.15E-05 8.60E-06 

1.08E-04 1.08E-06 1.08E-05 1.08E-05 

1.08E-06 1.08E-04 1.08E-05 1.08E-05 

1.08E-06 2.15E-04 1.08E-05 1.08E-05

942 732 732 604 

975 841 841 664 

756 652 652 512 

604 579 579 491

747 475 475 390 

732 579 579 451 

567 439 439 372 

457 421 421 335

5.65E-05 

1.09E-04 

2.36E-06 

2.01E-06 

ELBERT-PARTING CONFINING UNIT

73 73 73 61 

91 79 79 76 

98 91 91 79 

85 98 98 79

1.08E-06 1.08E-06 1.08E-06 3.23E-07 

1.08E-07 1.08E-07 1.08E-05 1.08E-07 

1.08E-07 1.08E-05 1.08E-05 1.08E-08 

1.08E-07 1.08E-04 1.08E-07 1.08E-08

622 488 488 390 

671 591 591 482 

482 408 408 323 

354 347 347 302

2.77E-06 

1.85E-06 

1.28E-06 

9.33E-07 
GROUND-WATER FLOW AND MIGRATION OF HYDROCARBONS J13

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remained the same. Because of the relative thinness of this 

unit, hydraulic properties of the section were essentially 

unchanged from the previous period.

At the end of deposition of the Middle Jurassic Entrada 

Sandstone, total thickness of the section varied from about 

2,300 to 3,000 m (7,500-9,800 ft), aquifer thickness from 

about 1,450 to 2,100 m (4,800-6,900 ft), and transmissivity 

from 7x10^ to 3xlO~3 m2/s (table 2). Cumulative thickness 

retains the same general pattern exhibited since the Late Permian; however, the northwestward increase in transmissivity 

that started with deposition of the Navajo Sandstone is further accentuated by deposition of the Entrada Sandstone. 

This variation in transmissivity had little effect on the immediately subsequent flow system because marine conditions 

dominated the depositional period of the Middle Jurassic 

Summerville and Curtis Formations.

At the end of deposition of the Summerville Formation, 

total thickness of the section varied from about 2,300 to 

3,050 m (5,500-10,000 ft) and transmissivity from 8x10^ to 

3xlO~3 m2/s (table 2). Owing to the thinness of the Curtis 

and Summerville, hydraulic properties of the total section 

changed only very slightly.

At the end of deposition of the Upper Jurassic Morrison 

aquifer (Salt Wash Member), total thickness of the section 

varied from about 2,400 to 3,200 m (7,900-10,500 ft), aquifer thickness from about 1,600 to 2,200 m (5,200-7,200 ft), 

and transmissivity from 8x10^ to 3xlO~3 m2/s (table 2). 

Again, the relatively thin unit had little effect on the hydraulic properties; however, the Morrison Formation represents a 

major change in topographic slope. Although the Early and 

Middle Jurassic were dominated by low-slope marine, 

sabkha, and eolian environments, the Late Jurassic exhibited 

a dominant northeast slope that persisted until the early late 

Cenomanian. In this northeast direction, total thickness, 

aquifer thickness, and transmissivity all decrease and 

indicate ground-water discharge.

It is instructive to consider flow through the White Rim 

Sandstone during this period of northeastward ground-water 

flow. It is necessary to determine if conclusions for the section as a whole apply to the White Rim Sandstone, which 

was in the subsurface at this time. I consider the hydraulic 

properties for the section up through the White Rim and 

attempt to determine if there was exchange with the section 

above the White Rim. Gradients from southwest to northeast 

for the part of the section up through the White Rim increase 

for total thickness, decrease slightly for aquifer thickness, 

and increase for transmissivity; thus, there is no clear evidence for any systematic variation in thickness or transmissivity. This suggests that there was little exchange between 

the sections above and below the White Rim Sandstone. 

Thus, flow through the White Rim apparently was virtually 

horizontal as near as can be determined. Because the thinning of the total section and the aquifers below the Morrison 

mostly reflects the Navajo Sandstone, it is likely that discharge through the Morrison Formation came from the
J14 EVOLUTION OF SEDIMENTARY BASINS PARADOX BASIN

Navajo Sandstone and did not affect the White Rim Sandstone. The same can be said for the whole period dominated 

by northeastward flow from Late Jurassic through 

Cenomanian time.

At the end of deposition of the Morrison confining unit 

(Brushy Basin Member), total thickness of the section varied 

from about 2,600 to 3,200 m (8,500-10,500 ft), and transmissivity from 8x10^ to 3xlO~3 m2/s (table 2). Topographic 

slope was still to the northeast, and ground-water flow was 

essentially the same as during deposition of the Salt Wash 

Member, although the lower slope suggests slower flow 

rates.

At the end of deposition of the Upper Cretaceous 

Dakota aquifer, total thickness of the section varied from 

about 2,600 to 3,200 m (8,500-10,500 ft), aquifer thickness 

from about 1,600 to 2,200 m (5,200-7,200 ft), and transmissivity from 9xl(H to 3xlO~3 m2/s (table 2). Flow conditions 

were relatively the same for the time period from deposition 

of the Salt Wash Member through deposition of the Dakota 

Sandstone except for some variations due to changes in 

slope.

At the end of deposition of the Upper Cretaceous Mancos confining unit, total thickness of the section had 

increased by about 600 m (2,000 ft) (table 2). Because all of 

the Mancos has been removed from the study area, there is 

no way to evaluate variations in thickness or transmissivity. 

Compaction may have been the most important driving force 

for ground-water flow, although even the maximum compaction-driven flow would be some two to four orders of 

magnitude less than gravity-driven flow (Sanford, 1990). 

Compaction-driven flow would have been upward and 

outward.

By the end of deposition of the Upper Cretaceous 

Mesaverde Group, approximately another 600 m (2,000 ft) 

of section was added, all of which has been removed by erosion. Ground-water flow was dominantly to the east during 

most of the deposition of the Mesaverde except for the final 

stages during deposition of the Campanian and Maastrichtian Fairer and Tuscher Formations when flow was 

north-northeast and north (Franczyk and others, 1992). 

Because of the lack of data for the Mancos and Mesaverde, 

it is impossible to evaluate variations in thickness and transmissivity of the total section; however, it is possible to evaluate the effect of eastward ground-water flow on the section 

that is preserved and focus on flow above and below the 

White Rim Sandstone. From west to east, total thickness 

increases, aquifer thickness decreases, and cumulative transmissivity is variable. Because of the discrepancies among 

the three approaches and the local variations, it is difficult to 

determine any consistent pattern. As well as can be determined, ground-water flow was horizontal, and there was little significant exchange between units above and below the 

White Rim Sandstone.

PENNSYLVANIAN-PERMIAN 

AQUIFERS

In order for petroleum to move from the source to the 

reservoir there must be a permeable pathway. The most 

favorable pathways for oil to reach the Tar Sand Triangle are 

sandstone units in hydrologic continuity with the White Rim 

Sandstone. A map of hydrologically connected Pennsylvanian and Permian sandstone aquifers constructed from 

numerous sources (principally Baars, 1962; Blakey and others, 1988; Hintze, 1988; Geldon, in press) shows that the 

White Rim was potentially in hydrologic communication 

with most of the upper Paleozoic rocks in Utah and adjacent 

areas until major thrusting associated with the Sevier 

orogeny disrupted the units (fig. 14).

To the south of the Tar Sand Triangle, the White Rim 

Sandstone is in hydrologic continuity with the De Chelly and 

Coconino Sandstones. In this region, an upper aquifer consisting of the White Rim, De Chelly, and Coconino Sandstones is separated from a lower aquifer consisting of the 

Cedar Mesa and Esplanade Sandstones by the Organ Rock 

and Hermit Shales that act as the confining units even where 

fractured (Geldon, in press). Thus, the upper and lower aquifers would be expected to be mostly independent hydrologically.

West of the Tar Sand Triangle and northwest of a line 

marking the pinchout of the Organ Rock and Hermit Shales, 

there is just one sandstone aquifer variously identified as the 

White Rim, Cedar Mesa, or Queantoweap. Farther to the 

west, these sandstones correlate with the Talisman Quartzite 

and the Arcturus Formation, which consist of dolomitic 

sandstone. Locally, some of these units are absent due to 

nondeposition or subsequent removal, but, if restored, the 

correlative units may have formed a continuous hydrologic 

pathway. Thus, it is possible that water and petroleum 

flowed easterly within Permian sandstone aquifers for more 

that 300 km from eastern Nevada to eastern Utah. After 

Sevier thrusting, the thrust faults probably fragmented the 

hydrologic system into separate systems. Ground water and 

petroleum may have migrated along the faults into permeable zones and thence eastward to the White Rim, or the 

thrust faults may have impeded flow.

Northwestward from the Tar Sand Triangle the White 

Rim Sandstone correlates with the Diamond Creek Sandstone. In the Oquirrh Basin of northwestern Utah, the 

Pennsylvanian-Permian Oquirrh Group forms a thick (4,300 

m, 14,000 ft) section that includes abundant sandstone. In 

northeastern Utah the partly equivalent Middle Pennsylvanian to Lower Permian Weber Sandstone and Upper Mississippian to Lower Permian Wells Formation are important 

aquifers. Before Sevier thrusting, the Pennsylvanian-Permian sandstones (Oquirrh Group, part of Wells Formation, 

and Weber Sandstone) were probably in hydrologic communication with the overlying Diamond Creek Sandstone and
GROUND-WATER FLOW AND MIGRATION OF HYDROCARBONS J15

114

39° 

EXPLANATION

Thrust fault Sawteeth on upper plate

Upper aquifer 

Confining unit 

Lower aquifer

Thickness 

(feet) 

2000

Wells Formation 

(part)

Weber 

Sandstone

Diamond Creek 

Sandstone

' Arcturus 

Formation

Permian sandstone 

removed White Rim 

Sandstone Permian

sandstone

not deposited

Permian 

sandstone

not 

deposited

Tar Sand Triangle

A

Talisman y 

Quartzite

White Rim Sandstone 

Organ Rock Shale 

Cedar Mesa Sandstone

Queantoweap 

Sandstone

DeChelly Sandstone 

Organ Rock Shale 

Cedar Mesa Sandstone

Cedar Mesa Sandstone

Coconino Sandstone 

Hermit Shale 

Esplanade Sandstone

38° 

37° 

Figure 14. Pennsylvanian and Permian aquifers (dashed lines) in Utah and adjacent States. Height of bar is proportional to thickness. 

Aquifers are unshaded, and confining units are shaded. Triangle indicates location of Tar Sand Triangle. Compiled from numerous 

sources, principally Baars (1962), Blakey and others (1988), Hintze (1988), and Geldon (in press).
J16 EVOLUTION OF SEDIMENTARY BASINS PARADOX BASIN

with the White Rim Sandstone. Thus, it may have been possible for ground water and petroleum to have flowed from 

northern Utah, southern Idaho, and southern Wyoming south 

to the Tar Sand Triangle. After thrusting, the Oquirrh Group 

and Diamond Creek Sandstone were separated from the 

Weber and White Rim by thrust faults that may have isolated 

the flow systems.

The White Rim and Cedar Mesa Sandstones both grade 

into undifferentiated Cutler Formation arkose to the east of 

the Tar Sand Triangle. Still farther to the east, the Culler thins 

to zero on the flanks of the Uncompahgre uplift. Long-range 

migration of ground water and oil from the east was virtually 

impossible, although ground-water flow from the 

Uncompahgre uplift to the Tar Sand Triangle was possible.

In summary, long-range transport of petroleum through 

Pennsylvanian and Permian sandstone aquifers that were 

hydrologically continuous with the White Rim Sandstone 

was possible until Sevier thrusting. The aquifers would have 

allowed long-range flow from the south, west, and north but 

not from the east. After thrusting, long-range migration 

would have been impeded or diverted by the thrust faults.

HYDROCARBON SOURCE ROCKS

Significant organic-rich potential source rocks are 

numerous in the region (fig. 15). As will be shown later, 

ground-water and maturation history rule out certain of these 

sources.

The Late Proterozoic Chuar Group and equivalents are 

present in the subsurface from north-central Arizona through 

central Utah to southwestern Wyoming (fig. 15) (Palacas, 

1992). Where exposed in the Grand Canyon, the Chuar 

Group (divided into the Galeros Formation below and the 

Kwagunt Formation above) is 1,637 m (5,370 ft) thick and 

consists of predominantly very fine grained siliciclastic 

rocks and thin sequences of sandstone and stromatolitic and 

cryptalgal carbonate rocks (Reynolds and others, 1988). 

More than half of the sequence consists of organic-rich gray 

to black mudstone and siltstone. Environments of deposition 

include a sediment-starved basin rich in organic material, a 

coastal or alluvial plain, and a mixed coastal or paludal 

swamp and alluvial plain (Reynolds and others, 1988). Total 

organic carbon content may be as much as 10 weight percent 

(Chidsey and others, 1990), extractable organic matter as 

much as 4,000 ppm, and genetic potential (Sj + 82) as much 

as 16,000 ppm (average -6,000 ppm) (Palacas and Reynolds, 1989). A 281-m (920 ft)-thick section consisting of 

the Walcott Member of the Kwagunt Formation (upper part) 

averages 3 weight percent total organic carbon (Palacas and 

Reynolds, 1989). Source rocks in the Walcott Member are 

within the oil generation window, whereas those in other 

units of the Chuar are mature to supermature. Saturated 

hydrocarbon gas chromatograms, biomarker distributions, 

and carbon isotope data suggest a common origin for solid

bitumens in solution-collapse breccia pipes in northern Arizona and for bitumens ("tar") in the tar-sand deposits of 

southern Utah, including the Tar Sand Triangle (Wenrich 

and Palacas, 1990). The Chuar Group has been considered 

the source for heavy oil in the Tar Sand Triangle and elsewhere in the Colorado Plateau (Allin, 1990). Although 

Chuar Group samples are similar in some respects to breccia-pipe and tar-sand samples, the similarities are not striking enough to conclude with certainty that the Chuar Group 

was the source (Wenrich and Palacas, 1990). The Mississippian Chainman Shale is the major petroleum source rock in 

the Great Basin of Nevada and western Utah (fig. 15) (Poole 

and Claypool, 1984). The Chainman consists of flysch that 

accumulated in a trough in front of the Antler erogenic highlands. The Chainman contains from less than 0.1 to 10 

weight percent total organic carbon, from 15 to 2,600 ppm 

bitumen, and from 10 to 2,000 ppm hydrocarbons (Poole and 

Claypool, 1984). Locally, it has the characteristics of a 

low-grade oil shale on the basis of Rock-Eval total hydrocarbon data (81+82) that suggest pyrolytic oil yields of 12-19 

mg/g (3-5 gal/ton). Its organic matter is favorable for petroleum generation in many parts of east-central Nevada and 

west-central Utah, and the Chainman has been identified as 

the source rock for several oil fields in Nevada. Oil generation and migration probably occurred first in the late Paleozoic or Mesozoic, perhaps associated with the Sevier 

orogeny, and later during basin and range subsidence. Several other units in the Great Basin area are also potential 

source rocks, including the Ordovician Vinini Formation, 

the Upper Devonian and Lower Mississippian Pilot Shale, 

the Mississippian Delle Phosphatic Member of the Woodman Formation, and the Upper Mississippian to Middle 

Pennsylvanian Manning Canyon Shale.

Shales of the Upper Mississippian Doughnut Formation in northeastern Utah and northwestern Colorado are in 

part equivalent to the Chainman (Meissner and others, 

1984). They represent lagoonal and estuarine deposits in a 

shallow trough. Total organic carbon content averages 2.5 

weight percent. Although the maturation level of the 

Doughnut is favorable for oil generation, the quantity of 

hydrocarbons is not significant (S wetland and others, 

1978).

The Middle and Upper Pennsylvanian Hermosa Group 

contains kerogen-rich black shale interbedded with evaporites and carbonate rocks mainly in the Paradox Formation of 

the Paradox Basin of southeastern Utah and southwestern 

Colorado. The black shales were the source of petroleum that 

now resides in overlying carbonate reservoir rocks (Hite and 

others, 1984). The shales contain as much as 21 weight percent total organic carbon. One 9-m (30 ft)-thick interval 

averaged 2.5 weight percent total organic carbon. The shales 

are thought to have produced 400 million barrels (53.6 million metric tons) of oil and 1 trillion cubic feet (28.4xl09 m3) 

of gas (Baars and Stevenson, 1982). Geothermal gradients 

suggest that maximum burial temperatures were as high as
115'

GROUND-WATER FLOW AND MIGRATION OF HYDROCARBONS

111° 109° , 115° 113° 111° 109° ... 115° 113°

J17

111° 109°

Doughnut and 

Manning Canyon 

Formations

Delle Phosphatic 

Member

Paradox Formation

PENNSYLVANIA 11 x

is

Twin Creek and 

Arapien Formations

IDAHO 

NEVADA | UTAH

Green River 

Formation

NEVADA ' i 1TAK

Kaibab 

Formation

TRIASSIC AND JURASSIC

100 200 300 400

I i i I

500 KILOMETERS

Figure 15. Potential source rocks in Utah and adjacent States for various time periods. Triangle indicates location of Tar Sand Triangle. 

Compiled from J.G. Palacas (written commun., 1992) and Meissner and others (1984).

77°C (170°F). Vitrinite reflectance and transformation ratios 

(Si/(Si+S2» are variable and difficult to interpret, but some 

of these values indicate conditions within the oil generation 

window (Hite and others, 1984). Analysis of burial history 

indicates that the Hermosa Group in the eastern and thickest 

part of the Paradox Basin was within the oil generation window in Permian and Triassic time (V.F. Nuccio, written 

commun., 1993).

The Lower Permian Phosphoria Formation of southeastern Idaho and adjacent States formed at the periphery of 

a foreland basin between the Paleozoic continental margin 

and the North American cratonic shelf (Maughan, 1984). It 

contains two members, the Meade Peak and Retort Phosphatic Shale, that consist of dark-gray shale, phosphorite, 

and chert of marine origin. The members represent the

maximum marine transgression in two cycles. Total organic 

carbon content in the Meade Peak Member is typically 

0.9-4.2 weight percent and hydrocarbon content 11-1,280 

ppm (Claypool and others, 1978). In the Retort Phosphatic 

Shale Member, total organic carbon content ranges from 0.5 

to 16 weight percent, and hydrocarbon content ranges from 

10 to 3,320 ppm (Claypool and others, 1978). A total of 

1.75xl09 million tons of extractable heavy hydrocarbons has 

been calculated for the Phosphoria black shale (Claypool and 

others, 1978), most of which is in mature and overmature 

rocks. The Phosphoria is thought to be the source of much of 

the petroleum in upper Paleozoic rocks of the northern and 

central Rocky Mountain region (Claypool and others, 1978) 

and has been proposed as the source for the Tar Sand 

Triangle deposit (Demaison, 1977).
J18 EVOLUTION OF SEDIMENTARY BASINS PARADOX BASIN

The Lower Permian Toroweap and Kaibab Formations 

consist of clastic rocks, limestone, and gypsum deposited on 

a stable continental shelf in central Utah (Bissell, 1969). Evidence of oil is present but sparse. The Kaibab is a reservoir 

for oil in the Upper Valley field on the Kaiparowits Plateau 

of southwestern Utah (Doelling, 1975). Asphalt fills vugs 

and other cavities, and sandstone and sandy limestone beds 

are petroliferous (Gilluly, 1929; Hunt and others, 1953; 

Smith and others, 1963). In the Kaiparowits Plateau, the 

Kaibab reached hydrocarbon maturity in the Late Cretaceous, and conditions remained favorable for oil generation 

through the Miocene (V.F. Nuccio, written commun., 1993). 

Because of its marine character, the Kaibab has been suggested as a possible source rock for the Tar Sand Triangle 

(Baars and Seager, 1970); however, abundant organic-rich 

black shales or other likely source rocks have not been documented. The oil that is present probably migrated in from 

another source.

The Lower and Middle(?) Triassic Moenkopi Formation is a redbed sequence that grades from dominantly fluvial 

clastic rocks in east Utah to shallow-marine limestone, dolomite, and siltstone in west Utah (Stewart and others, 1972). 

The Moenkopi is a reservoir for oil in the Virgin oil field in 

southwestern Utah. Petroliferous material has been reported 

in sandy siltstone and siltstone but was probably introduced 

after sedimentation (Stewart and others, 1972). Detrital 

asphalt has been reported from the Sinbad Limestone Member (Gilluly, 1929). Abundant organic-rich black shales have 

not been reported.

The Middle Jurassic Twin Creek and Arapien Formations of central Utah have been proposed as petroleum 

source rocks (Britt and Howard, 1982; Meissner and others, 

1984). Surface samples have total organic carbon contents of 

1.1 weight percent or less, but subsurface samples have total 

organic carbon contents as high as 4 weight percent.

Cretaceous shales are reported to have source rock 

potential, namely the Lower Cretaceous Skull Creek Shale 

and the Upper Cretaceous Mancos Shale (Britt and Howard, 

1982), Mowry Shale, Greenhorn Limestone Member of the 

Mancos Shale, Niobrara Formation, and equivalents (Meissner and others, 1984). For the latter group of formations total 

organic carbon content ranges from 0.7 to 4.0 weight percent 

(Meissner and others, 1984). The organic material is dominantly type II kerogen (oil prone). In other Upper Cretaceous 

units, such as the Frontier, Mesaverde, and Lance, organic 

matter is dominantly type III kerogen (gas prone). Because 

Upper Cretaceous shales have not reached thermal maturity 

in adjacent areas, it is doubtful whether they did in the 

Canyonlands area.

The Paleocene and Eocene Green River Formation is an 

important petroleum source rock in the Uinta Basin of northern Utah (Fouch and others, 1992). The Green River Formation consists of lacustrine and fluvial sediments that 

accumulated in a closed basin. Almost 500 million barrels of 

oil, 12-13 billion barrels of tar, and more than 1.3 trillion

cubic feet of gas were derived from the Green River through 

1991 (Fouch and others, 1992, in press). Some kerogenous 

carbonate beds ("oil shale") have total organic carbon contents as high as 60 weight percent and averaging about 6.0 

weight percent. Hydrogen indexes are as high as 500 mg 

hydrocarbons per gram of total organic carbon. The Green 

River is both source and reservoir rock. Oil generation 

probably began at the base of the Green River about 40 Ma 

and high in the section about 25 Ma (Fouch and others, in 

press).

DIAGENETIC EVIDENCE FOR 

HYDROCARBON MIGRATION

Pennsylvanian and Permian rocks of the Canyonlands 

area typically are red, and white rocks are distinctive. Field 

observations show that bleaching occurred after reddening. 

Bleaching clearly involves reduction, and probably also dissolution, of iron. Water-soluble organic acids are known to 

reduce and dissolve iron (McMahon and Chapelle, 1991; 

Cozzarelli and Baedecker, 1992). Organic-acid generation 

typically predates oil generation (Surdam and others, 1989). 

Organic acids can increase porosity by the dissolution of carbonate cement (Surdam and others, 1993). Assuming that 

bleaching is caused by water-soluble organic acids, the field 

distribution of bleached rock indicates the passage of 

organic-acid-bearing ground water (Surdam and others, 

1993) and suggests sources for subsequently generated 

petroleum.

The coloration of Pennsylvanian and Permian rocks 

was examined from White Canyon northeast to the confluence of the Green and Colorado Rivers (fig. 16). The White 

Rim Sandstone is characteristically bleached in this entire 

area. The Cedar Mesa Sandstone is thoroughly bleached 

from White Canyon to Gypsum Canyon. At The Needles on 

the south side of the Colorado River and at The Maze on the 

north side of the river, the Cedar Mesa shows interfingering 

red and bleached layers. The color variation is not lithologically controlled because the Cedar Mesa is homogeneous 

sandstone; instead, the variation may be a weakening of the 

bleaching. Approximately 5 km northeast of the Green 

River, the Cedar Mesa begins to interfmger with red, undifferentiated Cutler Formation arkose. The transition from 

white to red rocks is likely the result of the oxidation of 

organic acids by hematite in the rocks.

Sandstones of the Pennsylvanian Hermosa Group and 

Permian Cutler Group exposed in Dark and Gypsum Canyons are mostly red, except for fracture-related bleaching 

(fig. 16). Bleaching has occurred along networks of fractures 

and in seemingly unfractured rock. Isolated spheroidal 

reduction spots also are present. In Gypsum Canyon a progression from thin (1 mm) reduction zones at the edges of 

isolated fractures to thick (20 cm) reduction zones mantling 

networks of fractures to thoroughly bleached rock showing
GROUND-WATER FLOW AND MIGRATION OF HYDROCARBONS J19

sw NE

White Canyon

Dark Canyon ' 

33 0> Q-

\ Gypsum Canyon

_». Bleached -^

R

Bleached 

fractures

Bleached 

fractures

ISI

(0 

^ 




_05 

(U

Z

White Rim 

Sandstone

Cedar Mesa 

Sandstone

T Green Hi'uer

ed ^

 =

Red

\ Deadhorse Point

Undifferentiated 

^1 Cutler 

r=~ Formation

20 KILOMETERS

Figure 16. Schematic diagram showing distribution of red and 

bleached (white) Permian rocks in the Canyonlands area and inferred flow directions (arrows) of organic-acid-bearing ground 

water.

no sign of original red color is present. The progression 

shows that the bleaching postdated the reddening and that 

most bleaching is related to fractures.

Inferred ground-water flow directions are upward and 

northeastward. Because hydrocarbon generation occurs 

first at depth and because basin ground-water flow is typically upward, it is reasonable to assume upward flow in the 

fracture systems of the Hermosa and Cutler (fig. 16). In the 

Cedar Mesa Sandstone, the transition from white to red 

suggests northeastward transport of organic acids. Likewise, the pinchout of the White Rim Sandstone into red 

Cutler arkoses suggests northeastward ground-water flow. 

Thus, the coloration of rocks suggests that the source for 

petroleum in the Tar Sand Triangle was to the southwest 

and was stratigraphically below the White Rim Sandstone.

Other diagenetic reactions help constrain the timing of 

oil migration (Hansley, 1992, unpublished data). Nonferroan 

calcite cement and possibly gypsum precipitated soon after 

sedimentation, and later this calcite dissolved. An inverse 

relationship between calcite and oil suggests that organic 

acids preceding the oil caused the calcite dissolution. Abundant quartz overgrowths protrude into secondary voids and 

are coated by oil. Silica may have been transported by 

organo-silica complexes. Kaolinite fills pores and is oil 

stained (P.L. Hansley, unpublished data). Pyrite was oxidized after oil emplacement (Hansley, 1992). These data 

suggest that oil migration took place late in the burial history, possibly in the Late Cretaceous or early Tertiary.

A minimum age is indicated by the relationship 

between oil and Grand Canyon downcutting by the Colorado 

River. Oil is present on both sides of the canyon of the Green 

River, a tributary of the Colorado (I.E. Huntoon, oral commun. to P.L. Hansley, 1992). Therefore, oil must have been 

emplaced prior to canyon downcutting (P.L. Hansley, 

unpublished data). Thus, an age of about 10 Ma for initiation 

of Grand Canyon downcutting (Lucchitta, 1972; Larson and 

others, 1975) is a minimum age for oil emplacement.

EVALUATION OF HYDROCARBON 

SOURCES

A favorable petroleum source rock must be consistent 

with ground-water flow directions and with the quantity of 

organic matter and maturity of the source rock. Each potential petroleum source requires a particular flow direction to 

the reservoir; however, the implied flow direction may not 

be consistent with actual flow directions. Flow history thus 

can be used to evaluate the likelihood of a particular source. 

The Tar Sand Triangle is estimated to contain 16 billion barrels of tar (Campbell and Ritzma, 1979). The source must 

have the potential of yielding such a large quantity. The presence of adequate volumes of thermally mature organic-rich 

rocks is considered the most critical factor that limits the ultimate hydrocarbon reserves (Demaison, 1977). Both the 

amount of hydrocarbons and their maturity must be favorable. Further, the source must be mature during the time that 

ground-water flow is favorable for transport.

Petroleum from the Chuar Group must have flowed 

mainly east to reach the Tar Sand Triangle, although the 

wide distribution of the Chuar permitted flow that was southeast, northeast, and directly upward (fig. 15). Petroleum 

migration would have been crossformational up to the Permian aquifers, presumably through faults and fractures. 

From there, flow along the Permian aquifers, such as the 

White Rim, Cedar Mesa, and equivalents, would have been 

easy. Flow directions were favorable during the Late Jurassic to middle late Cenomanian and the late Campanian. The 

thickness and organic content of the organic-rich zones 

(Palacas and Reynolds, 1989) suggest that enough petroleum 

could have been generated to account for that in the Tar Sand 

Triangle. The fact that some of the Chuar is overmature 

(Palacas and Reynolds, 1989) suggest that some petroleum 

may have been generated prior to maximum burial, possibly 

in the Late Jurassic or in the Early to mid-Cretaceous. A 

northeast flow direction is also consistent with bleaching discussed above. From the standpoint of ground-water flow and 

quantity and maturity of organic matter, the Chuar is a highly 

plausible source rock.

The Chainman Shale and other potential source rocks, 

such as the Vinini Formation, Pilot Shale, Delle Phosphatic 

Member of the Woodman Formation, and the Manning Canyon Shale, in Nevada and western Utah all require eastward 

or northeastward ground-water flow directions. Such flow 

occurred from Late Jurassic to middle late Cenomanian and 

late Campanian. Favorable Permian aquifers include the
J20 EVOLUTION OF SEDIMENTARY BASINS PARADOX BASIN

Arcturus Formation, Talisman Quartzite (prior to 

metamorphism), Queantoweap Sandstone, and White Rim 

Sandstone. The presumed late Paleozoic-Mesozoic age of 

oil generation (Poole and Claypool, 1984) is compatible with 

Late Jurassic to late Campanian migration. The greatest difficulty with this source is the migration across the zone of 

thrust faults in central and western Utah. Perhaps oil migration occurred early in the erogenic episode, before the faults 

had propagated eastward. Alternatively, oil migrated across 

and along the thrusts. The Chainman and other formations in 

Nevada and western Utah are thus plausible sources for oil 

in the Tar Sand Triangle; however, there are major 

difficulties with this interpretation.

The Doughnut Formation, a partial equivalent to the 

Chainman, requires a southeastward ground-water flow 

direction to reach the Tar Sand Triangle. There was no 

known time during which ground-water flow was southeastward except in the last 10 m.y., and the dissection of the tar 

by the Green River rules out an age this young, as discussed 

previously. Thus, the Doughnut is an unlikely source.

A source in the Paradox Formation requires petroleum 

to migrate westward or northwestward. Ground water 

flowed northwest during the lengthy period from Late Permian to Middle Jurassic and flowed northward from the middle late Campanian to the late Miocene. The quantity of 

contained organic matter (Baars and Stevenson, 1982; Hite 

and others, 1984) suggests that the Paradox could account 

for the tar in the Tar Sand Triangle. Calculations suggest that 

organic matter in the Paradox Formation 30 km east of the 

Tar Sand Triangle reached maturity in the Late Permian to 

Early Triassic (V.F. Nuccio, written commun., 1993). These 

facts are consistent with oil generation and northeast migration to the Tar Sand Triangle in the Late Permian to Middle 

Jurassic period. The middle late Campanian to late Miocene 

is another possible time of migration from the Paradox to the 

Tar Sand Triangle. To reach the White Rim Sandstone in the 

Tar Sand Triangle, petroleum from the Paradox must have 

migrated through the undifferentiated Permian Cutler Formation, the Cedar Mesa Sandstone, and the Organ Rock 

Shale. Although the Cedar Mesa and White Rim are thoroughly bleached, suggestive of alteration by organic acids, 

the undifferentiated Cutler typically is red, which suggests a 

scarcity of organic acids (fig. 16). The Organ Rock has low 

permeability and also typically is red. The White Rim 

pinches out to the southeast and therefore would be favorable as a facies trap for southeast-migrating petroleum but 

not for northwest-migrating petroleum. Thus, favorable 

times for petroleum migration from the Paradox to the White 

Rim were the Late Permian to Middle Jurassic and the middle late Campanian to late Miocene; however, the configuration of aquifers and the distribution of alteration fails to 

confirm such migration.

The Phosphoria Formation requires southeastward 

petroleum migration. As discussed for the Doughnut, there 

was no time characterized by such flow prior to Grand

Canyon downcutting. Thrust faults also would have isolated 

the flow in northwestern Utah from that in southeastern 

Utah. Despite the abundant mature hydrocarbons in the 

Phosphoria (Claypool and others, 1978), it is an unlikely 

source owing to the unfavorable migration direction.

The Kaibab and Toroweap Formations, possibly partly 

correlative with the Phosphoria Formation, require 

ground-water flow to the east or northeast. Favorable flow 

existed from the Late Jurassic to the middle late Cenomanian and during the late Campanian. Because the White 

Rim is probably facies equivalent to the Toroweap and possibly to the lower Kaibab (Baars, 1979), a hydraulic connection to the Tar Sand Triangle is very straightforward. A 

serious drawback to a Kaibab or Toroweap source is the 

lack of suitable source beds. The contained petroleum 

mainly fills vugs and other cavities (Gilluly, 1929; Hunt 

and others, 1953; Smith and others, 1963), and thus probably is mostly secondary. Maturity calculations suggest that 

rocks in the Kaiparowits area reached the petroleum generation window in the Late Cretaceous (Vito Nuccio, written 

commun., 1993). Despite the convenient hydrologic pathway, favorable flow directions, and maturity, these units 

cannot be considered viable source rocks because of the 

lack of thick organic-rich source beds.

The Moenkopi is stratigraphically above the White Rim 

Sandstone of the Tar Sand Triangle. Most of the Moenkopi 

extends to the west of the Tar Sand Triangle. Petroleum 

would have had to migrate downward and eastward. 

Although the Moenkopi is in hydrologic continuity with the 

White Rim, downward migration of petroleum is problematic. The Moenkopi is a confining unit (Geldon, in press), 

and thus downward flow would be impeded. Source beds are 

present but not abundant. The lack of abundant organic-rich 

source beds also is unfavorable for a Moenkopi source.

The Twin Creek and Arapien Formations are in the 

thrust belt of western Utah. If they were sources, petroleum 

would have migrated downward stratigraphically, eastward 

and across the thrust faults. Eastward flow was most likely 

during the late Campanian. Downward flow would have 

been through two confining units, the Upper Triassic Chinle 

Formation and the Lower and Middle(?) Triassic Moenkopi 

Formation, and the thrust faults would have been an additional hydrologic barrier. Organic matter is abundant in certain samples, but whether the total quantity is sufficient to 

account for the Tar Sand Triangle is questionable. Thrusting 

may have repeated units enough to bury the Twin Creek and 

Arapien to maturation depths. Thus, the hydrologic barriers 

and the dubious quantity of hydrocarbons indicate that the 

Twin Creek and Arapien Formations are unlikely source 

rocks for the Tar Sand Triangle.

The Mancos and other Upper Cretaceous shales require 

downward migration of petroleum through many confining 

units including the Brushy Basin Member of the Morrison 

Formation, the Chinle Formation, and the Moenkopi Formation. The buoyancy of oil and the low permeability of these
GROUND-WATER FLOW AND MIGRATION OF HYDROCARBONS J21

confining units argues against such migration. The generally 

red rocks above the White Rim provide no evidence of the 

migration of organic matter.

The Green River Formation requires flow that was 

southward and stratigraphically downward. Southward flow 

is unknown prior to Grand Canyon downcutting. Downward 

flow would have had to traverse several confining units 

including the Mancos Shale, the Brushy Basin Member of 

the Morrison Formation, the Chinle Formation, and the 

Moenkopi Formation. Although the Green River has sufficient hydrocarbon content and maturity, it is unlikely, 

because of buoyancy, the presence of confining units, and an 

unfavorable flow direction, that petroleum could have 

reached the Tar Sand Triangle.

SUMMARY AND CONCLUSIONS

Six distinctive periods of ground-water flow are recognized in the Tar Sand Triangle of southeastern Utah. (1) 

From Late Permian to Middle Jurassic (256-157 Ma), 

ground water flowed northwest with tributary flow southwest off the Uncompahgre uplift. (2) From the Late Jurassic 

to the middle to late Cenomanian (155-93.5 Ma), ground 

water flowed northeast from the Elko and Sevier highlands. 

(3) From the late Cenomanian to the Campanian 

(93.5-76.6), the Mancos Shale was deposited and conditions 

were almost hydrostatic. (4) During the late Campanian 

(79.4-74 Ma), ground water flowed eastward from the 

Sevier highlands. (5) From middle late Campanian to late 

Miocene (74-10 Ma), flow was northward toward the Uinta 

Basin. (6) From late Miocene (10 Ma) to the present, flow 

was generally southwestward, but dissection by the 

Colorado River set up highly localized flows.

Analysis of the transmissivity of the hydrostratigraphic 

units through time shows that flow was mostly parallel with 

bedding in the Lower Permian White Rim Sandstone of the 

Tar Sand Triangle. There are no detectable transmissivity 

variations that would cause significant upward or downward 

flow.

Regional Pennsylvanian and Permian aquifers are 

widely distributed in Utah and adjacent States, and many are 

hydrologically connected. Thrust faults typically form barriers to flow and may have divided the hydrologic systems of 

western and eastern Utah. Thus, ground-water flow probably 

was mostly unimpeded until the Sevier orogeny. After the 

Sevier orogeny, hydrologic systems probably were more 

localized except where ground water found favorable routes 

across the thrust faults.

Potential source rocks for the hydrocarbon in the White 

Rim Sandstone include the (1) Late Proterozoic Chuar 

Group in central Utah, (2) Mississippian Chainman Shale 

and other rocks in Nevada and western Utah, (3) Upper Mississippian Doughnut Formation in northeastern Utah and 

northwestern Colorado, (4) Middle Pennsylvanian Paradox

Formation in the Paradox Basin of Utah and Colorado, (5) 

Lower Permian Phosphoria Formation of southeastern Idaho 

and adjacent States, (6) Lower Permian Toroweap and 

Kaibab Formations in central Utah, (7) Lower and Middle(?) 

Triassic Moenkopi Formation in Utah, (8) Middle Jurassic 

Twin Creek and Arapien Formations in central Utah, (9) 

Lower Cretaceous Skull Creek Shale, Upper Cretaceous 

Mancos Shale, Mowry Shale, Greenhorn Limestone Member of the Mancos Shale, Niobrara Formation, and equivalents, and (10) Paleocene and Eocene Green River 

Formation in the Uinta Basin of northern Utah.

Source rocks that require southward migration are least 

likely because southward ground-water flow is unknown. 

Thus, despite the richness in hydrocarbons, the Doughnut, 

Phosphoria, and Green River Formations are unlikely 

sources for hydrologic reasons.

Paradox Formation source rocks, which require northward or northwestward migration, were hydrologically 

favored during two periods, the Late Permian to Middle 

Jurassic and the middle late Campanian to late Miocene. 

Both periods may have been within the oil generation window. The main difficulties with a Paradox source are (1) 

ground water would have had to pass through the undifferentiated Cutler Formation which shows no evidence of large 

amounts of organic acids or oil, and (2) the pinchout of the 

White Rim Sandstone is favorable for trapping oil from the 

northwest not from the southeast.

The Chainman Shale and related units in Nevada, as 

well as units in western Utah such as the Twin Creek and 

Arapien Formations, require long-distance eastward migration across the thrust belt. The direction of ground-water 

flow was favorable from the Late Jurassic to the middle late 

Cenomanian and during the late Campanian. Many of these 

units, notably the Chainman Shale, may have contained sufficient organic matter to supply the Tar Sand Triangle. The 

major drawback is the migration across the thrust belt; 

however, migration could have occurred prior to thrusting.

Potential source rocks west of the Tar Sand Triangle but 

east of the thrust belt, namely the Chuar Group and the Toroweap, Kaibab, and Moenkopi Formations, are very favorable from a hydrologic standpoint. The direction of 

ground-water flow was favorable from the Late Jurassic to 

the middle late Cenomanian and during the late Campanian. 

Lateral flow would have been easy through the Queantoweap, Esplanade, Cedar Mesa, Coconino, and White Rim 

Sandstones. The direction of transport is consistent with field 

observations of bleaching of Pennsylvanian and Permian 

redbeds. The Toroweap, Kaibab, and Moenkopi are poor 

sources because of the scarcity of hydrocarbon-generating 

organic matter, but the Chuar Group contains abundant 

organic matter of sufficient maturity. Thus, given the present 

state of knowledge, the Chainman Shale (and other nearby 

units) and Paradox Formation cannot be ruled out, but the 

Chuar Group is the most likely source. In order to confirm 

that the Chuar or any other rock unit is indeed the source of
J22 EVOLUTION OF SEDIMENTARY BASINS PARADOX BASIN

the Tar Sand Triangle heavy oils, the composition of the 

indigenous organic matter of the potential source rock must 

be determined and compared with that of tar sand oils. In 

other words, crude oil-source rock correlations made using, 

for example, biomarker and saturated and aromatic hydrocarbon distributions and carbon isotope ratios should be conducted in order to validate or to disqualify suspected source 

rocks.

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Published in the Central Region, Denver, Colorado 

Manuscript approved for publication April 6, 1995 

Edited by Judith Stoeser 

Graphics and photocomposition by Patricia L. Wilber

U.S. GOVERNMENT PRINTING OFFICE: 1995 - 673-046 / 20000 REGION NO. 8