geology of utah importante

7/31/2019 Geology of Utah Importante

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INTRODUCTION

Grand Staircase-Escalante National Monument was

established by presidential proclama tion on September 18,

1996 to p rotect an array of geological, paleontological, his-

toric, archaeological, and b iological resources. Following

the creation of the monu ment, Congress passed the U tah

Schools and Land Exchange Act, which transferred own-

ership of all trust lands administered by the Utah School

and Institutional Trust Lands Administration (SITLA)

(176,699 acres) and trust mineral interests (24,000) acres

within the mon um ent bound aries, to the Federal Govern-

men t. In exchange for these interests, and other lands and

interests within national parks and monuments in Utah,

the State of Utah received title to federal lands elsewhere,

mineral royalties from other federal lands in Utah, and a

one-time cash paym ent. It is the first national monumen t

man aged by the U.S. Bureau of Land Managemen t (BLM),

incorporating the principles of the Federal Land Policy

and Man agemen t Act (FLPMA). The proclamation gov-

erns how the provisions of FLPMA will be applied within

the monum ent. FLPMA directs the BLM to manage pub-

lic land on the basis of mu ltiple use and in a man ner that

will protect the quality of scientific, scenic, historic, eco-

logical, environmental, air and atmospheric, water re-

sources, and archaeological resources (U.S. Depa rtmen t of

Interior, 2000).

The monument covers about 1.9 million acres of land

in south-central Utah (figure 1). Abou t 68 percent of the

monument is in Kane County, while the remaining 32 per-cent is in Garfield County. Conversely, about 49 percent of

Kane Coun ty and 18 percent of Garfield County lie within

the monu ment bound aries. The monu ment is primarily

surround ed on three sides by n ational forest and national

par k lands, as well as other BLM adm inistered lands to the

south and west. Kodachrome State Park also adjoins the

monu ment near Cannonville. For more information on

monument management and use restrictions, the reader

should refer to the app roved m anagement p lan (U.S. De-

partment of Interior, 2000)

1

Geology of Grand Staircase-EscalanteNat ional Monument, Utah

Hellmut H. Doelling1, Robert E. Blackett1, A lden H. Hamblin2, J. Douglas Powell3,

and Gayle L. Pollock4

Geology of Utahs Parks and Monuments

2000 Utah Geological Association Publication 28

D.A. Sprink el, T.C. Chid sey, Jr., and P.B. And erson , editor s

1Utah Geological Survey, Salt Lake City, UT 84114-6100

2Fremont Indian State Park and Museum, Sevier, UT 84766

3Grand Staircase-Escalante National Monument, Kanab, UT 84741

4Bryce Canyon N ational Hist ory A ssociation, Bryce Canyon N ational

Park, UT 84717-0002

ABSTRACT

The 1.9-million-acre Gran d Staircase-Escalante N ational Monum ent w as created Septem ber 18, 1996 by Presiden t Clin

ton and was the first national monument to be placed under the management of the U.S. Bureau of Land Management

Located in sou thern Utah, the m onu men t contains an ar ray of geological, paleontological, historic, archaeological, and b iological resources. It lies in a remote area comp rised of canyons, plateau s, mesas, and cliffs set in an environm ent of col

orful geologic forma tions.

The monum ent is surround ed by several national and state parks, a primitive area, and a national recreation area. I

can be d ivided into three geograph ical sections: from w est to east these are the Gran d Staircase, Kaiparow its Basin, and Es

calante Canyons sections. Rock formations exposed in these sections range in age from Perm ian to Cretaceous comp rising

more than 200 million years of Earths history. Structu rally, these rocks dip gen tly northw ard , and are deformed by m ost

ly north -south-trend ing faults, anticlines, synclines, and mon oclines.

The monu ment area contains known coal, oil and gas, and mineral resources and p otential resources which are gener

ally u nd eveloped because m arket areas are distant and because w ays of transporting the commod ities out of the region

have never been in place. As a national monum ent, the area will provide many future opportu nities to stud y a region o

remarkably well-exposed geology.


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H.H. Doelling, R.E. Blackett , A.H. Hamblin, J.D. Powell, and G.L. Pollock Geology of Grand Staircase-Escalante National Monument, Utah

2

Fi ure 1. Index ma for the Grand Staircase-Escalante National Monument in Garfield and Kane Counties

N

U TA H

0 20 miles

JunctionLong Valley

Glendale

Alton

Panguitch

Hildale

Hatch

Antimony

BoulderTown

Escalante

Tropic

Henrieville

Cannonville

Paria

AdairvilleChurch Wells

Big Water

Orderville

Mt Carmel

Kanab

JohnsonCanyon

Bullfrog

CapitolReefNationalPark

CanyonlandsNational Park

GlenCanyonNational

RecreationArea

Dixie National ForestDixie

National

Forest

BryceCanyonNationalPark

PariaCanyon

PrimitiveArea

ZionNationalPark

Grand Staircase-Escalante

National Monument

GARFIELD CO.

KANE CO.

Grand Staircase-Escalante National Monument

Glen Canyon National Recreation Area

Dixie National Forest

National Parks

Paria Canyon Primitive Area

BLM, State, and private land

Towns and settlements

Figure 1. Index map for Grand Staircase-Escalante National Monument in Garfield and Kane Counties, Utah. The 1.9-million-acre monument is

encircled by national parks, a national recreation area, a primit ive area, and a national forest. Four state parks, Coral Pink Sand Du nes, Kodachrome

Escalante Petrified Forest, and A nasazi Indian Village State Parks are also in the area, west of Kanab, near Cannonville, near Escalante, and nea

Boulder Town, respectively.

12

U T A H

A R I Z O N A

S

kutum

pah

road

PariaTownsite

JohnsonCynroad

Cottonw

ood W

ash

road

SmokyHollowLooproad

Crotonroa

d

S

moky

Mtn

road

KitchenCorralWas

hroad

G A R F I E L D C O U N T Y

K A N E C O U N T Y

Stra

ight

Cliffs

orFiftym

ile

Mountain

Cannonville

Tropic

Henrieville

Escalante

Boulder

Glendale

Orderville

Kanab

Burr Trail

WolverineLooproad

Hole-in-the-R

ockroad

Collet C

ynroad

AlveyWashroad

0 5 10 15 20

MILES

1

2

34

5

6

7

8

9

10

13

11

14

15

16

17

18

19

24

25

24

23

20

21

22

22

22

27

2527

26

27

Big Water

Grand Staircasesection

Kaiparowits Basinsection

EscalanteCanyonssection

25

8989

89

12

12

Figure 2. Map showing the locations of the classic geologic sites (nu mbers) within Grand Staircase-Escalante National Monument in southern Utah

See text for descriptions of these sites. Also, the Grand Staircase section is shown in blue, the Kaiparowits Basin section in yellow, and the Escalante

Canyons section in green.


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GEOGRAPHY

Grand Staircase-Escalante National Monument is lo-

cated within the Colorado Plateau physiographic

prov ince, near its western margin. It is bordered by the

gateway communities of Boulder, Escalante, Henrieville,

Cann onville, Tropic, Glenda le, Kanab, and Big Water (fig-

ures 1 and 2). Ann ua l precipitation in the region varies

from about six inches at the lowest altitudes near Lake

Powell (4,000 ft), to about 25 inches at the h ighest altitud es

near Can aan Peak (9,280 ft). The variations in altitude an d

precipitation produ ce three climatic zones: up land , semi-

desert, and desert. At the highest altitud es, precipitation

falls primar ily du ring the winter. The majority of precipi-

tation in the semi-desert and desert areas occurs during

the summer months.

The monum ent may be divided into three broad areas:

from west to east these are the Gran d Staircase, Kaiparow -

its Basin, and Escalante Can yons sections (figure 2). The

Grand Staircase section is a broad feature that encom-

passes the western third of the monum ent, and consists of

a series of topographic benches and cliffs that, as its nam eimplies, step progressively up in elevation from south to

north . The risers correspond to cliffs and the steps corre-

spond to the benches, terraces, or plateaus in the staircase

(figure 3). The bottom of the staircase commences at the

top of the Kaibab up lift, wh ich correlates with and is in the

same stratigraphic position as the highest bench of the

Grand Canyon in Arizona. The first riser above this bench

is the Chocolate Cliffs, wh ich are n ot well developed in the

Grand Staircase section and consists of the Upper Red

Member of the Lower Triassic Moenkopi Formation

capped by the Upper Triassic Shinarump Member of the

Chinle Formation. Descriptions of these form ations are

given in the stratigraphy section of this paper. Discontin-

uous Shinarump outcrops explain why this riser is not

well developed in the monum ent. The next step is known

as the Shinarum p Flats. This bench is mostly developed

on top of the hard Shinarump Member and the overlying

soft Petrified Forest Member of the Chinle Formation. The

Vermilion Cliffs form the next riser, which is well devel-oped in the monu ment. The cliffs are made up of the re-

sistant red sandstone beds of the Lower Jurassic Moenave

and Kayen ta Form ations. The Wygaret Terrace form s the

next step an d includes the soft upp er part of the Kayenta

and the lower parts of the Lower Jurassic Navajo Sand-

stone. The imp osing White Cliffs form the next riser and

consist of the upp er part of the N avajo Sandstone and the

Middle Jurassic Co-op Creek Limestone Member of the

Carm el Formation. The bench on this riser is the Sku-

tumpah Terrace built on the remaining soft parts of the

Carmel Formation and the overlying Entrada Sandstone

The Gray Cliffs are a series of low cliffs formed by hard

Cretaceous sand stone beds. Several benches have form edbetween these cliffs in the softer shales and sandstones of

the Tropic, Straight Cliffs, Wahw eap, an d Kaiparowits For-

mations. The final riser, mostly north and west of the

monument, in Dixie National Forest and Bryce Canyon

Na tional Park, is formed by the Pink Cliffs. The Pink Cliffs

consist of lower Tertiary limestones and marls that are

sculpted into the beautiful natural features found in Bryce

Canyon . The cliffs culminate as the Paunsaugun t Plateau

wh ich is the u pp ermost bench or step of the Grand Stair-

case.

D.A . Sprinkel, T.C. Chidsey, Jr., and P.B. Anderson, editors 2000 Utah Geological Association Publication 28

3

North

South

Claron Formation

Kaiparowits-Wahweap-Straight Cliffs Fms.

Tropic Shale

Entrada-Carmel-Page

Navajo Sandstone

Kayenta Formation

Moenave Formation

Chinle Formation

Moenkopi Formation

Permian Formations

PINK CLIFFS

GRAY CLIFFS

WHITE CLIFFS

VERMILION CLIFFS

CHOCOLATE CLIFFS

Dakota Formation

89Kaibabuplift

W ygaret

Terrace

Skutumpah

Terrace

PaunsauguntPlateauMostly in Grand Staircase-Escalante

National Monument

Mostly in Dixie National Forestor Bryce Canyon National Park

Figure 3. Diagrammatic block diagram of the Grand Staircase section of the monum ent.

Strata dip generally northward. See text for descriptions of map unit s.


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The boundary between the Grand Staircase and

Kaiparowits Basin sections is The Cockscomb, a series of

hogbacks along the East Kaibab monocline, where strata

are folded sharply dow nw ard to the east. The Cockscomb

trends ap proximately N. 20 E. from the Arizona border to

Grosvenor Arch (No. 11 on figure 2) as a sharp fold in the

strata. Dips diminish and become more gentle as the trend

wraps northwesterly north of the towns of Henrieville,Cann onville, and Tropic. The character of rocks strati-

grap hically higher than th e Tropic Shale is like that in m ost

of the Kaipa rowits Basin section an d sh ould be considered

a part of that section.

The Kaiparowits Basin section is centrally situated in

the monument and is mostly exemplified by the

Kaiparow its Plateau. Doelling an d Davis (1989) described

this section as a series of plateaus, buttes, and mesas

carved in Cretaceous rocks that reflect the structures of the

un der lying geologic strata. The Kaiparow its Basin covers

about 1,650 square miles in the central part of the monu-

men t (figure 4). The feature is a broad stru ctural basin;

however, the topographic expression is that of a north-ward -tilted, highly d issected p lateau that has been mod i-

fied by generally north -south-trend ing folds. The Aqu ar-

ius and Table Cliff plateaus lie northward and topograph -

ically above the Kaiparow its Plateau.

The Kaiparow its Plateau is bound ed by the base of the

Cretaceous strata (Hettinger and others, 1996) or the base

of the Dakota Formation. The Straight Cliffs form a prom i-

nent escarpment that rises 1,100 feet or more and extends

for more than 50 miles northwest to southeast above th e

Dakota and Tropic Forma tions. The cliffs rough ly mark

the plateaus east boundary with the Escalante Canyons

section of the monum ent. Some Jura ssic strata are exposed

in the Kaiparowits Basin section of the monument, along

its south ern bound ary, below the Cretaceous cliffs. These

Jurassic rocks have a Canyonlands character and, in-

deed, make u p the canyonlands above Glen Canyon of the

Colorado River.

The Escalante Canyons section provides a web ofmulti-hued, steep, narrow canyons and slickrock,

sculpted in the drainage basin of the Escalante River (fig-

ure 5). The section is bound ed on the southw est by the

Straight Cliffs, on the north by the Aquarius Plateau and

Boulder Mountain, on the east by the Waterpocket Fold,

and on the south by Glen Canyon of the Colorado River

The Escalante Canyons section can be subd ivided into tw o

landscapes based on physiography: Escalante canyons

and benchland s, and the Circle Cliffs uplift. The latter is a

large dou bly plun ging anticline, the core of which is erod-

ed into a large kidney-shaped physiographic basin sur-

rounded by the imposing vertical cliffs of the Wingate

Sandstone.

CLASSIC GEOLOGIC SITES WITHIN THE

MONUMENT

This 1.9-million-acre monument in colorful southern

Utah u nd oubtedly has th ousand s of sites to excite not only

professionals in geology, archaeology, botany, zoology, and

paleontology, but also any visitor with an eye for the un-

usu al and beau tiful features of natu re. Now here else in

the world are the rocks and geologic features so well ex-

4

Coal seams

Dakota Formation

Straight Cliffs Formation(coal-bearing)

Wahweap FormationKaiparowits Formation

THE COCKSCOMB

Cottonwood Wash

Chinle Formation

Glen Canyon Group(Navajo SandstoneKayenta Formation,

& Wingate-Moenave)

Carmel-Page Fms.

Entrada Sandstone

Tropic Shale

Permian Formations

Moenkopi Formation

Morrison Formation

FIFTYMILE MOUNTAINSTRAIGHT CLIFFS

Wahweap Creek

East

West

Figure 4. Diagrammatic block diagram and east-west cross section across the Kaiparowits Basin section of the monument . View is from the north

looking south. The deepest part of the basin is aligned north-south along Wahweap Creek. The strata dip generally northward, but north-south-

trendin g ant iclines and synclines warp the block. The Straight Cliffs mark the east boundary and the Cockscomb marks the west boundary of the

section.


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posed, so brilliantly colored, and so excitingly displayed.

The area is large enough to allow for many new discover-

ies to be mad e; certainly to allow for rediscoveries and re-

evaluations of geologic features, processes, and theories,

whether in the scale of the microscopic or in scales of the

vast panoramas that w ill unfold before you. In an area of

this size, not all classic sites can be mentioned because of

space constraints. The list below is small comp ared to

what is available for those who will leave their autos,

ATVs, and bicycles behind, and venture into the back-

country on their own .

The approximate locations of the following classic ge-

ologic sites are shown by nu mber on figure 2. They are al-

ph abetically arranged below. Larger scale maps, availablefrom local monu ment/ BLM offices and at the Utah Geo-

logical Sur vey offices in Salt Lake City, will help guid e you

to these features.

Access descriptions given here are general, and some

roads may not be open to the pub lic. Visitors will need to

check with Grand Staircase-Escalante N ational Monumen t

offices, contact stations, and visitor centers in local com-

mu nities to verify available access routes to these sites.

1. Buckskin Gulch and the Kaibab uplift: Buckskin

Gulch, a continuation of Kitchen Corral Wash, forms a

deep gash through Buckskin Mountain at the north end of

the Kaibab uplift in the Grand Staircase section of themon um ent (figure 6). This gash exposes the oldest rocks

(Permian) of the mon um ent: (ascending) the Hermit Shale,

Coconino Sandstone, Toroweap Formation, and Kaibab

Limestone. The Early Triassic Timpoweap Mem ber of the

Moenkopi Formation forms a carapace on top of this sec-

tion which app ears as a wh aleback from U.S. Highway

89. U.S. Highw ay 89 makes a loop aroun d the up lift,

avoiding the inclines of Buckskin Mou ntain. Access to the

top of the deep gash is provided by following a side road

(high-centered vehicles only) off the House Rock Valley


5

Moenkopi Fm.Chinle Fm.

Page-Carmel

LowerMancos Shale

UpperMancos Shale

MesaVerdeFormation

San RafaelGroup

(SummervilleEntrada)

MorrisonFormation

Page-Carmel

NavajoSandstone

Navajo SandstoneKayenta Fm.

Permian andolder formations

EastWest

EscalanteRiver

CIRCLE CLIFFS

Wagon Box

Mesa

WingateSandstone

WaterpocketFold

Escalante Canyonsand Benchlands

Circle Cliffs uplift

Figure 5. Diagrammatic block diagram across the Escalante Canyons section of the monument . This section consists of two parts. To the west are

Glen Canyon Group bench and canyonlands in cised by the Escalante River and its t ributaries. To the east is t he Circle Cliffs uplift , a large doubly

plunging, north-south-trending anticline that exposes a fossil oil field in its core. The steeply dipping Waterpocket Fold makes up the east boundary

of the uplift and is in Capitol Reef National Park.

Figure 6. Aerial view of Kaibab Gulch with the Vermilion and Whit e

Cliffs in the background. Kaibab Gulch is a cut through Buckskin

Mountain and exposes the oldest (Permian) rocks in the Grand Stair-

case section of the monument.


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H.H. Doelling, R.E. Blackett , A .H. Hamblin, J.D. Powell, and G.L. Pollock Geology of Grand Staircase-Escalante National Monument, Utah

road, w hich extends south ward from U.S. Highw ay 89 just

before the highway cuts eastward through the Cockscomb.

Hiking through Buckskin Gulch is also worthwhile.

2. Burning Hills: This area of redd ened and baked rocks

is found in the southeastern Kaiparowits Plateau

(Kaiparow its Basin section). Here, as coal beds were ex-

hum ed by erosion, coal fires were ignited by sp ontaneous

combustion as heat w as generated by the oxidation of coal

in the atmosphere. The coal was reduced to ash, reducing

the volum e by more than 90 percent. The overlying rocks

collapsed into the space, being fractured in the process.

Cracks formed by the collapse propagated to the surfaceand allowed more oxygen to reach additional coal below

the surface, keeping the fires going. The encasing rocks

were baked during the burning; shales were altered to

varicolored brick and sandstone and iron imp urities were

oxidized to give a redd ened color. Several fires still bur n

in this area. They are best recognized in the winter, wh en

steam and gases conden se at the surface. Even in the sum -

mer, however, a strong creosote smell exudes from cracks

in the ground . The Burn ing Hills can be seen from the

Croton road (No. 2 on figure 2).

3. Calf Creek Falls: Calf Creek is a south-flowing tribu-

tary of the Escalante River (Escalante Canyons section)

that heads on Boulder Mountain. It has carved a deep

canyon into the Navajo Sandstone and the Kayenta For-

mation, being controlled along a shallow syncline. Two

exquisitely beautiful and high waterfalls have formed in

the monument and are known as Upper and Lower Calf

Creek Falls. Figu re 7 gives a view of Lower Calf Creek

Falls. Calf Creek forms only one of the many spectaculartributary canyon s of the Escalante River. A two-m ile hike

up the canyon from a campsite off State Road 12 provides

access to the base of the lower falls. A view of the up per

falls can be obtained by hiking a trail that extends west

from State Road 12 a few m iles north of the campsite.

4. Circle Cliffs breached anticline: Remnan ts of a large

oil field can be seen in the rocks of the Circle Cliffs area

(Escalante Canyons section). Oil and gas became trapp ed

in this area after the rocks were deformed or folded into

this broad , north west-south east elongate dome. As ero-

sion cut throu gh the surface of the dome and into the oil

and gas reservoir, the lighter, more volatile fractions of theoil vented to the atmosphere. Left behind w ere only the

heavier, more viscous residues such as heavy bitumen or

tar, which saturated the sandstones (tar sands) of the Tor-

rey and Moody Canyon Members of the Triassic

Moenkopi Formation. Fractures formed d uring the fold-

ing process, as seen in the Jurassic Wingate Sandstone,

probably contributed to the m ovement of oil and gas into

the Moenkopi Formation from Pennsylvanian and Permi-

an source rocks. The 300-foot-high Wingate Sand stone

cliffs surroun d the d eeply erod ed center of the Circle Cliffs

anticline, giving the feature its nam e (figure 31). Drive the

Wolverine loop road to see the tar sands, cliffs, and other

features of the anticline.

5. Colt Mesa mines: These mines are found at the base of

a very thick channel of the Shinarump Member of the

Chinle Formation in the sou th p art of the Circle Cliffs area

in the Escalante Canyon s section of the monu men t. These

mines were opened in the early 1970s for the purpose of

prod ucing copp er. The ore dep osits were quite rich but

small and, in addition to copper, contained silver, molyb-

den um , and cobalt. These mines are highly interesting be-

cause the ore minerals are brightly colored and the ore

horizon is easily identifiable so that anyone can begin to

un derstan d ore emp lacemen t processes. Similar processes

were important in the emplacement of the Colorado

Plateau u ranium ores, wh ich helped usher in the Atomic

Age. The ore horizon here is a massive, med ium -grained

sandstone with tiny bits of coal interspersed throughout

The ore is in pods in the lower 6 feet of this sandstone

wh ere blue an d green copp er minerals coat, cement, and,

in some cases, replace the sand g rains. Minerals that have

been identified at this property include chalcopyrite,

pyr ite, malachite, bornite, chalcocite, and ery thrite. Access

to the mines is along a road extending south from the

Wolverine loop road . Visitors will need to walk about 1/ 4-

6

Figure 7. Lower Calf Creek Falls in the Escalante Canyons section of

the monument.


7/43

mile from a pullout to the mine site.

6. Dance Hall Rock: This prominent m onolith w ithin th e

Gun sight Butte Mem ber of the Entrad a Sand stone is locat-

ed rou ghly 40 miles southeast of Escalante along the H ole-

in-the-Rock Road (Escalante Canyons section). While the

Hole-in-the-Rock trail was being forged in 1879, Mormon

pioneers camped at Fortymile Spring and held meetings

and dances in the shelter of the stage-like erosional feature

of the Entrada Sand stone know n as Dance Ha ll Rock. The

site was designated a National Historical Site by the U.S.

Depa rtmen t of the Interior in 1970. The Hole-in-the-Rock

trail was constructed to provide access from Escalante toareas on the opposite side of the Colorado and San Juan

Rivers in southeast Utah. The pioneering effort to forge

the road, negotiate the sheer cliffs, and to cross the Col-

orado with wagons and livestock and settle southeast

Utah is considered one of the more interesting pioneering

achievements in western history. The Gun sight Butte

Member of the Entrada Sandstone has a very irregular

contact with the upper part of the Carmel Formation in

this area. In some places the smooth, round ed, orange-

brown sandstone of the Gunsight Butte Member appears

to have sunk d eeply into the bedd ed Carmel Formation

7. Devils Garden: At Devils Garden , Mother Natu re has

sculpted the Entrada Sandstone into goblins, stone babies,

monuments, and delicate arches to delight the beholder

(figure 24). The features are formed a long the contact of

the Gunsight Butte and Cannonville Members of the En-

trada Sandstone and are accessible along a short side road

extending west from the H ole-in-the-Rock Road (Escalante

Canyon s section). Some of the features are bizarre and vis-

itors have comm only attached their own informal nomen-

clature to them. When you visit the garden have fun

doing the same.

8. Entrada track site: Nor mally devoid o f fossils, the Es-

calante Member of the Entrada Sandstone at this site dis-

plays approximately 250 tracks of as many as 30 individ-

ual dinosaur s (Escalante Canyon s section). Most are three-

toed tracks of bipedal (two-legged) carnivorous d inosaur s

The site also has a trackway of a quadrupedal (four-

legged) sauropod dinosaur (herbivorous) which appears

to hav e left tail drag m arks (figure 8).

9. Escalante Canyons: Erosion of the Colorado Plateau

has resulted in the sculpting of a series of deep magnifi-

cent canyons in the Escalante Canyons section of the mon-

um ent. In mid -Tertiary time (before 15 million year s ago)

Utahs surface was a little above sea level. To the p resent

that 15-million-year-old surface wou ld have been elevated

as mu ch as 15,000 feet had erosion no t started to atta ck the

up lift. The ancestral Colorado River and its tributa ries

have irregularly cut into the rocks of the region leaving

high plateaus (some at over 10,000 feet above sea level)

cliffs, benches, and d eep canyons. A stream eroding a hard

rock formation cuts a deep canyon because it cannot erode

fast enough to keep up w ith the rate of up lift. When a

stream erodes a soft rock it can form w ider valleys. In

order to d o so it meand ers across its valley floor eventual-

ly widening the valley. These mean der s may become en-

trenched in to hard er rocks after the softer rock above is re-


7

Figure 8. Din osaur tracks in the Escalante Member of the Entrada

Sandstone near Twentymile Wash in the Escalante Canyons section of

the monument.

Figure 9. Death Hollow, aerial view looking southeast shows deeply

entrenched stream channel within Jurassic Navajo Sandstone.


8/43


moved below the stream bed. The Glen Canyon Group of

rocks, which consist of the Wingate Sandstone, KayentaFormation, and Navajo Sandstone, are relatively hard and

so the tributaries of the Escalante River have cut deep

canyons. Locally mean der s have been entrenched into the

hard er rock. The stream may locally be able to erode

across loops in the meanders to form rincons after en-

trenching has taken place, adding interest to the canyons.

Locally, natural arches and bridges are encountered in the

canyons. Figu re 9 show s Death Hollow, a tributary to the

Escalante River.

The upp er reaches of these canyons are in the m onu-

ment; the lower an d d eeper canyons are found in the Glen

Canyon Recreation Area. Access for hiking these canyonsis from the monu men t. Favorite canyons accessible from

the Hole-in-the-Rock Road include Harris Wash, Twenty-

five Mile Wash, Coyote Gu lch, Hu rricane Wash, Fortymile

Gulch, and Sooner Gulch. The upp er reaches of the Es-

calante River, together with the lower canyons of Death

Hollow, Sand Creek, Calf Creek, and Bould er Creek are ac-

cessible from State Road 12. The Wolverine Loop road and

the Burr Trail road provide access to the canyons of Deer

Creek, The Gulch, Wolverine Creek, and Death Hollow

(figu re 9).

10. Escalante monocline: The Escalante mon ocline is a

sharp flexure predominantly involving the Jurassic Nava-jo Sandstone (Esca lan te Canyons section). This m onoclin e

folds strata down to the west and trends N. 30 W. A nice

view of this feature can be seen north of the Escalante

High School or the Escalante cemetery, east of town , along

State Road 12. The Pine Creek road, which extend s north-

ward from Escalante, parallels the monocline and offers

correspond ing views. Most overlying rocks have been

stripped off the Navajo Sandstone, which helps to accen-

tuate the flexure. As viewed from high above the town of

Escalante (figure 30) the dar k rocks in the backgrou nd , on

the Aquarius Plateau and Boulder Mountain (beyond the

monument boundary), are mostly Tertiary welded tuffs(volcanic rocks). The Escalante mon ocline is the steep

west limb of the Escalante anticline, the axis of which lies

to the east. Anticlines are geologic structu res that may

trap oil and gas. The north end of the Escalante anticline

beyond the m onum ent bound ary, is known to contain car-

bon dioxide resources.

11. Grosvenor Arch: Grosvenor Arch was named after

Gilbert C. Grosvenor, the founder of the National Geo-

grap hic Society. The arch is located near the east bound -

ary of the Grand Staircase section of the monument and is

8

Figure 10. Grosvenor arch is a double free-standing feature cut in the Henrieville Sandstone, Cedar Mountain Formation, and lower part of the Dako

ta Formation in the Grand Staircase section of the monument.


9/43


10/43


this as the most sublime geologic area in the world.

18. Peek-A-Boo Gulch: Na rrow slot canyons have been

carved into Navajo Sandstone benches by small washes as

influenced by joints. During summ er monsoon storms,

these slot canyons flood with sediment-laden waters

which fur ther scour the walls and d rill poth oles. Peek-A-

Boo Gulch and Spooky Gu lch are tw o of the more pop ular

slot canyons within the mon um ent. They are located

abou t 25 miles dow n the Hole-in-the-Rock Road in th e Es-

calante Canyons section.

19. Petrified Hollow : Petrified H ollow is located east of

Kanab below the Vermilion Cliffs of the Grand Staircase

section of the monu ment near the Paunsaugu nt fault. Pet-

rified wood occurs in the Petrified Forest and Monitor

Butte Members of the Chinle Forma tion. Though collect-

ing is no longer allowed, it was a p opu lar rock-hound ing

area for man y years.

20. Phipps Arch: Set in the Navajo Sand stone, this arch

stand s above Phipp s Canyon. Over time the erosive forces

of gravity, ice, wind, and water cut this arch through a nar-

row ridgeline. This arch is located not far dow nstream

from the place where State Road 12 crosses the Escalante

River near its confluence with Calf Creek in the Escalante

Canyons section.

21. Sand dunes at Little Egypt: Wind -blown sand collects

as dunes in the Little Egypt area in the Escalante Canyons

section. H ere, Mesozoic eolian sand stones un derg oweathering, erosion, and redeposition to form an active

du ne field. The source of sand is the Entrada Sand stone.

Generally sandy areas are ubiquitous on Entrada outcrops.

22. Straight Cliff s: Forming a nearly continu ous escarp -

ment for more than 50 miles along the eastern edge of the

Kaiparowits Plateau (Kaiparowits Basin section), the

Straight Cliffs present a series of stacked m arine sand stone

layers within the Straight Cliffs Formation. These sand -

stone layers were probably barrier islands d uring th e Late

Cretaceous nearly 90 million years ago. Behind t hese bar-

rier islands swamps formed that favored the creation of

the thick coal beds seen in the Kaiparowits Plateau area.

Today, the Straight Cliffs closely follow an ancient shore-

line of the Late Cretaceous Western Interior Seaw ay. An-other name for the Straight Cliffs is Fiftymile Mountain

Between Escalante and the Colorad o River, a distance of 50

miles, only two canyons break the otherwise straight line

of cliffs (figure 12).

23. The Blues: The Kaiparow its Formation is an Upp er

Cretaceous unit that was deposited very thickly in the

Kaiparowits Basin section of the mon um ent. It forms out-

standing badlands topography in the area just south of

Powell Point. The gray or gray-blue Kaiparow its Forma-

tion is about 2,500 feet thick at the BLM viewpoint along

State Road 12. The viewpoint overlooks a nearly comp lete

section of the formation, where it is not covered by vege-tation or other debris to mar the view. Known for its abun-

dant fossil record, the Kaiparowits Formation has yielded

specimens of small mammals, sharks, crocodiles, turtles

hadrosaurs, theropods, and an kylosaurs.

24. The Cockscomb: This feature is the physiograp hic

disp lay of the East Kaibab monocline. This sharp flexure

of the earths crust is the bound ary between th e Kaiparow-

its Basin section and the Grand Staircase section of the

mon um ent; it extends 35 miles from the Arizona bord er

north ward into Garfield County. The rock strata dip

abruptly eastward at angles ranging from 15 degrees to

slightly overturned, with an average dip of 40 to 60 de-grees in the steepest pa rt of the flexure (figure 29). Rocks

on the east side of this flexure have been displaced down-

ward as mu ch as 5,000 feet. The landforms along the m on-

ocline consist chiefly of a series of closely spaced hogbacks

and strike valleys. Because of the steep folding, the rocks

have been locally faulted an d attenu ated and app ear to be

thinner than they w ere originally dep osited. The Cotton-

wood Wash road parallels the feature.

25. Vermilion Cliffs: The Jura ssic Moenave and Kayenta

Formations com bine to form th e m assive Vermilion Cliffs

10

Figure 12. The Straight Cliffs extend for fifty miles from Escalante to the Colorado River broken only by the mouths of two canyons. The Straight

Cliffs are mostly lenses of beach sand in the Straight Cliffs Formation.


11/43

a riser or step of the Grand Staircase. In the monu men t,

they can be seen north of U.S. Highw ay 89 from Johnson

Canyon to the Cockscomb, but essentially extend alongthe Utah-Arizona boundary from Washington County,

Utah to the Colorado River at Lees Ferry. Iron-oxide ce-

men t gives these formations th eir brilliant color for w hich

they are so well know n.

26. White Canyon Flat tar seep: Most of the tar exposed

in the Circle Cliffs breached anticline is in the Moenkopi

Formation, but locally, some is found in sandstone chan-

nels of the Shinarump Member of the Chinle Formation.

Located along the east edge of the monument (Escalante

Canyons section) at White Canyon Flat, tar drips from

sand stone pore spaces in the sum mer. The oil originally

filled the bottom of the Shinarum p chann el and w as prob-ably derived from the same source as that in the Moenkop i

Formation.

27. White Cliffs: The Jura ssic Navajo Sand stone is often

described a s a fossilized d esert because of its eolian or igin.

In the Grand Staircase section, the 1,800-foot-thick Navajo

consists of three parts, based on post-depositional ground-

water coloring action. The lower part is brown and cliff-

forming. The midd le par t is pink and forms both cliffs and

slopes. The upp er part is white and forms a magnificent

500- to 600-foot cliff or riser of the Grand Staircase called

the Wh ite Cliffs (figure 20). The White Cliffs are a line of

cliffs extending from Zion National Park eastward to the

Cockscomb and lie above the Verm ilion Cliffs. Take ashort drive north of U.S. Highway 89 on the Kitchen Cor-

ral Wash road throu gh the Vermilion Cliffs to get excellent

views of the White Cliffs.

28. Wolverine petrified wood area: The Wolverin e pe tri-

fied wood area is located in the Circle Cliffs (Escalante

Canyon s section). The Petrified Forest Member of the

Chinle Formation contains numerous petrified logs, at

least one of wh ich m easures 6 feet in diameter an d is near-

ly 90 feet long (figure 13). The logs represent conifer trees

covered by volcanic-ash-derived stream sed iments. Silica

from the ash replaced much of the original organic matter

in the logs du ring the p rocess of petrifaction. Araucarioxy-lon an d Woodworthia are the most common plants repre-

sented by the petrified w ood.

HISTORY

Geologic

Nearly 270 million years of geologic history is re-

vealed in the exposed rocks and paleontology of the mon-

um ent (Baars, 1972; Hintze, 1988). The oldest rocks record


11

Figure 13. View of part of a 90-foot petrified tree trunk in the Wolverine area in the Circle Cliffs.


12/43


a time when the North Am erican p late was situated su ch

that the equ ator angled n ortheasterly from southern Cali-

fornia and across the southeast corner of Utah. The area

was a marginal marine lowland of streams, flood plains,

and tidal flats. The sea lay to the west, but it occasionally

spread eastward across the area, depositing limestone

beds containing diverse shells, sponges, and other fossils

between the red beds of sandstone and mudstone that

were being dep osited on adjacent lowland s. The HermitShale, Toroweap Formation, Kaibab Limestone and

Moenkopi Formation (Blakey and others, 1993; Blakey,

1996), which crop out in the Circle Cliffs and at Buckskin

Mountain, record th e events of the first 35 million years of

exposed geologic history in the monu ment. A missing

record of nearly 20 million years separates the last record

of the Permian Period from th e Triassic Period in th e mon -

um ent (figure 14). Evidence for climatic regimes, environ-

men ts of dep osition, and other pa leohistoric data are avail-

able only from the rocks that we currently see in the mon-

um ent, or on ly 43 percent of the 270-million-year interv al.

One might ask what happened during the remaining

57 percent of time. Strata may have been deposited onlyto be eroded before the next sequence was laid down.

They may have been d eposited or eroded in environments

that differ from those recorded in the rocks that are pres-

ent. Unfortunately the missing intervals are generally not

recorded in neighboring localities; the events th at affected

the monum ent affected the region similarly. Nevertheless

there is a wealth of information found in the 43 percent of

the rocks that are present and mu ch information remains

to be gleaned from them.

The Upper or Late Triassic-age rocks in the Circle

Cliffs section have remarkable specimens of petrified

wood, includ ing logs exceeding 90 feet in length . Theselogs represent conifer trees that were left as driftwood on

river flood p lains. Cellular organic tissues were replaced

by silica derived from volcanic ashes which were deposit-

ed as p art of the Chinle Formation (Dubiel, 1994). Fossils

of other kinds of plants, fish, amphibians, and reptiles,

tracks of early dinosaurs, and freshwater clam and gastro-

pod shells also give hints about the environment an d life

in the monument during Late Triassic time (Foster and

others, 1999).

Following the Late Triassic, and a p eriod of 5 to 6 m il-

lion years of non-deposition and erosion, sand was de-

posited du ring Early Jurassic time (208 to 187 million years

ago). In the Escalante Canyon s section this sand w as ini-

tially deposited in a sand-dune desert (Wingate Sand-

stone). The desert environment changed for a time and

streams d eposited sand in channels and overbank dep osits

on flood p lains (Kayenta Formation). The desert climate

returned and sand was again deposited in a huge area of

sand d un es (Nava jo Sand stone). In the Grand Staircase

section, Lower Jura ssic tidal flats (lower M oenave Forma-

tion) gradually changed to flood plains (upper Moenave

and Kayenta Formations), and finally ended in a wind-

blown sand environment (Navajo Sand stone). These

Lower o r Early Jurassic-age rocks form the Vermilion and

White Cliffs in the Grand Staircase section and make up

the walls of the canyon and tributary canyons of the Es-

calante River. Many p eople consider these Lower Jura ssic

rocks to be the most interesting and scenic of the monu-

men t. Though generally devoid of fossils, these rocks

commonly exhibit tracks of small to medium-sized di-

nosau rs (Hamblin, 1998).

Middle Jurassic time in the monument is mostly rep-resented by the Carmel and Entrada Formations. The

Carmel was d eposited n ear the south m argin of a shallow

sea that advanced into the area from the north. Carmel

limestones contain marine mollusks, brachiopods

crinoids, coral, and algae. Desert sand du nes (beach and

back-beach sands of the Entrada Sandstone) were deposit-

ed on Carmel sediments and limestones in the wake of the

retreating Carm el sea. Anoth er 3 to 5 million year s elapsed

between the time the Entrada sands were deposited and

Upper Jurassic Morrison Formation sediments were laid

dow n. In the Escalante Canyons section, the Morrison was

dep osited by north east-flowing streams. The sluggish me-

andering an d an astomosing streams of Morrison time de-veloped broad flood plains. Dinosaurs roamed the mon u-

ment in profusion and sloshed across the streams and

through the ponds and lakes that developed on the flood

plain.

Late Jurassic to early Tertiary compressive forces in

the Earths crust formed high mou ntain ranges in w estern

Utah and eastern N evada w hich p eaked in the Late Creta-

ceous. This mou ntain-building event is known as the Sevi-

er orogeny. Simultaneously, an epicontinental sea spread

to the foot of these mountains and inundated the monu-

men t area. The sea covered most of the interior of the

North American continent from the Arctic Ocean to theGulf of Mexico, dividing the continent into two pa rts. At

its maximum extent the sea stretched to the Cedar City

area in southw est Utah, west of the monum ent. Sedi-

ments, provided by the erosion of the Sevier mountains,

were carried eastward by rivers and streams to the sea.

Dakota Formation sediments were deposited in coastal

areas ahead of the encroaching sea. The Tropic Shale rep-

resents the muds deposited at the bottom of the sea, and

the Straight Cliffs, Wahw eap, and Kaiparow its Forma tions

represent sediments deposited on a piedmont belt be-

tween the mountains and the sea after the sea retreated

east of the monu ment area. The west part of the monu-

ment area was elevated before sediments w ere deposited

during the transgressive and regressive stages of the epi-

continental sea. In the west part of the monu ment all

Upper Jurassic and a good part of the Middle Jurassic

rocks were removed by erosion before the Cretaceous sed-

iments w ere dep osited (see figure 14).

The thickness, continuity, and broad temporal distri-

bution of the Kaiparowits Plateau stratigraphy provide

opportunities to study the paleontology of Late Creta-

ceous time. Significant fossils, including marine and

brackish-water mollusks, turtles, crocodilians, lizards, di-

12


13/43


13

UPPER PERMIAN

Tcw

Tcp

Claron Formation

TKcPine Hollow Fm.Grand Castle Fm.Canaan Peak Fm.

~1,400

0-1,300

Kaiparowits Formation

2,000-3,000 Kk

Drip Tank Mbr.

Wahweap Formation

1,000-1,500 Kw

John Henry Mbr.

Smoky Mtn. Mbr.

Tibbet Cyn. Mbr.

KsStraight Cliffs Fm.

900-1,800

Tropic Shale500-750

Dakota & Cedar Mtn Fms. 3-370

Kt

Kd

Morrison Formation 0-950 Jm

Escalante Mbr.Cannonville Mbr.

Gunsight Butte Mbr.

Entrada Ss.0-1,000

Je

Upper

Lower

Jcu

JclJc

Carmel-Page Fms.180-1,040

Moenave Fm & Wingate Ss 100-350JmoJw

Kayenta Formation 150-350 Jk

Navajo Sandstone

1,300-1,500

Jn

JktTenney Cyn Tongue

Lamb Pt. Tongue

Main body

Jnl

Petrified Forest Mbr.

Shinarump Mbr.

Chinle Fm.

425-930

Trc

Trm

P

Upper red mbr.Shnabkaib Mbr.Middle red mbr.

Virgin, lower red, & Timpoweap

Kaibab Fm.Toroweap-White Rim-Coconino

Hermit Fm.

Moenkopi Fm.440-1,150

Permian Fms.655+

White mbr.

Pink mbr.

Formations, members, andthicknesses in feet

MapSymbol

Profile

Figure 6. Age, thickness and names of formations and members of geologic units exposed in the Grand Staircase-Escalante National Monument. Symbols are those used on geologic maps, figures 7, 8, and 9. Profile-lithology plot shows true relative thickness (averages) as compared with geologic time. Gray areas denotetime with missing rock records. Je includes Romana Mesa Sandstone and Henrieville Formation. Ma

Eroded

Kt-Ks

75

100

Kd

Kcm

99

LATE CRETACEOUS

EARLY CRETACEOUS

125

Jm

144

150

159

LATE JURASSIC

Je & Jc175

180

MIDDLE JURASSIC

JnJk

Jmo-Jw200

206

EARLY JURASSIC

Trc

225

227

LATE TRIASSIC

250

242Trm248

MIDDLE TRIASSIC

LOWER TRIASSIC

275

LOWER PERMIANP

50

Ma AGE

65.0

TERTIARY

Ks

Kw

Kk

TKc

Tcw & Tcp

256

Figure 14. Age, thickness and names of formations and members of geologic un its exposed in the Grand Staircase-Escalante National Monument

Symbols are those used on the geologic maps shown in figures 7, 8, and 9. Profile-lithology plot shows t rue relative thickness (averages) as compared

with geologic time. Gray areas denote time with missing rock records. Je includes Romana Mesa Sandstone and Henrieville Formation. Ma stands

for millions of years ago. Numbers between period designations indicate age of time boundary.


14/43


nosaurs, fish, and mam mals have been recovered from the

Dakota Formation, Tropic Shale, Straight Cliffs, Wahweap,

and Kaiparowits Formations. These formations prov ide

evidence of a d iverse terrestrial vertebrate fauna, especial-

ly for mammals and dinosaurs, in the 20 million years

after the retreat of the epicontinental sea. This sequen ce of

rocks in the mon um ent contains one of the best and most

continuou s records of Late Cretaceous terrestrial life in the

world (Kirkland and others, 1998; Eaton and others, 1999).The research on these strata is still in its earliest stages.

The Canaan Peak Formation straddles the boundary

between Cretaceous and Tertiary time. Dinosau rs became

extinct during its d eposition an d changes in dep ositional

environm ents followed. The Sevier mou ntains to the west

were gradually removed by erosion by early Tertiary time

and several large lakes occupied areas extending from

southw estern Wyoming to southw estern Utah. The

Claron Formation, which forms the Pink Cliffs at Powell

Point and Bryce Canyon N ational Park, was d eposited in

a lake which covered mu ch of the mon um ent area.

Much volcanic activity took place in central Utah in

mid dle Tertiary time. Today, volcanic rocks cap the Aqu ar-ius Plateau and Boulder Mountain north of the monu-

men t, but volcanic bou lders litter benches in the north p art

of the Escalante Canyon s section. All du ring the midd le

Tertiary Utah and surroun ding areas lay at low elevations,

not far above sea level. A general rise of the land scape and

tectonic activity (faulting) occurred in latest Tertiary time

and continues into the present. The Colorado Plateau up -

lift began about 15 million years ago. In western Utah th e

up lift was accompan ied by faulting brou ght on by crustal

extension (stretching). This faulting formed grabens,

horsts, and tilted fault blocks that form the north-south-

trending basins and ranges in western Utah and Nevada.The monument is located at the east edge of this basin-

and -range faulting. The Johnson Canyon and Paun-

saugun t faults are the easternmost of the basin and range

faults. Although detailed fault and seismic stud ies are

necessary, the Johnson Canyon and Paunsaugunt faults

may be active and may relate to small earth tremors and

earthquakes that have been experienced in the area

(Doelling and Davis, 1989; University of Utah Seismology

Catalog, 1986). The Grand Can yon uplift occur red simu l-

taneously with the Colorado Plateau uplift and its specific

effect extends into the monum ent area as the Kaibab up lift

(McKee & McKee, 1972; Lucchitta, 1972).

The Colorad o Plateau is still rising. The Colorad o

River and its tributaries cut deep canyons into the land-

scape and into the colorful formations dep osited in late Pa-

leozoic and Mesozoic time. The basin-and -range fau lts

continue to m ove and affect the Grand Staircase section of

the monu ment. The unconsolidated fluvial and wind -

blown d eposits that are temporarily lodged in the hollows

of the eroding formations, and on their way to the ocean,

hold the secrets of the events of the last few million years

and hold m ost of the evidence of human habitation for the

last few thou sand years.

Cultural

Archaeologists have divided th e cultu ral history of the

monu ment into six generalized periods. They are the

Paleo-Indian period (11,500-9,000 years ago), Archaic peri-

od (9,000-2,000 years ago), Early Agricultural period

(2,000-1,500 years ago), Form ative per iod (1,500-700 year s

ago), Late Prehistoric-Protohistoric period (700-150 years

ago), and the Historic period (150-0 years ago) (Spangler

and Metcalf, in preparation).

The Paleo-Indian period began at the Pleistocene-

Holocene bounda ry or at the end o f the last Ice Age. The

inhabitants of this time period hunted big game animals

such as mam moth , bison, camel, and h orse. Evidence of

their existence has been found throughout the Colorado

Plateau region in the form of large Clovis and Folsom

spear points.

The Archaic period began after post-Pleistocene

warming was complete and many of the larger mammals

had become extinct. These inhabitan ts adapted to a gath-

ering and small-game hunting way of life.

In the Early Agricultural period, corn and squashfarming was introduced into the region and by 1,200 years

ago became the dom inant means of making a living.

The Formative period is the most obvious and studied

cultural period in the monum ent area. The inhabitants

constructed more permanent storage facilities and

dw ellings, they made pottery, and the pop ulation reached

a high level. Formative people were farm ers and small-

game hunters as were those of the two previous periods

Two different groups of people were present at this time:

the Fremont culture in the northeast part an d the Anasazi

culture in the southwest part of the monu ment.

During the Late Prehistoric period, between 1300 and1500 A.D., both Anasazi and Fremont cultures left the re-

gion, most likely because of extended periods of drought

(Gieb and others, 1999).

The first written accounts of native American cultures

in this region were made by Fathers Dominguez and Es-

calante as they p assed through the region on a Spanish ex-

ped ition in 1776. Their accounts describe the inhabitants

of the Protohistoric period . These explorers noted an In-

dian culture that w as later nam ed the Southern Paiute cul-

ture. No other explorers ventured near the monum ent

until Mormon settlers began colonizing southern Utah in

the 1850s.

The last and most recent p eriod, know n as the H istoricperiod, commences with the Mormon colonization of

south ern Utah. Jour nals of these settlers described the

Southern Paiute Indians as nomadic people that moved

with the seasons to maximize their hu nting and gathering

activities. This time per iod coincides with the great west-

ern expansion of the United States of Am erica. In the

years that followed, several famous surveyors and explor-

ers traveled throu gh the monu ment region. These include

Jacob Ham blin, John Wesley Powell, Almon H. Thom pson

Clarence Dutton, G.M. Wheeler, and G.K. Gilbert. In the

14


15/43


15

MAP SYMBOLS

Q

Qg

Qb

Tc

Uncons. Quat. rocks

Pediment-mantle deps.

Basalt (lava)

Claron Formation

Kk Kaiparowits Fm.

Kw Wahweap Fm.

Ks Kws Straight Cliffs Fm. or

Str. Cliffs-Wahweap Und.Kt Tropic Shale

Kd Dakota Formation

Je Entrada Sandstone

Jcu Upper Carmel Fm.

Jcl L. Carmel & Page

Jn Navajo Sandstone

Jk Kayenta Fm.

Jmo Moenave Fm.

Trc Chinle Fm.

Trm

P

Moenkopi Fm.

Permian rocks

Faults

HighwaysRoads

Monumentboundary

Town Center

KkKwKs

Ks

Kw

Qg

Qg

Qg

Qg

Qg

Qg

Kws

Jcu

Jcl

Tc

Tc

Kt

Kt

Jcl

Jcu

Jcu

Q

Q

Q

Q

Jcl

Jn

Jk

Jkt

Jn

Jcl

Jn

Jcl

Jcl

Q

Trc

Trc

Trm

PJn

Q

Jcu

Ks

Kw

Kk

Kt

Jcl

P

Jk

Trc

Jmo

Jk

Jmo

TrcTrm

Q

Q

Q

Paunsaugun

t

fau

lt

Bucks

kin

Mou

ntain

TROPIC

CANNONVILLE

HENRIEVILLE

12

89

89

Paunsaug

unt

Pla

teau

A R I Z O N A

COCKSCOMB

COCK

SCOMB

COCKSCOMB

KAIP

AR

OWI

TS

PLATEAU

Figure 7. Generalized geologic map of the Grand Staircase section of the Monument. The Grand Staircase isnamed for a series of cliffs. The lowermost Chocolate Cliffs are aligned along the Moenkopi-Chinle (Trm-Trc)contact. The Vermilion Cliffs are aligned along the Moenave-Kayenta (Jmo-Jk) outcrops; the White Cliffs are

0 5 Miles

Qb

Qb

Kws

N

Kk

Kd

Kd

Kd

Figure 15. Generalized geologic map of the Grand Staircase section of the monument . The Grand Staircase is named for a series of cliffs. The low-

ermost Chocolate Cliffs are aligned along the Moenkopi-Chinle (Trm-Trc) contact. The Vermilion Cliffs are aligned along the Moenave-Kayenta (Jmo-

Jk) outcrops; the White Cliffs are aligned along the upper third of the Navajo Sandstone (Jn); the Gray Cliffs are here aligned along the Dakota For-

mation (Kd), and the highest Pink Cliffs are aligned just above the Kaiparowits-Claron (Kk-Tc) contact. See text for descriptions of map units.


16/43


early 1900s, H.E. Gregory began the first detailed geologic

stud y of the region. In more recent times, the lure of pre-cious metals, oil, gas, coal, uranium, and other minerals

drew prospectors, miners, and energy compan ies into the

region that p roduced m ore detailed reports on the geolo-

gy, natu ral resources, and u nique sites of the region. Due

to its harsh and remote character, the monu ment area w as

one of the last places in the continental U.S. to be mapp ed.

Today, the area is largely un pop ulated except for the sm all

and scattered communities found along the edges of the

monu ment (Cassity and Trum an, in preparation).

STRATIGRAPHY AND PALEON TOLOGY

Bedrock exposed in the m onum ent ranges in age fromEarly Permian to Late Cretaceous. Precambrian, Cambri-

an, Devonian, Mississippian and Pennsylvanian rocks are

present in the subsur face. Additionally, there are several

types of unconsolidated dep osits ranging in age from late

Tertiary to H olocene. Since the area is p resently one of ac-

tive erosion, the unconsolidated deposits are geologically

temp orary, but imp ortant w ith respect to geologic hazard s

environmental issues, and hu man habitation patterns.

The monument is large, a little over 70 miles from its

southernmost p oint to its northernmost point and about 82

16

Jn

Town Center

Q Ucons. Quat. rocks

Qg Gravel deposits

Qms Landslides & slumps

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Pine Hollow Fm.Grand Castle Fm.Canaan Peak Fm.

Kaiparowits Fm.

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Tropic Shale

Dakota Formation

Morrison Fm.

Entrada Sandstone

Jc Carmel Formation

Navajo SandstoneJn

Faults

HighwaysRoads

Monumentboundary

KAIPAROWITS PLATEAU

POWELL

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GEOLOGY NOTSHOWN12

A R I Z O N A

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ESCALANTE

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89

Figure 16. Generalized geologic map of the Kaiparowits Basin section of the monum ent. This section represents a large structural basin, but is topo-

graphically high. Part of the Escalante Canyons section is represented northeast of Fiftymile Mountain. See text for descriptions of map unit s.


17/43


17

N

Figure9.Generalizedgeolo

gicmapoftheEscalanteCanyonssectionoftheMonument.Thissection

iscomprisedoftwoparts:theCircle

Cliffsareatotheeast

whichabutsagainsttheWaterpocketFold(CapitolReef

NationalParkandtheBench-and-Ca

nyonlandsareatothewest,dominatedbytheNavajo

Sandstonebenches

.Seetextfordescriptionsofmapun

its.

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Volcanicrocks

TarantulaMesaSandstone

MuleyTwist-MasukFms.

Ferron-BlueGateFms.

StraightCliffsFormation

Tropic-TununkShale

DakotaFormation

MorrisonFormation

Entrada-Summerville-Curtis

Carmel-PageFormations

NavajoSandstone

KayentaFormation

WingateSandstone

ChinleFormation

MoenkopiFormation

Permianformations

MAPSYMBOLS

Faults

Roads

Monument

Boundary

TownCenter

Q

Q

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Figure17.

Generalizedgeologicmap

oftheEscalanteCanyonssectionofthemonument.Thissectioniscomprisedoftwoparts:theCircleCliffsareatotheeastw

hichabutsagainsttheWa-

terpocketFold(CapitolReefNational

Park)andtheBench-and-Canyonlandsar

eatothewest,dominatedbyNavajoSand

stonebenches.

Seetextfordescriptionsofmapunits.


18/43


miles from its westernmost point to its easternmost point.

Some of the geologic formations un dergo significant facies

and oth er changes over these distances. Exposed strata in

the Grand Staircase section total from 6,000 to 7,000 feet

and ran ge from Permian to Cretaceous in age. Exposed

strata in the Kaiparowits Basin section also total from 6,000

to 7,000 feet, but r ange in age from Midd le Jura ssic to lat-

est Cretaceous, with a much thicker Cretaceous section.

Exposed stra ta in th e Escalante Can yons section total 4,500

to 5,500 feet and range in age from Permian to Late Jur as-

sic. A list of un its is given on figure 14 and are shown on

the geologic map s, figu res 15 to 17.

Permian Rocks (P)

Permian rocks are the oldest rocks exposed in the

monu ment. Outcrops are present in Buckskin Gulch and

in adjacent canyons associated with the Kaibab uplift in

the Grand Staircase section and are present in scattered

places in the core of the Circle Cliffs uplift in the Escalante

Canyon s section. In the Kaibab up lift the (ascending ) Her -

mit Shale, Coconino Sand stone, Toroweap Form ation, and

Kaibab Limestone are exposed; in the Escalante section-

Circle Cliffs uplift the White Rim Sandstone and the

Kaibab Formation are exposed.

Hermit Shale

Only the upper 55 feet of the Hermit Shale is exposed

in Buckskin Gu lch. The Herm it is red silty sand stone, silt-

stone, micaceous shale, claystone, and m inor dolom ite. It

correlates with the Organ Rock Shale in eastern Utah,

wh ich m ay u nd erlie the White Rim Sandstone in the Cir-

cle Cliffs area. Wells ind icate the Hermit-Organ Rock

ranges from 100 to 600 feet thick, thickening southward

und er the monum ent. The unit was deposited partly in a

fluvial environment and partly in a tidal-flat environment.

As yet no fossils have been found in the Hermit Shale

within the mon um ent. Fossils from the H ermit Shale out-

side the monument include land plants, insects, amphib-

ian footprints, and worm trails (Gillette and Hayden,

1997).

Coconino Sandstone

Less than 64 feet of Coconino Sandstone is present

above the H ermit Shale in Buckskin Gu lch. There it con-

sists of alternating beds of arenaceous limestone and ir-

regularly bedded fine-grained buff sand stone. The lime-stones contain poorly preserved m arine fossils. At the

Grand Canyon it is 330 to 350 feet thick and is a uniform

fine-grained, cross-bedded, white to light-gray sandstone

with siliceous cement. At Buckskin Gu lch it probably in-

terfingers with the lower p art of the Brady Canyon Mem-

ber of the Toroweap Formation. Drill holes indicate it is

present only in the south half of Kane County. The Co-

conino is probably a near-shore deposit grading south-

ward into a beach sand.

Toroweap Formation-White Rim Sandstone

The Toroweap Formation can be divided into two

members in Buckskin Gulch: a lower 90-foot section ofcliff-forming, cherty, fossiliferous limestone interbedded

with calcareous sandstone and 175 feet of slope-forming,

mostly yellow preceded by mostly gray to red, very fine

and medium -grained (bimodal) gypsiferous sandstone

The upper beds locally contain gypsum, marl or traver-

tine, and intraforma tional conglomer ate. The lower cliff-

former is known as the Brady Canyon Member and the

upper slope-former is known as the Woods Ranch Mem-

ber. The Toroweap was dep osited in and ad jacent to a

shallow sea and represents a single marine transgressive

and regressive cycle (McKee, 1938).

The oldest exposed geologic unit in the Circle Cliffsup lift is the White Rim Sandstone. There it can be divid ed

into two units. The lower un it, of which up to 108 feet is

exposed, is white quartzose cross-stratified sandstone of

eolian origin. The grains are very fine to fine, subangu lar

to angu lar, and are mostly siliceously cemen ted. The

lower unit intertongues with the upper. The upper un it is

thin to thick planar-bedd ed and is 65 to 155 feet thick. It

consists of pale-yellow to yellow-brown dolomitic sand-

stone with a few sand y dolomite beds. Grains are very

fine to fine and subround ed to round ed. Some beds con-

tain poorly preserved fossils such as fragments of gas-

tropods and pelecypod s. It is assumed that these beds

were laid dow n as a tran sgressive marine deposit as Per-mian seas encroached eastward . The White Rim Sand-

stone in the Circle Cliffs area is a resistant unit.

The Toroweap Formation and White Rim Sandstone

grad e into each other u nd er the Kaiparowits Basin section

Logs of oil-test wells west of the basin recognize only th e

Toroweap Form ation. Logs of oil-test-wells in the basin

generally give thicknesses for the Toroweap or for both the

Toroweap and Wh ite Rim. East of Fiftymile Mountain, in

the Escalante section of the monument, only White Rim

thicknesses are reported.

18

Upper red mbr.

Shnabkaib Mbr.

Middle red Mbr.

Virgin Limestone Mbr.

Lower red mbr.

Timpoweap mbr.

Moody Canyon Mbr.

Torrey Member

Sinbad Member

Black Dragon Mbr.

Chinle Formation

Permian Formations

Circle Cliffs areaGrand Staircase section

Figure 18. Correlation of the Moenkopi Formation members between

the Grand S taircase section and Circle Cliffs area. Green-colored mem-

bers represent marine encroachments from the west; pink-colored mem-

bers are red-bed deposits. The Moenkopi thickens westward.

W E


19/43

Kaibab Formation

The Kaibab Formation is present under most of the

monu ment, but generally thickens westward . In the

Kaibab uplift it is about 160 to 280 feet thick, but the Circle

Cliffs outcrops (in the Escalante Canyons section) are at

most 60 feet thick. In the Circle Cliffs area the Kaibab is a

thin-bedd ed, light-yellow dolom ite. It is absent in the

southern part of the Circle Cliffs, where it may have been

removed by Late Permian an d Early Triassic erosion ratherthan by just pinching ou t to the east. The Kaibab has been

encountered in oil-test wells east of the monument.

In the Circle Cliffs area the Kaibab is a very fine to

fine-grained , oolitic, porou s dolom ite. Interbedd ed are a

few partings of green glauconitic feldsp athic sand stone. It

erodes to ledgy slopes and the upper beds contain small

quartz geod es, stringers of gray chert, and gray chert nod-

ules and fragm ents. Locally the beds contain fossils with

fossil hash as much as 6 inches thick. The hash includes

crinoid colum nals, pelecypods, gastropods, p roductid bra-

chiopods and various spines and spicules (Davidson,

1967).In the Kaibab uplift (in the Grand Staircase section),

the Kaibab Formation can be divided into two members.

The lower Fossil Mountain Member is 140 to 200 feet of

massive cliff-forming, fossiliferous, cherty gray limestone

and calcareous, commonly cherty, well-indurated fine-

grained sandstone. The chert is found as nodu les, in beds,

and in irregular bodies. White sph eroidal chert is most

distinctive. Some beds are qu ite fossiliferous, containing a

wide variety of mar ine fossils includ ing branched and fen-

estellid-type bryozoans, rugosid corals, crinoids, bra-

chiopods and the sponge Actinoceolia (Foster and others,

1999).

The upper Harrisburg Member is 15 to 80 feet thick.Beds in the upper member are medium to thick bedded

and unfossiliferous. The lower p art of the up per mem ber

is mostly cherty limestone. Toward the top, sand stone

beds become num erous. The unit is capp ed by a hackly

weathering blocky gray limestone bed. The upp er half of

the bed displays vertical tubes filled with brown, rough-

weathering, sandy chert (biotur bation features?). The Fos-

sil Mountain Member w as deposited in an ad vancing sea

and the H arrisburg Mem ber in a retreating sea.

Triassic Rocks

Moenkopi Formation (Trm)

The Lower Triassic Moenkopi Formation is divisible

into four to six members in the monum ent. In the Grand

Staircase section the members are (ascending) Tim-

poweap, Lower Red, Virgin Limestone, Middle Red, Shn-

abkaib, and Up per Red. In the Escalante Canyon s section

the members are (ascending) Black Dragon, Sinbad, Tor-

rey, and Moody Canyon. A Black Dragon equivalent may

not be present in the Grand Staircase section. The Tim-

pow eap Member correlates in time w ith the Sinbad Mem-

ber, while the Lower Red, Virgin Limestone and Middle

Red Members correlate with the Torrey Member. The

Shnabkaib and Upper Red Members correlate with the

Moody Canyon Mem ber (Blakey, 1974). In the Grand

Staircase section, the Moenkopi Formation ranges from

910 to 1,150 feet in thickness. In the Escalante Canyons

section, the Moenkopi ranges from 440 to 730 feet in th ick-

ness.

The Moenkopi Formation is bounded above and

below by regional un conformities. The lower bound arymay be described as a disconformity of low relief. The

upper boundary is also a disconformity, but locally, chan-

nels of the overlying Shinarump Member have cut d eeply

into the Moody Canyon and Upper Red Members.

Moenkopi Formation m ember relationships are show n on

figure 18 (Blakey, 1974).

Fossils from th e Moenkop i are a mix of terrestrial and

mar ine taxa. They include plants, crinoids, brachiopod s

gastropods, bivalves, ammon oids, nautiloids, arthrop ods

fish, reptiles, labyrinthodont amphibians, and reptile foot-

prints (Gillette and H ayden, 1997). Reptile tracks are

know n from a nu mber of localities in both the Grand Stair-

case and Escalante Canyons sections of the m onu men t (seeHamblin, this volum e). Horseshoe crab tracks have been

found in the Circle Cliffs area (Foster and others, 1999).

Black Dragon Member: The Black Dragon Member is ex-

posed in the north Circle Cliffs area in the Escalante

Canyons section of the monu ment w here it ranges up to 40

feet in thickness. It is not present in the area south of the

Burr Trail road. Typically the member consists of laminat-

ed to very thin-bedd ed siltstone and silty sand stone. It is

locally ripple marked and intercalated with thin-bedded

very fine-grained , micaceous sand stone. Comm only the

base of the member contains chert or qu artz pebbles and

locally chert-pebble conglomerate. It form s a steep slope

and w eathers flaggy or earthy. Locally, some gypsum m ay

be found in this un it. It is though t that the unit was de-

posited on a mu dflat or tidal flat and in associated lagoons

(Blakey, 1974).

In the Grand Staircase section, the Timpoweap Mem-

ber rests directly on the Harr isburg Mem ber of the Kaibab

Formation. In a short gulley being eroded into the side of

the steep flank of the Kaibab uplift, a very thin section of

tan and red sand y siltstone is foun d betw een the top of the

Kaibab and normal Timpow eap Member beds, wh ich m ay

correlate w ith the Black Dragon Mem ber.

Sinbad Member - Timpoweap Member: The Sinbad

Member overlies the Black Dragon Member in the Circle

Cliffs area in the Escalante Canyons section of the monu-

men t. The Sinbad Member is up to 55 feet thick in the Cir-

cle Cliffs area, thickening to the northw est. It is missing in

the southeast part of the Circle Cliffs, but its outcrops ex-

tend a little farther southeastward than those of the Black

Dragon Mem ber. On the Kaibab up lift (Buckskin Moun-

tain) the Timpoweap Member forms a thin but resistant

20- to 50-foot carapace over the u plift wh aleback.

In the Circle Cliffs area th e Sinbad Member consists of


19


20/43


yellow-gray to pale-orange-brown weathering limestone,

dolom ite, and calcareous siltstone. The beds are thin,

weather platy, and form bench-forming ledges. It inter-

tongues with the Black Dragon Member below and the

Torrey Member above. Some limestone bed s are fossilifer-

ous, containing mostly poorly preserved pelecypods and

gastropods. The Meekoceras zone has been correlated into

the Sinbad -Timpow eap Mem bers, but no truly recogniza-

ble cephalopod s have yet been found so far in either unitin the monument (Davidson, 1967; Blakey, 1974).

At Buckskin Mou ntain, the Timpow eap Mem ber con-

sists of highly resistant carbonate rocks, sandstone, chert

breccia, and siltstone. Some of the sand stones are pebbly.

The overall color is light brown to yellow gray and the in-

dividual beds are thin to thick bedd ed and blocky. The

up per half is more resistant than the lower p art. The con-

tact between the Kaibab and Timpoweap is difficult to dis-

cern, but the Timpoweap is generally slightly darker than

the very light Kaibab Forma tion beds. The Sinbad -Tim-

pow eap Member was deposited in a marine environment

representing a transgression that extended the farthest

east in the Moenkop i dep ositional basin. The thin, even

beds in th e Circle Cliffs might ind icate qu iet water d eposi-

tion, whereas the chert breccias in the Timpoweap might

indicate dep osition in more turbu lent waters.

Lower red member: The lower red member of the

Moenkopi laps onto the lower parts of the Kaibab uplift

whaleback, where it is 140 to 220 feet thick, thickening

westward . It consists of red to chocolate-brow n, interbed -

ded and thin-bedd ed siltstone and fine-grained sandstone.

The unit is earthy w eathering an d forms slopes w ith slight

ledges. The sandstones are silty, arkosic, and m icaceous.

The ledges weather platy and display abundant ripplemarks. The lower red member was dep osited on a tidal

flat traversed by meander ing streams (Irwin, 1976). It cor-

relates with the lower part of the Torrey Member in the

Circle Cliffs area.

Virgin Limestone Member: The Lower Red Member is

overlain by the Virgin Limestone Member around the

Kaibab up lift south of Paria. The un it is only 10 to 30 feet

thick, and thickens to the west. It is conspicuou s because

it is ledge forming. It consists of interbedded yellow-

brown sandstone, siltstone, and limestone. The limestone,

a minor constituent here, is very sandy and grades into

calcareous sand stone in eastern sections. The pinchout ofthe Virgin Limestone Member probably is not far to the

east of Buckskin Mountain. It is not fossiliferous in the

monu ment w here it marks the eastern limit of a Moenkopi

mar ine incursion. The Virgin Limestone Member corre-

lates with part of the Torrey Member in the Circle Cliffs

area.

Torrey Member: The Torrey Mem ber overlies the Sinbad

Member in the Circle Cliffs up lift in the Escalante Canyon s

section of the monumen t. There it is 240 to 310 feet thick

and like the other members in the u plift, thickens north-

westerly. The very fine to fine-grained san dston e and silty

sandstone forms thin- to medium-bedded ledges, cliffs,

and slopes. The slope-forming constituen ts are generally

quite micaceous and the ledge formers display ripple

marks, load casts, drag structures, and even animal trails.

A few mud -pebble conglomerate lenses and mud stone

lenses are also present in the un it. The color of the mem -

ber ranges from p ale red-brown to gray red w here not sat-

urated with tarry hydrocarbons. Locally hydrocarbonshave bleached the Torrey Member, making it pale yellow-

brown to gray and even black, according to the degree of

saturation.

The Torrey Member correlates with the Lower Red

Member, Virgin Limestone M ember, and low er pa rt of the

Middle Red Member in the Grand Staircase section of the

monu ment. The Torrey Member was d eposited in a delta-

ic and shoreline environment. The upp er contact with the

Moody Canyon Member is intertonguing to gradational

and sometimes d ifficult to place.

Middle red member: The midd le red member overlies the

Virgin Limestone Member in the a rea betw een the Vermil-ion Cliffs and the Kaibab u plift in the Gran d Staircase sec-

tion of the monu men t. Much of it is covered by Quater-

nary unconsolidated deposits (alluvium and colluvium)

It is the thickest of the Moenkopi members in this section

and the least resistant to erosion. Its soft and slope-form-

ing nature h as indu ced many of the local drainages to flow

along its strike. It is 280 to 400 feet thick and probably

thickens westward .

The midd le red member consists of interbedded med i-

um-brown to chocolate-brown mudstone and siltstone

and light-brown, tan, or gray-green, fine-grained silty

sand stone. Many of the beds are criss-crossed with gyp-

sum veinlets. The more resistant thin-bedd ed sand stones

are commonly ripp led. The amou nt of gypsum in the

member increases up ward . It was probably deposited in

mu dflat and tidal flat environm ents. Blakey (1974) corre-

lated the lower midd le red member w ith the upper p art of

the Torrey Member and the upper part of the middle red

member with the lower part of the Moody Canyon Mem-

ber in the Circle Cliffs uplift.

Shnabkaib Member: The Shnabkaib Member overlies

the middle red member in the area between the Vermilion

Cliffs and Kaibab uplift in the Grand Staircase section of

the m onu men t. There it is 150 to 250 feet thick, thickening

westw ard . It is a ledge- and slope-forming u nit consisting

of ledges of white to light green silty gypsum and light-

brown very fine-grained sandstone and slopes of earthy

weathering very fine-grained sandstone and red and

green-gray siltstone. The lower contact is placed just

und er the first thick gypsum bed and the up per just above

the uppermost thick gypsum bed.

The Shnabkaib was probably deposited in restricted

embayments of a sea surrounded by low tidal-flat and

mu d-flat areas. The open sea lay to the west and en-

croached eastward from time to time, carrying in a fresh

20


21/43

supply of calcium and sulfate ions needed to precipitate

the gypsum.

Upper red member: The upp er red m ember is the upp er-

most mem ber of the Moenkopi Formation an d overlies the

gypsiferous Shnabkaib Member in the area between the

Vermilion Cliffs and the Kaibab uplift in the Grand Stair-

case section. It is 90 to 180 feet thick, thickening to the

west. It is a dark chocolate-brown to red-brown un it. The

lower half forms a steep slope and the up per h alf weathersinto ledges. The chocolate-brown ledge- and cliff-forming

characteristic at the top of the member, coupled with the

overlying cliff-forming Shinarump Member of the Chinle

Formation form the Chocolate Cliffs riser of the Grand

Staircase. How ever, the Chocolate Cliffs are better devel-

oped to the west, between the Hurricane and Paunsau gunt

faults on the Arizona strip. In the monum ent, the Shi-

narum p is discontinuous and does not form a conspicuou s

and continuou s line of cliffs.

The upper red member is composed of interbedded

siltstone and sand stone. The siltstones are dark chocolate

brown to red brown, micaceous and sandy, and shaly tothin bedd ed. The sandstones are light brown to red

brown, very fine grained, micaceous, and calcareous. The

principal ledges are medium to thick bedded but w eather

blocky, platy, or shaly. As in most Moenkop i members,

many sand stone beds are ripp le marked and mu d cracked.

The upp er red m ember is mainly a tidal flat deposit.

Moody Canyon Member: The Moody Canyon Member is

200 to 330 feet th ick in the Circle Cliffs up lift area of the Es-

calante Canyons section, thickening to the west. It is most-

ly a slope former composed of red-brown interbedd ed silt-

stone and mu dstone. Dolomite, gypsum , and sandstone

are minor constituents. It is finely to poorly laminated tothin bedded, but is generally earthy weathe

geology of utah importante

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