USGS Logo Geological Survey Water-Supply Paper 1475-M
Ground-Water Resources of the Bryce Canyon National Park, Utah

GEOLOGY

STRATIGRAPHY

The oldest rock formation known to underlie the Bryce Canyon area is the Redwall limestone of Mississippian age. This formation was penetrated at a depth of 10,189 feet below the surface in an oil test in Johns Valley (table 4) about 12 miles northeast of the lodge and headquarters area (off pl. 24). This same test hole passed through 779 feet of Pennsylvanian strata comparable to the Molas and Hermosa formations. Rocks of Permian age were penetrated in the Lion Oil Co. test hole, 4 miles northwest of the lodge and headquarters area (pl. 24; table 4). These rocks were the Coconino sandstone, the Toroweap formation, and the Kaibab limestone.

TABLE 4.—Logs of wells and auger holes in the Bryce Canyon National Park area, Utah
[See pls. 24, 25A for location. All water levels in this table are in feet below land surface]


Thickness
(feet)
Depth (feet)
Headquarters well, National Park Service
Yield, 160 gpd; diameter, 48 in. to 30 ft, 12 in. to 50 ft, 8 in. to 80 ft.
Static water level, 49 ft.


Alluvium: Old dug well3030
Wasatch formation:
   Rock1040
   Fractured rock1050
   Rock3080
Well 1, Utah Parks Co.
Yield, 180 gpm; diameter, 12 in.

Alluvium:
   Clay1212
   Gravel315
   Porous formation924
   Tight formation630
Wasatch formation: Dry chalky formation5080
Well 2, Utah Parks Co.
Yield, 90 gpm; diameter, 12 in.
Static water level, 4 ft.


Alluvium:
   Clay66
   Sand and gravel410
   Clay212
   Gravel214
   Clay418
   Gravel and sand826
   Clay430
Wasatch formation: Rock--30+
Daves Hollow Ranger Station, Forest Service
Yield, 90 gallons per hour; diameter, 6 in.
Static water level, 15 ft.


Alluvium: Clay, sandy, and gravel2020
Kaiparowits formation:
   Clay, sandy, gray1535
   Clay, sandy, gray (water)1550
   Clay, sandy, gray60110
   Clay, sandy, gray (very hard)12122
   Shale, sandy, brown (caving)3125
   Clay, sandy, gray82207
Bryce Canyon Airport, Civil Aeronautics Administration
Yield, 10 gpm; diameter, 6 in.
Static water level, 33 ft.


Alluvium:
   Conglomerate and hardpan1212
   Clay, yellow416
   Clay, light brown723
   Clay, blue-gray1134
   Clay, gray-brown943
   Clay, sandy, light-brown548
   Clay, sandy, light351
Kaiparowits formation:
   Sandstone, gray4091
   Shale, gray899
   Shale, sandy, blue26125
   Shale, sandy, hard, blue2127
   Shale, sandy, blue9136
   Shale, sandy, hard, blue2138
   Shale, sandy, soft12150
Sawmill Well, E. A. Crofts
Yield, 40 gpm; diameter, 6 in.
Static water level, 18 ft.


Alluvium:
   Clay2020
   Sand (little water)1535
   Clay2560
   Gravel (water)666
Kaiparowits formation: Shale, light-gray (no water)244310
Lion Oil Co. water well
Yield, 10 gpm; diameter, 6 in.

Alluvium:

   Sand rock7070
   Rock formation, porous676
   Sand rock40116
   Rock formation, porous6122
   Sand rock8130
   Rock, porous6136
Lion Oil Co. oil test
Kaiparowits formation and Wahweap and Straight Cliffs sandstones940940
Tropic shale1,3052,245
Dakota sandstone4152,660
Morrison formation1,9654,625
Carmel formation1,4306,005
Navajo sandstone2,0758,130
Chinle formation, upper part5988,728
Shinarump member of Chinle formation1298,857
Moenkopi formation1,1259,982
Timpoweap member of Moenkopi formation10410,086
Kaibab limestone47910,565
Toroweap formation45111,016
Coconino sandstone20511,221
The Pines Motel, Mayo Rich
Diameter, 6 in.
Static water level, 15 ft.


Alluvium: Clay, sandy1010
Wasatch formation: Sand rock, red160170
Forest Oil Corp. oil test
[about 3 miles west of Lion Oil Co. oil test, off pl. 24]
Wasatch formation496496
Kaiparowits formation155651
Wahweap sandstone231882
Straight Cliffs sandstone2,3983,280
Tropic shale1,1304,410
Dakota sandstone2184,628
Winsor formation5075,135
Entrada sandstone4705,605
Carmel formation5866,191
Navajo sandstone516,242
California Co. oil test, Johns valley No. 1 in sec. 22, T. 35 S. R. 2 W.
Wahweap and Straight Cliffs sandstones910910
Tropic shale8981,808
Dakota sandstone2022,010
Morrison formation6852,695
San Rafael group9553,650
Glen Canyon group2,0855,735
Chinle formation, upper part5606,295
Shinarump member of Chinle formation756,370
Moenkopi formation9957,365
Kaibab limestone9238,288
Coconino sandstone1,0229,410
Formations comparable to Hermosa and Molas formations (combined)77910,189
Redwall limestone14610,335
Logs of auger holes in alluvium of East Creek valley
AUGER HOLE 1

Sand, clayey tan1414
Gravel and sand, tan (water)
14-1/2
AUGER HOLE 2

Sand, clayey tan2-1/22-1/2
Gravel and sand, tan (dry)
2-1/2
AUGER HOLE 3

Soil, dark clayey22
Gravel and clay, light-brown24
Gravel, angular, white (water)15
AUGER HOLE 4

Clay, sticky, gray-brown22
Sand, clayey, brown24
Gravel, fine; sand and clay, tan26
Gravel, coarse, reddish-white (water)17
AUGER HOLE 5

Soil, sandy, dark-gray22
Clay, sticky, gray24
Clay, sticky, yellow48
Gravel, sand and clay, yellow (water)
8
AUGER HOLE 6

Soil, clayey, black22
Clay, sticky, black24
Clay, sandy, (water)15
AUGER HOLE 7

In gully about 15 ft below general land surface.

Bank of gully, red sand1515
Red sand6-1/221-1/2
Gravel (dry)
21-1/2
AUGER HOLE 8

Clay, sandy, dark-gray8-/128-1/2
Gravel and clay, white1/29
Sand, reddish-white1-1/210-1/2
Gravel (dry)
10-1/2
AUGER ROLE 9, DAVES HOLLOW

Pit44
Clay, sticky, red812
Sand, fine, red113
Gravel, reddish-white (dry)114

The thickness and the geologic and hydrologic character of the Mesozoic and Cenozoic rocks underlying Bryce Canyon National Park are given in table 5. Of these formations the oldest shown on the geologic map (fig. 55) is the Winsor formation of Late Jurassic age.

FIGURE 55—Geologic map of the northern part of Bryce Canyon National Park area, Utah. Modified from Gregory (1951). (click on image for an enlargement in a new window)

The Mesozoic rocks in table 5 are predominantly sandstone and shale with only minor limestone or conglomerate beds. Except for the Navajo sandstone, most formations have gypsum as a common cementing agent. This mineral is easily soluble, and thus may be present in much of the ground water contained in these beds. Gypsum is not so common in rocks of Cenozoic age, which are mostly limestone or sand and gravel.

TABLE 5.—Generalized section of the geologic formations in the Bryce Canyon National Park area, Utah
[Based on information obtained from several sources, including Gregory (1951), Gregory and Moore (1931), and Harshbarger and Repenning (1934)]

SystemSeriesGeologic unit Thickness (feet)Depth to
bottom of
formation1
(feet)
Physical characterWater supply
QuaternaryRecent and
Pleistocene
Alluvium 0-1360 Gravel, sand, silt, and clay filling the valley bottoms of East Creek, Daves Hollow, and other small streams, and the valley of the East Fork of the Sevier River. Attains maximum thickness in Emery valley. Fills valley bottoms of water, Campbell, and Bryce Canyons, Yellow and Sheep Creeks, Swamp Canyon, and other canyons below the rim. Gravel and sand lenses in the alluvial valleys on the Paunsaugunt Plateau yield as much as 180 gpm to a well. Gravel fill in the canyons below the rim is very porous and in the washes this gravel is very permeable; yields large quantities of water where saturated, but in general the gravel contains water only in the vicinity of bedrock springs, with resultant limited yields.
Unconformity
TertiaryEoceneWasatch formation150-700 at the rim.
1,000 at Boat Mesa.
0-700 between the East Fork of the Sevier River and the rim.
500 Upper white beds present on Boat Mesa and Whiteman Bench are white, gray, or light-brown sandstone, conglomerate, and limestone containing siliceous cement and volcanic tuff and ash.

Middle pink beds, chiefly pink, gray, and white massive limestone and interbedded sandstone and conglomerate.

Basal conglomerate consists of pebbles poorly cemented by calcium carbonate; absent in Swamp Canyon and Yellow Creek; 10 to 30 ft thick at Bryce Point, composed of sandstone and conglomerate; 30 ft thick at Campbell Canyon, composed of lenses of conglomerate in limestone.
The white beds support springs of unstable yield on Whiteman Bench.

A few small springs issue from sandy lenses and fractures, but the beds are not likely to yield water to wells.

Basal conglomerate beds support several springs just below the rim and in the valley of the East Fork of the Sevier. If lenses of conglomerate are penetrated, the basal conglomerate might yield moderate quantities of water to wells.
Unconformity
CretaceousUpper
Cretaceous
Kaiparowits
formation
Absent in Bryce and Campbell Canyons.
400 in Yellow Creek and Sheep Creek areas.
900 Dark-gray, gray-green, yellow, and tan coarse- and medium-grained arkosic sandstone poorly cemented by calcium carbonate and in part by gypsum and iron oxide. Brown, white, and greenish limestone and blue and purple shale. Contains vertebrate bones, fossil wood, invertebrates, and ironstone nodules and concretions. Yields water to several springs below the rim. Wells that penetrate this formation have very low yields (10 gpm or less).
Unconformity
Wahweap sandstone880+1,750 Yellow and buff fine to medium sandstone, 40 to 60 ft thick in upper part. Interbedded sandstone and shaly sandstone in extensive lenses in lower part. Cemented mainly by calcite, but hard layers are cemented by iron oxide. Contains some gypsum and wood. These two formations support most of the prolific springs below the rim. Although no water wells penetrate these formations in the Bryce Canyon area, they might yield water to wells in sufficient quantity for a public supply. The extensive sandstone layers make up most of the two formations which are saturated throughout the area; thus, most wells are apt to penetrate water-bearing material. (Lithologic equivalent in the Navajo Indian Reservation yields 20 to 40 gpm.)
Straight Cliffs sandstone Tan sandstones make up 95 percent of this formation, and sandstone layers greater than 10 ft thick make up 60 percent. Some of the sand is fine, but most is medium to coarse, and some conglomerates contain pebbles 1 to 3 in. across. Cemented mainly by calcite but in part by some iron oxide. Disseminated gypsum and carbonaceous beds occur.
Tropic shale8002,550 Bluish-drab clayey to sandy shale; irregularly bedded sandstones; abundantly fossiliferous; gypsum and selenite crystals are common. Contains sand lenses 2 to 15 ft thick and carbonaceous beds. Very poor water-bearing formation. Forms impermeable barrier along Paunsaugunt fault, causing faultline springs. Sandstone lenses might produce small quantities of water, but such water would be high in calcium and sulfate and probably of unsatisfactory quality.
Dakota sandstone302,580 Buff-gray medium- to coarse-grained sandstone and conglomerate containing some shale and carbonaceous beds. Sandstones are weakly cemented. Contains some silicified wood. Springs issue from the base of this formation in the Paria Valley. If sufficient thickness is penetrated, this formation would yield some water to wells. It is saturated everywhere west of the Paunsaugunt fault. The water might be of unsatisfactory quality owing to seepage from the overlying Tropic shale. (Yields 5 to 10 gpm in Navajo Indian Reservation, but water is highly mineralized.)
Unconformity
JurassicUpper JurassicWinsor formation 600-7003,280 Thin-bedded red- and white-banded arkosic sandstone. Sand is medium- to coarse-grained; cemented by iron oxide, calcite, and gypsum. Many of the creeks become perennial on or just below the outcrop of this formation. Several springs undoubtedly issue from this formation but only one at the base has been observed. Yields to wells should be moderate to small, but the water may be of poor quality.
Unconformity
San Rafael
Group
Curtis formation 110-1803,460 Massive gypsum, dense thin-bedded limestone, calcareous sandstone and shale, and gypsiferous very sandy shale. Very poor water-bearing formation, would yield very small amounts of highly mineralized water to wells.
Unconformity
Entrada sandstone170-2403,630 Thinly stratified friable fine-grained and very fine grained red, brown and gray sandstone; some limestone, shale, and gypsum beds; contains abundant gypsum, which constitutes the chief cement, and fills cracks. Thickest individual sand bed about 30 ft. Springs issue at various horizons from the Entrada, but owing to the fine texture of the sand, yields to wells would be small unless abundant fractures improved the permeability. Under the Paunsaugunt Plateau water would probably be highly mineralized.
Carmel formation0-1653,795 Regularly interstratified beds of tan and blue-gray shale, limestone, and sandstone, containing smaller amounts of gypsum and conglomerate in both thin and thick lenticular beds. Very poor water-bearing formation. Water probably highly mineralized.
Unconformity
Jurassic and Jurassic(?)Middle
Jurassic
Glen Canyon GroupNavajo sandstone 1,200-1,8005,595 Light creamy-yellow, white, and buff highly crossbedded sandstone. Forms the White Cliffs. Probably would yield largest amounts of good-quality water of any formation below the Wahweap and Straight Cliffs sandstones. (Yields as much as 70 gpm in the Navajo Indian Reservation.)
Unconformity
TriassicUpper TriassicChinle formation Upper part
of Chinle
formation
600-8006,395 Red and brown shale, sandstone, and limestone. Probably not water bearing.
Shinarump member0-1156,510 Red and gray conglomerate. May yield a small quantity of water to wells, hub water would probably be somewhat mineralized.
Unconformity
Middle(?)
and Lower
Triassic

Moenkopi formation 5007,010 Chocolate-brown shale and some sandstone. Probably not water bearing.
1Representative of depths and thicknesses underlying the vicinity of Paria View observation point in park.

STRUCTURE

The principal structural features of the Bryce Canyon National Park area are gently northeastward-dipping beds and several major normal faults. The regional dip of the beds ranges from 1/2° to 3° north, northeast, and east. Departures from the regional dip are found only in the immediate vicinity of faults and in gentle folds. A gently north-plunging anticline in the vicinity of Willis and Heward Creeks was described by Hager (1957). The axis of this anticline is west of the Pink Cliffs escarpment in the Heward Creek area, but it crosses the escarpment in the vicinity of Sheep Creek.

Faulting is restricted to a few large-scale normal faults; two of these faults—the Paunsaugunt and Sevier—are regional in extent. The Sevier fault is about 7 miles west of the area covered by this report. These two faults trend northward, and the east block of each fault is upthrown in relation to the west block. The Paunsaugunt fault does not coincide with the Pink Cliffs escarpment and, in fact, is not noticeable as a topographic feature of any kind. Two cross faults that trend generally eastward, connecting the Sevier and Paunsaugunt faults, are evident as topographic features—faultline scarps that form the borders of Emery Valley.

Each of these structural features exercises some control on the occurrence and movement of ground water in the bedrock aquifers of the area. Ground water moves through the rocks in the general direction of the regional dip, which accounts for the many springs along the eastern scarp of the Paunsaugunt Plateau. Along the Paunsaugunt fault, springs occur where the eastward movement of ground water is blocked by upfaulted relatively impervious beds, which force the water to rise to the surface. Tension fractures along the axis of the Bryce Canyon anticline (fig. 55) might create secondary permeability and afford an opportunity to obtain successful water supplies from wells penetrating the bedrock.



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Last Updated: 28-Jul-2007