USGS Logo Geological Survey Professional Paper 516—E
A Geophysical Study in Grand Teton National Park and Vicinity, Teton County, Wyoming

By J. D. Love

The area discussed in this report is of unusually great interest because (1) Jackson Hole was downfaulted in late Cenozoic time, thereby preserving a part of the geologic record that has been lost elsewhere in Wyoming; (2) it includes mountain ranges of different ages and origins; (3) its crustal disturbances are undoubtedly related to volcanism in the adjoining Yellowstone National Park area; (4) the thick stratigraphic section includes all systems except the Silurian; (5) strata of all Cenozoic epochs are thick, fossiliferous, and well exposed; and (6) the completeness of the stratigraphic record enables us to demonstrate the chronologic development of most structures.

The relation of Jackson Hole to upfolded and faulted mountains and to downwarps is shown in figure 1; the distribution of major rock units and significant structural features is shown on plate 1. The recognized sedimentary and volcanic rock units and their relation to tectonic events are shown in table 1. Details of stratigraphy, structure, petrography, geologic history, and paleontology of Jackson Hole and adjacent areas are given in reports listed in "References Cited."

TABLE 1.—Summary description of sedimentary and volcanic rocks and of tectonic events in the Grand Teton National Park and vicinity

AgeSedimentary rocks Thickness
Volcanic rocks Tectonic events
RecentModern stream deposits and alluvial fans. Quartzite gravel along streams; fans composed of Paleozoic, Mesozoic and Cenozoic rocks, all of which are on east side of Jackson Hole. 0—120
Minor faults break alluvial fans along east base of Teton Range and offset surfaces in National Elk Refuge.
PleistocenePinedale glacial deposits and associated outwash. Moraines, largely from Precambrian core of Teton Range and quartzite gravel outwash spread out to south. 0—60White ash from undetermined source.

White ash, probably from Yellowstone National Park.
Outwash plains tilted west because of recurrent movement on Teton fault; Flat Creek Valley was down-dropped about 60 m.

Floor of Jackson Hole tilted west; some faulting may have accompanied tilting.
Loess Silt, light-gray, poorly bedded, soft. 3—20 Rhyolite extruded in Pitchstone area of Yellowstone National Park; age uncertain. Minor faults developed in National Elk Refuge.
Bull Lake glacial deposits and associated outwash. Moraines, largely from Precambrian core of Teton Range and from a few areas on the east side of Jackson Hole; associated quartzite outwash gravel, chiefly in southern part of Jackson Hole. 0—120

Oldest glacial deposits. Remnants of morainal debris composed of many rock types, at high and low elevations in Jackson Hole. 0—60?

Upper lake sequence. Shale, brown-gray; very soft gray sandstone and locally derived conglomerate. 0—150
Jackson Hole sagged; tilting of floor raised the lower lake sequence on the east side 300 m above remnants in central part; extensive faulting occurred near Gros Ventre Buttes in southern Jackson Hole. New lake basin was created in central Jackson Hole and in it the upper lake sequence was deposited.
Lower lake sequence. Shale, claystone, siltstone, and sandstone, red, green, gray, and black; lower part deposited in deep water. 0—60 Probably some volcanic activity in adjacent areas contributed pyroclastic debris to sediments.

Red and black andesite extruded; 300 m thick in places. Light-gray glassy porphyry bodies intruded. Gray basalt extruded; 150 m thick in places. Pink and gray pumice breccia; 10 m thick.

Southern Jackson Hole sagged and thereby created a lake basin in which the lower lake sequence was deposited.

Hoback normal fault developed in southern Jackson Hole; east edge of west block dropped 3,000 m or more.

Central part of Jackson Hole tilted west by continued downdropping of valley block along Teton fault.
Pleistocene or Pliocene. Bivouac Formation. Conglomerate of Tertiary igneous rocks, quartzite boulders, and granite; purplish-gray rhyolite welded tuff in upper part. 0—300 Purplish-gray rhyolite welded tuff.

Basalt flows on east side of Jackson Hole. Major movement (3,000 m or more) took place along Teton fault, west block up, east block down. The fault cut nearly at right angles across the ancestral Teton-Gros Ventre uplift, and the east block hinged down. Middle Pliocene rocks on southwest side of Snake River Range were overridden by Cambrian limestone.
Teewinot Formation. Limestone, tuff, and claystone, with white soft conglomerate at base. 0—1,800 Rhyolite flows and welded tuff interbedded with pyroclastic rocks in northern part of Jackson Hole. East-trending normal fault developed across Jackson Hole at north margin of Gros Ventre Buttes and caused formation of Teewinot lake basin.
Camp Davis Formation. Conglomerate, red and gray; white tuff, diatomite, limestone, and red and green claystone in lower part. 0—1,700 Rhyolite tuff, probably derived from Yellowstone National Park area. Southwest margin of Gros Ventre Range was thrust over some lower Pliocene rocks and others were deposited on thrust blocks. This fault (Cache thrust) extends through Jackson and west-northwest across Teton Pass and on into Idaho. Some movement may have been earlier.

Sharp north-trending folds developed at north end of Teton Range.
Miocene Colter Formation Volcanic conglomerate, tuff, and sandstone, white to greenish-brown; contains locally derived basalt and andesite rock fragments. 0—2,100 Pyroxene andesite and basalt extruded from large vents in northern and eastern parts of Jackson Hole. Floor of northern part of Jackson Hole sagged several thousand meters.

Ancestral Teton-Gros Ventre uplift and area to east raised and partly stripped of Cenozoic rocks.
Oligocene Wiggins Formation. Volcanic conglomerate, gray to brown, with white tuff layers. 0—1,000 Andesite and basalt vents along northeastern margin of Jackson Hole extruded large quantities of agglomerate and ash.
Eocene Tepee Trail Formation. Volcanic conglomerate, tuff, and claystone, bright-green to olive-drab. 0—300 Pyroxene andesite and basalt were extruded from vents along east margin of Jackson Hole.
Aycross Formation. Claystone, siltstone, and sandstone, brightly variegated to green and white, soft, bentonitic; quartzite conglomerate lenses. 0—150 Rhyolite and andesite tuff of intermediate composition, probably derived from vents in the Absaroka Range. Uplift of south-central Jackson Hole caused extensive stripping of Pinyon Conglomerate; 600 m of this debris was redeposited on south side of ancestral Gros Ventre Range.
Wind River and Indian Meadows Formations. Claystone, siltstone, and sandstone, brightly variegated; drab coal-bearing zone 30-90 m thick in middle. 0—1,000 Hornblende andesite tuff present in easternmost sections. Northwest-trending Tripod Peak fault developed in northeastern part of Jackson Hole; east side was raised and stripped of 2,600 m of strata.

Salt River, Wyoming, Hoback, and Snake River Ranges moved northeast along low-angle thrust faults and overrode conglomerates of late Paleocene age.
Paleocene Sandstone and claystone sequence and Pinyon Conglomerate. Sandstone and claystone, greenish-gray and brown; underlain by light-brown conglomerate composed of highly rounded quartzite rock fragments. Coal and gray shale at base. 0—1,200
Ancestral Gros Ventre uplift rose in late Paleocene time and was folded with gentle northeast flank and steep southwest flank. This caused deposition of thick locally derived conglomerates along southwest margin.

Targhee uplift northwest of ancestral Teton Range reached maximum size and provided several hundred cu km of quartzite debris to Pinyon Conglomerate in Jackson Hole.

Asymmetric northwest-trending folds, with thrust faults on their southwest flanks, extended obliquely northwest from the ancestral Gros Ventre uplift. The Washakie Range rose and was thrust southwestward.
Cretaceous Harbell Formation. Sandstone, olive drab, silty; drab siltstone and dark-gray shale; thick beds of quartzite conglomerate in upper part; chalky white sandstones in southernmost sections. 0—1,500
The ancestral Teton-Gros Ventre uplift rose as a broad gentle arch with the Targhee uplift at its northwest end. Another gentle fold marked the first movement of the Wind River Mountains.
Meeteetse Formation. Sandstone, gray to chalky white; blue-green to gray biotitic siltstone; thin coal; and green to yellow bentonite. 0—200

Mesaverde Formation. Sandstone, white, massive, soft; thin gray shale; sparse coal. 07—300

Lenticular sandstone, shale, and coal sequence. Sandstone and shale, gray to brown; abundant coal in lower 600 m. 1,100±

Bacon Ridge Sandstone. Sandstone, light-gray, massive, marine; gray shale; many coal beds. 280—370

Cody Shale Shale, gray, soft; thin glauconitic sandstone; some bentonite; marine. 400—670

Frontier Formation. Sandstone, gray, and black to gray shale; marine; many persistent white bentonite beds in lower part. 300

Mowry Shale Shale, silvery-gray, hard, slliceous; contains many fish scales; thin bentonite beds; marine. 200

Thermopolis Shale Shale, black, soft, fissile; persistent sandstone at top; marine. 50—60

Cretaceous and Jurassic. Cloverly and Morrison (?) Formations. Sandstone, light-gray, sparkly; rusty near top; underlain by variegated soft claystone; basal part is silty dully variegated sandstone and claystone. 200

Jurassic Sundance Formation. Sandstone, green; underlain by soft gray shale and thin highly fossiliferous limestone; marine. 150—200

Gypsum Spring Formation. Gypsum, white; interbedded with red shale and gray dolomite; partly marine. 240—300

Jurassic(?) and Triassic (?). Nugget Sandstone. Sandstone, salmon-red, hard, fine-grained. 0—110
Regional tilting southward caused Nugget Sandstone to be stripped from north half of Jackson Hole.
Triassic Chugwater Formation. Siltstone and shale, red, thin-bedded; one thin marine limestone in upper third. 300—500

Dinwoody Formation. Siltstone, brown, hard, thin-bedded; marine. 60—120

Permian Phosphoria Formation and stratigraphic equivalents. Dolomite, gray, cherty; black shale and phosphate beds; gray-brown sandstone; marine. 50—75

Pennsylvanian Tensleep Sandstone and Amsden Formation. Sandstone, light-gray, hard; underlain by red shale; basal part is red sandstone; marine. 200—500

Mississippian Madison Limestone. Limestone, blue-gray, hard, fossiliferous; thin red shale in places near top; marine. 300—370

Devonian Darby Formation. Dolomite, dark-gray to brown, fetid, hard; brown, black, and yellow shale; marine. 60—150

Ordovician Bighorn Dolomite. Dolomite, light-gray, siliceous, very hard; white dense very fine grained dolomite at top; marine. 90—150

Cambrian Gallatin Limestone. Limestone, blue-gray, hard, thin-bedded; marine. 55—90

Gros Ventre Formation. Shale, green, flaky; about 100 m of hard cliff-forming limestone in middle; marine. 180—240

Flathead Sandstone. Sandstone, reddish-brown, very hard, brittle; partly marine. 50—60


Regional unconformity cuts across all Precambrian rocks.



Jackson Hole is a complexly folded and faulted downwarp and within it are several structurally deep areas. One is an elongate trough adjacent and parallel to the west margin of Jackson Hole. Within it, at shotpoint 4.1, the top of the Precambrian is about 3 km below sea level (fig. 10), whereas on top of Mount Moran to the west the same horizon is about 4 km above sea level. The present structural configuration of this trough was caused by dropping in late Cenozoic time of the western part of Jackson Hole along the Teton fault and by sagging of the floor in the northeastern and southeastern sections, perhaps under the weight of a thick section of Miocene and Pliocene rocks in addition to the older strata (table 1).

A second deep area, which is also broad, lies between the Whetstone anticline and the Buffalo Fork thrust fault. Here, the top of the Precambrian is estimated to be 3.4 km below sea level. A third deep area, perhaps the deepest of all, is east of the north end of the Bacon Ridge anticline where the Precambrian surface is estimated to be at least 4.5 km below sea level.


The Green River topographic basin lies southeast of Jackson Hole and is separated from it, but the two structural basins are connected by a narrow gooseneck-shaped enormously deep syncline that has been overridden by both the Hoback and Gros Ventre Ranges (fig. 2). Precambrian rocks at the bottom of this syncline are estimated to be at a depth of more than 9 km (Love and Keefer, 1965).

FIGURE 2.—Tectonic map of Teton County, Wyo. (click on image for a PDF version)


Bordering Jackson Hole are four types of mountains: (1) a horstlike upfaulted block (Teton Range), (2) intricately folded and faulted mountains of sedimentary rocks underlain by low-angle thrust faults rather than by a Precambrian core (Snake River and Hoback Ranges), (3) folded asymmetric anticlinal uplifts with Precambrian cores and thrust or reverse faults along the steep flanks (Gros Ventre and Washakie Ranges), and (4) mountains that are remnants of thick piles of nearly horizontal pyroclastic rocks (Absaroka Range and Yellowstone Volcanic Plateau).


The Teton Range is a north-trending uplifted block of Precambrian and Paleozoic rocks about 60 km long and 15-25 km wide. It is bounded on the east by the Teton normal fault (pl. 1; cross section, fig. 7) and on the west by another, virtually parallel normal fault (unnamed and incompletely known; not shown in fig. 2) along the Wyoming-Idaho State line. This fault is not exposed but is inferred because a sharp linear topographic break in alluvial deposits coincides with steepened west dips in Paleozoic rocks of the Teton Range at the east margin of Teton Basin (fig. 1). If this interpretation is correct, the Teton Range is a horst between the two downfaulted blocks, Teton Basin and Jackson Hole. The core of the mountain is largely granite and metamorphic rocks (Reed, p. E12 of this report) overlain by west-dipping Paleozoic rocks on the west side; these are faulted off on the east side.

The Teton Range was formed in two stages. During Late Cretaceous and early Tertiary times it was the northwestern part of a broad northwest-trending fold continuous with the Gros Ventre Range. Later in Cenozoic time this uplift was thrust southwest. Then the overriding block was broken by a series of faults, the largest of which is the Teton fault. The area of downfaulted blocks became the southern part of Jackson Hole, and thereby separated the uplift into two very different segments. The Teton Range continued to rise, whereas the Gros Ventre Range did not.


The Snake River and Hoback Ranges are composed entirely of Paleozoic and Mesozoic sedimentary rocks that are intricately folded, overturned in places, and faulted. No Precambrian rocks are exposed. The ranges are piles of overlapping thrust sheets emplaced along low-angle thrust faults, such as the Jackson, Darby, Absaroka, St. John, Game Creek, and Bear Creek (fig. 2). Dominant movement was to the northeast, and the amount of displacement probably was many kilometers. The thrust sheets were apparently emplaced during early Eocene time, but some thrusting or gravity faulting occurred much later and in the opposite direction. For example, southwest of the mapped area, overturned Cambrian limestones along the southwest margin of the Snake River Range moved southwestward onto middle Pliocene rocks.

The Snake River and Hoback Ranges are structurally separated, but they are genetically related; both are composed of low-angle thrust sheets of about the same age, and, on their northern margins, both are underlain and bounded by the Jackson thrust. The trace of the Jackson fault curls around the east side of the Hoback Range where Paleozoic and Mesozoic rocks have been shoved onto conglomerates of latest Paleocene age.


The Gros Ventre Range is an asymmetric anticlinal uplift that has Precambrian rocks in the core. The northeast flank is a broad area of gently dipping Paleozoic and Mesozoic strata. The steep southwest flank overrides the Green River basin along the Cache thrust (fig. 2). Vertical displacement on top of the Precambrian from the crest of the mountains to the bottom of the underlying basin is estimated to be more than 12 km. Maximum horizontal displacement is about 13 km.

The range was a broad gentle uplift as far back in time as latest Cretaceous. Major thrusting after middle Eocene time peeled back the north edge of the previously emplaced Jackson thrust block. Thrust masses (Love, 1956b), which were preserved because they were dropped by movement along the Hoback normal fault, 8 km southwest of the Gros Ventre Range (fig. 2), probably were emplaced during early Pliocene time as a result of rise of the mountain arch and movement on the Cache thrust. The separation of this uplift from the Teton Range by normal faulting during late Cenozoic time has been noted above.


The Washakie Range, like the Gros Ventre Range, is an asymmetric anticline that has a Precambrian core, a gentle northeast flank, and a steep thrust-faulted southwest flank. In several places the fault along the southwest side, the Buffalo Fork thrust, steepens and becomes a high-angle reverse fault. The throw on the Precambrian rocks between the top of the uplift and the bottom of the overridden syncline to the southwest is 6 km or more. During latest Cretaceous time the range was a broad low fold that subsequently rose and probably was thrust faulted during the Paleocene. At that time it may have been the dominant mountain range in the area. Post-Oligocene normal faulting near the south boundary of Yellowstone National Park lowered this part of the range by at least 300 m (meters).


The Absaroka Range is different from all other mountains in the region because it is not a structural uplift but an erosional remnant of a formerly vast nearly horizontal pyroclastic deposit several hundred meters thick that buried the adjacent folded mountains during Eocene and Oligocene time. The source of this debris was the Yellowstone-Absaroka volcanic area northeast and east of Jackson Hole. During middle and late Cenozoic time this was a relatively stable area affected by only minor warping and faulting in most places. Thus, it contrasts markedly with the spectacularly unstable major part of the Teton-Jackson Hole area only 30 km to the southwest.

Late Cenozoic erosion reexcavated the adjacent basins, exhumed the older folded mountains, and left the Absaroka Range as a series of high sharp drainage divides and steep-sided remnants of the original plateau. The underlying Washakie Range has been partly exhumed, and one type of mountain range can be seen overlapping the other.


The Yellowstone Volcanic Plateau is not strictly a mountain range but is a broad rolling upland of more than 5,000 km2, interrupted by a few peaks and ridges of volcanic rocks and by sharp steep-sided canyons. The rocks are chiefly andesite and basalt of Eocene and Oligocene age in the eastern part, rhyolite of Pliocene and Pleistocene age in the middle part, and rhyolite and basalt of similar age in the western part. These rocks have been warped and faulted in some places, but they are commonly nearly horizontal.


Many large anticlines 15-30 km long and with 1,500-3,000 m amplitude, which range in age from pre-middle Paleocene to Pleistocene, are present in the Jackson Hole area (pl 3). Most of these folds have thrust or reverse faults on their southwest sides, and at least two were monoclines until Pliocene time. A few of the anticlines are described in order to show the variety present.

The Spread Creek anticline, which is 30 km long and has at least 2,000 m of closure, is bounded on the southwest by a thrust fault (crossed in one deep oil well). The anticline involves Paleozoic rocks (penetrated in two oil wells) and was formed before deposition of the Paleocene Pinyon Conglomerate. The Bacon Ridge anticline, which is more than 30 km long and has only a small amount of closure, plunges to the northwest and is bounded on the southwest by a small thrust fault. This anticline involves Paleozoic rocks, and is in part older than the Pinyon Conglomerate and in part younger. The Whetstone anticline is a broad open southeastward-plunging fold formed in post-Paleocene time.

The Red Hills anticline is a sharp fold involving Paleozoic rocks but is older than the Pinyon Conglomerate. The adjoining Ramshorn anticline to the northwest, however, was apparently a northeast-dipping monocline until post-middle Pliocene subsidence of the western part of Jackson Hole. At that time, westward tilting was sufficient to produce the west limb of the fold. The Munger anticline south of Jackson Hole was formed likewise; it was a southwest-dipping monocline until the Hoback normal fault became active in Pliocene time. Movement along this fault caused the rocks to the west to hinge down in such a way that the northeast flank of the anticline was created. This fold is one of several caused by tension rather than compression.

The Little Granite anticline, east of the Munger, was formed after Paleocene time, for it involves youngest Paleocene rocks, but before emplacement, along the Jackson thrust, of the Hoback Range which, moving northeastward, completely overrode the anticline in places (fig. 2). Subsequently, the north flank of this anticline was overridden by the Gros Ventre Range block, which moved southwestward along the Cache thrust.


Three types of thrust faults are present in the mapped area. (1) The low-angle type which involves both competent and incompetent sedimentary beds but no mountain cores of Precambrian rocks, as in the Snake River and Hoback Ranges, and which commonly have many kilometers of horizontal displacement. (2) The steeper type, which involves Precambrian cores of the mountain uplifts and which have only a few kilometers of horizontal displacement, such as the Cache and Buffalo Fork thrusts. These faults grade from thrust to reverse in many places. (3) Thrust faults which involve incompetent beds on anticlines and whose displacement is less than 2 km, such as the Spread Creek and Bacon Ridge thrusts. In places along the crest of the Bacon Ridge anticline, some of the bentonitic Cretaceous rocks are so incompetent that they were squeezed into recumbent folds before breaking.


Three normal faults are especially important in the structural development of Jackson Hole. (1) The Teton normal fault, which is 80 km long and has a maximum vertical displacement of about 7 km with the east block down, is responsible in part for the uplift of the Teton Range as we know it today; it originated within the last 10 million years and is still active. (2) The Hoback normal fault, which is 40 km long and has at least 3 km displacement, with the west block down, probably began slightly later than the Teton fault and it also continues to be active. (3) The Warm Spring fault, cutting across the southern part of Jackson Hole, is about 19 km long and has at least 2 km of displacement, with the north block down; it is of Pliocene age. Subsidence of the north block during middle Pliocene time probably was responsible for impounding Teewinot lake in which 2 km of sediment accumulated. The fault has been inactive since late Pleistocene time.


The chronology of tectonic events in Grand Teton National Park and vicinity is summarized in table 1. The Teton Range apparently rose at the time the valley floor to the east subsided, but the volume of the lifted block is considerably less than that of the dropped block. This discrepancy still requires explanation.

Volcanism began in the Yellowstone-Absaroka area in early Eocene time and continued to the Pleistocene. Considerably more than 4 X 104 km3 (cubic kilometers) of debris were blown out and spread to the east by wind and water. Jackson Hole did not subside during the first 20 million years of volcanism in the adjacent Yellowstone-Absaroka area despite the extrusion of an enormous volume of debris. However, from Miocene time to the Pleistocene, large-scale subsidence of Jackson Hole was coincident with extensive volcanic activity, not only in the sinking area (for the first time) but to a much greater extent in the Yellowstone-Absaroka area which did not subside. This relation suggests that Jackson Hole sank as subcrustal material moved laterally into the area of greatest volcanism.

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Last Updated: 14-Jul-2009