GEOLEX

Summary of Citation: Bishop

Publication:
Bryant, B.H., Naeser, C.W., Marvin, R.F., Mehnert, H.H., 1990,
   Upper Cretaceous and Paleogene sedimentary rocks and isotopic
   ages of Paleogene tuffs, Uinta basin, Utah, IN Evolution of
   sedimentary basins; Uinta and Piceance basins: U.S. Geological
   Survey Bulletin, 1787-J, p. J1-J22

Usage in Publication:
Bishop Conglomerate*

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits Overview	Uinta basin Piceance basin

Summary:
Some conglomerates mapped by earlier workers as Bishop Conglomerate are mapped as Starr Flat Member of Duchesne River Formation in this report. Doesn't seem to be any significant difference in lithology and age between the Starr Flat and Bishop. Bishop mapped along north side from eastern Duchesne into Uintah Co, UT, Uinta basin, and eastward into Moffat Co, CO, Piceance basin. Mapped as a cap on flat-topped, southward-protruding shoulders of the Uinta Mountains that seldom form outcrops because it is weakly cemented and commonly covered by well-developed soil. Oligocene age.

Summary of Citation: Bishop

Publication:
Hansen, H.J., 1984, Hydrogeologic characteristics of the Waste
   Gate Fromation, a new subsurface unit of the Potomac Group
   underlying the eastern Delmarva Peninsula: Maryland Geological
   Survey, Information Circular 39, 22 p.

Usage in Publication:
Bishop Conglomerate*

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Greater Green River basin Uinta basin Uinta uplift

Summary:
Remnants of Bishop are present on both flanks of the Uinta Mountains, Uinta basin, Uinta uplift, and Greater Green River basin, but remnants are more extensive on south flank of mountains. A few remnants found in Greater Green River basin 50-80 km north of Uintas. Consists of loosely cemented bouldery, cobbly conglomerate and coarse, poorly sorted, pebbly, friable sandstone. Clasts of Red Creek Quartzite, Mississippian Madison Limestone, and Pennsylvanian Round Valley Limestone, and some reworked Eocene found in Bishop. Deposited during a time of protected crustal stability. Probably formed a continuous bajada around north, south, and east flanks of Uintas. Direction of drainage reversed after Bishop time. Bishop deposition was from south; Browns Park deposition was from north. Reversal caused by tilting. Tuff (at several horizons) yielded K-Ar ages on biotite and hornblende of 29 m.y. Deposition ended when tilting and faulting changed the hydrologic regime and initiated dissection. Oligocene age assigned.

Summary of Citation: Bishop

Publication:
Rowley, P.D., Hansen, W.R., 1979, Geologic map of the Plug Hat
   quadrangle, Moffat County, Colorado: U.S. Geological Survey
   Geologic Quadrangle Map, GQ-1514, 1 sheet, scale 1:24,000

Usage in Publication:
Bishop Conglomerate*

Modifications:	Geologic Province:	Dominant Lithology:
Mapped 1:24k (Moffat Co, CO)	Greater Green River basin	Conglomerate Sandstone

Summary:
Is Oligocene formation mapped along northern part of map area in southwest Moffat Co, CO (Greater Green River basin). Unconformably overlies various Mesozoic formations; is youngest formal bedrock unit mapped in quadrangle. Map unit described as poorly consolidated light-gray, tan, or white thin-bedded poorly sorted medium-grained fluvial sandstone and interbedded poorly sorted pebble, cobble, and boulder fluvial conglomerate. Locally tuffaceous. Boulders as much as 1 m (3 ft) long in conglomerate consist largely of red sandstone derived from the Uinta Mountain Group (Precambrian Y) and to a lesser extent of light- to medium gray limestone derived from Paleozoic rock units. Unit fills a broad valley cut on Mesozoic rocks. Unit in large part overlain by tan sandy Quaternary deposits, mostly derived from erosion of the Glen Canyon Sandstone. Unit might be correlated with the Browns Park Formation (Miocene), but its high present elevation near the crest of this part of the Uinta Mountains, and its lithology suggest that it is better assigned to the Bishop Conglomerate. The age of the Bishop Conglomerate is problematical, but based on K-Ar ages of tuff beds exposed in the unit elsewhere in the eastern Uinta Mountains (G. R. Winkler, written commun., 1969), it is generally considered to be Oligocene. Thickness probably as much as 50 m (150 ft).

Summary of Citation: Bishop

Publication:
Powell, J.W., 1876, Report on the geology of the eastern Uinta
   Mountains and a region of country adjacent thereto: U.S.
   Geological and Geographical Survey of the Territories (Powell),
   v. 7, 218 p.

Usage in Publication:
Bishop Mountain group*

Modifications:	Geologic Province:	Dominant Lithology:
First used	Uinta uplift Greater Green River basin	Conglomerate Sand Clay

Summary:
First published use of name applied to a unit about 300 ft thick that is primarily conglomerate preserved as isolated remnants over a large area in southwest WY, northwest CO, and northeast UT. No type locality designated. Named for Bishop Mountain in Sweetwater Co, WY. Can be seen at Queen Hornet Mountain and on Sage Creek. Consists of boulders and cobbles of sandstone, quartzite, and schist in a calcareous matrix. Has calcareous cement, and some clay and sand. Rests unconformably on rocks of several ages. Columnar sections. Recognized in the Uinta Mountain area of the Greater Green River basin and Uinta uplift. Considered to be a fluvial deposit. Of Cenozoic age.