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El Paso Formation and Bliss Sandstone, undivided

El Paso Formation and Bliss Sandstone, undivided
State Texas
Name El Paso Formation and Bliss Sandstone, undivided
Geologic age Phanerozoic | Paleozoic| Cambrian-Furongian(?) Ordovician-Early
Comments (following from Van Horn--El Paso Sheet, Geol. Atlas of Texas) Bliss is the older unit and is Upper Cambrian?-lower Ordovician unit that overlies Precambrian rocks : Bliss Sandstone. Franklin Mtns. sandst.mostly fine grained, medium to thick bedded, a few beds of quartzitic, some glauconitic beds in upper half; weathers dk reddish brown; max. thickness 250 ft, locally absent. Hueco Mtns. sandst. in part coarse grained,thick bedded; weathers reddish brown; thickness 200 ft. Beach and Baylor Mtns. sandst. in part argillaceous, v. fine to coase grained, comglomeratic near base, friable to indurated, pinkish to yellowish gray, grades to dull maroon and green, some interbeds of green andpurple sandy shale; thickness 105-160 ft. El Paso Formation (the younger of the two units) Limestone, dolomite, and sandstone. Franklin Mtns. upper 1,050 ft mostly ls. inequigranular, inpart cherty, lower 540 ft dolomite, in part sandy, thickness 1,590 ft. Hueco Mtns. upper two-thirds mostly ls., granular, impure; lower one-third mostly dolomite, some sandy intervals; thickness 1,300 +-ft. Beach Mountain mostly dolomite, upper 50 ft. earthy, locally sandy, next 813 ft very fine grained to microgranular, scattered sand grains in several beds, in part cherty; lower 252 ft sandst., ls., and dolomite; thickness 1,115 ft.
Primary rock type limestone
Secondary rock type dolostone (dolomite)
Other rock types sandstone; conglomerate
Lithologic constituents
Sedimentary > Carbonate > Limestone (Bed)In Franklin and Hueco Mtns., map unit is between half and two-thirds limestone
Sedimentary > Carbonate > Dolostone (Bed)in Franklin Mts. and Hueco Mtns., map unit is roughly one-third dolostone
Sedimentary > Clastic > Sandstone (Bed)
Map references
Bureau of Economic Geology, 1992, Geologic Map of Texas: University of Texas at Austin, Virgil E. Barnes, project supervisor, Hartmann, B.M. and Scranton, D.F., cartography, scale 1:500,000
Unit references
Repetski, J.E., 1988, Ordovician conodonts from the Bliss Sandstone in its type area, West Texas, in Contributions to Paleozoic paleontology and stratigraphy in honor of Rousseau H. Flower: New Mexico Bureau of Mines and Mineral Resources Memoir 44, p. 1
Evans, K. V., 1988, Cambrian-Ordovician (500 Ma) alkalic plutonism in southwestern New Mexico: U-Th-Pb isotopci data from the Florida Mountains: American Journal of Science, v. 288, p. 735-755.
Hayes, P.T., 1972, Stratigraphic nomenclature of Cambrian and Lower Ordovician rocks of easternmost southern Arizona and adjacent western-most New Mexico: U.S. Geological Survey Bulletin 1372-B.
Bureau of Economic Geology, 1968, Van Horn-El Paso Sheet, Geologic Atlas of Texas: Bureau of Economic Geology, The University of Texas at Austin, scale 1:250,000.
Counties Culberson - El Paso - Hudspeth