State | Texas |
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Name | Montoya Dolomite |
Geologic age | Middle and Late Ordovician |
Lithologic constituents | Major
Sedimentary > Carbonate > Limestone (Bed)thin sandstone bed locally present at base
Sedimentary > Carbonate > Dolostone (Bed)
|
Comments | (described fr. Van Horn--El Paso Sheet of Geologic Atlas of Texas, 1968) Dolomite, limestone, and sandstone. Upper part--dolomite and ls., aphanitic to medium grained, thin to thick bedded, white to dk dray, cherty. Lower part--limestone and dolomite, aphanitic to v. coarse grained, light to medium gray, local motled zones near base, chert scarce to absent, thin sandstone bed locally at base. Thickness--Franklin Mountains, 250-430 ft; Hueco Mtns 320+- ft; Sierra Diablo, 250-500 ft. Southeastern Baylor Mtns; includes Middle Ordovician Simpson Group rocks not separately mapped. Stratig. divisions used in Orogrande Basin, NM described in Kelley and Silver (1952) |
Stratigraphic units | Cutter Member (at top), Aleman Chert Member, Upham Member, and Cable Canyon Sandstone Member (basal member) (not shown on Texas State map) |
References | 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.Udden, J.A., Baker, C.L., and Boise, E., 1916, Texas Univ. Bur. Econ. Geology and Tech. Bull. 44 p. 39.Kelley V.C., and Silver, C., 1952, Geology of the Caballo Mountains: Univ. of New Mexico Publications in Geology, no. 4, University of New Mexico Press.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.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. |
NGMDB product | |
Counties | Culberson - El Paso - Hudspeth |