Word Formation

Word Formation
State Texas
Name Word Formation
Geologic age Permian; Guadalupe Series
Lithologic constituents
Major
Sedimentary > Carbonate > Limestone (Bed)
Minor
Sedimentary > Clastic > Mudstone > Shale (Bed)
Sedimentary > Carbonate > Dolostone (Bed)
Incidental
Sedimentary > Clastic > Sandstone (Bed)
Comments Characterized by great lateral variation in thickness and lithology. Thickest to southwest; thins to north and northeast. Divided into an eastern and western facies, with transition taking place in region of Hess Canyon. Coarser sediments to southwest. Eastern facies: (ascending) cherty limestone, in part dense and bituminous, in part light gray and crystalline; siliceous shale, some quite sandy; interbedded limestone layers; about 300 ft below top is a persistent sandstone bed; at top is a buff sandy dolomite. Western facies: contains 4 thick limestone beds. Third bed from base contains rich ammonite fauna, the upper bed is quite cherty, and all are abundantly fossiliferous. Base is marked by a thin layer of platy bituminous limestone. Thickness 580 to 800 ft.
Stratigraphic units Revised--includes Vidrio Limestone, Appel Ranch, Willis Ranch, and China Tank Members (Grant,1969).
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.

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 Brewster - Pecos