Dockum Group, undivided

Dockum Group
State Texas
Name Dockum Group, undivided
Geologic age Late Triassic
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Shale (Bed)
Minor
Sedimentary > Clastic > Mixed-clastic > Sandstone-mudstone (Bed)
Incidental
Sedimentary > Carbonate > Limestone (Bed)
Sedimentary > Clastic > Conglomerate (Bed)
Comments Well exposed near town of Dockum, Dickens Co., TX. Continental redbed sequence deposited unconformably on Upper Permian (Quartermaster Fm in Tucumcari Sheet (1983). Shale, sandst., siltst., ls., and gravel; mostly shale, miceous, thinbedded, variegated; thickness up to 300 ft. or 400 ft +_ on Lubbock Sheet (1983). correlative with Chinle Fm (above) and Santa Rosa Ss (below).
Stratigraphic units basal unit Santa Rosa Formation (Sandstone), ascending units are Tecovas Formation, Trujillo Formation, Chinle Formation
References

Bureau of Economic Geology, 1983, Tucumcari Sheet, Geologic Atlas of Texas, Bureau of Economic Geology, University of Texas at Austin, scale 1:250,000.

Finch, W.I., 1988, Description of the principal reference for the Santa Rosa Formation, Chapter A, in Principal reference section for the Santa Rosa Formation. . ., Guadalupe County, New Mexico: U.S. Geological Survey Bulletin 1804, p. 1-10.

https://pubs.er.usgs.gov/publication/b1804

Bureau of Economic Geology, 1983, Lubbock Sheet, Geologic Atlas of Texas: University of Texas at Austin, Bureau of Economic Geology, scale 1:250,000.

Bureau of Economic Geology, 1976, Hobbs Sheet, Geologic Atlas of Texas: University of Texas at Austin, Bureau of Economic Geology, 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.

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 Andrews - Armstrong - Borden - Briscoe - Coke - Crane - Crosby - Dawson - Deaf Smith - Dickens - Ector - Fisher - Floyd - Garza - Howard - Kent - Loving - Lubbock - Lynn - Martin - Midland - Mitchell - Motley - Nolan - Randall - Reeves - Scurry - Sterling - Stonewall - Upton - Ward - Winkler