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Markley Formation

Markley Formation
State Texas
Name Markley Formation
Geologic age Phanerozoic | Paleozoic | Carboniferous Pennsylvanian Permian
Comments Overlies Canyon Grp. Basal formation of Bowie Group (new), Hentz (1988). Continental and minor paralic strata on Bend arch and Ft Worth syncline (Young, Jack, Clay, Montague Cos., TX) Sandst., mudst., conglomerate, coal, scarce thin limest. Easternmost outcrop, fluvial and minor fluvial-deltaic sandst. and chert-pebbly conglomerates form marker beds. Markley contains 15 sandst. members which occur as mappable stacked bodies and horizontally contiguous belts, separated by thin mudstone zones. Mudst. contains sandst. and siltst. lentils and discontinuous seams of subbituminous coal and carbonaceous shale (Newcastle Coal and others). In lower part are thin beds of weathered and fissile subbituminous coal. Ranges in thickness 320-600 ft.
Primary rock type sandstone
Secondary rock type mudstone
Other rock types conglomerate; coal; limestone
Lithologic constituents
Major
Sedimentary > Clastic > Sandstone (Bed)
Minor
Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)
Incidental
Sedimentary > Clastic > Conglomerate (Bed)
Sedimentary > Coal > Sub-bituminous (Bed)
Sedimentary > Clastic > Mudstone > Claystone (Bed)
Sedimentary > Carbonate > Limestone (Bed)Crystal Falls Limestone in so. Young Co, 1-2 ft in discontinuous otcps.
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
Bureau of Economic Geology, 1987, Wichita Falls-Lawton Sheet, Geologic Atlas of Texas: University of Texas at Austin, Bureau of Economic Geology, scale 1:250,000.
Hentz, T., 1988, Lithostratigraphy and paleoenvironments of upper Paleozoic continental red beds, north-central Texas: Bowie (new) and Wichita (revised) Groups: Texas Bureau of Economic Geology, Report of Investigations 170.
Counties Archer - Clay - Culberson - Jack - Montague - Throckmorton - Young