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Munn Formation

Munn Formation
State Texas
Name Munn Formation
Geologic age Phanerozoic | Paleozoic | Permian [Guadalupe]
Comments Dolomite, limestone, siltstone, and sandstone. Upper part--mostly dolomite and limestone, fine to coarse grained, in part oolitic, medium to thick bedded, white to grayish orange; some siltstone and fine-grained quartz sandstone proportion increases southward. Lower part--mostly dolomite and dolomitic limestone, fine grained, very thick bedded, light brownish gray to pale yellowish brown, weathers a distinctive brown; thin beds of siltstone and fine-grained sandstone scarce, more numerous northward. Marine megafossils and microfossils. Thickness 450+ ft.
Primary rock type dolostone (dolomite)
Secondary rock type limestone
Other rock types siltstone; sandstone
Lithologic constituents
Major
Sedimentary > Carbonate > Dolostone (Bed)
Sedimentary > Carbonate > Limestone (Bed)
Minor
Sedimentary > Clastic > Mixed-clastic > Sandstone-mudstone (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
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