Abstract: Petrology of Catahoula Sandstones in East Texas

John Scheldt, William C. Ward

Lower Catahoula sandstones (Oligocene-Miocene) in East Texas consist of two similar members, the "Corrigan" and Chita sandstones, distinguished by stratigraphic position.

Medium-grained Catahoula sandstones from Trinity, Polk, Tyler, and Jasper Counties are submature subarkoses. Framework grains are quartz and detrital chert, 70 to 80%; feldspar, 5 to 20%; and rock fragments, 3 to 13%. Quartz types recognized and mean percentages in samples are: monocrystalline, 85%; polycrystalline, 9%; and microcrystalline (chert), 6%. Feldspar types are: microcline, 32%; orthoclase, 24%; sanidine, 24%; plagioclase, 13%; and microperthite, 7%. Rock fragments are: volcanic-rock fragments, 95%; metamorphic-rock fragments, 4%; and plutonic igneous-rock fragments, 1%. The nonopaque heavy-mineral suite mainly consists of subrounded to rounded zircon, subangular to subrounded epidote and kyanite, and rounded tourmaline, with lesser amounts of rutile, hornblende, garnet, py oxene, barite, sillimanite, and staurolite.

Major sources of the fluvial Catahoula sandstones and conglomerates were sedimentary rocks of northern Texas-southern Oklahoma, as is indicated by cross-bedding directions and by the constituents of detrital chert, well-rounded quartz, and rounded zircon and tourmaline. In addition, the presence of kyanite, sillimanite, and staurolite suggest recycling of older sedimentary rocks that ultimately were derived from the southern Appalachians before the Mississippi Embayment developed. Possible sources for lesser amounts of the detritus were Tertiary volcanic rocks of Trans-Pecos Texas, metamorphic rocks of the Ouachita foldbelt, and granitic rocks of the Wichita and Arbuckle Mountains.

The presence of "unstable" constituents such as polycrystalline quartz, various feldspars, metamorphic heavy minerals, and metamorphic-rock fragments in the Catahoula sandstones, most of which were derived directly from older sedimentary rocks, indicates that these "unstable" minerals survived recycling, perhaps multiple recycling, during accumulation of the coastal-plain sediments.

AAPG Search and Discovery Article #90967©1977 GCAGS and GC Section SEPM 27th Annual Meeting, Austin, Texas