ABSTRACT

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 consisting of 70-80% quartz and chert, 5-20% feldspar, and 3-13% rock fragments. Quartz types are: monocrystalline, 85% (mean %); polycrystalline, 9%; and microcrystalline (chert), 6%. Feldspars 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 non-opaque 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, pyroxene, 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, 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 granite rocks of the Wichita and Arbuckle Mountains.

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