STRATIGRAPHY AND GEOCHEMISTRY OF THE LOWER CENOMANIAN MANESS SHALE OF EAST TEXAS

The Lower Cenomanian Maness Shale is a marine mudrock unit lying between the Buda Limestone and the Woodbine sandstones in East Texas and between the Buda Limestone and Eagle Ford shales in South Texas. The Maness has been studied since the 1950’s, yet much is still unknown, such as its sediment source, depositional environment, and source rock potential. This study focused on the Maness Shale in its type area of East Texas, and encompassed biostratigraphic, mineralogic, elemental, and petrographic analyses from East Texas cores in conjunction with well-log correlations. The biostratigraphic analyses used age-diagnostic calcareous nannofossils and foraminifera and determined that the East Texas Maness Shale is age-correlative to the mudrock identified as Maness near the San Marcos Arch. The mineralogic and elemental analyses determined the bulk mineralogy, clay content, and elemental abundances of the mudrock for source rock and depositional environment interpretations. Regional log cross sections were constructed to correlate the Maness Shale from the East Texas field to the Brazos Basin and helped to constrain the sediment source for the Maness.