Abstract: Bio- and Sequence Stratigraphy of the Upper Kincaid Formation, Frost Bluff, Milam County, Texas

Anthony E. D'Agostino, Thomas E. Yancey

A sequence biostratigraphic interpretation of the upper Pisgah and Tehuacana members of the Kincaid Formation, exposed at Frost Bluff along the west bank of the Brazos River in Milam County, is based on 27 m of measured section and ten samples analyzed for foram biostratigraphy. The P1c-P2 zonal boundary occurs at approximately 11 m above the base of the section, in the upper portion of the Pisgah Member. This implies the Pisgah Member is part of cycle TA1.3 of Haq et al. A sequence boundary interpreted at the base of the Tehuacana Member is therefore correlated with the base of cycle TA1.4. Lithologic and faunal characteristics suggest the basal 0-2.2m of the measured section is part of the TST/Condensed Interval of TA1.3. Sediments of this interval are interpreted as de osits of deep outer neritic (150-200 m) normal marine environment, with a fauna dominated by planktics and diverse deep-shelf benthics. The base of the HST of cycle TA1.3 lies at the base of a silty bed at 2.5 m. This silty bed is characterized by low planktic diversity and abundance. HST deposits of the 2.5-15 m interval record increasing silliness and systematic upward-decreasing diversity of deeper-water benthics and overall relative abundances. Interpreted paleobathymetry at the top of the sampled section is middle neritic (50-100 m).

AAPG Search and Discovery Article #90950©1996 AAPG GCAGS 46th Annual Meeting, San Antonio, Texas