ELSIK, WILLIAM C., The MycoStrat Connection, Snook, TX; and THOMAS E. YANCEY, Texas A&M University, College Station, TX

Middle Eocene assemblages of east Texas contain diverse populations of tropical and subtropical palynomorphs. The paleoclimate cooled over the period ca. 42 Ma to ca. 32 Ma, and was the driving force for the gradual disappearance of tropical elements and the appearance of cooler elements in the palynofloras. A short-term cooling event near the end of the Eocene set the stage for further changes in the early Oligocene.

Eight assemblage zones and one range zone are recognized in samples from 15 sections of the Crockett, Yegua, Caddell, Manning and Catahoula (Gueydan) formations. Zones recognized in the middle Eocene are the Nuxpollenites Assemblage Zone, Bombapollis texensis Assemblage Zone, Friedrichipollis claibornensis Assemblage Zone, and Hoheria Assemblage Zone. The upper Eocene is characterized by the Rhizophora Assemblage Zone, Mutisieae Range Zone, Nudopollis terminalis Assemblage Zone, and Bombacacidites Assemblage Zone. The Hypoxylonites Assemblage Zone marks the lower Oligocene.

The age of the lower Gueydan Formation is early Oligocene based on the occurrence of Kallosphaeridium biornatum at a locality northwest of Huntsville, Texas.

ELSIK, WILLIAM C., and THOMAS E. YANCEY

AAPG Search and Discovery Article #90908©2000 GCAGS, Houston, Texas