--> Abstract: Palynology of the updip Wilcox Group in Central Texas, by Regina Dickey; #90167 (2013)

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Palynology of the updip Wilcox Group in Central Texas

Regina Dickey
[email protected]

The Wilcox Group is an intensely studied group of sediments deposited primarily during the Laramide orogeny in the western United States and is important economically both onshore and offshore. This particular updip stratigraphic section in the northwestern part of the Gulf of Mexico region has limited documentation of the changes in microbiota, despite the high level of interest in the interval. The organic acids produced by the decay of plant tissue have resulted in the diagenetic loss of nearly all carbonate remains. Therefore, palynology provides the best means of correlation, age determination, and paleoenvironment. Palynological sampling within a 30 m section of Calvert Bluff and Carrizo Formation strata contain a rich assemblage of well-preserved palynomorphs and occasional dinoflagellates (Figs. 2 and 3) in outcrops containing a major sequence boundary. Calvert Bluff strata consist of shoaling-upwards, fine-grained shallow marine deposits; the sequence boundary is marked by a paleosol and incised channel fill; the Carrizo is a transgressive marine sand deposit (Fig. 1). The upper Calvert Bluff is placed in the upper part of the Middle Wilcox and is correlative to the subsurface Yoakum shale, making this palynological analysis is a high resolution tool that can be used in subsurface correlations and age determinations for parts of the Wilcox in the absence of other definitive markers or in addition to lithologic correlations. Figure 1. Location of study area and stratigraphic section Figure 2. Palynomorphs of the Calvert Bluff Formation Figure 3. Dinoflagellates

AAPG Search and Discovery Article #90167©2013 GCAGS and GCSSEPM 63rd Annual Convention, New Orleans, Louisiana, October 6-8, 2013