FUNGAL PALYNOMORPHS ACROSS THE PETM IN WILCOX GROUP SEDIMENTS, CENTRAL TEXAS, PRELIMINARY RESULTS

An integrated re-study of Wilcox Group strata has led to the realization that the PETM is likely expressed in condensed sections exposed in outcrops near Bastrop, Texas. This interpretation is based on a combination of sedimentology, ichnology, and palynology, especially an abundance peak of Apectodinium species and floral turnover occurring on either side of this peak. While the majority of the succession is marine, or just onshore in the case of associated sub-bituminous coals, variations in the types and quantities of fungal palynomorphs occur in the context of both changing depositional environments and climate. In initial stages of the work, it became clear that processing techniques used to extract palynomorphs from these strata had a significant impact on the analytical results. Samples were minimally processed, with the net result that a diverse, abundant flora was obtained, including that of fungal palynomorphs. Here we present our preliminary findings on the distribution of fungal palynomorphs across the PETM. Fungi present in the samples represent mycorrhizae, saprophytes, and parasites. The dominant mycorrhizal type present in each sample is correlative to major plant communities. Key observations to date include: arbuscular mycorrhizal fungi predominate where dryland plant taxa are most abundant, Lacrimasporites and Fusiformisporites types are present in tidal marsh facies, and ascocarps of epiphyllous parasitic fungi are common in horizons with fossilized leaves, as are stellate conidia cf. Arthrinium pterospermum.