Palynology, petrology, and depositional environments of some early tertiary lignites in Texas

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Abstract
Predominantly nonmarine early Tertiary sediments of the Wilcox Group in Texas include numerous local lignite deposits. Recent subsurface mapping has defined several interrelated depositional systems representing six sedimentary environments, in outcropping and subsurface Wilcox in Texas. Lignite occurs in three of the environments so defined; these are (1) fluvial, (2) deltaic, and (3) lagoonal. Plant microfossils and coal macerals from the Wilcox lignites comprise a relatively homogenous, recurring association, but substantial differences also exist between the lignites from the various environments. Petrographic differences include: (1) greater abundances of certain lithotypes, (2) predominance of certain macerals, (3) relative abundance of mineral matter. Palynologic differences can be summarized in terms of distribution of assemblages and species groups within the flora. Assemblages recognized are the (1) Corylus‐Sphagnum Assemblage, (2) Palm Assemblage, and (3) Marine Influence Assemblage. Species groups include (1) locally indigenous forms, (2) reworked forms, (3) temperate genera and (4) tropical genera. Quantitative distinctions within the flora are suggested by species diversity indices. Paleoecologic inferences derived from this study suggest agreement with environmental interpretations based on mapping. This study is seen as a basis for further biostratigraphic and paleoecologic investigations in the Gulf Coast Tertiary.