Biomarker analysis of a Late Cretaceous shale (Eagleford shale, Woodway, TX) yielded information regarding organic matter source, water column conditions, and biotic/abiotic alteration. Previous analyses of this locality were limited to the freely-extractable lipids (n-alkanes, isoprenoids, carotenoids, steranes, and diasterenes). Chemical treatments have been shown to provide distinct biomarker distributions in natural materials with respect to total lipid extraction, as organo-mineral matrices can provide effective protection from extraction with conventional methods.  To account for potential bias due to organo-mineral association, the shale organic matter was fractionated into three categories: freely extractable, base-hydrolyzable, and unhydrolyzeable lipids.  We employed base hydrolysis, HCl/ HF demineralization, and sequential extraction processes to reconstruct representative biomarker distributions.  It is likely that systematic OC fractionation can aide in more robust paleoenvironmental reconstruction for geologic materials, and also closely trace the variation in biomarker parameters resulting directly from matrix protection.

Assessing the role of organo-mineral association in molecular biomarker analysis of a Late Cretaceous shale

247th National Meeting (2014)

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