Integrating Geochemical and Petrographic Analyses to Better Understand Proximal to Distal Variations in Source Rocks, Using an Example from the Bashkirian in the United Kingdom; #10781 (2015)

Mudstone lithofacies are now known to be highly variable, impacting on all aspects of their source, seal and reservoir potential in different locations within the basin. Previously, much of this variability has been interpreted by examining chemical proxies and their subtle variability in redox sensitivities (particularly the presence of anoxia). However, some of the interpretations from geochemistry appear to be at odds with conclusions reached from the petrographic and detailed logging studies. The aim of this article is to investigate these discrepancies and refine stratigraphic models to provide a clear insight into how a source rock varies laterally within a basin. This is achieved by integrating detailed (sub-mm to 10s m scale) petrographic analyses of lithofacies (grain size, mineralogy, fabric), total organic carbon and inorganic geochemical data acquired from a well-constrained proximal to distal succession of Bashkirian-aged mudstones (beds enclosing the Bilinguites gracilis horizon) in the UK Pennsylvanian basin.