Triggers for Organic Matter Accumulation in the Middle and Upper Devonian Horn River Shale, Canada, Identified from Microsampling of Drill Cores

Organic matter (OM) enrichment is mainly controlled by productivity, redox conditions and dilution. However, these parameters also affect each other in ways that often conceal the factor actually triggering OM burial. At the scale we commonly sample drill cores, interplays or feedback loops between productivity and redox controls commonly result in apparently synchronous variation in proxies for these parameters. For example, shifts to both higher productivity and more anoxic conditions may be indicated at points in a shale formation where total organic carbon (TOC) increases. Our research applied chemical analysis at 1 – 2 mm stratigraphic resolution to directly distinguish triggers for organic richness of Horn River Shale, Horn River Basin, Western Canada Sedimentary Basin.