Organic carbon burial rate and the molybdenum proxy: Theoretical framework and application to Cenomanian‐Turonian oceanic anoxic event 2

Abstract

In this study the controls on organic carbon burial and molybdenum accumulation in ancient strata are investigated through an integration of biogeochemical modeling and data analysis. Critical aspects of the study are employment of a biogeochemical model for organic matter degradation to explore the controls on pore water sulfide generation and authigenic molybdenum accumulation and use of accumulation rate data for Mo, OC, CaCO3, Fe, and Ti to reconstruct organic matter remineralization processes. The model results form a conceptual framework for the interpretation of primary production estimates and geochemical burial fluxes (calculated on the basis of a high‐resolution orbital timescale) for the Cenomanian‐Turonian (C‐T) oceanic anoxic event 2 interval in the Western Interior basin. The results of this study suggest that the strong correlation between source rock development and intervals of transgression in the geologic record (such as the C‐T) could reflect a confluence of biogeochemical processes within sediments that obviates the need for large‐magnitude changes in primary production levels or oceanographic conditions (such as prolonged periods of stable water column stratification).