Sedimentary organic matter diagenesis : oxidative transformations and dynamics upon pyrolysis.

Abstract

The organic matter fraction preserved in ancient sediments is the largest carbon pool on earth, and holds immense importance in the context of global biogeochemical cycling and as petroleum source rock. This dissertation represents an organic geochemical approach to furthering the understanding of several diagenetic processes that contribute to the nature and properties of organic matter in marine, lacustrine, and soil environments. Specifically, the dynamics of low-temperature “early” oxidation of organic matter, the post-depositional microbial oxidation of organic matter in outcrop, and the experimental thermal alteration of organic matter (programmed anhydrous and hydrous pyrolysis) were explored, as these diagenetic pathways represent important transformative processes and rate modifiers in the global carbon cycle. Specific attention is paid the kerogen fraction, or the fraction of sedimentary organic matter operationally-defined as insoluble in common organic solvents, which is the most abundant, structurally-diverse, and underutilized component of fossil organic matter.