Characterization of Natural Organic Matter in Bentonite Clays and Clay-rich Sediments

• Main Author: Marshall, Hannah Marie Michaela
• Other Authors: Simpson, J. Myrna, Chemistry
• Format: Thesis
• Language: unknown
• Published: 2014
• Subjects: Arctic; Biomarker; Clay; Natural organic matter; Nuclear magnetic resonance spectroscopy; Nuclear waste; 0485
• Online Access: http://hdl.handle.net/1807/67857

Natural organic matter (NOM) was characterized in clays that are being considered for a used nuclear fuel sequestration concept and in clay-rich subsurface Arctic sediments. Molecular-level techniques including biomarker analysis and nuclear magnetic resonance spectroscopy were employed to gain insight into NOM chemistry. Plant waxes were identified as the main input to NOM in these samples. NOM in all samples was in an advanced state of digenesis based on several calculated degradation ratios. The compounds detected in bentonite clays are hypothesized to be mainly recalcitrant and unlikely to act as a microbial substrate. One of the Arctic sediments contained more labile material and evidence of active microbes while NOM detected in the other two Arctic sediments is hypothesized to be mainly recalcitrant. These results suggest that NOM in these samples is primarily refractory and unlikely to undergo further diagenesis. The biogeochemical stability of refractory NOM requires further study. M.Sc.