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Microbial Biosignatures In High-Iron Thermal Springs, Mary Nichole Parenteau

Dissertations and Theses

Debate exists regarding whether abiotic or biotic mechanisms were responsible for the oxidation of Fe²+ and the subsequent accumulation of ferric (Fe³+) iron assemblages in Precambrian Banded Iron Formations (BIFs). Direct paleontological evidence for a microbial role in the deposition of BIFs has been sought in the occurrence of microfossils and lipid biomarkers in these structures.

This study has characterized the formation of such biosignatures in modern iron deposits. The metabolic impact of microbes on Fe2+ oxidation in this system has previously been described (Pierson et al., 1999; Pierson and Parenteau, 2000). Cyanobacterial and filamentous anoxygenic …