2014 Annual Science Report
Pennsylvania State University Reporting | SEP 2013 – DEC 2014
Biosignatures in Ancient Rocks - Ohmoto Group
This project has been aimed at understanding the chemical and biological natures of the ocean-atmosphere-lithosphere systems during the Archean. A second objective is testing a hypothesis that the MIF-S isotope signatures, which characterize some Archean and younger sedimentary rocks, were generated during reactions between hydrothermal fluids and organic-rich sediments, rather than through atmospheric reactions.
Based largely on the behaviors of redox-sensitive elements (Fe, Mn, Mo, U, Cr, S, C, etc) in massive sulfide deposits and banded iron formations in the oceans, and in subaerial hydrothermal deposits of different geologic age, we have recognized that the redox chemistry of the ocean and atmosphere has been essentially the same throughout the geologic history, i.e., the globally oxygenated oceans with regionally stratified anoxic oceans. Several manuscripts for publication are in progress.
Andrew Chorney has completed a master thesis on the topic of MIF-gerantion during thermochemical sulfate reduction. A manuscript for publication is in preparation.
PROJECT MEMBERS:Hiroshi Ohmoto
RELATED OBJECTIVES:Objective 1.1
Formation and evolution of habitable planets.
Earth's early biosphere.
Effects of environmental changes on microbial ecosystems