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Microbial Fossilization in Mineralizing Environments: Relevance for Mars "EXOPALEONTOLOGY"The goals of post-Viking exobiology include the search for a Martian fossil record. How can we optimize future exploration efforts to search for fossils on Mars? The Precambrian fossil record indicates that key factors for the long-term preservation of microbial fossils include: 1) the rapid entombment and/or replacement of organisms and organic matter by fine-grained, stable mineral phases (e.g. silica, phosphate, and to a lesser extent, carbonate), 2) low-permeability host sediments (maintaining a closed chemical system during early diagenesis), and 3) shallow burial (maintaining post-depositional temperatures and pressures within the stability range for complex organic molecules). Modem terrestrial environments where early mineralization commonly occurs in association with microbial organisms include: subaerial thermal springs and shallow hydrothermal systems, sub-lacustrine springs and evaporites of alkaline lakes, and subsoil environments where hardpans (e.g. calcretes, silcretes) and duricrusts form. Studies of microbial fossilization in such environments provide important insights preservation patterns in Precambrian rocks, while also playing a role in the development of strategies for Mars exopaleontology. The refinement of site priorities for Mars exopaleontology is expected to benefit greatly from high resolution imaging and altimetry acquired during upcoming orbital missions, and especially infrared and gamma ray spectral data needed for determining surface composition. In anticipation of future orbital missions, constraints for identifying high priority mineral deposits on Mars are being developed through analog remote sensing studies of key mineralizing environments on Earth.
Document ID
20010051285
Document Type
Conference Paper
Authors
Farmer, Jack D.
(NASA Ames Research Center Moffett Field, CA United States)
DesMarais, David J.
(NASA Ames Research Center Moffett Field, CA United States)
Morrison, David
Date Acquired
August 20, 2013
Publication Date
January 1, 1994
Subject Category
Life Sciences (General)
Meeting Information
COSPAR Meeting(Hamburg)
Funding Number(s)
PROJECT: RTOP 185-52-82
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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