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Fossil Record of Precambrian Life on LandThe argument that the earth's early ocean was up to two times modern salinity was published in 'Nature' and presented at the 1998 Annual Meeting of the Geological Society of America in Toronto. The argument is bolstered by chemical data for fluid inclusions in Archean black smokers. The inclusions were 1.7 times the modern salinity causing the authors to interpret the parent fluids as evaporite brines (in a deep marine setting). I reinterpreted the data in terms of the predicted value of high Archean salinities. If the arguments I presented are on track, early life was either halophilic or non-marine. Halophiles are not among the most primitive organisms based on RNA sequencing, so here is an a priori argument that non-marine environments may have been the site of most early biologic evolution. This result carries significant implications for the issue of past life on Mars or current life on the putative sub-ice oceans on Europa and possibly Callisto. If the Cl/H2O ratio on these objects is similar to that of the earth, then oceans and oceanic sediments are probably not the preferred sites for early life. On Mars, this means that non-marine deposits such as caliche in basalt may be an overlooked potential sample target.
Document ID
20010047676
Document Type
Contractor or Grantee Report
Authors
Knauth, Paul (Arizona State Univ. Tempe, AZ United States)
Date Acquired
August 20, 2013
Publication Date
January 1, 2000
Subject Category
Exobiology
Report/Patent Number
ASU-PVA-6527/TE
Funding Number(s)
CONTRACT_GRANT: NAG5-4860
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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