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Project Progress

We wrote 4 papers on:

• Brines on Mars (In press)
• Caliche as a target for astrobiological prospecting on Mars ( in revision following review)
• Climatic temperature of the Archean Earth (in revision following review)
• Brines on Mars as electrical conductors susceptible to geophysical detection (in revision following review)
  

We did field work in Australia with University of California, Los Angeles (UCLA) NAI team. Isotopic and petrographic analyses of sampes are under way.

The main results, then, were to shore up and publish the idea that eutectic brines in the megaregolith of Mars are an inevitable consequence of the ?warm, wet, early Mars? hypothesis and could be the source of the recently observed features interpreted as fluid seeps.

We documented a broad range of isotopic values for caliche (carbonate formed by arid weathering of terrestrial basalts) in the Sonoran Desert of Arizona. Values obtained for the subsurface portions of caliche deposits exhibit light values indicative of a biological source. This observation has important potential applications in Mars exploration. If caliche is discovered on Mars, this would be direct evidence for a ?warm and wet? early history. Trends to light values with depth may be a biosignature.

We finished isotopic analyses of Archean cherts to test various explanations of the low γ18^O always observed in these rocks. The best explanation is that the Earth at 3.5 Ga (before present) was very warm, on the order of 55^sC.