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Clues to Atmospheric Evolution in Earth's Earliest Sediments

Presenter: Mark Claire, University of St. Andrews
When: April 14, 2014 11AM PDT

Understanding how the Earth system has evolved through time is a grand challenge for astrobiologists. In particular, study of atmospheric oxygen concentrations through time has led us to the realization that the early Earth was truly an alien planet. Anomalies in the minor isotopes of sulfur indicate the complete absence of O2 from Earth’s atmosphere prior to 2.4 billion years ago.

The goal of this NPP project was to identify additional constraints on the early atmosphere beyond the absence of O2. We enhanced a 1-D photochemical model to include 3 isotopes of sulfur and used it to make quantitative predictions that can be compared to sediments in the rock record. We test hypothesis for how sulfur MIF forms in the atmosphere and show that multiple atmospheric compositions including O2, CH4, CO2, total sulfur, and organic haze are capable of altering the 32/33/34 S isotopes signatures. We will discuss how ongoing laboratory measurements and experiments should allow for quantitative constraints on the early atmosphere in the near future.

NPP Alumni Seminars

  • The NASA Postdoctoral Program has been extraordinarily successful in supporting new leaders in the astrobiology community. Upon completion of their postdoctoral fellowships, the Astrobiology Fellows are given the opportunity to present a seminar to share their work with one another and with the astrobiology community at large.
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