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May 9, 2013: Recent Observations of Mass Independent Compositions in Atmospheric Species

Posted on Apr 29, 2013 in Seminars

Mark Thiemens (Scripps Institute of Oceanography)

The first observation of a chemically produced mass independent process suggested application to the early solar system, which remains relevant to date. In the subsequent development of a quantum mechanical understanding of the isotopic process, numerous applications in the terrestrial atmosphere arose. At present, with the exception of water, every oxygen bearing species in the Earths atmosphere is mass independent and does not lie on the so called terrestrial fractionation line, with species both above and below the fractionation line defined by silicate rocks. In each case, new information on source strengths and transport and chemical transformation is provided that would otherwise have been unrecognized. One of the least understood components of global climate is the role of aerosol particles. The application of mass independent isotope measurements has lead to new insights into this issue. Specific aspects of the role of particles with ozone has been particularly important as the role of chemically transformation is captured. What is more important is that the record is stable and the change over time is recorded and ice core samples provide the only paleo ozone record available. Finally, measurements of Martian meteorites secondary minerals may be better interpreted from combined laboratory, atmospheric, and ice core and geologic record. Recent measurements will be discussed