[Eoas-seminar] Colloquium Friday March 2nd, 3:30pm

eoas-seminar at lists.fsu.edu eoas-seminar at lists.fsu.edu
Fri Feb 23 14:28:21 EST 2018


Dear EOAS Colleagues,

I would like to invite you all to attend an EOAS Colloquium at 3:30pm by Prof. Laura Wasylenki, visiting from Indiana University.

Title: What nickel isotopes can and cannot tell us about the Great Oxidation Event

Abstract: The Great Oxidation Event, when free O2 first accumulated in the atmosphere, at ~2.4 Ga, was arguably one of the most profound turning points in the history of Earth and life. The causes and exact timing of this transformation are still debated, but some recent studies argue persuasively that the transition from an anoxic, Archean atmosphere to a slightly oxygenated Paleoproterozoic atmosphere required a dramatic decrease in the flux of biogenic methane to the atmosphere. The drop in methane production is thought to have resulted from either (1) unsuccessful ecological competition of methanogens with sulfate-reducing bacteria (Zahnle et al., 2006) or (2) a methanogen “Ni famine,” resulting from greatly reduced fluxes to seawater of this critical trace nutrient for methanogens (Konhauser et al., 2009, 2015). In an effort to piece together how the controls on the Ni supply to the oceans may have changed in the Latest Archean Eon, we have measured Ni isotope signatures in several suites of terrestrial and marine rocks. Our results to date indicate that the biogeochemical cycle of Ni did undergo a transformation at ~2.7 Ga. The continental crust became much poorer in Ni, so Ni flux to the ocean waned, but the onset of sulfide weathering on land sustained a small, but crucial flux of Ni to the oceans. We hypothesize that, although methanogens likely became Ni-limited, they were able to continue producing just enough methane to prevent the Earth from entering prolonged and severe ice ages.


Hope to see everyone there!

Seth


Dr. Seth A. Young
Assistant Professor
Department of Earth, Ocean, & Atmospheric Science
Florida State University
Tallahassee, FL 32306-4520
CAR 305
sayoung2 at fsu.edu<mailto:sayoung2 at fsu.edu>

http://www.sethallenyoungphd.com/

"Change is not something that we should fear. Rather, it is something that we should welcome. For without change, nothing in this world would ever grow or blossom, and no one in this world would ever move forward to become the person they’re meant to be.”  –B.K.S. Iyengar






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