[Save] ESI Seminar- This Friday

[Matthew Gardner]

Earth System Initiative Seminar

Friday October 10, 12 Noon, 56-154
"Did Extinction at the Precambrian-Cambrian Boundary lead to the Cambrian 
Radiation of Animals?"
Professor John Grotzinger
Department of Earth Atmospheric and Planetary Sciences, MIT

Biostratigraphic, carbon isotopic, and uranium-lead zircon geochronological 
data from globally distributed regions indicate an abrupt last appearance 
of Precambrian metazoans coincident with a large-magnitude, but short-lived 
negative excursion in the carbon-isotopic composition of seawater that is 
globally coincident with the Precambrian-Cambrian boundary. U-Pb zircon age 
data from an intercalated ash bed in Oman directly constrain this negative 
excursion to be 542.0 Ma ± <0.5 Ma, consistent with previous constraints 
from Siberia and Namibia. Combined with the global biostratigraphic record, 
these new data strengthen hypotheses invoking mass extinction within 
terminal Proterozoic ecosystems at or near the Precambrian-Cambrian boundary.


Pick up some lunch immediately before the seminar in 16-168.

Next Seminar:

Thursday October 23, 12 Noon, 16-160.
Joint ESI-CEE Distinguished Seminar Series
Professor Edward DeLong
Monterey Bay Aquarium Research Institute




Matthew Gardner, Ph.D.
Program Administrator
Earth System Initiative, 16-177
Massachusetts Institute of Technology
Cambridge, MA, 02139
617.253.6895
http://web.mit.edu/esi
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