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Seminar Detail
New and Emerging Perspectives on Late Precambrian 'Snowball Earth' Glaciation
Presenter: Tim Raub ()
February 26, 2007 11:00 AM Pacific
Geological and geophysical evidence for a dramatically severe planetary glacial response during Earth's Precambrian Eon (the "Snowball Earth") continues to grow. Recent geochemical measurements and modeling suggest that each late Precambrian glaciation might have boosted levels of atmospheric oxygen, ultimately changing patterns of carbon cycling in the ocean and permitting bodyplan complexity in early animals. The Snowball deglacial timescale appears long with respect to Plio-Pleistocene deglacial records and ice dynamic expectations.
Alternatively, a nonuniformitarian configuration of Earth's geomagnetic field could permit rapid deglaciation but introduce new ambiguities for climate forcing feedbacks. This talk enumerates multiple working hypotheses sustained by astrobiologists attacking this aspect of the fundamentally unusual, Precambrian Earth system.Participation Instructions
With a Polycom....RSVP to Marco Boldt (Marco.Boldt@nasa.gov) and connect to WebEx as instructed below. If you need Polycom help during the live event, call the videoconferencing help-desk at (650) 604-6412
The slides from the seminar can be accessed real-time using WebEx at:
https://nasa.webex.com
Enter the meeting number: 921 906 643 Hit the "join now" button.
Enter your name or site name (this is not an assigned log-in name, please use your institution name or your first and last name), email and the password: raub123* (case sensitive)
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Without a Polycom...There are two ways to participate:
1) You can listen to the seminar on the telephone while viewing the slides in WebEx (see WebEx instructions above). The NASA conference phone number will be displayed when joining the WebEx meeting.
2) You can watch the Realplayer webcast at: http://vanseg-1.arc.nasa.gov/2007/AB070226-01.ram and view the slides in WebEx (see WebEx instructions above) There is a 30 second delay for the webcast, so you will need to control the slides manually using the arrow buttons in WebEx. Questions for the speaker can be posted in the WebEx chat area to be answered at the end of the talk. Do not try to watch the Realplayer webcast at the same time as the Polycom or the phone. Due to the delay in the webcast, it will sound awful, unless you like dissonance.December 21, 2007
The Director’s Seminar series features talks from scientists who are invited by the NAI Director to present their research results to the community. A primary goal of the seminars is to encourage interdisciplinary collaboration across NAI teams and within the astrobiology community at large.
Team Overview Seminars describe the work of the fourteen NAI teams and NAI Central. They offer an opportunity to find out more about the science, E/PO and other activities being performed by the NAI teams and the NAI Central office.
The Forum for Astrobiology Research (FAR) provides an opportunity for graduate students to present their research results and to meet as a student community for networking and mutual support.
The University of Washington seminar series is hosted by the NAI Virtual Planetary Lab (VPL) team from the UW campus in Seattle.
