MBG Auditorium, PPPL (284 cap.)
COLLOQUIUM: Extending the Ice Core Record of Atmospheric Composition and the Global Carbon and Oxygen Cycles Beyond 1 Million Years
Ice cores serve as a critical archive of past environmental conditions, providing constraints on global atmospheric composition and the climate of polar regions. Reconstructions of atmospheric CO2 and CH4 from air trapped in ice cores dating as far back as 800 ka indicate a link between greenhouse gases and global climate in the form of 100 kyr glacial cycles. These climate cycles are recorded in proxy records from deep-sea sediments reflecting variations in ocean temperature and continental ice volume. Deep-sea records indicate that the 100 kyr glacial cycle developed only ~900,000 years ago (the Mid-Pleistocene transition or MPT). Prior to this, and going back to 2.8 Ma, glacial cycles lasted on average 40 kyr. The origins of both the 100 kyr and 40 kyr glacial cycles, their links to orbital forcing, and changes in atmospheric greenhouse gases, are hotly debated. In this talk I will present the first direct ‘snapshots’ of atmospheric composition during the MPT from an ice core drilled at Site BIT-58 in the Allan Hills blue ice area and discuss implications for the MPT. I will also present a new record of atmospheric O2/N2 over the last 800,000 years from ice cores and show how this record provides novel insights into the processes that control atmospheric CO2 and O2 on geologic timescales.
The Princeton Plasma Physics Laboratory 2019-2020 Colloquium Committee is comprised of the following people. Please feel free to contact them by e-mail regarding any possible speakers or topics for future colloquia.
- Carol Ann Austin 609-243-2484
Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.
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