U.S. Geological Survey and the National Academies, USGS OF-2007-1047, Extended Abstract 165 Cenozoic variations of the Antarctic Ice Sheet: A model-data mismatch?
Summary Cenozoic variations of global ice volume deduced from δ18O deep-sea-core records are compared with results from 3-D ice sheet-climate models. After the initial growth of major Antarctic ice at the Eocene-Oligocene boundary ~34 Ma, δ18O records indicate numerous excursions throughout the Olig...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.553.1490 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea165.pdf |
| Summary: | Summary Cenozoic variations of global ice volume deduced from δ18O deep-sea-core records are compared with results from 3-D ice sheet-climate models. After the initial growth of major Antarctic ice at the Eocene-Oligocene boundary ~34 Ma, δ18O records indicate numerous excursions throughout the Oligocene and early Miocene with timescales of ~105 to 106 years and amplitudes of ~20 to 80 meters of sea level. During most of this period, proxy atmospheric CO2 levels in proxy records were low, around 1x pre-industrial. These observations conflict with coupled model results that once a large East Antarctic ice sheet formed at 34 Ma, CO2 levels must have been in the ~3x to 4x range to induce significant retreat and re-growth. Several mechanisms are discussed that could possibly have caused large ice-volume fluctuations, all of which are highly speculative. |
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