62 New Perspectives on Paleoclimate from Advances in Glacial Geology
Wednesday, 25 March 2015
8:00 AM - 9:10 AM
Gifford Room
MISMATCH OF GLACIER EXTENT AND SUMMER INSOLATION IN SOUTHERN HEMISPHERE MIDLATITUDES
Paper number: 62-3
Program: Theme Sessions
Time: 8:25 AM – 8:45 AM
Authors
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Roseanne SchwartzLDEO, Palisades, NY
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Joerg M. SchaeferColumbia University, Palisades, NY
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Aaron E. PutnamColumbia University, Palisades, NY
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George DentonUniversity of Maine, Orono, ME
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Michael KaplanPO Box 1000, 61 Route 9WComer Geochem Building, Palisades, NY
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David BarrellGNS Science, Dunedin
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Bjorn AndersenUniversity of Oslo, Oslo
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Samuel KelleyUniversity at Buffalo, Buffalo, NY
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Robert C. FinkelUniversity of California, Berkeley, Berkeley, CA
Abstract
Here we address a long-standing puzzle of ice-age climate called the "fly in the ointment of the Milankovitch theory". Using geomorphic mapping and surface exposure dating, we find that 10Be ages of moraine boulders from Mackenzie Basin, New Zealand show multiple glacial maxima: 41,760 ± 1090; 35,500 ± 1260; 27,170 ± 680; 20,270 ± 600; and 18,290 ± 490 years old. These maxima span an entire precession cycle suggesting that the behavior of mid-latitude glaciers was not tied to local summer insolation intensity. Instead, we see a closer link between New Zealand glacier expansion and Southern Ocean surface temperatures and atmospheric carbon dioxide.