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Cosmogenic nuclide chronology of millennial-scale glacial advances during O-isotope stage 2 in Patagonia

2004; Geological Society of America; Volume: 116; Issue: 3 Linguagem: Inglês

10.1130/b25178.1

1943-2674

Michael R. Kaplan, Robert P. Ackert, Brad S. Singer, Daniel C. Douglass, Mark D. Kurz,

Methane Hydrates and Related Phenomena

Research Article| March 01, 2004 Cosmogenic nuclide chronology of millennial-scale glacial advances during O-isotope stage 2 in Patagonia Michael R. Kaplan; Michael R. Kaplan 1Department of Geology and Geophysics, University of Wisconsin, Madison, Wisconsin 53706, USA Search for other works by this author on: GSW Google Scholar Robert P. Ackert, Jr.; Robert P. Ackert, Jr. 2Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Clark 419, MS 25, Woods Hole, Massachusetts 02543, USA Search for other works by this author on: GSW Google Scholar Brad S. Singer; Brad S. Singer 3Department of Geology and Geophysics, University of Wisconsin, Madison, Wisconsin 53706, USA Search for other works by this author on: GSW Google Scholar Daniel C. Douglass; Daniel C. Douglass 3Department of Geology and Geophysics, University of Wisconsin, Madison, Wisconsin 53706, USA Search for other works by this author on: GSW Google Scholar Mark D. Kurz Mark D. Kurz 4Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Clark 419, MS 25, Woods Hole, Massachusetts 02543, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Michael R. Kaplan 1Department of Geology and Geophysics, University of Wisconsin, Madison, Wisconsin 53706, USA Robert P. Ackert, Jr. 2Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Clark 419, MS 25, Woods Hole, Massachusetts 02543, USA Brad S. Singer 3Department of Geology and Geophysics, University of Wisconsin, Madison, Wisconsin 53706, USA Daniel C. Douglass 3Department of Geology and Geophysics, University of Wisconsin, Madison, Wisconsin 53706, USA Mark D. Kurz 4Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Clark 419, MS 25, Woods Hole, Massachusetts 02543, USA Publisher: Geological Society of America Received: 13 May 2002 Revision Received: 23 May 2003 Accepted: 23 Jun 2003 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2004) 116 (3-4): 308–321. https://doi.org/10.1130/B25178.1 Article history Received: 13 May 2002 Revision Received: 23 May 2003 Accepted: 23 Jun 2003 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Michael R. Kaplan, Robert P. Ackert, Brad S. Singer, Daniel C. Douglass, Mark D. Kurz; Cosmogenic nuclide chronology of millennial-scale glacial advances during O-isotope stage 2 in Patagonia. GSA Bulletin 2004;; 116 (3-4): 308–321. doi: https://doi.org/10.1130/B25178.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The terrestrial glacial record reflects past snowline variability and atmospheric temperature changes. When combined with secure chronologies, these data can be used to test models of ice-age climate. We present new in situ cosmogenic 10Be, 26Al, and 3He exposure ages, supported by limiting 40Ar/39Ar and 14C ages, for seven of the youngest moraines east of Lago Buenos Aires, Argentina, 46.5°S, that were deposited by a large outlet glacier of the Patagonian Ice Cap. Following a major glaciation that deposited extensive moraines prior to 109 ka, paired 10Be-26Al ages indicate that the next youngest complex of moraines was deposited from 23.0 ± 1.2 to 15.6 ± 1.1 ka (1σ). During the last glaciation, ice was at its maximum extent prior to 22 ka and at least five moraines were deposited in less than 10 k.y. These data are in good agreement with three 14C ages of ca. 16 ka from varved sediment banked on top of the youngest of these five moraines and limiting 3He ages, which range from ca. 33 to 19 ka. The most extensive ice marginal deposits preserved within the last 109 k.y. were formed during marine oxygen isotope stage 2; no moraines dating to stage 4 were found. For stage 2, the distribution of ages at Lago Buenos Aires is similar to cosmogenic nuclide-based glacial chronologies from western North America. In fact, the structure of the last mid-latitude South American ice age—specifically, the overall timing, a maximum ice extent prior to 22 ka, and deglaciation after 16 ka—is indistinguishable from that of the last major glaciation in the Northern Hemisphere, despite a maximum in Southern Hemisphere insolation during this period. The similar mid-latitude glacial history in both hemispheres implies that a global climate forcing mechanism, such as atmospheric cooling, as opposed to oceanic redistribution of heat, synchronizes the ice age climate on orbital time scales. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.