Holocene history of the Larsen-A Ice Shelf constrained by geomagnetic paleointensity dating
- Stefanie Brachfeld*1,
- Eugene Domack*2,
- Catherine Kissel*3,
- Carlo Laj*3,
- Amy Leventer*4,
- Scott Ishman*5,
- Robert Gilbert*6,
- Angelo Camerlenghi*7 and
- Lorraine B. Eglinton*8
- 1Byrd Polar Research Center, Ohio State University, Columbus, Ohio 43210, USA
- 2Department of Geology, Hamilton College, Clinton, New York 13323, USA
- 3Laboratoire des Sciences du Climat et de l'Environment, Unite mixte Commissariat à l'Energie Atomique et Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
- 4Department of Geology, Colgate University, Hamilton, New York 13346, USA
- 5Department of Geology, Southern Illinois University, Carbondale, Illinois 62901, USA
- 6Department of Geography, Queen's University, Kingston, Ontario K7L 3N6, Canada
- 7Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Trieste, Italy
- 8Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
Abstract
A sedimentary record collected from beneath the former Larsen-A Ice Shelf reveals the Holocene history of the Larsen-A region. The record begins with the transition from grounded ice to a floating ice shelf, completed by 10.7 ± 0.5 ka, and ends with the modern recession. The record contains several late Holocene diatomaceous ooze layers that suggest proximity to productive open-water events. Radiocarbon ages obtained from these sediments were complicated by the presence of detrital and reworked carbon. We have eliminated these complications and constructed a chronology for the Larsen-A Ice Shelf history via tuning of the geomagnetic field paleointensity record with a reference curve. This approach provides chronological control to sediment sequences that lack appropriate material for radiocarbon dating. Geomagnetic paleointensity features with wavelengths of 2–3 k.y. can be recognized and interhemispherically correlated, illustrating the potential to use geomagnetic paleointensity variations as a global correlation and dating tool at sub-Milankovitch time scales.
Footnotes
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↵*Present address: Department of Earth and Planetary Sciences, Montclair State University, Upper Montclair, New Jersey 07043, USA
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- Accepted May 15, 2003.
- Received March 4, 2003.
- Revision received May 13, 2003.
- Geological Society of America
