ABSTRACT

We present a Holocene record of geomagnetic field paleointensity variations that enables us to import absolute ages to sediment accumulating on the Antarctic continental shelf via tuning with a reference curve. We apply the paleointensity dating method to a sedimentary record collected from beneath the former Larsen-A Ice Shelf. This record contains a complete Holocene sequence beginning with the transition from grounded ice to a floating ice shelf and ending with the modern recession of the Larsen-A ice shelf. The paleointensity dating approach provides chronological control to sediment sequences that lack appropriate material for radiocarbon dating. Geomagnetic paleointensity features with wavelengths of ~2000 years can be recognized and interhemispherically correlated, illustrating the potential to use geomagnetic paleointensity variations as a long-range correlation tool at sub-Milankovitch time scales. Ice shelf disintegration in the Larsen-A region appears limited to the late Holocene, with temperature and/or reduced precipitation contributing to ice shelf instability.