title: Glacier advance during Marine Isotope Stage 11 in the McMurdo Dry Valleys of Antarctica.
abstract: We mapped six distinct glacial moraines alongside Stocking Glacier in the McMurdo Dry Valleys, Antarctica. Stocking Glacier is one of several alpine glaciers in the Dry Valleys fringed by multiple cold-based drop moraines. To determine the age of the outermost moraine, we collected 10 boulders of Ferrar Dolerite along the crest of the moraine and analyzed mineral separates of pyroxene for cosmogenic3He. On the basis of these measurements, the exposure age for the outermost moraine is 391 ± 35 ka. This represents the first documented advance of alpine glacier ice in the Dry Valleys during Marine Isotope Stage (MIS) 11. At this time, Stocking Glacier was ~20-30% larger than today. The cause of ice expansion is uncertain, but most likely it is related to increased atmospheric temperature and precipitation, associated with reduced ice extent in the nearby Ross Embayment. The data suggest complex local environmental response to warm climates in Antarctica and have implications for glacial response to Holocene warming. The study also demonstrates the potential for using alpine glacier chronologies in the Transantarctic Mountains as proxies for retreat of grounded glacier ice in the Ross Embayment.
authors.affiliation: Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, 1 University Avenue, Lowell, MA 01854, USA.
authors.forename: Kate M
authors.initials: KM
authors.lastname: Swanger
authors.affiliation: Lamont-Doherty Earth Observatory, The Earth Institute at Columbia University, Route 9W, Palisades, NY 10964, USA.|Department of Earth and Environment, Boston University, 685 Commonwealth Avenue, Boston, MA 02215, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Lamp
authors.affiliation: Lamont-Doherty Earth Observatory, The Earth Institute at Columbia University, Route 9W, Palisades, NY 10964, USA.
authors.forename: Gisela
authors.initials: G
authors.lastname: Winckler
authors.affiliation: Lamont-Doherty Earth Observatory, The Earth Institute at Columbia University, Route 9W, Palisades, NY 10964, USA.
authors.forename: Joerg M
authors.initials: JM
authors.lastname: Schaefer
authors.affiliation: Department of Earth and Environment, Boston University, 685 Commonwealth Avenue, Boston, MA 02215, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Marchant