Plio-Pleistocene history of Ferrar Glacier, Antarctica: Implications

enter for Earth-surface Dynamics, University of Minnesota-Twin Cities, 3101 Present address: Department of Geology and Geophysics, National Cglacial geologic data, Ferrar 1 is modern; cosmogenic ages for cobbles on this moraine suggest a value for nuclide inheritance of ∼50 ka. The Ferrar drifts are...

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Bibliographic Details
Main Authors: J. W. Staiger A, D. R. Marchant A, J. M. Schaefer B, P. Oberholzer B, J. V. Johnson C, A. R. Lewis A, K. M. Swanger A
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Subjects:
Ferrar Glacier
Vernier Valley
Antarc*
Antarctica
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.563.755
http://people.bu.edu/marchant/Dave_FullText_Papers/Staiger_EPSL_2006.pdf
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Summary:enter for Earth-surface Dynamics, University of Minnesota-Twin Cities, 3101 Present address: Department of Geology and Geophysics, National Cglacial geologic data, Ferrar 1 is modern; cosmogenic ages for cobbles on this moraine suggest a value for nuclide inheritance of ∼50 ka. The Ferrar drifts are most easily interpreted in terms of a progressive reduction in the ice-surface elevation of upper Ferrar Glacier during Plio-Pleistocene time. Relative to today, the surface of upper Ferrar Glacier was ∼100 to 125 m higher during the Pliocene Climatic Optimum and ∼50 m higher during early to mid Quaternary time. Conversely, during MIS 2, the ice-surface elevation of upper Ferrar Glacier was likely no larger than today and may have stood below modern levels. The texture and sedimentology of all Ferrar drifts indicate that during ice recession from Vernier Valley the upper Ferrar Glacier lacked surface-melting ablation zones, even during the Pliocene Climatic Optimum. Results from a simple 2-D glaciological flow-band model demonstrate that upper Ferrar Glacier also lacked basal-melting zones during ice recession. We show that the development of weathering pits and desert varnish on cobbles exposed at the surface of Ferrar drifts varies in accord with cosmogenic age. The mean width and depth of the largest surface pits on boulders from Ferrar drifts increases by ∼10 mm Ma−1 and ∼6.7 mm Ma−1, respectively; the maximum thickness of desert varnish on surface boulders increases by ∼1.5 mm Ma−1. These rates may be used to help calculate ages for dolerite-rich drifts elsewhere in the western Dry Valleys region.

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