Establishing a chronology for the world’s oldest glacier ice

• Main Author: D. E. Kowalewski
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Beacon Valley; Mullins Valley; Taylor Glacier
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.505.718; http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea054.pdf

ancient glacier ice. Four independent dating techniques confirm that the glacier age ranges from ~10 ka near the valley head, to>8 Ma at its diffuse terminus in central Beacon Valley (where it abuts opposing buried ice that originated from Taylor Glacier; e.g., Sugden et al., 1995). The dating methods include 1) cosmogenic-nuclide analyses of boulders from a sublimation till that caps the ice; 2) numerical ice-flow modeling of the glacier system; 3) 40Ar/39Ar analyses of in-situ ash fall from relict polygon troughs at the till surface; and, 4) modern horizontal ice-flow velocities as determined from synthetic aperture radar interferometry (InSar, from Rignot et al., 2002). Multi-channel seismic surveys demonstrate that the ancient ice is ~45 to ~100 m thick in Mullins Valley and ~150 m thick in upper Beacon Valley.