2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 259-6
Presentation Time: 5:05 PM


MOLNIA, Bruce F.1, DEATON, Laura E.2 and ANGELI, Kim M.2, (1)National Civil Applicatons Program, U.S. Geological Survey, 562 National Center, 12201 Sunrise Valley Drive, Reston, VA 20192, (2)Eastern Geographic Science Center, U.S. Geological Survey (USGS), 562 National Center, Reston, VA 20192, bmolnia@usgs.gov

Bering and Malaspina Glaciers are the two largest glaciers in continental North America. Each has maximum ice thicknesses that approach 1 kilometer. Both originate in Wrangell – St. Elias National Park (WRST), with significant parts of each located in WRST. Together, they are two of the most dynamic and rapidly changing glaciers on Earth. Both surge and each has been the subject of multiple-year ice-surface investigations, airborne and ice-surface ice-penetrating radar studies (IPR), and repeat imaging. Each glacier supports a complex piedmont lobe characterized by the growth of a mature forest on part of its stagnant terminus. The photographic record of Malaspina Glacier began 125 years ago, while that of the upper Bering Glacier began less than a decade later. Each glacier occupied its Little Ice Age (LIA) maximum position within the past 150 years, while Late LIA thinning and retreat of each glacier began near the beginning of the 20thcentury. Both are underlain by deep, complex fiord systems that appear to connect to pre-Holocene age fiords located on the adjacent Gulf of Alaska Continental Shelf. Fiord depths underlying the near-coastal parts of each glacier’s piedmont lobe approach 400 meters below sea level. The complex fiord systems have significant impacts on glacier hydrology and ice flow.

This presentation describes how combining Landsat; commercial electro-optical imagery; commercial synthetic aperture radar (SAR) data; airborne SAR imagery: Global Fiducials Program (GFP) imagery from US National Imagery Systems; ice-surface, ice-penetrating radar data; NASA Warm Ice Sounding Explorer (WISE) airborne IPR data: digital elevation models (DEMs); and marine and lacustrine geophysical data sets produced a series of images and working GIS layers that resulted in the determination of bed morphology, ice thickness, surface reflective characteristics, surface elevations, and recent elevation changes of both Bering and Malaspina Glaciers.