Paleoshoreline Record of Crustal Uplift in the Dry Valleys Region, Antarctica: A Pilot Study Using Airborne Laser Scanning (LiDAR) Digital Elevation Data Abstract

abstract

  • In much of the world, key records used for mapping and modeling glacial-isostatic crustal motions come from raised shorelines and isolation basins. Such records are extremely scarce in Antarctica. A unique digital elevation data set was acquired by NASA's Airborne Topographic Mapper (ATM) system during the 2001-2002 austral summer field season. This Airborne Laser Scanning (ALS) digital elevation data was used to map lake paleoshoreline elevations and tilts in the Dry Valleys region of Antarctica, providing a unique record of vertical crustal motion spanning the last 15,000 years. Laser points were derived by NASA and the computation and verification of Digital Elevation Models (DEMs) was completed by Ohio State University in 2003. Resulting DEMs have 2 meter horizontal resolution, sufficient for discerning lake-surface geomorphic features that were horizontal at deposition. DEM data were filtered to highlight paleoshorelines and deltas, where multiple delta deposits were available from a single lake level. Highlighted features were digitized, and elevation data extracted along the digitized profiles. Changes in elevation along the length of these profiles were then used to define regional tilt angles and directions, reflecting crustal motions since the time of deposition. Finally, derived tilts were linked with C14 age data from previous studies, allowing calculation of rates of crustal motion over the past 15,000 years. This record of crustal uplift can be integrated with GPS data acquired in the same region to model glacio-isostatic motion due to ice mass change and to constrain thickness and rheological properties of the crust and mantle. Results from this study represent the first application of paleoshoreline tilt data mapped from ALS data in Antarctica.

publication date

  • 2008

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