Differential movement across Byrd Glacier, Antarctica, as indicated by apatite (U-Th)/He thermochronology and geomorphological analysis

The objectives of this study were to assess possible differential movement across an inferred fault beneath Byrd Glacier, and to measure the timing of unroofing in this portion of the Transantarctic Mountains. Apatites separated from rock samples collected from known elevations at various locations north and south of Byrd Glacier were dated using single crystal (U-Th)/He analysis. Results indicate a denudation rate of c. 0.04 mm a21 in the time range c. 140-40 Ma. Distinct age v. elevation plots from north and south of Byrd Glacier indicate an offset of c. 1 km across the glacier with south side up. A Landsat image of the Byrd Glacier area was overlain on an Aster Global Digital Elevation Model and spot elevations of the Kukri erosion surface to the north and south of Byrd Glacier were mapped. The difference in elevation of the erosion surface across Byrd Glacier also shows an offset of c. 1 km with south side up. Results support a model of relatively uniform cooling and unroofing of the region with later, post-40 Ma fault displacement that uplifted the south side of Byrd Glacier relative to the north.