Grounding-line basal melt rates determined using radar-derived internal stratigraphy

• Main Authors: Catania, Ginny, Hulbe, Christina L., Conway, Howard
• Format: Text
• Language: unknown
• Published: PDXScholar 2010
• Subjects: Stratigraphic geology > Antarctica > Ross Island; Ice sheets > Antarctica; Geology > Antarctica; Glaciers > Antarctica > Ross Island; Geology; Glaciology; Ross Island; Siple; Roosevelt Island; Siple Dome; Antarc*; Antarctica; Ice Shelf
• Online Access: https://pdxscholar.library.pdx.edu/geology_fac/22; https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1021&context=geology_fac

We use ice-penetrating radar data across grounding lines of Siple Dome and Roosevelt Island, Antarctica, to measure the spatial pattern, magnitude and duration of sub-ice-shelf melting at these locations. Stratigraphic layers across the grounding line show, in places, a large-amplitude downwarp at, or slightly downstream of, the grounding line due to sub-ice-shelf basal melting. Localized downwarping indicates that melting is transient; melt rates, or the grounding line position, have changed within a few hundred years in order to produce the observed stratigraphy. Elsewhere, no meltrelated stratigraphic signature is preserved. In part, heterogeneity in the amount of sub-ice-shelf melt is due to regional circulation patterns in the sub-shelf cavity, but local (on the order of tens of kilometers) heterogeneity in the melt pattern may reflect small differences in the shape of the ice-shelf base at the grounding line. We find that all of the grounding lines crossed have been in place for at most ~400 years.