The subglacial topography in East Antarctica has been revealed by airborne radar surveys1-3. However, how this ice-hidden landscape has evolved over time is less well known2-12. Low pre-glacial erosion rates since the Permian period have been reported12, challenging arguments for enhanced erosion during the Cretaceous period4,6. Here we present a record of long-term East Antarctic erosion by applying multiple dating techniques to over 1,400 detrital mineral grains from onshore moraines and offshore sediments of Cretaceous to Quaternary age in the region of Lambert Glacier and Prydz Bay. Ages from pre-glacial sediments support overall low erosion rates before the expansion of the ice sheet, apart from a discrete interval of magmatic heating about 115 Myr ago that is inconsistent with widespread Cretaceous erosion. We find a shift towards younger and broader age distributions since ∼34 Myrago that necessitates spatially localized erosion of over 2 km in the Lambert Glacier catchment over this time. We infer that the trough containing Lambert Glacier was incised almost entirely by selective glacial erosion following initial expansion of the East Antarctic ice sheet. This implies that the early ice sheet was dynamic with ice flow concentrated along fixed ice streams.
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)