Glaciation and ice flow in western Dronning Maud Land, East Antarctica, during early Oligocene
(Research experience for undergraduates during sophomore year, Wesleyan University, 2018-2019)
The Oligocene epoch was a time of rapid climate change. At the Eocene-Oligocene Transition (EOT) there is an abrupt, >1 per mil, increase in benthic δ18O attributed to ice growth on Antarctica (Zachos et al., 2001). From ~34 Ma to 26 Ma, there is little variation in the global benthic δ18O, interpreted as a stable East Antarctic ice sheet. Around 26 Ma the climate warmed rapidly, followed by the Mi-1 glaciation at ~24 Ma. Understanding these transitions has significant implications for our understanding of the development and behavior of the Antarctic cryosphere and its influence on deep ocean circulation.
Marine sediments from Ocean Drilling Programs (ODP) near the coast of East Antarctica are the keys to ancient ice sheets: many sediments are rock fragments that are broken off from their bedrocks by the erosional power of glaciers, and got carried away by the calved icebergs on ocean currents. Their radioactive ages pinpoints geological sectors from which we can infer the extent of the ice sheet.
I used the zircons and apatite in the recovered ocean sedimentary cores to understand the provenance (French for “origin”) of these minerals, which might suggests the ice sheet extent and/or the possible existence of temperate, wet-based glaciers during this era. We were interested in the ages from primary two radio-active decay systems: zircon U-Pb and apatite U-Th-He, each representing thermal controls from different geological processes.
