PROPOSED RESEARCH: DOES THE SEDIMENT MASS BALANCE OF THE LARSEN BASIN, ANTARCTIC PENINSULA, SUPPORT EPHEMERAL CRETACEOUS GLACIATION?

Recent geochemical, sequence stratigraphic, and integrated investigations of marine strata from several continental margins and ocean basins suggest that ephemeral ice sheets may have existed on Antarctica during parts of the Cretaceous and early Paleogene. The existence of these ice sheets during the Cretaceous, despite a greenhouse global climate driven by atmospheric CO₂ levels two to four times the modern concentration, underscores an insufficiency in our understanding of the relationship between climate change, glaciation, and sea level rise that could affect our ability to predict deglaciation and sea level changes as a result of anthropogenic warming.

Preliminary mass-balance calculations between the Larsen Basin, a sedimentary basin adjacent to the northernmost Antarctic Peninsula, and the Peninsula itself suggest that at least 40% of the sediment in the basin originated from regions other than the proximal Antarctic Peninsula. Further, new detrital zircon geochronology from the early Paleogene strata of the Larsen basin indicate substantial contributions of sediment from non-Peninsular sources, of which the Ellsworth Mountains is the most likely. The presence of sediment from the Ellsworths in the distant Larsen Basin implies that ephemeral, but extensive, ice sheets could have been responsible for transporting the sediment to the basin during the Cretaceous greenhouse period.

We propose to reconstruct the sedimentation history of the Larsen Basin by developing a high-resolution age model of the basin, and to constrain the exhumation history of the adjacent Antarctic Peninsula using multiple low-temperature thermochronometers. Comparing the two histories will enable us to calculate the source-to-sink mass balance between these regions through geologic time and thereby assess likely periods of glacial sediment transport.