This research project is part of the ANDRILL Southern McMurdo Sounds Drilling Project. Lower and middle Miocene shallow marine sediments, deposited in the subsiding Victoria Land Basin on the coastal plain seaward of the rising Transantarctic Mountains, record repeating lithological changes that reflect variations in sea-level, glacial proximity, and climate from non-polar climate conditions to Pleistocene maximum glacial conditions. Distinct transitions in sand grain composition were identified by detailed petrographic modal analysis and SEM-Cathodoluminescence to identify recycling of quartz. ~50% of the quartz grains have been recycled through the sedimentary Beacon Supergroup before being eroded from the Transantarctic Mountains and deposited offshore in the Victoria Land Basin alongside angular grains, which have been derived directly from the basement Granite Harbour Group. The loss of Beacon/Ferrar and increasing abundance of marble and other basement-derived grains upsection indicate a broad unroofing sequence. However, variations in concentrations of Beacon/Ferrar derived grains indicate local derivation from the nearby Transantarctic Mountains versus more distal derivation. This suggests growth of local glaciers alternating with collapse during the Miocene possibly linked to the growth and collapse of the West Antarctic ice sheet.
Kari Bassett
Senior Lecturer Above the Bar
Sedimentology & Basin Analysis
- Basin analysis
- Basins of New ...