Brad Opdyke - 'Paleoclimate records and stratigraphy from Lake George: what we can learn about climate change and our future'

Brad will discuss the sedimentary record of Lake George going back almost 4 million years. Pollen records indicate much greater rainfall in the past. Records of lake-levels date from 1820, and are relevant to climate change. 

Four million years ago atmospheric CO2 levels were close to those we have in 2024. Pollen records indicate that rainfall must been 2 to 3 times what we have experienced over the past several decades. In addition to the deep cores we have taken in the Lake bed, our team has been studying the stratigraphy of the Bungendore Sands quarry on the south eastern shore of Lake George. These records, in comparison, only reach back about 60,000 years but offer a detailed look at the dynamism of water levels with the Lake. There are times within the 50 to 60 thousand year time window when the Lake was relatively full (37 meters deep) and thick layers of clay were draped over the landscape of the Lake George basin. These clays persist today and make groundwater recharge difficult, as well as making runoff within the basin very efficient. 

Biography

Brad is an Associate Professorial Fellow at the Research School of Earth Sciences and has been doing Paleoclimate research there for the past 30 years. He received his Bachelor’s degree in Geochemistry from Columbia University in NYC in 1984. He received his Masters degree in 1987 and PhD in 1990 from the University of Michigan before joining the ANU in 1994.

Bookings open 21 February 2025.

Booking link: https://www.trybooking.com/CXZXI