May 17, 2023

12:00 pm 1100 TLSB

Regan Dunn
La Brea Tar Pits

" Harbinger of the future: Drought, fire, and extinction in the latest Pleistocene at Rancho La Brea "

Debate over causation of the Late Pleistocene megafaunal extinction has raged for 70 years. Although multiple hypotheses have been put forth, the most widely accepted and debated are 1) over-hunting by humans, 2) climate change, and 3) some combination of the two. The diverse and extraordinary Late Pleistocene faunas preserved in the asphaltic traps at Rancho La Brea (RLB) in Los Angeles, California are among the best in the world to test these hypotheses because there are high numbers of individual megafaunal species that can be precisely dated using ultra-filtration 14C radiometric techniques. While a concurrent record of plants at the La Brea Tar Pits is yet lacking, published pollen and charcoal records for Late Pleistocene-Holocene sediments in Southern California exist from which vegetation, fire and climate can be reconstructed along with a record of human occupation estimated from archeological dates. Combined, these records provide a high-resolution record of a profound and rapid ecosystem state shift ~13,200 years ago that resulted in the extinction of the Ice Age titans and formation of today’s coastal California environments.


*Light refreshments will be available

Host: EEB Graduate Students