Biology 1A, 001 - Fall 2013 Creative Commons 3.0: Attribution-NonCommercial-NoDerivs

Epidemiologic Methods I

Special Topics in Area Studies

Extraterrestrial impact in Yucatán, lava floods in India, and the great Cretaceous-Tertiary extinction: A New Autopsy Report on T. rex and Friends Mark Richards, Executive Dean of Letters & Science, Dean of Mathematical & Physical Sciences, and Professor of Earth & Planetary Science, presents his latest research on the extraordinary events surrounding the disappearance of dinosaurs, first introduced at Berkeley as the famous ""Alvarez hypothesis."" This lecture was given at an event recognizing his administrative achievements as he resumes his scholarly pursuits as a professor and researcher. The dinosaurs and about 70% of all species disappeared 66 million years ago. This apocalypse was probably caused by a meteor or comet impact that left a 200 km wide crater on the Yucatan Peninsula in Mexico. However, at about the same time, a torrent of lava was unleashed in western India in a series of volcanic eruptions known as the Deccan Traps. New evidence suggests that the largest of these may have been triggered by the Yucatan impact, with the resulting discharge of carbon dioxide and sulfate aerosols into the atmosphere perhaps contributing to the Cretaceous-Tertiary extinctions.