lec 13: cretaceous-paleogene mass extinction

what caused the 4 extinction events in the end-permian mass extinction, carnian pluvial episode, end-triassic mass extinction and K-Pg (End-cretaceous) mass extinction

EPME, CPE, and TME: volcanism

K-Pg: long-term environmental destabilization by large scale volanism and sea regression -→ Deccan trap volcanism, extraterrestrial impact

what is the evidence for an asteroid impact? who are credited with this discovery?

just above K-pg boundary, thick layer of clay with no fossils at all, pointing to an almost complete extinction of microscopic sea life

iridium spike at boundary

• commonly found on Earth at low levels

• levels high in asteroids

shocked quartz and tektites

chicxulub crater

what other climate-changing event is occurring when the asteroid hit?

deccan trap volcanism

climate destabilized

did some birds go extinct from the K-Pg mass extinction event

some birds did, but many did not

became large

terror birds: diatrymas (herbivore) and phorusrhacids (carnivore)