Geology Department Colloquium, April 4th

Alexandra Davatzes (’99), Temple University

Title: “The Earth During the Extended Late Heavy Bombardment”

Please join us: Thursday, April 4th @ 11AM in Edmunds 130

Abstract:  Three processes fundamentally shaped the early Earth: the Late Heavy Bombardment, the onset of plate tectonics, and the early evolution of life. During this time, these three processes overlapped and influenced each other in fundamental ways that are ultimately responsible for the transition to the modern environment. They have largely been studied through models, but analyses of Archean rocks preserved on Earth document the results and interplay of these processes.

I will discuss evidence of large meteor impacts, in the form of what are termed spherules, preserved on the Earth from 3.5 to 2.5 billion years ago. The frequency, scale and geochemistry of these spherule layers indicate that the Late Heavy Bombardment was longer than initially believed, extending all the way through the Archean. In addition, the geochemistry of these layers retains a record of crustal and atmospheric chemistry at the time, giving us a window into what the early Earth was like.