Amateur Astronomers Association of Princeton (AAAP) Monthly Meeting

Precambrian Meteor Impacts and Implications for Early Earth.

Along about 65 million years ago, at the end of the Cretaceous period, an asteroid impact initiated a mass extinction that, among other things, is famously thought to have ended the reign of the dinosaurs. Less well known are even larger impact events that took place between 3.5 to 2.3 billion years ago. Prof. Davatzes will talk about 18 spherule beds identified in rocks in western Australia and South Africa that represent 13 separate impact events that would have local, regional, and global effects lasting seconds to decades after the impacts. Particularly large impacts, such as those in the Precambrian, may have resulted in: (1) earthquakes, large-scale tsunamis, thermal effects, and distal ejecta reentry; (2) ejection of rock vapor, dust, soot, carbon dioxide, water vapor, methane, and sulfur oxides into the atmosphere, resulting in atmospheric heating and acid rain formation; (3) evaporation in the oceans, leading to destruction of shallow water ecosystems and to hot salty surface waters; and (4) delivery of elements essential to life or transient high oxygen concentration that might have led to biodiversification. In addition, discovery and confirmation of these impact layers is critical for our understanding of the rate of impacts to the early Earth and solar system. This is gaining importance as researchers revisit and redefine the concept of a Late Heavy Bombardment.

Date & Time

April 13, 2021 | 7:30pm – 9:30pm

Location

Virtual Meeting

Speakers

Alexandra Kroll Davatzes

Affiliation

Temple University