[ESS] Nadja Drabon (Harvard)

The surface environment of the early Earth remains obscure due to the dearth of a rock record for Earth’s first ~500 million years. Although life likely emerged then, key questions remain about how crust formed, how widespread liquid water was, and what habitats existed. The surviving archive from that time is carried by the mineral zircon, most famously from the Jack Hills in Western Australia. In this talk, I will extend that record by adding a second locality in South Africa with detrital zircons spanning 4.2 to 3.3 Ga and present a recently increased dataset of zircon oxygen and hafnium isotopes, together with trace elements. These data provide constraints on early crustal evolution, document the presence of liquid water and its interaction with the crust, and provide new information on habitats available to early life.