FEST: "Emergence of the Earth’s earliest landmass(es)"

Friday Earth Sciences Talk

Speaker and topic: Prof. Dr Paul Mason: “Emergence of the Earth’s earliest landmass(es)”

The growth of the continental crust through geological time has been accompanied by an increase in landmass. Land current makes up 27.5 percent of the Earth’s surface. Oceans first appeared in the Hadean eon, between 4400 and 4200 million years ago, creating a dominant ‘water-world’. It remains unclear when the first significant amounts of crust emerged above sea level, with widely diverging estimates for the Paleoarchean from zero to tens of percent. Answering this question has major implications for determining the onset of the carbonate-silicate weathering cycle, nutrient delivery to the oceans and biological evolution.

In this talk, I will outline a new method for calculating the extent of the crust between 3600 and 3200 million years ago using strontium isotopes in hydrothermal barites. Our results show that the onset of crustal weathering into the ocean basins matches the appearance of the first extensive greenstone belts and the first convincing traces of microbial life. Geological and biological evolution on the early Earth were most likely intimately interlinked.

With the Friday Earth Sciences Talks (FEST) we intend to bring the departments of Earth Sciences and Physical Geography together. The aim is to present (mostly) Utrecht-based Earth Sciences in an accessible way in order i) to stay familiar with each other’s work across disciplines and ii) to help (in particular MSc.) students in their orientation on possible graduation specialisations and future careers. Alumni are also invited.