Seawater chemistry and mass extinctions

Seawater chemistry and mass extinctions

Speaker: Dr Rob Newton, School of Earth and Environment, University of Leeds.

An image of a Sabkha environment from the middle east where we have modern day deposition of gypsum: Changes in the deposition of gypsum from the ocean through time play an important role in the story.

There are various lines of evidence that show that seawater chemistry has changed markedly through time, but these records have multiple limitations and are generally have very low time resolution, often with gaps of many millions of years. More recent approaches for a specific component of seawater, sulphate, establish a link between low concentrations of this ion and mid-Phanerozoic extinctions such as the Permo-Triassic and end-Triassic. Rob will explain the possible mechanism that links these phenomena which fits with the established framework of other correlations between ocean anoxia, large igneous province volcanism and marine extinction, based on carbon cycling in the oceans and marine sediments, and particularly the generation of methane.