The Archean–Proterozoic transition records major geochemical changes. While the cause of isotopic shifts during this period have long been ascribed to atmospheric, biologic, and geologic processes, the influence of plate tectonics remains unknown. An appraisal of the global geologic record from about 2.3 to 2.2 billion years ago demonstrates a tectonomagmatic lull when global-scale continental magmatism (plume and arc magmatism) decreased and relative plate motions were subdued. Additionally, the age of large igneous provinces reveals a step-change in the proportion of subaerial eruptions at ~2.4 Ga implying a rapid development of continental freeboard at this time. A precipitous rise in atmospheric oxygen at about 2.3 Ga has been implied to be driven by the evolution of oxygenic photosynthesis. While the geochemical proxies of atmospheric oxygenation is recorded at the atmosphere-lithosphere or atmosphere-ocean interface, how it may have affected the deeper lithosphere is more cryptic. In this seminar, I will discuss some of the advances of my research program that explores the interconnection of tectonic processes with atmospheric and biologic evolution.
|Date||Wednesday, 11 March 2020|
|Time||1:00pm - 2:00pm|
|Location||Benson Common Room (Gs9), Geology Building, University of Otago Dunedin Campus|