Date: 16:00-18:00, Thursday, July 18, 2019
Place: 3F, 336, Faculty of Science Bldg. 1
Speaker：Prof. Ray Burgess (Professor of The University of Manchester)
Title: The role of seawater subduction in the Earth’s halogen cycle
Abstract: Halogens play a critical role in establishing habitable conditions on Earth. These elements control the salinity of the oceans and, during volcanic emissions, can cause ozone destruction in the upper atmosphere. Short and long-term changes in the global halogen cycles may therefore exert a strong influence on the oceans ability to support life and the levels of UV radiation at the surface of the Earth. In my talk, I will consider the influence of seawater subduction processes on the global halogen cycle, with implications for environmental changes. The direction, magnitude and timescale of halogen fluxes in or out of the Earth’s mantle are largely unknown. The sub-continental lithospheric mantle may act be a repository of halogens and other volatiles that may periodically be mobilised and released during large volcanic eruptions associated with flood basalt provinces. In contrast, deeper subduction to the mantle regions supplying magma to the mid oceanic ridges, may provide a means to reduce the salinity of the oceans overs billion year timescales.