Earth Seminar 22 November - Associate Professor Mark Kendrick

Seafloor alteration and subduction-zone volatile cycling

Abstract

Multiple lines of evidence demonstrate the presence of seawater-derived volatiles in the Earth’s mantle (e.g. water, halogens, noble gases). This overturns the long-standing idea that subduction-zone metamorphism is a ‘barrier’ to volatile subduction.  I’ll briefly summarise how halogen group elements can be used to fingerprint subduction zone devolatilisation processes and constrain an internally consistent subduction-zone and whole mantle volatile budget.  The argument developed depends on an understanding of the processes controlling halogen relative abundance ratios in altered ocean crust.  I’ll then present some new geochemical data, obtained in UQ’s RIF lab, that test my prejudices and build on our understanding of metamorphic processes in the oceanic basement.  The data include the first LA-ICPMS measurements of Cl, Br and I in hydrothermal carbonate combined with carbonate vein U/Pb ages from the Atlantis Bank metamorphic core complex on the SW Indian Ridge.

Biography

Mark Kendrick recently joined SEES as A/Prof of Geochemistry from the ANU Research School of Earth Sciences. He has long standing interests in crustal fluids and mantle volatiles with particular interests in halogens and noble gases. He previously held an ARC Future Fellowship at the ANU and a QEII Fellowship at the University of Melbourne.  He first moved to Australia in 2004 having survived a postdoc in Trondheim (Norway) and an education in the UK (Manchester and Edinburgh).