Sune Nielsen

CRPG Nancy

Etat redox de l’océan Archéen

My research interests are broad, encompassing topics ranging from the earth’s climate history to crustal recycling into the mantle and the evolution of the early solar system. Over the last decade I have focused on several key questions within these broad topics -- 1) What is the timing and evolution of oxygenation in the ocean over Earth history and how did it affect Earth habitability? 2) What processes control the transfer of material into the deep Earth in subduction zones and how do these affect the composition and evolution of the mantle? 3) How and when were water and other volatiles delivered to Earth and other planetary objects in the solar system?

To address these fundamental questions I spend significant time developing novel stable isotopic tools that allow me to put new constraints on these key research topics beyond what is possible with more conventional analytical techniques. These tools can generally be applied to all aspects of my research program and I have made significant contributions in all three areas over the last decade. Most prominently, I have put constraints on changes in ocean oxygenation during the last deglaciation ; shown for the first time that the trace element and isotope systematics of global arcs record the physical mixing of sediments, fluids and serpentinized mantle, consistent with the formation of mélanges at the slab-mantle interface; and provided the first constraints on the timing and mechanisms of water delivery to the inner solar system.