Lehrstuhl für Endogene Geodynamik (Prof. Dr. Haase)
Project Title: Immiscible sulfide melts: insights into fractionation processes of chalcophile elements in oceanic crust.
Magmatic sulfides result from segregation of a sulfide melt and this affects the distribution of chalcophile elements between the sulfide and silicate melts. It has already been found that sulfides from island arcs, backarc basins, and mid-ocean ridges exhibit systematic chemical and mineralogical differences. In addition, factors influencing sulfide solubility in the silicate melt (such as temperature, pressure, oxygen fugacity, and fractionation degree) are known to be different for subduction zones and mid-ocean ridges. However, the processes responsible for the systematic differences are poorly understood.
This research project focuses on the investigation of the processes leading to these systematic differences in order to develop a better understanding of the distribution of chalcophile elements (e.g. Co, Ni, Cu, Se, Ag, Te, PGE, Au, Bi) in the oceanic lithosphere. For this purpose, analyses have been performed on magmatic sulfides from samples of cores from the DSPD, ODP, and IODP expeditions in combination with samples of ancient oceanic crust (e.g., Troodos ophiolite). These samples cover a full spectrum from peridotites to gabbros and sheeted dykes to young lavas, allowing the development of models for the global cycling of chalcophile elements throughout the oceanic lithosphere.
Main elements: EPMA
Traceelements: LA-ICP-MS, Quadrupol-ICP-MS