Alexander Potrafke¹, Burkhard Schmidt², Hilmar von Eynatten³ and Roland Stalder¹, (1)University of Innsbruck, Institute of Mineralogy and Petrography, Innsbruck, Austria, (2)Geoscience Center Goettingen (GZG), Department of Experimental and Applied Mineralogy, Goettingen, Germany, (3)Geoscience Center Göttingen (GZG), Sedimentology & Environmental Geology, Göttingen, Germany