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A number of key unresolved issues in the understanding of the Earth´s interior involve the generation, transport and chemical interactions of silicate melts. Among these are global problems such as the nature (i.e. homogenous or heterogeneous) of core formation processes during the early history of the Earth, which were responsible for the high abundance of the siderophile elements in the Earth’s mantle (known as the ‘siderophile element anomaly’). Other problems dealing with melt generation and migration in the mantle are: origin and genesis of carbonatites associated with ultramafic alkaline rocks in complex intrusive bodies, the controversial petrogenesis of glass-inclusions of exotic compositions in spinel peridotite mantle xenoliths and the highly debated origin of potassic and ultrapotassic magmas (i.e. homogeneous or heterogeneous melting).

The multi-anvil, the piston-cylinder, and the rotating centrifuge autoclave high-pressure devices at the Geoinstitute have been used to contribute extensively and systematically to these questions. Reproducing the composition and features (e.g. element-patterns, dissolution structures) of natural materials is a common target of high-pressure experimental studies.

The main goals of the projects described below are: (1) The measurement of element partitioning between magnesiowüstite and silicate melt at high pressures and temperatures in an attempt to test whether mineral fractionation contributed to the siderophile element depletion in the present mantle. (2) The investigation of element partitioning between immiscible carbonate and silicate liquids. The use of a specially designed rotating centrifuge autoclave avoids various technical and analytical difficulties. (3) The study of orthopyroxene dissolution in alkaline silicate melts which aims to clarify whether or not glass inclusions in xenoliths have been formed by metasomatic processes in the mantle. (4) The investigation of the origin of highly potassic magmas by means of melting experiments in heterogeneous vein-wallrock systems.