Feldspars under conditions of high temperature-high pressure

As one of the most important minerals in geology, feldspar might enter the deep interior of the Earth via slab subduction process. Consequently, its phase relations and physical-chemical behaviors at high pressures could be very significant to the geodynamic process of the Earth's interior. Here we summarized in some phase diagrams all known high pressure-high temperature experimental data about feldspars with various compositions. These phase diagrams evident that a full picture about feldspar at high pressure is still unavailable, so that further high-pressure experimentation is necessary. Additionally, we briefly reviewed the available physical properties of the high-pressure phases derived from the feldspar compositions, and integrated them into pressure-density profiles which were subsequently compared to die pressure-density profile of pyrolite. The comparison suggested that the density of the different high-pressure phase assemblages for the feldspar compositions is larger than that of the pyrolite for the pressure interval of 5 to 23GPa, leading to positive sinking into the upper mantle of the Earth.