Stability of phlogopite at high pressures and possible presence of phlogopite in the earth's upper mantle

摘要: Abstract High-pressure experiments have been made on the stability of natural and synthetic phlogopites by tetrahedral-anvil type high-pressure apparatus in pressure range from 41 to 96 kb (kilobars) temperature 1030° 1680°C. Water is probably equal or slightly lower than total during runs. It found that phlogopite breaks down garnet unidentified mineral at pressures higher least 40 about 1200°C. The formed breakdown most likely contains 5 wt % K 2 O, as determined electron probe microanalyser. suggested could be a possible potassium-bearing upper mantle 150–200 km continental areas, forming phlogopite-bearing peridotites. In deeper parts may mineral. At shallower levels (e.g., less 100 km) amphibole mineral.instead addition phlogopite. Kimberlites some potassium-rich basalts partial melting peridotites mantle.