SIMULATION OF LOW-CALCIUM PYROXENES CRYST ALLIZATION IN BASITE SYSTEMS

New parameters of equations of low-calcium pyroxenes - melt geothermom eters have been obtained using new experimental data. The new Opx - me lt geothermometer allows one to calculate Wo contents in solid more pr ecisely than the old ones, This feature is important to calculate some dynamic parameters of intrusion formation by means of reverse modelli ng. The proposed Opx geothermometer has average error of orthopyroxene crystallization temperature of about 8 degrees C, it reproduces compo sitions with En, Fs, Wo better than 1-2 mol.% with 92% chance of occur ring. The new Pig - melt geothermometer allows one to calculate pigeon ite liquidus temperatures with average precision approximate to 5 degr ees C, compositions - better than 1.5 mol.% with 88, 92, and 85% chanc e of occurring for En, Fs, Wo respectively. It has been stated that to o low calculated pigeonite crystallization temperatures as compared wi th the experimental ones were clue to insufficient precision of the ge othermometers Ol-, Pl-, and Aug- melt within the area of crystallizati on of ternary and quaternary cotectics where pigeonite appeares in the natural magmas. The developed geothermometers can be applied for comp uter simulation of crystallization of Earth's basite magmas.