|Budget Amount *help
¥3,000,000 (Direct Cost : ¥3,000,000)
Fiscal Year 1998 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1997 : ¥2,000,000 (Direct Cost : ¥2,000,000)
My research results are summarized as follows :
1. Thermodynamic Properties of Olivine arid Clinopyroxene in the System CaO-FeO-MgO-SiO_2
(a) Olivine behaves as the disordered two-site solution from the theoretical study on the thermodynamic properties of Ca-Fe-Mg divines (Mineral. 1., 20, 135-149, 1998).
(b) Experiments on the Ca-Fe-Mg partitioning between olivine and chnopyroxene make it clear that the Fe-Mg distribution coefficient is highly dependent on CaO contents of olivine, and increases with increasing in Ca^<2+> and Fe/(Fe+Mg) in the system (Rev. High Pressure Sci. Tecnol., 7, 95-97, 1998).
(c) Mixing propeties of clinopyroxene are approximated as time multi-site regular solution cooperating intracrystalline exchange equilibria (Geochem. J., 33, 33-58, 1999).
(d) Experimental study on the solvus of Ca-Fe-Mg olivine shows that the ohivine is the two-site regular solution in which the Fe^<2+> and Mg^<2+> are radomly mixing although Ca^<2+> are strictly lucallized in M2 site of olivi
ne (submitted to Am. Mineral.).
2. Experimental Study of Phase Equilibria in the system FeO - MgO - A1_20_<>3 - SiO_2 from the Lower Crust to the Upper Mantle pressures.
(a) Time Fe-Mg partitioning between orthopyroxene and cordierite shows that this reaction is sensitive for the variation of temnprature, and this would be a good geothermometer (Proc. NIPR Symp., Antarct. Geosci., 10, 150-159 1997).
(b) The mineral assemblage of orthopyroxene+cordierite+spinel is unstable and changes into the olivine+cordierite+spinel at a certain temperature between 10000C and 102500 at 1 atm in the Mg_3Al_2Si_3O_<12> system (J.Japan. Assoc. Pet. Min. Econ. Geol., 93, 18-26, 1998).
(c) high pressure experiments on the AI_2o_3 solubility in orthopyroxene in equi1ibium with in assemblages of spinel+quartz and sapphirine+quartz in time Mg_3AI_2Si_3O_<12> (pyrope composition) system shows the phase boundary of the univariant reaction : 2MgAI_20_4 (SpI) + Si0_2 (Qtz) = Mg_2Al_4Si0_<10> (Spr), locates within a certain pressure between 1.5 and 1.75 GPa at 1300ﾟC (prepareing to Contrib. Mineral. Petrol.). Less