2024-03-28T19:00:50Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/366992022-11-17T02:08:08Zhdl_2115_34854hdl_2115_34816hdl_2115_116Clinopyroxenes and Spinels in the System CaMgSi2O6-CaAl2SiO6-CaCrAlSiO6 : A Preliminary ReportOnuma, KosukeTohara, Tatsuhideopen access450The system CaMgSi2O6-CaAl2SiO6-CaCrAlSiO6 has a wide liquidus field for spinel at 1 atm. In the CaMgSi2O6-rich portion, however, clinopyroxene appears as second phase and then spinel disappears to react with liquid and the phase assemblage at subsolidus temperatures becomes clinopyroxene single phase and clinopyroxene + spinel + anorthite, indicating in congruent melting of chromian pyroxene into spinel + liquid. Clinopyroxenes and spinels in the assemblage of clinopyroxene + spinel + liquid at 1 atm and higher pressure were analysed. The Cr2O3 contents of clinopyroxenes and spinels increase with increasing those of bulk compositions and attain 3.16 wt% and 48.99 wt% respectively, at the bulk composition containing 1.86 wt% Cr2O3. The Cr/Al ratios of spinels are higher than those of the bulk compositions and increase with an increase of Cr/AI ratios of the bulk compositions. Spinels and clinopyroxenes crystallizing from a composition containing 1.86 wt% Cr2O3 at 8 kbar and 1300℃ with over-saturated water contain about 70 wt% and 0.1 wt% Cr2O3, respectively. Spinels coexisting with clinopyroxene in the present system have higher Cr/Al ratios than the clinopyroxene.北海道大学Hokkaido University1981-02engdepartmental bulletin paperVoRhttp://hdl.handle.net/2115/366990018-3474北海道大学理学部紀要Journal of the Faculty of Science, Hokkaido University. Series 4, Geology and mineralogy194495503https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/36699/1/19_4_p495-503.pdfapplication/pdf1.58 MB1981-02