Pressure-Temperature Path Recorded in the Yangkou Garnet Peridotite, in Su-Lu Ultrahigh-pressure Metamorphic Belt, Eastern China |
| |
| Authors: | YOSHIDA DAISUKE; HIRAJIMA TAKAO; ISHIWATARI AKIRA |
| |
| Institution: | 1 DEPARTMENT OF GEOLOGY AND MINERALOGY, GRADUATE SCHOOL OF SCIENCE, KYOTO UNIVERSITY, KYOTO 606-8502, JAPAN
2 DEPARTMENT OF EARTH SCIENCES, FACULTY OF SCIENCE, KANAZAWA UNIVERSITY, KANAZAWA 920-1192, JAPAN |
| |
| Abstract: | Chemical variations along with changes in microstructure ofthe principal constituent minerals make it possible to identifyat least four equilibrium stages in the evolution of the Yangkougarnet peridotite in the Su-Lu ultrahigh-pressure metamorphicbelt, eastern China: Stage I—a primary garnet lherzolitestage represented by coarse-grained (a few millimeters size)porphyroclastic aluminous pyroxenes + chromian spinel ±garnet; Stage II—an ultrahigh-pressure (UHP) stage definedby fine-grained matrix phases (0·1–0·3 mmsize) of garnet + extremely low-Al orthopyroxene + high-Na clinopyroxene+ chromite; Stage III—a medium-pressure stage definedby fine-grained mineral aggregates (<0·1–0·2mm size) mainly composed of aluminous spinel + high-Al orthopyroxenein the matrix; Stage IV—an amphibolite- to greenschist-faciesstage defined by poikiloblastic amphibole. Orthopyroxene–clinopyroxenethermometry and an empirical spinel barometer give temperaturesof around 800–830°C and pressures of 1·2–2·9GPa for porphyroclasts of Stage I. Garnet–orthopyroxene,garnet–clinopyroxene and empirical spinel geothermobarometersgive relatively uniform P–T conditions for the matrixgarnet–orthopyroxene–clinopyroxene–chromiteassemblage of Stage II ( |
| |
| Keywords: | : China garnet peridotite isothermal decompression path Shandong Su-Lu UHP belt |
| 本文献已被 Oxford 等数据库收录！ |
|
