大别山地区榴辉岩及伴生石榴石橄榄岩的矿物化学研究

STUDY ON MINERAL CHEMISTRY OF ECLOGITE AND ASSOCIATED GARNET PERIDOTITE IN DABIESHAN AREA

本文报道了我国大别山地区榴辉岩及伴生石榴石橄榄岩中的矿物化学特征。利用电子探针分析榴辉岩中的12个石榴石,1个斜方辉石和12个单斜辉石以及石榴石橄榄岩中的6个石榴石、1个斜方辉石、6个单斜辉石和6个橄榄石。利用矿物地质温压计估算了榴辉岩和石榴石橄榄岩的成岩压力分别为16千巴和18千巴,成岩温度分别为600—800℃和600—700℃,两者形成于基本相同的物理化学环境,为基性岩和超基性岩在地幔边界处经深成变质作用形成。

This paper reports the mineral chemistry of eclogite and associated garnet peridotite in dabeishan area of China. 12 garnets, 1 orthopyroxene and 12 clinopyroxenes in eclogite and 6 garnets, 1 orthopyroxene and 6 clinopyroxenes in garnet peridotite were analyzed by electronprobe instrument, Estimated by mineral geothermometer and geobarometer the rock forming temperature and pressure of eclogite and garnet peridotite are 16 kbar, 600—800℃ and 18 kbar,600(-)700℃ respectively. Both of them were formed in same physico-chemical environments,by hypozonal metamorphism at boundary between crust and mantle of basic and/or ultrabasic rocks.