大别山榴辉岩岩石学及地球化学特征

Petrology and Geochemistry of Ecologite in The Dabie Mountains

本文分析了大别山地区榴辉岩的产出特点,矿物化学、岩石化学及元素地球化学特征。所获资料表明大别山榴辉岩与围岩一起经历了超高压变质作用,但其化学成分特征与围岩存在一定的差异,兼有大陆玄武岩和大洋玄武岩的特征。这些岩石大部分可能为板块俯冲过程中带入的大洋岩石残片。在深部变质形成榴辉岩后又随大别杂岩一起被抬升到地表,在抬升过程中经历了不同程度的退变质作用。

This paper analyzes the mode of occurrence and mineral chemical , petrochemical and element geochemical characteristics of eclogite in the Dabie Mountains area. The data show that e- clogite in the study area underwent ultrahigh-pressure metamorphism together with its surrounding rocks , but chemical compositions of eclogite show certain differences from those of the latter. The eclogites show geochemically charcacteristics of both continental and oceanic basalt. Most of the rocks might be originally fragments of oceanic rocks introduced during plate subduction. They were exhumed upto the surface together with the Dabie complex after they were metamorphosed into eclogite at depth. During exhumation eclogite underwent different degrees of retrometamorphism.