江西弋阳地区斜长角闪岩与浙江陈蔡群斜长角闪岩地球化学特征及成因的对比

CORRELATION OF GEOCHEMICAL FEATURES AND GENESIS BETWEEN THE AMPHIBOLITES IN YIYANG AREA OF JIANGXI AND THOSE IN CHENCAI GROUP OF ZHEJIANG

江西弋阳存在与浙江陈蔡群相对应的两类斜长角闪岩 ,Ⅰ类为由拉斑玄武质岩石变质而成的正变质岩 ,Ⅱ类为由白云质泥灰岩经变质而成的副变质岩。通过对两地斜长角闪岩原岩的化学成分、微量元素、稀土元素、同位素及同位素年代学的对比研究 ,发现浙江陈蔡群的Ⅰ类斜长角闪岩原岩为大洋拉斑玄武岩 ,江西弋阳Ⅰ类斜长角闪岩原岩为岛弧拉斑玄武岩 ;显示两地Ⅰ类斜长角闪岩产出于不同的构造环境 ,并于晋宁期、加里东期、印支期共同受构造作用影响。

Corresponding to the Chencai Group of Zhejiang, two types of amphibolite are recognizable in Yiyang of Jiangxi. Type I is an ortho-metamorphic rock derived from tholeiitic rock, while type II is a para-metamorphic rock resulted from metamorphism of dolomitic marl. Through correlation study of the primary rocks of amphibolites between these two places in chemical composition, trace elements, rare earths, isotopes and isotopic geochronology, the authors found that the primary rock of type I amphibolite in the Chencai Group of Zhejiang and in Yiyang, Jiangxi are oceanic tholeiite and island arc tholeiite respectively, suggesting that the primary rocks of type I amphibolites from these two places were formed in different tectonic environments, and that both of them have undergone the Jinningean, Caledonian and Indosinian tectonism.