摘要
本文通过对宁镇地区侵入岩岩体地质、岩石化学、微量元素及侵位方式特征的研究,并与国内外典型构造环境的岩浆岩进行对比后,认为宁镇地区侵入岩形成在以张性作用为主,挤压作用为辅的构造环境中,是裂谷作用初期—断裂拗陷阶段的产物。
The granitoid rock in Ning-Zhen area is Ⅰ-type granite.Based on the petrochemical analysis. the granite contains more alkalic content and less Ca and Al.and characterized by high differe- ntiation and low calc-alkalic index.The whole rock appears a little alkaline.All these evidences indicate that the granitoid rock was intruded in the environment of low pressure and deep origin where only small part of earth's crust was melted.The above features of Ning-Zhen granitoid rock is same as the typical granites formed in tensional tectonic environment. Trace elements are quite effective in the determination of tectonic environment in order to classify the granitoid rocks.It is a sensitive geochemical tracer.The research on these trace elements showes that the intrusive rock in Ning-Zhen area belongs to the granite within plate and island arc granite.Therefore,its forming condition shall be graben environment within plate while including the influence of volcanic arc because the granitoid rock is characterized by not only the obvious tension but.also slight compression properties.This is due to the movement of the rift valley of Tan-Lu fault system and the sudduction of Pasific plate.
出处
《江苏地质》
1990年第1期17-20,共4页
Jiangsu Geology
