摘要
本文主要研究和讨论中国北方三类构造环境中的蓝片岩,认为内蒙古温都尔庙地区的蓝片岩的形成是与古蒙古海洋板块的俯冲消减有关,为B型蓝片岩;陕西商南松树沟的蓝片岩的成因是与板块碰撞后的仰冲作用有关,为C型蓝片岩;商南赵川一带的蓝片岩的形成是与大型剪切推覆有关,为A型蓝片岩。文中对三类蓝片岩的地质地球化学特征作了一定的对比研究,提出了各自的鉴别特征。
This paper deals with the characteristics of A-, B-and C-type blueschists in three tectonic environments.
1. The origin of bluesehist in Ondor Sum, Nei Mongol, is related to the subduction of the Mongolian paleo-oceanic plate. It is classified as B-type blueschist and its main characteristics are as follows:
a) The blueschist belt is wide and there are a great variety of high-pressure minerals in this type of blueschist. b) The blueschist is associated with ophiolite. The ophiolite exhibits a strata sequence and the geological and geochemical characteristics of oceanic crust.
c) The blueschist belt is a part of the paired metamorphic belts.
2. The origin of blueschist in Songshugou(Shangnan, Shaanxi)is related to the obduction of the plate. It is classified as C-type blueschist and the main characteristics are:
a) The blueschist is associated with ophiolite which has either the geological and geochemical characteristics of oceanic crust or oceanic-continental transitional crust.
b) The blueschist belt is narrow and there are no paired metamorphic belts.
3. The blueschist in Zhaochuan, Shangnan, Shaanxi, is classified as A-type blueschist and the main characteristics are:
a) The blueschist is obviously controlled by fault zones and may occur in various types of ortho-and para-metamorphic rocks.
b) The blueschist is not associated with ophiolite.
c) The blueschist belt is narrow and there are no paired metamorphic belts
出处
《地质论评》
CAS
CSCD
北大核心
1990年第3期200-219,共20页
Geological Review
