苏北锦屏地区构造变形及片麻岩舌状体成因研究

通过对锦屏山地区详细填图,确认了苏鲁造山带南缘超高压变质带与高压变质带的界线性质为一韧性剪切带,锦屏地区不存在区域性褶皱,而是由于朐山花岗质片麻岩和云台岩群变质火山岩构成强干岩层,锦屏岩群变质沉积岩构成软弱岩层,形成夹心饼式(layer cake assemble）组合。在印支期右行剪切作用下,形成不均一剪切,使朐山花岗质片麻岩形成长约10km,宽约5km的无根剪切舌状体,物质运动方向指向南。

Tectonic deformation and origin of tongue-like gneiss in the Jinping area, northern Jiangsu

According to detailed mapping in the Jinping area on the southern edge of the Su-Lu orogen, it is affirmed that the boundary between the ultrahigh-pressure metamorphic belt and high-pressure metamorphic belt is a ductile shear zone. No regional folds occur in the area, but instead, as the Jushan granitic gneiss and metavolcanic rocks of the Yuntai Group-complex form a competent rock layer, an incompetent rock layer was formed by metasedimentary rocks of the Jinping Group-complex; they combine to form a "layer cake"-style rock assemblage. In the Indosinian period, dextral shear gave rise to heterogeneous shear deformation; as a result, a rootless tongue-like fold of the Jushan granitic gneiss was formed. It is about 10 km long from north to south and about 5 km wide. The material movement is south-vergent in the Jinping area.