华北克拉通集宁地区孔兹岩系矿物学研究和P-T轨迹探讨

Mineralogy and P-T Path of Khondalites in Jining Region of the North China Craton

以华北克拉通西部陆块集宁地区出露的孔兹岩系为研究对象,主要研究孔兹岩系的岩石学、矿物学特征,利用电子探针数据分别计算出集宁地区孔兹岩系变质反应峰期前、峰期和峰期后三个不同阶段的温度和压力条件,得出了顺时针的变质反应P-T轨迹图。集宁地区地理位置、岩石学和矿物学特征、P-T轨迹以及华北克拉通基底三分的构造模型(华北克拉通基底可以分为东、西部陆块和中部构造带),反映出陆-陆碰撞的构造环境;此等温降压顺时针变质反应P-T-t轨迹记录了东、西部陆块碰撞拼合,并最终形成华北克拉通统一结晶基底的过程。

The khondalite series in Jining Region of the North China Craton （NCC） is determined to be the object of this paper. By the studies of petrology, mineralogy and the P-T conditions of pre-peak, peak and after-peak metamorphism from the EPMA analyses data of khondalite series in Jining Region, a clockwise P-T metamorphic path is presented. Considering the location of Jining Region, a clockwise P-T metamorphic path and three-fold tectonic subdivision model of NCC （the basement of NCC can be divided into the eastern, western blocks and the middle tectonic zone）, the khondalite series in Jining Region are suggested to have experienced a clockwise P-T metamorphic path. The geological background of continent-continent collision, therefore, is stand to the reason. This clockwise metamorphism P-T path records the integrated process of collision between the eastern and western blocks and finally combined to the whole basement of NCC.