摘要
中条山早元古代变质岩石呈北东向分布,经历了中低级变质作用。本文在变质作用研究的基础上,结合地质构造和显微构造,利用近来发展的石榴石环带定量测定P-T轨迹的技术,建立了绛县群和中条群泥质岩石经历的PTt轨迹。PTt轨迹表明绛县群经历拉张作用,地壳发生抬升,产生绿片岩相变质;在中条第Ⅰ期运动中,地壳略有增厚或不变升温和抬升,产生低角闪岩相变质;而中条群岩石经历低绿片岩相埋深变质后,于中条第Ⅰ期运动中,呈现增厚升温和抬升的轨迹,经历低角闪岩相变质。中条第Ⅱ期运动则使地壳彻底抬升剥蚀,发生区域热变质和退变质作用。
Early Proterozoic supracrustal rocks of the Zhongtiao Mountains consist of three groups-Jiangxian Group, Zhongtiao Group and Danshanshi Group, which range in tnetamorphic grade from greenschist to lower amphibolite facies.This discussion focuses on pelttic rocks in the Jiangxian Group and Zhongtian Group, from which information about the P-T paths of the tectonic evolution can be obtained.The P-T paths of the Jiangxian Group display slight temperature rise and pressure decline during D1 deformation and M1 metamorphism and slight pressure and temperature increases during D2 deformation and M2 metamorphism. The P-T paths of the Zhongtiao Group show temperature and pressure increases during D2 deformation and M2 metamorphism. There exist thermic metamorphism and retro-metamorphism during D3 deformation and M3 metamorphism.The rocks of the Jiangxian Group experienced uplift under the influence of the Jiangxian defomation and Zhongtiao deformation, and the rocks of the Zhongtiao Group experienced crustal thickening during the uplift and erosion of the crust.
出处
《地质论评》
CAS
CSCD
北大核心
1994年第1期36-47,T001,共13页
Geological Review
关键词
中条山
早元古代
变质岩
PTT轨迹
Zhongtiao Mountain, Early Proterozoic, zoned garnet, microstru- cture, metamorphic P-T paths, tectonic evolution
