Application of General Shear Theory to the Study of Formation Mechanism of the Metamorphic Core Complex:A Case Study of Xiaoqinling in Central China |
| |
| Authors: | ZHANG Jinjiang Institute of Geology Chinese Academy of Sciences POBox Beijing ZHENG Yadong and LIU Shuwen |
| |
| Institution: | ZHANG Jinjiang Institute of Geology,Chinese Academy of Sciences,P.O.Box,Beijing ZHENG Yadong and LIU Shuwen Department of Geology,Peking University,Beijing |
| |
| Abstract: | The kinematic vorticity number and strain of the mylonitic zone related to the detachment fault increase from ESE to WNW along the moving direction of the upper plate of the Xiaoqinling metamorphic core complex (XMCC) and the geometry of quartz c-axis fabrics changes progressively from crossed girdles to single girdles in the same direction. Therefore, pure shear is dominant in the ESE part of the XMCC while simple shear becomes increasingly important towards WNW. However, the shear type does not change with the strain across the shear zone, thus the variation of shear type is of significance in indicating the formation mechanism. The granitic plutons within the XMCC came from the deep source and their emplacement was an active and forceful upwelling prior to the detachment faulting. The PTt path demonstrates that magmatism is an important cause for the formation of the XMCC. The formation mechanism of the XMCC is supposed to be active plutonism and passive detachment. Crustal thickening and magmatic doming caused necking extension with pure shear, and magmatic heating and doming resulted in detachment extension with simple shear and formed the XMCC. |
| |
| Keywords: | Xiaoqinling Metamorphic Core Complex (XMCC) formation mechanism shear type magmatism PTt path |
| 本文献已被 CNKI 万方数据 等数据库收录！ |
| 点击此处可从《Acta Geologica Sinica》浏览原始摘要信息 |
| 点击此处可从《Acta Geologica Sinica》下载免费的PDF全文 |
