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地质力学学报:2018,24(6):748-758
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佳木斯—伊通断裂韧性剪切变形时代及其地质意义
(1.中国地质科学院地质力学研究所, 北京 100081;2.中国地质科学院页岩油气评价重点实验室, 北京 100081)
THE DUCTILE SHEAR DEFORMATION AGE OF THE JIAMUSI-YITONG FAULT AND ITS GEOLOGICAL SIGNIFICANCE
(1.Institute of Geomechanics, Chinese Academy of Geological Science, Beijing 100081, China;2.Key Lab of Shale Oil and Gas Geological Survey, Chinese Academy of Geological Science, Beijing 100081, China)
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投稿时间:2018-08-19    修订日期:2018-10-30
中文摘要: 作为郯庐断裂北段主干断裂的佳木斯-伊通断裂(简称佳-伊断裂),其最早开始活动的时代一直以来都存在争议。为了更好确定其活动时代,对佳-伊断裂昌图段南城水库附近的韧性剪切带展开了详细研究。野外构造解析和显微构造特征显示,剪切带糜棱面理走向北北东-南南西,其上发育北东方向的缓倾拉伸线理,指示该剪切带为逆冲-走滑韧性剪切特征。锆石U-Pb年龄测试结果表明,剪切带中糜棱花岗岩形成在174~173 Ma,该糜棱岩带被后期未变形辉绿岩脉侵入,辉绿岩脉的锆石U-Pb年龄为164 Ma,从而限定该期次韧性变形发生在174~164 Ma之间的中侏罗晚期。取自剪切带糜棱花岗岩内的变形黑云母40Ar/39Ar测试结果表明,糜棱花岗岩在187~166 Ma左右受到了显著的热事件的扰动。这些证据证明,佳-伊断裂在中侏罗晚期发生过显著的左行走滑韧性剪切,结合对东北地区火成岩研究成果的分析,佳-伊断裂中侏罗晚期的韧性变形可能与古太平洋板块向欧亚大陆的俯冲有关,该时期侵位的岩浆活动开始显著受到俯冲引发的挤压应力作用的影响。
Abstract:As a major section in the northern part of Tan-Lu fault, the ductile shear deformation age of Jiamusi-Yitong fault (Jia-Yi fault for short) is still an unsolved scientific problem. In this study, a ductile shear zone was discovered near the Nancheng reservoir in the Changtu section of Jia-Yi fault. The field structural analysis and microstructural features show that the shear zones strike ~NNE, dip at a high angle, with a trending ~NE stretching lineation, indicating the shear zone a thrust-slip shear ductile shear. The U-Pb age of zircon from mylonite granites in the shear zone indicate that the granite was formed at 173-174 Ma, which was invaded by the later diabase, and the U-Pb age of zircon from the diabase dykes was 164Ma, so the shear ductile deformation occurred in the late Middle Jurassic between 174-164 Ma. The deformed biotite taken from within the shear zone was disturbed by significant thermal events around 187-166 Ma. The result suggest that significant left-lateral strike-slip ductile shear occurred at the northern section of Tan-Lu fault during the Middle-Late Jurassic. Combined with recent research achievements of igneous rock in Northeast China, the ductile shear deformation of Jia-Yi fault may be associated with the subduction of the Paleo-Pacific plate under the East Asia continent, and magmatic emplacement during Mid-Late Jurassic began to be significantly affected by the compressive stress induced by the subduction.
文章编号:     中图分类号:P542    文献标志码:
基金项目:中国地质调查局工作项目(DD20189614);国家自然科学基金项目(41702204)
引用文本:
高万里,王宗秀,李磊磊,等,2018.佳木斯—伊通断裂韧性剪切变形时代及其地质意义[J].地质力学学报,24(6):748-758.DOI:10.12090/j.issn.1006-6616.2018.24.06.077
GAO Wanli,WANG Zongxiu,LI Leilei,et al,2018.THE DUCTILE SHEAR DEFORMATION AGE OF THE JIAMUSI-YITONG FAULT AND ITS GEOLOGICAL SIGNIFICANCE[J].Journal of Geomechanics,24(6):748-758.DOI:10.12090/j.issn.1006-6616.2018.24.06.077

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