| 江苏东海CCSD主孔超高压变形与折返变形的叠加关系 |
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| 引用本文： | 唐哲民,陈方远.江苏东海CCSD主孔超高压变形与折返变形的叠加关系[J].岩石学报,2009,25(7):1639-1644. |
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| 作者姓名： | 唐哲民 陈方远 |
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| 作者单位： | 中国地质科学院地质研究所,国土资源部大陆动力学重点实验室,北京,100037 |
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| 基金项目： | 科技部973项目（2003CB716500）、中国地质调查局地质大调查项目（121201056606）和中国大陆科学钻探工程项目 |
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| 摘 要： | 位于苏鲁超高压变质地体南部的中国大陆科学钻探工程（CCSD）主孔岩石经历了超高压变形及多期折返变形。第一期折返变形为伸展折返变形,榴辉岩发生角闪岩相退变质作用,没有新生面理或线理的发育,基本保留了超高压阶段的S-L组构,并有显示熔融体特征的强退变榴辉岩发育。第二期折返变形为SEE-NWW向挤压折返变形,超高压变形期形成的不同岩石类型在本期变形中表现出不同的叠加变形现象,榴辉岩类岩石早期形成的S倾面理主体部分转为SEE倾,但拉伸线理产状与超高压变形期的近SN走向基本一致,反映早期面理沿NNE轴向的重褶作用,局部又被向SEE缓倾的韧性剪切带切割;而片麻岩类岩石在超高压变形期形成的S-L组构的主体部分已被新生成的总体向SEE缓倾的S-L组构置换,反映早期面理不仅重褶,而且大部分再度发生韧性剪切变形,具SEE向NWW的逆冲剪切指向,矿物普遍重新定向。第三期折返变形发育具NWW向SEE正滑剪切指向的韧性剪切带,并伴随大量“Z”型褶皱构造的发育。第四期折返变形以NWW向SEE正滑的张性或张扭性脆性断裂活动为主。探讨了苏鲁超高压变质地体折返变形的力学机制及CCSD主孔岩石面理变化的形成机制。
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| 关 键 词： | CCSD主孔 超高压变形 折返变形 叠加变形 |
| 收稿时间： | 2008/12/12 0:00:00 |
| 修稿时间： | 2009/5/10 0:00:00 |
Superimposed relation of deformation in ultrahigh-pressure stage and exhumed deformation in main borehole from CCSD, Donghai County, Jiangsu Province |
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| TANG ZheMin and CHEN FangYuan.Superimposed relation of deformation in ultrahigh-pressure stage and exhumed deformation in main borehole from CCSD, Donghai County, Jiangsu Province[J].Acta Petrologica Sinica,2009,25(7):1639-1644. |
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| Authors: | TANG ZheMin and CHEN FangYuan |
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| Institution: | Key Laboratory for Continental Dynamics,MLR,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;Key Laboratory for Continental Dynamics,MLR,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China |
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| Abstract: | Rock in main borehole of Chinese Continental Scientific Drilling (CCSD) located in southern part of SuLu ultrahigh-pressure metamorphic terrane experienced deformation in ultrahigh-pressure stage and multiperiodic exhumed deformations. Exhumed deformation of the first stage is extensional exhumed deformation, eclogite happened retrogressive metamorphism in amphibolite faces condition, did not have new foliation and lineation, kept S-L fabrics in ultrahigh-pressure stage, and have strongly retrogressive metamorphic eclogite melting partly. Exhumed deformation of the second stage is compression exhumed deformation of SEE-NWW direction, different rock style that formed in ultrahigh-pressure stage had different superimposed deformation in this stage, foliation dipping to south of eclogites in the first stage turned to dipping mainly to SEE, but attitude of stretching lineation is identical basically with SN strike in the first stage, reflect foliation in the first stage refolded along NNE arial line, dissected partly by ductile shear zone dipping to SEE; S-L fabric of gneiss formed in ultrahigh-pressure stage has been replaced mainly by new S-L fabric dipping to SEE, reflect foliation in the first stage not only refolded, but deformed ductilely, have SEE-NWW thrust shear sense, mineral oriented again. Exhumed deformation of the third stage is ductile shear zone with NWW-SEE normal-slip shear sense, and have a lot of fold structure of "Z" style. Exhumed deformation of the fourth stage is extensional brittle faulting with NWW-SEE normal-slip shear sense. This article discusses mechanical mechanism of exhumed deformation of SuLu ultrahigh-pressure metamorphic terrane and forming mechanism of foliation changing in main borehole of CCSD. |
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| Keywords: | Main borehole of CCSD Deformation in ultrahigh-pressure stage Exhumed deformation Superimposed deformation |
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