Deformation features of gneiss and UHP eclogite from ductile shear zone and its relation with seismic velocity anisotropy: Evidences from core samples at depth of 680-1200m of CCSD
文献类型：期刊论文
| 作者 | Chen, Y; Jin, ZM; Ou, XG; Jin, SY; Hu, HJ |
| 刊名 | ACTA PETROLOGICA SINICA
 |
| 出版日期 | 2004 |
| 卷号 | 20期号:1页码:97-108 |
| 关键词 | ductile shear zone gneiss UHP eclogite anisotropy seismic deep reflection Chinese Continental Scientific Drilling(CCSD) |
| ISSN号 | 1000-0569 |
| 文献子类 | Article |
| 英文摘要 | Several ductile shear zones developed at depth of 680 similar to 1200m of CCSD. The main rock types in the shear zone include gneisses and UHP eclogites. The strain axes of deformed quartz in gneisses and stretch garnets and omphacites in eclogites are expressed as X > Y > Z ratios. Their flinn coefficients vary from 0.11 to 0.27, 0.22 to 0.23 and 0.23 to 0.24, respectively. In the gneiss sample the C - axis fabric of deformed quartz shows a great circle normal to the foliation and a maximum near Z. With the strengthening of mylonitization, the fabrics become a great circle near the foliation and a maximum near Y. P- and S-wave velocities were measured at room temperature and pressure. Calculated P- and S-wave velocity anisotropies of gneisses vary from 30.17% to 60.97% and 11.52% to 35.79%, while those of eclogite vary from 0.17% to 11.19% and 2.41% to 6.70%, respectively. Seismic velocity anisotropies are mainly caused by lattice preferred orientation( LPO), shape preferred orientation( SPO) of the major minerals, and oriented microcracks. P-wave velocity anisotropies of gneiss increase with strengthening mylonitization. LPO and SPO of biotite, quartz and omphacite are responsible for the velocity anisotropy of deformed rocks. P-wave velocity anisotropies of water-saturated gneiss are lower than those of dry gneiss. The strongly reflective zone beneath the Donghai drill site can be explained by the impedance contrasts between the different lithologies. Contacts between eclogite/retrograde eclogite and biotite-plagioclase gneiss may give rise to strong seismic reflections. In addition, lattice preferred orientation-related seismic anisotropy can increase reflectivity, thus the mylonitized gneiss in ductile shear zone may be good reflectors. The strong anisotropy of ductile shear zone provides important constraints on interpretations of seismic deep reflection results. |
| WOS关键词 | WAVE VELOCITIES ; CENTRAL CHINA ; IVREA ZONE ; ROCKS ; REFLECTIONS ; PRESSURE ; MYLONITES ; BELT |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000221036600008 |
| 出版者 | SCIENCE CHINA PRESS |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/79767]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Chen, Y |
| 作者单位 | 1.China Univ Geosci, Wuhan 430074, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China |
| 推荐引用方式 GB/T 7714 | Chen, Y,Jin, ZM,Ou, XG,et al. Deformation features of gneiss and UHP eclogite from ductile shear zone and its relation with seismic velocity anisotropy: Evidences from core samples at depth of 680-1200m of CCSD[J]. ACTA PETROLOGICA SINICA,2004,20(1):97-108. |
| APA | Chen, Y,Jin, ZM,Ou, XG,Jin, SY,&Hu, HJ.(2004).Deformation features of gneiss and UHP eclogite from ductile shear zone and its relation with seismic velocity anisotropy: Evidences from core samples at depth of 680-1200m of CCSD.ACTA PETROLOGICA SINICA,20(1),97-108. |
| MLA | Chen, Y,et al."Deformation features of gneiss and UHP eclogite from ductile shear zone and its relation with seismic velocity anisotropy: Evidences from core samples at depth of 680-1200m of CCSD".ACTA PETROLOGICA SINICA 20.1(2004):97-108. |
入库方式： OAI收割
来源：地质与地球物理研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。