| 阿尔泰—阿尔金地学断面地壳结构 |
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| 引用本文： | 王有学,韩果花,姜枚,袁学诚,Walter D Mooney.阿尔泰—阿尔金地学断面地壳结构[J].地球物理学报,2004,47(2):240-249. |
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| 作者姓名： | 王有学 韩果花 姜枚 袁学诚 Walter D Mooney |
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| 作者单位： | 1.桂林工学院资源与环境工程系，桂林 540014 2 中国地质科学院地质研究所，北京 100037 3 中国地质调查局发展研究中心，北京 100081 4 United State Geological Survey, Menlo Park, CA 94025, USA 5 Department of Geology and Environment Sciences, Stanford University, California 94305, USA |
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| 基金项目： | 国家 973项目 ( 2 0 0 1CD40 9810 )，国土资源部重大科技专项基金 ( 2 0 0 0 10 10 2 0 1)资助 |
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| 摘 要： | 根据阿尔泰—阿尔金地学断面的地震纵、横波资料，建立了地壳速度及泊松比结构. 测区的地壳具有明显的三分结构特征，其纵波速度自上而下依次为6.0～6.3km/s、6.3～6.6km/s及6.9～7.0km/s；阿尔泰南缘的地壳最厚，为56km，准噶尔盆地的地壳最薄，为46km，大部分地区的地壳厚度为50km 左右. 准噶尔盆地与天山之间上地幔顶部的纵波速度为7.7～7.8km/s ；阿尔泰南缘及塔里木盆地上地幔顶部的纵波速度较高，为7.9～8.0km/s. 测线南部，包括东天山及塔里木东缘，自地表至30km深处的地壳纵波速度低，泊松比为0.25，表明上地壳主要为石英及花岗质成分；而测线北部(包括阿尔泰及准噶尔盆地)的中、上地壳则呈现较高的泊松比（0.26～0.27），可能为基性地壳的体现. 厚15～30km的下地壳纵波速度（6.9～7.0km/s）较高，泊松比为0.26～0.28，可能以镁铁质的麻粒岩成分为主. 位于天山及其南侧地壳中部的低速层（VP=5.9km/s, σ=0.25）则可能为晚古生代的构造热事件中的花岗质侵入岩.
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| 关 键 词： | 阿尔泰—阿尔金 地学断面 地壳结构 泊松比 |
| 文章编号： | 0001-5733(2004)02-0240-10 |
| 收稿时间： | 2003-1-27 |
| 修稿时间： | 2003-11-2 |
Crustal structure along the geosciences transect from Altay to Altun Tagh. |
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| WANG You Xue,HAN Guo Hua,JIANG Mei,YUAN Xue Cheng,Walter D Mooney Robert G Coleman.Crustal structure along the geosciences transect from Altay to Altun Tagh.[J].Chinese Journal of Geophysics,2004,47(2):240-249. |
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| Authors: | WANG You Xue HAN Guo Hua JIANG Mei YUAN Xue Cheng Walter D Mooney Robert G Coleman |
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| Institution: | 1.Department of Resources and Environmental Engineering, Guilin Institute of Technology, Guilin 540014, China 2 Geological Institute, Chinese Academy of Geosciences, Beijing 100037, China 3 Development and Research Center, China Geological Survey, Beijing 100081, China 4 United State Geological Survey, Menlo Park, CA 94025, USA 5 Department of Geology and Environment Sciences, Stanford University, California 94305, USA |
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| Abstract: | Based upon the P and S wave data acquired along the geoscience transect from Altay to Altun Tagh in Northwest China, the crustal structures of velocities and Poisson's ratio are determined. The crustal velocity structure features an obvious three layer structure with velocities of 6.0～6.3km/s, 6.3～6.6km/s and 6.9～7.0km/s from surface to depth, respectively. The crustal thickness al ong the entire profile is mostly 50km with the thickest crust (56km) benea th t he Altay and the thinnest (46km) beneath the Junggar basin. The velocities unde rlying Moho are 7.7 to 7.8km/s between the Tianshan and the Junggar basin, and 7.9 to 8.0km/s below the Altay Mountains and eastern margin of the Tarim basin. The southern half of the profile, including the eastern Tianshan Mountains and eastern margin of the Tarim basin, shows low P wave velocities and σ=0.25 to a d epth of 30km, which suggests a quartz rich, granitic upper crustal composition . The northern half of the profile below the Altay Mountains and Junggar Accretio nal Belt has a higher Poisson's ratio of σ=0.26～0.27 to a depth of 30k m, indica tive of an intermediate crustal composition. The entire profile is underlain by a 15 to 30km thick high velocity (6.9～7.0km/s; σ=0.26～0.28) lower crus tal laye r that we interpret to have a bulk composition of mafic granulite. At the southe rn end of the profile a 5km thick mid crustal low velocity layer (VP=5 .9km/s, σ=0.25) underlies the Tianshan and the region to the south, and may be indi cative of granitic intrusive in Late Paleozoic. |
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| Keywords: | Altay-Altun Tagh Geoscience transect Poisson's ratio Crustal structure |
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