| 残余壳根与"三明治"结构——燕山造山带中段地壳结构的主要特征 |
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| 引用本文：李秋生,高锐,张成科,赵金仁,管烨,张季生.2008.残余壳根与"三明治"结构——燕山造山带中段地壳结构的主要特征[J].地球学报,29(2):129-136. |
| DOI：10.3975/cagsb.2008.02.01 |
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| 基金项目:中国地质大调查项目(编号:200213000040); 国家自然科学基金项目(编号:40334035) |
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| 中文摘要:摘要昌黎一承德一达莱诺尔宽角反射／折射地震剖面完成于1985年，呈NW向横过燕山造山带中段，部分测段与2002年实施的120km深反射地震剖面重合。为获得区域深部构造背景并在与反射地震剖面交互解释基础上，对该剖面的4炮原始资料进行了处理、解释，获得了一个厚35-38km，局部残余壳根，夹有低速层的“三明治”式的地壳结构模型。该结构样式明显不同于板缘俯冲／碰撞造山带常见的楔入（挤入）样式，也区别于澳大利亚Alice Spring造山带的厚皮变形样式，在世界陆内造山带中独具特色。燕山造山带的地壳结构模型暗示该区保持着中生代区域收缩变形形成的地壳结构基本格架，下地壳和Moho的特征显示了后期区域性伸展作用的影响。 |
| 中文关键词:燕山造山带 深地震测深剖面 地壳结构 残余壳根 |
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| Remainder Crustal Root and Decoupling-Main Characteristics of Crust Structure beneath the Yanshan Intracontinent Orogen |
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| Abstract:The Changli-Chengde-Dalainuoer wide-angle/refraction seismic profile completed in 1985 extends northwestward across the Yanshan orogen. It is partly overlapped by a reflection seismic profile completed in 2002. For the purpose of understanding the regional deep tectonic setting and on the basis of interactive interpretation between the near-vertical reflection profile and the wide-angle reflection profile, this paper dealt with four shot data from the profile. As a result, a sandwich style crust structure model of the remainder crustal root 35～38 km in thickness intercalated with an intracrust lower velocity layer was obtained. This pattern is evidently different from the diagram of wedge /insert that often appears under the interplate underthrust or collision orogen, and is also different from the 'thick-skinned' pattern under the Alice Spring orogen of Australia, thus having its distinct features in the intra-continent orogenic belts of the world. The crustal structure suggests that the framework formed by Mesozoic regional contraction deformation was preserved in the Yanshan orogen. Nevertheless, characteristics of the lower crust and Moho indicate the existence of the influence of late regional stretching. |
| keywords:Yanshan orogen deep seismic sounding (DSS) profile crustal structure remainder crustal root |
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