| 中国及其邻区地球三维结构初始模型的建立 |
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| 引用本文： | 朱介寿,曹家敏.中国及其邻区地球三维结构初始模型的建立[J].地球物理学报,1997,40(5):627-648. |
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| 作者姓名： | 朱介寿 曹家敏 |
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| 作者单位： | 成都理工学院应用地球物理系, 成都 610059 |
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| 基金项目： | 国家自然科学基金（NSFC），国际岩石圈计划（ILP），国际理论物理中心（ICTP）资助 |
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| 摘 要： | 对人工地震测深及天然地震面波体波三维层折反演数据进行统一处理，建立了中国及其邻区地球三维结构初始模型．此模型图像表明，中国及其邻区地球各圈层横向变化明显．岩石圈及软流圈内速度分布主要反映这一区域自古生代以来板块及地块拼合模式．各主要板块或地块（塔里木、扬子、中朝、青藏、哈萨克斯坦、印度、印度支那）岩石圈增厚或有很深的地慢根，板块或地块间的造山带岩石圈减薄，软流圈速度降低。下地幔底部及核幔边界D″层出现高速异常，表明古太平洋及古特提斯洋俯冲板块因重力坍塌已进入地球深层，形成亚洲超级下降地幔柱。这一下降地幔柱引起地球表层物质向中亚、东亚地区集中，印度半岛、青藏高原、新疆、蒙古至贝加尔一带，成为全球岩石圈最大的汇聚场所．
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| 关 键 词： | 地球三维结构 岩五圈分块 超级下降地幔柱 中国 |
THE RECONSTRUCTION OF PRELIMINARY THREE-DIMENSIONAL EARTH'S MODEL AND ITS IMPLICATIONS IN CHINA AND ADJACENT REGIONS |
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| ZHU JIE-SHOU, CAO JIA-MIN, LI XIAN-GUI, ZHOU BIN.THE RECONSTRUCTION OF PRELIMINARY THREE-DIMENSIONAL EARTH''''S MODEL AND ITS IMPLICATIONS IN CHINA AND ADJACENT REGIONS[J].Chinese Journal of Geophysics,1997,40(5):627-648. |
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| Authors: | ZHU JIE-SHOU CAO JIA-MIN LI XIAN-GUI ZHOU BIN |
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| Institution: | Dept. of Applied Geophysics, Chengdu Institute of Technology, Chengdu 610059, China |
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| Abstract: | The continent of China and its adjacent regions formed by a series of plates and blocks convergence rapidly in the late Paleozoic （about 200-300 Ma）. The Indian subcontinent collided with Eurasian continent causing the crust shorted and uplifted in the late Mesozoic to Paleocene epoch forming the highest plateau of Qinghai-Tibet and Pamir, and orogens of Himalayan and Hindu Kush. Based on the Global Creosciences Transects（GGT） and the results of tomographic inversion by seismic body wave and surface wave data, the three dimensional velocity structure from upper crust to Core-Mantle Boundary （CMB） have been reconstructed in China and its adjacent regions. It shows the great lateral various for each spherical layers in lithosphere /asthenosphere system （depth from 0 to about 400 km）.Alpine-Himalayan belt throughout the Northern Pakistan （Hindu Kush and Pamir）, Qinghai-Tibet plateau including Tarim basin and Tian-Shan mountain chain characterized by the continent-continent collision zone with thick crust and lithosphere.The eastern part is influenced by the motion of Pacific plate and with the thin crust and lithosphere. The average thickness of lithosphere in the region is about 100 km,several paleonuclei and paleolands, such as Tarim, Yangtze, Ordos and Indian shield are represented by great thickness of lithosphere. T'he fold belts, such as Altai, Qinlin belt, North-South tectonic belt, southeast continental margin, South China sea, East China sea. Ryukyu trench represented by thin lithosphere.In the lower mantle （depth in 700-1200 km） the velocity distribution shows the northsouth trend. The high velocity regions are presented in the Japan sea and East China sea, and also appear in the N-S tectonic belt through out central China. In the depth 2200-2800 km close the CMB region a huge high velocity anomaly is distributed from east to west, this could be explained as a super cold downwelling plume in the east and central Asia.The super downwelling plume underneath Asia is the dominant pattern of vertical mantle flow in the modem Earth. This huge cold plume is formed by the multi-subduction of oceanic plates of paleo Tethys and Pacific, the cold slabs was supplied by plates at trench and down to lower part of upper mantle （670 km in depth）, where they were accumulated, and after a geologically significant time the stagnant mass of cold slabs gravitationally collapsed onto the CMB. Once it is formed in lower mantle, the mantle convection patterns in the upper mantle tends to be strongly controlled by a sole downwelling superplume in the lower mantle. Thus all continents tend to be swallowed into the cold superplume until they are collision and amalgamation to form a super-continent.The central Asia, from Indian subcontinent to Tibet, Xijiang, Mongolia and Baikal regions are the present largest convergence place in the world. there are thicken crust and lithosphere, showing high compressional stress in the crust, low heat flow and broad distributed earthquakes, and negative gravity anomaly, lowest geoid,all of these characteristics indicate the mantle materials fall down to the CMB and continents converged in this region. |
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| Keywords: | Three-dimensional structure of earth Blocks dividing in lithospheres Downwelling superplume of lower mantle China |
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