| 从特提斯到青藏高原形成:构造-岩浆事件的约束 |
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| 引用本文： | 莫宣学,潘桂棠.从特提斯到青藏高原形成:构造-岩浆事件的约束[J].地学前缘,2006,13(6):43-51. |
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| 作者姓名： | 莫宣学 潘桂棠 |
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| 作者单位： | 1. 中国地质大学(北京)地球科学与资源学院,北京,100083
2. 国土资源部,成都地质矿产研究所,四川,成都,610082 |
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| 基金项目： | 国家重点基础研究发展计划(973计划);国家自然科学基金;国土资源部青藏高原重点研究计划项目 |
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| 摘 要： | 青藏高原被誉为“世界第三极”。然而,从特提斯的形成演化到青藏高原的形成,经历了一个漫长的复杂过程。这一过程分为三个明显的演化阶段:古特提斯阶段、新特提斯阶段、印度-欧亚大陆碰撞与青藏高原形成阶段。古特提斯洋自早石炭世开始打开,形成三个主支(修沟—玛沁洋、金沙江—哀牢山洋、澜沧江—昌宁孟连洋),至早二叠世扩张到最大规模后开始俯冲消减,逐渐缩小,至晚三叠世末—早侏罗世初洋盆闭合,冈瓦纳古陆的前缘与劳亚古陆的前缘碰撞拼合。这大约经历了150Ma的时间。大致与此同时或略早,古特提斯以南的新特提斯洋两支同时打开,并大致于早—中侏罗世之交扩张到最大规模,然后开始消减、缩小。北支班公湖—怒江洋在晚侏罗世初到早白垩世末(大致在160~100Ma的时间间隔内)闭合,完成拉萨地块与羌塘地块的碰撞拼合过程。南支雅鲁藏布洋闭合较晚,在白垩纪/古近纪之交(65/70Ma左右)印度大陆开始与拉萨地块(即欧亚大陆南缘)碰撞。新特提斯洋从打开到闭合,经历了约140Ma。印度-欧亚大陆碰撞是青藏高原形成的直接原因,从开始到完成,整个碰撞过程用了约20Ma(大致在65~40/45Ma时间间隔内);然后转入后碰撞阶段至今。很显然,几亿年时间尺度和几万公里空间尺度的特提斯的开合、演化、特别是印度-欧亚大陆碰撞和青藏高原隆升,必定对应着地球各圈层间巨大的物质与能量的调整和交换。而正是这种巨大的物质、能量交换,才是形成青藏高原及其资源环境效应的基本动力。
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| 关 键 词： | 青藏高原 特提斯演化 大陆碰撞 圈层间物质与能量交换 地球内部 |
| 文章编号： | 1005-2321（2006）06-0043-09 |
| 收稿时间： | 2006-10-31 |
| 修稿时间： | 2006年10月31 |
From the Tethys to the formation of the Qinghai-Tibet Plateau:constrained by tectono-magmatic events |
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| MO Xuan-xue,PAN Gui-tang.From the Tethys to the formation of the Qinghai-Tibet Plateau:constrained by tectono-magmatic events[J].Earth Science Frontiers,2006,13(6):43-51. |
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| Authors: | MO Xuan-xue PAN Gui-tang |
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| Institution: | 1. School of Earth Sciences and Resources, China University of Geosciences , Beij ing 100083 ,China; 2. Chengdu Institute of Geology and Mineral Resources, Chengdu 610082, China |
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| Abstract: | The Qinghai-Tibet plateau is known as “the third pole of the Earth”. The process from the evolution of Tethys to the formation of the Qinghai-Tibet plateau, however, is a complex long-term period. This process consists of three stages: the Paleo-Tethys, the Neo-Tethys and the India-Eurasia collision and formation of the plateau. The Paleo-Tethys opened since the early Carboniferous, formed three branches including the Xiugou-Maqing, the Jinshajiang-Ailaoshan and the Lancangjiang-Changning-Menglian oceanic basins. It reached the maximum width in the early Permian and then started with plate subduction. All the Paleo-Tethyan oceanic basins were closed at the end of the Triassic/the beginning of Jurassic, resulting in collision between the fronts of the Gondwana and Laurasia paleo-continents. This whole process for the evolution of the Paleo-Tethys took about 150 Mys period of time. Almost at the same time as the closure of the Paleo-Tethys or earlier, the Neo-Tethys opened and subsequently reached its maximum width in early/middle Jurassic, and then started with plate subduction and consumption. The Bangongco-Nujiang oceanic basin, i.e., the northern blanch of the Neo-Tethys, was closed up in the period from the late Jurassic to the early Cretaceous (about 160-100 Ma), given rise to collision between the Lhasa and the Qiangtang blocks. Later on, southern branch of the Neo-Tethys, the Yarlung Tsangbo oceanic basin started to close at the boundary between the late Cretaceous and the early Paleogene and caused the initiation of India-Eurasia continental collision, the real staring point of formation of the Tibetan plateau. The entire process of this collision took about 20 Mys (65-40/45 Ma or so)to be completed, and subsequently transformed into post-collisional time.Obviously, such a huge crustal and lithospheric movement mentioned above, with hundreds of million years in time scale and tens of thousand kilometers in space scale, must have corresponded to a huge mass-energy exchange among various geospheres of the Earth's interior. It was this huge mass-energy exchange that eventually caused the formation of the Qinghai-Tibet plateau and the influence on resources and environments. |
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| Keywords: | Qinghai-Tibet plateau the evolution of the Tethys continental collision interspheric mass-energy exchange the Earth's interior |
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