| 青藏高原的核心来自南半球冈瓦纳大陆 |
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| 引用本文： | 丁林,李震宇,宋培平.青藏高原的核心来自南半球冈瓦纳大陆[J].中国科学院院刊,2017,32(9):945-950. |
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| 作者姓名： | 丁林 李震宇 宋培平 |
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| 作者单位： | 中国科学院青藏高原研究所 大陆碰撞与高原隆升重点实验室 北京 100101;中国科学院青藏高原地球科学卓越创新中心 北京 100101,中国科学院青藏高原研究所 大陆碰撞与高原隆升重点实验室 北京 100101,中国科学院青藏高原研究所 大陆碰撞与高原隆升重点实验室 北京 100101 |
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| 基金项目： | 中国科技部深地专项（2016YFC0600303）,国家自然科学基金（41490615、41472185）,中科院战略性先导科技专项（B类）（XDB03010401）,中国博士后基金（2017M611016） |
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| 摘 要： | 羌塘与拉萨地块处于青藏高原的核心位置。青藏高原北羌塘及拉萨地块的年代学及古地磁学研究表明,北羌塘地块在距今约3亿年前位于南半球(21.9o±4.7oS)冈瓦纳大陆附近,因而不支持北羌塘地块来自北方劳亚大陆。北羌塘随后开始其持续的北向漂移过程,在约2.1亿年前到达当前纬度位置(34oN),形象地表明其是一只"冈瓦纳大陆的早飞鸟"。拉萨地块从冈瓦纳大陆裂离后的漂移演化史则与北羌塘地块差别明显。自晚古生代—中生代(石炭纪—三叠纪)拉萨地块从冈瓦纳大陆北缘裂离后,其运动学演化过程更显得"犹豫不决"。最新的古地磁研究表明拉萨地块自冈瓦纳大陆裂离后并未显示出明显的快速北向漂移趋势,而是呈现出较为慢速的漂移,直到距今约1.8亿年前(早侏罗世)到达位于南半球赤道附近(3.7o±3.4oS),随后与北面的羌塘地块在晚侏罗世首先从东部发生碰撞,随后于早白垩世时期两个地块完成拼贴。之后的印度次大陆快速向北漂移并在早新生代(距今6 500万年前)发生印度-亚洲大陆碰撞,继而对新生代时期欧亚大陆地形地貌格局产生了深远影响。
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| 关 键 词： | 北羌塘地块 拉萨地块 冈瓦纳大陆 劳亚大陆 漂移历史 |
| 修稿时间： | 2017/9/13 0:00:00 |
Core Fragments of Tibetan Plateau from Gondwanaland United in Northern Hemisphere |
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| Ding Lin,Li Zhenyu and Song Peiping.Core Fragments of Tibetan Plateau from Gondwanaland United in Northern Hemisphere[J].Bulletin of the Chinese Academy of Sciences,2017,32(9):945-950. |
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| Authors: | Ding Lin Li Zhenyu and Song Peiping |
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| Institution: | Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China;Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China,Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China and Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China |
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| Abstract: | Paleomagnetic and geochronological studies conducted in the North Qiangtang and Lhasa blocks indicate firstly, the North Qiangtang block was situated in the latitudinal band of 21.9°±4.7°S in southern hemisphere 297 Ma ago, ruling out the long-lasting working hypothesis on the North Qiangtang block of its Laurasian origin, and secondly, attest North Qiangtang''s Gondwana origin much earlier and subsequently started its northward drifting journey after rifted from northern margin of the Gondwanaland. The North Qiangtang block reached its present latitude some 210 Ma ago. Thus, the North Qiangtang block can be vividly viewed as "an early bird of the Gondwana" in this context. While northward drifting history of the Lhasa block is quite different from the North Qiangtang block''s. Conversely, "wandering back and forth" featured the Lhasa block since its rift from Gondwanaland during Late Paleozoic-Early Mesozoic. Subsequently, the Lhasa block drifted northward slowly since its rift instead of "fast moving" trend as it did for the North Qiangtang block. The Lhasa block reached 3.7°S in the southern hemisphere at~180 Ma (Early Jurassic), indicating its low-latitude presence around the equator then, and firstly collided with the Qiangtang block to the north in both eastern ends of two blocks during Late Jurassic. The suturing process was finished yet by Early Cretaceous. Clearly as we all know, the Indian subcontinent started its fast moving track since Early Jurassic and collided with the Eurasia at~65 Ma (Early Paleocene), this still ongoing convergence between the India and Eurasia has re-shaped the topography and landscape occurred not only in Asia, but also in Europe. |
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| Keywords: | North Qiangtang block Lhasa block Gondwanaland Laurasia drifting history |
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