| 从高分辨率地震层析成像看青藏高原软流圈的物质运动 |
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| 引用本文： | 杨文采,刘晓宇,陈召曦,江金生.从高分辨率地震层析成像看青藏高原软流圈的物质运动[J].地球科学,2022,47(10):3491-3500. |
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| 作者姓名： | 杨文采 刘晓宇 陈召曦 江金生 |
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| 作者单位： | 1.浙江大学地球科学学院, 浙江杭州 310027 |
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| 基金项目： | 中国地质调查项目12120113093800 |
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| 摘 要： | 通过分辨率达到0.5°×0.5°×10 km的青藏高原地壳与上地幔三维成像，为研究青藏高原在新生代的动力学作用提供了新的认识.软流圈的波速扰动数据证实，特提斯大洋板块在拆沉后只俯冲到410 km的间断面之上，并不是所有的大洋板块都会俯冲到上地幔底部.这种大洋板块在软流圈拆沉后激发的热流体上涌，造成高原中部大规模的火山喷发，是青藏高原隆升的主要动力来源之一.根据上地幔三维地震层析成像结果定量计算了岩石圈-软流圈界面（LAB）的深度，揭示了软流圈地幔物质的上涌或者岩石圈地块下沉的作用布局，表明青藏高原的东部在新生代动力学作用过程中是一个相对独立的岩石圈地幔块体.
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| 关 键 词： | 大陆动力学 青藏高原 软流圈 层析成像 LAB高分辨率 地球物理 |
| 收稿时间： | 2022-06-14 |
Asthenosphere Mass Movement in Qinghai-Tibetan Plateau Revealed by High-Resolution Seismic Tomography |
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| Abstract: | Through the three-dimensional seismic imaging of the upper mantle of the Qinghai-Tibet Plateau with a resolution of 0.5°×0.5°×10 km, it provides a new understanding for the study of the dynamic evolution of the plateau in the Cenozoic Era. The asthenosphere P-wave velocity disturbance data confirm that the Tethys Oceanic Plate only subducted to the 410 km discontinuity after its delamination, proving that not all oceanic plates were subducting to the bottom of the upper mantle. The upwelling of the thermal fluid, excited by this oceanic plate delamination in the asthenosphere and the rupture process of the continental lithosphere, caused a large-scale volcanic eruption in the middle of the plateau, which is one of the main sources of power for the uplift of the Qinghai-Tibet Plateau. According to the results of three-dimensional seismic tomography of the upper mantle, the depth of the lithosphere-asthenosphere boundary (LAB) was quantitatively calculated, revealing the upwelling locations of asthenosphere material and the sinking of lithosphere mass, indicating that the eastern part of the Qinghai-Tibet Plateau is a relatively independent continental lithosphere-mantle block in the regional dynamic process of Cenozoic dynamics. |
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