| 南海海盆三维重力约束反演莫霍面深度及其特征 |
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| 引用本文： | 吴招才, 高金耀, 丁巍伟, 沈中延, 张涛, 杨春国. 2017. 南海海盆三维重力约束反演莫霍面深度及其特征. 地球物理学报, 60(7): 2599-2613, doi: 10.6038/cjg20170709 |
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| 作者姓名： | 吴招才 高金耀 丁巍伟 沈中延 张涛 杨春国 |
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| 作者单位： | 国家海洋局第二海洋研究所, 杭州 310012 |
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| 基金项目： | 国家自然科学基金项目（41676037），海洋二所基本科研业务费专项资金项目（JT1601），"全球变化与海气相互作用"专项（GASI-02-SCS-DWZP1，GASI-GEOGE-05、01），科学技术部科技基础性工作专项（2013FY112900），科技部重大仪器专项"海洋-航空重力仪研制"（2011YQ12004505）资助. |
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| 摘 要： | 利用南海海盆及周边最新的重力，经过海底地形、沉积层的重力效应改正，并采用岩石圈减薄模型的温度场公式，校正了从张裂边缘到扩张海盆的热扰动重力效应.通过研究区的地震剖面和少量声呐数据得到的莫霍面深度点作为约束，采用基于"起伏界面初始模型"的深度修正量反演迭代公式，反演、计算了研究区的莫霍面深度及地壳厚度.结果表明，海盆区莫霍面深度在8~14 km之间，地壳厚度在3~9 km之间；东部海盆和西南海盆残留扩张中心沿NNE向展布向西南延伸至112°E，莫霍面深度超过12 km，地壳厚度在6 km以上，而西北海盆没有明显的增厚扩张中心；在西南海盆北缘的中沙地块南侧，存在一个近EW向地壳减薄带，地壳厚度在9~10 km；莫霍面深度14 km的等深线和地壳厚度9 km的等值线可指示洋陆边界位置.
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| 关 键 词： | 南海海盆 莫霍面深度 已知点控制 热重力异常改正 |
| 收稿时间： | 2016-05-03 |
| 修稿时间： | 2016-06-23 |
Moho depth of the South China Sea basin from three-dimensional gravity inversion with constraint points |
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| WU Zhao-Cai, GAO Jin-Yao, DING Wei-Wei, SHEN Zhong-Yan, ZHANG Tao, YANG Chun-Guo. 2017. Moho depth of the South China Sea basin from three-dimensional gravity inversion with constraint points. Chinese Journal of Geophysics (in Chinese), 60(7): 2599-2613, doi: 10.6038/cjg20170709 |
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| Authors: | WU Zhao-Cai GAO Jin-Yao DING Wei-Wei SHEN Zhong-Yan ZHANG Tao YANG Chun-Guo |
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| Affiliation: | Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China |
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| Abstract: | We calculate the gravity anomalies due to lateral changes in bathymetry from an independent topography compilation and those due to changes in sediment thickness and density. To estimate the Moho depth and the crustal thickness of the South China Sea basin,the 3D gravity inversion method is employed, which is based on the "initial model of fluctuated interface" from the constraint points from seismic data and sonobuoys. And then, the gravity data is corrected by the lithosphere thermal gravity anomalies within the continental margin of thinned lithosphere. Over most of the South China Sea basin, the Moho depth ranges 8~14 km, the crustal thickness is 3~9 km. The NNE trending fossil spreading center of the East and the Southwest subbasins extend to 112°E, the Moho depth is more than 12 km, and the crustal thickness is over 6 km in the spreading center. However, the crust of the spreading center at the northwest basin is not obviously thickened. In the northern margin of the southwest basin, south of Zhongsha block, there is a crustal thinning belt, nearly EW trending, where crustal thickness is about 9~10 km. The 14 km isoline of the Moho depth and the 9 km isoline of the crustal thickness are very close to the continent-ocean boundary (COB), respectively. |
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| Keywords: | South China Sea basin Moho depth Known control points Thermal gravity anomaly correction |
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