S-wave velocity structureand tectonic implications of the northwestern sub-basin and Macclesfield of theSouth China Sea.
S-wave velocity structureand tectonic implications of the northwestern sub-basin and Macclesfield of theSouth China Sea.
复制标题
南海西北次盆地和麦克尔斯菲尔德横波速度结构及其构造意义.
DOI：
10.1007/s11001-016-9288-x
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Weiwei Ding
中科院分区：
文献类型：
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作者：
Xiaodong Wei;Aiguo Ruan;Jiabiao Li;Xiongwei Niu;Zhenli Wu;Weiwei Ding
基于最佳P波模型，用二维射线追踪方法模拟了横跨西北次盆地(NWSB)和Macclesfield的广角地震剖面(OBS2006-1)的波速结构。结果表明，西北缘上、下地壳的波速分别为3.2~3.6公里/S和3.6~4.0公里/S，波速比分别为1.82~1.88和1.74~1.82，反映了典型的洋壳特征。NWSB上地壳的波速在NNW段略高于SSE段，而Vp/VS比值的横向变化则相反。我们认为，西北缘可能在海底扩张过程中经历了不对称的岩浆流动，这可能模糊了磁异常线理。南海北缘FS波速度对比表明，南海西段与东段不同，西北缘为非火山壳结构。北缘、麦克莱斯菲尔德和芦滩的波结构和P波速度模型表明，麦克莱斯菲尔德可能与芦滩有共轭关系。
Based on the optimumP-wave model, theS-wave velocity structure of a wide angle seismic profile (OBS2006-1), across the northwestern sub-basin (NWSB) and the Macclesfield, is simulated by a 2-D ray-tracing method. The results indicate theS-wave velocities in the upper and lower crust of the NWSB are 3.2–3.6 km/s and 3.6–4.0 km/s, withVp/Vs ratios of 1.82–1.88 and 1.74–1.82, respectively, which reflect typical oceanic crust characteristics. TheS-wave velocity in the upper crust of the NWSB is a little higher in the NNW segment than that in the SSE segment, while the lateral variation ofVp/Vs ratio is in the opposite. We suggest that the NWSB might have experienced asymmetrical magma flows during sea floor spreading, which may have blurred the magnetic anomaly lineation. The comparison ofS-wave velocities along the northern margin of the SCS shows that the west section is different from the east section, and the northwestern margin has a non-volcanic crust structure. TheS-wave structures andP-wave velocity models along the northern margin, Macclesfield and Reed Bank show that the Macclesfield might have a conjugate relationship with the Reed Bank.