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使用冲绳海槽地区地质、地球物理、地球化学数据与资料 ,对横跨大陆边缘—大洋板块的中国东部—冲绳海槽—琉球岛弧地区进行综合研究 .根据地震体波、面波成像结果 ,空间与布格重力异常及磁力异常的综合解释等结果 ,利用调和系数法对该研究区的地壳厚度进行了计算 ,并对地壳属性进行分析 .同时 ,选择中国东部东北地区的宽甸、华北地区的汉诺坝、华南的闵溪和台湾海峡的澎湖列岛与冲绳海槽和日本岛弧的新生代玄武岩开展元素—同位素对比研究 .结果认为冲绳海槽岩石层明显减薄 ,上地幔低速层已达到莫霍面 ,在地幔中已形成交代软流层 .元素—同位素研究表明 :它不同于中国东部 ,与琉球岛弧地区的特点也不相同 .综合分析认为 :冲绳海槽地壳属于过渡型地壳 ,与大洋地壳的许多特点颇为相似
Based on the geologic, geophysical and geochemical data and data of the Okinawa Trough, a comprehensive study of the eastern China-Okinawa Trough-Ryukyu Island arc across the continental margin-oceanic plate has been carried out.According to the results of seismic bulk wave and surface wave imaging, Space and Bouguer gravity anomalies and magnetic anomalies, the crustal thickness of the study area was calculated by using the harmonic coefficient method, and the crustal properties were analyzed.At the same time, Kuandian and North China in the northeast of China Elemental-isotope comparisons of Hannock Dam, Min-Min in South China and Penghu Islands in the Taiwan Strait, and the Cenozoic basalts of the Okinawa Trough and Japan Island arcs.The results show that the lithosphere of the Okinawa Trough is obviously thinned and the upper mantle Reaches the Moho area and has formed an account of the asthenosphere in the mantle.The elemental-isotopic studies show that it is different from the eastern part of China and has the same characteristics as the Ryukyu Island arc area.A comprehensive analysis shows that the Okinawa Trough crust belongs to the transitional crust Much like many features of the oceanic crust