Zhang Jinchang, Chen Jie
Key Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; Key Laboratory of Marine Mineral Resources, Ministry of Land and Resources, Guangzhou 510075, China.
South China Sea Institute of Planning and Environmental Research, State Oceanic Administration, Guangzhou 510310, China; Key Laboratory for Ecological Environment in Coastal Areas, State Oceanic Administration, Dalian 116023, China; Key Laboratory of Integrated Marine Monitoring and Applied Technologies for Harmful Algal Blooms, State Oceanic Administration, Shanghai 200137, China.
Sci Bull (Beijing). 2017 Jan 15;62(1):69-80. doi: 10.1016/j.scib.2016.11.003. Epub 2016 Nov 22.
Recent geophysical research programs survey the Tamu Massif within the Shatsky Rise oceanic plateau in the northwest Pacific Ocean to understand the formation of this immense volcano and to test the formation hypotheses of large igneous province volcanism. Massive sheet basalt flows are cored from the Tamu Massif, implying voluminous eruptions with high effusion rates. Seismic reflection data show that the Tamu Massif is the largest single volcano on Earth, characterized by a central volcanic shield with low-gradient flank slopes, implying lava flows emanating from its center and spreading massive area on the seafloor. Velocity model calculated from seismic refraction data shows that crustal thickness has a negative correlation with average velocity, implying a chemically anomalous origin of the Tamu Massif. Seismic refraction and reflection data reveal a complete crustal structure across the entire volcano, featured by a deep crust root with a maximum thickness of ∼30km, and Moho geometry is consistent with the Airy Isostasy. These recent findings provide evidence for the two end-member formation models: the mantle plume and the plate boundary. Both are supported by some results, but both are not fit with some either. Consequently, plume-ridge interaction could be a resolution that awaits future investigations.
最近的地球物理研究项目对西北太平洋 Shatsky 海隆大洋高原内的塔木大岩体进行了勘测，以了解这座巨大火山的形成过程，并检验大火成岩省火山作用的形成假说。从塔木大岩体获取了大量席状玄武岩流岩芯，这意味着存在大量高喷发率的火山喷发。地震反射数据显示，塔木大岩体是地球上最大的单体火山，其特征是具有低坡度侧翼斜坡的中央火山盾，这意味着熔岩从其中心流出并在海底大面积蔓延。根据地震折射数据计算出的速度模型表明，地壳厚度与平均速度呈负相关，这意味着塔木大岩体具有化学异常起源。地震折射和反射数据揭示了整个火山完整的地壳结构，其特征是有一个最大厚度约为 30 千米的深部地壳根，莫霍面几何形态与艾里均衡一致。这些最新发现为两种端元形成模型提供了证据：地幔柱模型和板块边界模型。两者都得到了一些结果的支持，但也都与一些结果不符。因此，地幔柱 - 洋中脊相互作用可能是一个有待未来研究的解决方案。
