Geophysical implications for the formation of the Tamu Massif-the Earth’s largest single volcano-within the Shatsky Rise in the northwest Pacific Ocean

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• 作者：Jinchang Zhang^a ; ^b ; Jie Chen^c ; ^d ; ^e ; ^{jchen@scsb.gov.cn}
• 关键词：Oceanic plateau ; Large igneous province ; Plume&ndash ; ridge interaction ; Marine geophysics ; Plate tectonics
• 刊名：Science Bulletin
• 出版年：2017
• 出版时间：15 January 2017
• 年：2017
• 卷：62
• 期：1
• 页码：69-80
• 全文大小：5114 K
• 卷排序：62

文摘

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 ∼30 km, 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.