Testing the Ontong Java Nui Hypothesis: The Largest Supervolcano Ever on Earth

Large Igneous Provinces (LIPs), such as the Ontong Java Plateau (OJP) in the western equatorial Pacific, provide information on mantle processes and composition, and their formation may have global environmental consequences. The OJP is the largest oceanic plateau and is probably the most voluminous igneous edifice on Earth. Despite its importance, the size, volume, and formation rate of the OJP are not yet well constrained. The maximum extent of OJP-related volcanism may be even greater than currently estimated, because volcanological studies indicate that long lava flows (or sills) from the OJP may have reached the adjacent Nauru, East Mariana, and possibly Pigafetta basins. Moreover, the similarity in age and some geochemistry of lavas from the Ontong Java, Hikurangi, and Manihiki plateaus suggests that they once may have been part of a single LIP (Ontong Java Nui, OJN). If true, the massive volcanism may have covered * 国立科学博物館地学研究部 ** 海洋研究開発機構海域地震火山部門火山・地球内部研究センター *** 千葉大学大学院理学研究院 **** 海洋研究開発機構海域地震火山部門地震発生帯研究センター ***** 東京工業大学地球惑星科学系 ****** 海洋研究開発機構超先鋭研究開発部門高知コア研究所 ******* 千葉大学大学院融合理工学府 * Department of Geology and Paleontology, National Museum of Nature and Science, Tsukuba, 305-0005, Japan ** Volcanoes and Earth’s Interior Research Center (VERC), Research Institute for Marine Geodynamics (IMG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, 237-0061, Japan *** Graduate School of Science, Chiba University, Chiba 263-8522, Japan **** Subduction Dynamics Research Center (SDR), Research Institute for Marine Geodynamics (IMG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, 236-0001, Japan ***** Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan ****** Kochi Institute for Core Sample Research, Institute for Extra-cutting-edge Science and Technology Avant-garde Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Nankoku, 783-8502, Japan ******* Graduate School of Science and Engineering, Chiba University, Chiba, 263-8522, Japan 地学雑誌 Journal of Geography(Chigaku Zasshi) 130(4)559­584 2021 doi:10.5026/jgeography.130.559