JpGU-AGU Joint Meeting 2020

Session information

[E] Poster

S (Solid Earth Sciences ) » S-CG Complex & General

[S-CG64] Crust-mantle connections

convener:Yoshihiko Tamura(Research Institute for Marine Geodynamics, Japan Agency for Maine-Earth Science and Technology), Osamu Ishizuka(Geological Survey of Japan, AIST)

The western portion of the Pacific Plate, the oldest oceanic plate in the world, has been drilled several times and, based on Ocean Drilling Program (ODP) Site 801, an understanding of its layers, from pelagic clay through chert to alkali basalts and tholeiitic mid-ocean ridge basalts (MORB), has been established. This oldest oceanic plate is experiencing a renaissance and we propose a strategy to drill the most suitable three sites to recover specific parts of the plate to continue its renaissance. This submitted IODP preproposal is entitled The Renaissance of the Oldest Oceanic Plate: REY (Rare Earth elements and Yttrium) rich Mud, Radiolarite of Jurassic-Cretaceous Boundary (JKB), and Jurassic Oceanic Crust without Moho. The drilling sites, MM, MAT, and MINA, target (1) the most complete sedimentary sequence of pelagic clay including REY-rich mud, (2) newly found outcrops of the Jurassic-Cretaceous boundary (JKB), and (3) MORB tholeiites without Moho, respectively. This session invite scientists who are interested in these exciting drillings.
It is common knowledge that the Moho is the boundary between the crust and the Earths mantle, discovered by and named after the Croatian seismologist Andrija Mohorovicic. The oceanic Moho is defined by seismic reflection images, but seismic profiles generally show that Moho reflections are not universal. Where the Moho can be detected clearly the crust is thicker. A good example is the profile from Kaneda et al. (2010) near Minami-Tori Shima, which is the main motivation for drilling at Site MINA. The session also seeks to explore the crust-mantle connections among ophiolites, at divergent and convergent plate boundaries and ocean island settings based on petrology, geochemistry, geophysics, geochronology, and geodynamics studies.

*Morihisa Hamada1, Hikaru Iwamori1,2,3, Philipp A. Brandl4, Takayuki Ushikubo1, Kenji Shimizu1, Motoo Ito1, He Li5, Ivan P. Savov6 (1.Japan Agency for Marine-Earth Science and Technology, 2.Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 3.Earthquake Research Institute, University of Tokyo, 4.GEOMAR Helmholtz Centre for Ocean Research Kiel, 5.Institute of Oceanology, Chinese Academy of Sciences, 6.School of Earth and Environment, University of Leeds)

*Takashi Miyazaki1, J B Gill2, C Hamelin3, S M DeBari4, Tomoki Sato1, Yoshihiko Tamura1, Jun-Ichi Kimura1, Bogdan Stefanov Vaglarov1, Qing Chang1, Ryoko Senda5, Satoru Haraguchi6 (1.Research Institute for Marine Geodynamics, Japan Agency for Marine-Earth Science and Technology, 2.University of California, Santa Cruz, 3.University of Bergen, 4.Western Washington University, 5.Kyushu University, 6.University of Tokyo)

Tomoki Sato1, Takashi Miyazaki1, *Yoshihiko Tamura1, James B Gill2, Martin Jutzeler3, Ryoko Senda4, Jun-Ichi Kimura1 (1.Research Institute for Marine Geodynamics, Japan Agency for Maine-Earth Science and Technology, 2.Department of Earth and Planetary Science, University of California Santa Cruz, Santa Cruz, California, USA, 3.School of Natural Sciences and Centre for Ore Deposit and Earth Sciences, University of Tasmania, Tasmania, Australia, 4.Faculty of Social and Cultural Studies, Kyushu University, Fukuoka, Japan)