K. IshizuT. GotoY. OhtaT. KasayaH. IwamotoC. VachiratienchaiW. SiripunvarapornT. TsujiH. KumagaiK. KoikeUniversity of Hyogo, KobeMahidol UniversityKyushu UniversityKyoto UniversityJapan Agency for Marine-Earth Science and TechnologyCurl-E Geophysics Co. Ltd.Commission on Higher EducationNippon Marine Enterprises, Ltd.2020-01-272020-01-272019-10-28Geophysical Research Letters. Vol.46, No.20 (2019), 11025-1103419448007009482762-s2.0-85074540983https://repository.li.mahidol.ac.th/handle/20.500.14594/50751©2019. American Geophysical Union. All Rights Reserved. Although seafloor massive sulfide (SMS) deposits are crucially important metal resources that contain high-grade metals such as copper, lead, and zinc, their internal structures and generation mechanisms remain unclear. This study obtained detailed near-seafloor images of electrical resistivity in a hydrothermal field off Okinawa, southwestern Japan, using deep-towed marine electrical resistivity tomography. The image clarified a semi-layered resistivity structure, interpreted as SMS deposits exposed on the seafloor, and another deep-seated SMS layer at about 40-m depth below the seafloor. The images reinforce our inference of a new mechanism of SMS evolution: Upwelling hydrothermal fluid is trapped under less-permeable cap rock. The deeper embedded SMS accumulates there. Then hydrothermal fluids expelled on the seafloor form exposed SMS deposits.Mahidol UniversityEarth and Planetary SciencesArticleSCOPUS10.1029/2019GL083749