Contribution of carbonatite and recycled oceanic crust to petit-spot lavas on the western Pacific Plate
K. Mikuni,
K. Mikuni,
N. Hirano,
N. Hirano,
S. Machida,
H. Sumino,
N. Akizawa,
A. Tamura,
T. Morishita,
Y. Kato,
Y. Kato,
Y. Kato
Affiliations
K. Mikuni
AIST, Geological Survey of Japan, Research Institute of Geology and Geoinformation, Central 7, 1-1-1, Higashi, Tsukuba, Ibaraki, 305-8567, Japan
K. Mikuni
Graduate School of Science, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan
N. Hirano
Graduate School of Science, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan
N. Hirano
Center for Northeast Asian Studies, Tohoku University, 41 Kawauchi, Aoba-ku, Sendai, 980-8576, Japan
S. Machida
Ocean Resources Research Center for Next Generation, Chiba Institution of Technology, 2-17-1 Tsudanuma, Narashino, 275-0016, Japan
H. Sumino
Research Center for Advanced Science and Technology, the University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
N. Akizawa
Atmosphere and Ocean Research Institute, the University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8564, Japan
A. Tamura
Earth Science Course, Kanazawa University, Kakuma, Kanazawa, 920-1192, Japan
T. Morishita
Earth Science Course, Kanazawa University, Kakuma, Kanazawa, 920-1192, Japan
Y. Kato
Ocean Resources Research Center for Next Generation, Chiba Institution of Technology, 2-17-1 Tsudanuma, Narashino, 275-0016, Japan
Y. Kato
Department of Systems Innovation, School of Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
Y. Kato
Submarine Resources Research Center, Research Institute for Marine Resources Utilization, Japan Agency for Marine–Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan
Petit-spot volcanoes, occurring due to plate flexure, have been reported globally. As the petit-spot melts ascend from the asthenosphere, they provide crucial information of the lithosphere–asthenosphere boundary. Herein, we examined the lava outcrops of six monogenetic volcanoes formed by petit-spot volcanism in the western Pacific. We then analyzed the 40Ar/39Ar ages, major and trace element compositions, and Sr, Nd, and Pb isotopic ratios of the petit-spot basalts. The 40Ar/39Ar ages of two monogenetic volcanoes were ca. 2.6 Ma (million years ago) and ca. 0 Ma. The isotopic compositions of the western Pacific petit-spot basalts suggest geochemically similar melting sources. They were likely derived from a mixture of high-μ (HIMU) mantle-like and enriched mantle (EM)-1-like components related to carbonatitic/carbonated materials and recycled crustal components. The characteristic trace element composition (i.e., Zr, Hf, and Ti depletions) of the western Pacific petit-spot magmas could be explained by the partial melting of ∼ 5 % crust bearing garnet lherzolite, with 10 % carbonatite flux to a given mass of the source, as implied by a mass-balance-based melting model. This result confirms the involvement of carbonatite melt and recycled crust in the source of petit-spot melts. It provides insights into the genesis of tectonic-induced volcanoes, including the Hawaiian North Arch and Samoan petit-spot-like rejuvenated volcanoes that have a similar trace element composition to petit-spot basalts.
