Trace element and helium isotope geochemistry of the Cenozoic intraplate volcanism in the East Sea (Sea of Japan): implications for lithosphere-asthenosphere interaction

Lee, W., Lee, H., Kim, D., Kim, J., Oh, J., Song, J.-H., Kim, C. H., Park, C. H. and Stuart, F. M. (2021) Trace element and helium isotope geochemistry of the Cenozoic intraplate volcanism in the East Sea (Sea of Japan): implications for lithosphere-asthenosphere interaction. Lithos, 388-89, 106075. (doi: 10.1016/j.lithos.2021.106075)

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Abstract

Extensive intraplate volcanism in the East Asia regions, including Dokdo and Ulleungdo (DU), occurred due to the extensional stress field during the Cenozoic era. However, the origin of magmatism is still controversial. Here we report new results of helium isotopes in olivine and clinopyroxene phenocrysts as well as major and trace element compositions from the DU basalts in order to determine the origin of the DU magmas and provide insights into Cenozoic mantle dynamics in East Asia. The DU volcanic islands were formed by magmatism after opening of the East Sea (Sea of Japan), a back-arc basin behind the Japanese arc, and are currently located in the Ulleung basin, one of sub-basins of the East Sea. The 3He/4He ratios range from 5.7 to 5.9 Ra for Dokdo and 4.5 to 6.0 Ra for Ulleungdo, respectively, similar to the sub-continental lithospheric mantle (SCLM) range of East Asia (4.6 to 7.7 Ra). Helium isotope compositions indicate that the depleted asthenosphere or the lower mantle plume might not be the direct source of the DU magmas. Also, there is no geochemical evidence that the DU magmas were influenced by subduction-derived components or the HIMU mantle source. Hence, we argue that SCLM provided enriched geochemical features in the DU basalts, contrary to basalts from other back-arc basins composed of the oceanic crust. In this respect, it is likely that the extended SCLM may still remain beneath the Ulleung basin. Our helium isotope and trace element mixing model shows the mixing trend between the metasomatized lithospheric melts and the asthenospheric melts. In addition, the presence of the low-velocity zone beneath the surface of the DU volcanoes in seismic tomography implies that the magmas were formed through the lithospheric melting due to the hot asthenospheric upwelling. Therefore, our study shows that the DU volcanism was mainly contributed by SCLM and that the lithosphere-asthenosphere interaction was the main mechanism that led to the Cenozoic magmatism in East Asia.

Item Type:Articles
Additional Information:This study was supported by the Ministry of Oceans and Fisheries, Korea—Sustainable Research and Development of Dokdo (PG51650) and the National Research Foundation of Korea (NRF-2019R1G1A1002297).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Stuart, Professor Fin
Authors: Lee, W., Lee, H., Kim, D., Kim, J., Oh, J., Song, J.-H., Kim, C. H., Park, C. H., and Stuart, F. M.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Lithos
Publisher:Elsevier
ISSN:0024-4937
ISSN (Online):1872-6143
Published Online:03 March 2021
Copyright Holders:Copyright © 2021 Elsevier B.V.
First Published:First published in Lithos 388-389: 106075
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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