This dataset includes the whole-rock and mineral chemistry, Sr–Nd–Pb isotopic ratios, and petrography of basaltic, doleritic, and gabbroic xenoliths in a petit-spot volcano on the northwestern Pacific Plate. It provides geochemical and isotopic data that characterize the deeper lithologies of in situ old oceanic crust, offering insights into its formation at the fast-spreading Izanagi–Pacific Ridge (130–140 Ma) and subsequent evolution. This dataset is linked to Mikuni et al. (2025) Marine Geology.

This dataset includes the major and trace element compositions and Sr, Nd and Pb isotopic compositions of the bulk-rock basalt samples (42 samples). Basalt samples were collected from the Central Indian Ridge at 14°30’S (segment 18). Measurements were performed via an X-ray fluorescence spectrometer (Primus II, Rigaku, Tokyo, Japan; for major elements), an inductively coupled plasma mass spectrometer (iCAP-Q, Thermo Fisher Scientific, Bremen, Germany; for trace elements), a thermal-ionization mass spectrometer (TRITON plus, Thermo Fisher Scientific; for Sr and Nd isotopes), and a multicollector inductively coupled plasma mass spectrometer (NEPTUNE plus, Thermo Fisher Scientific; for Pb isotopes).

In this study, we examined marine carbonate sediments of the late Paleocene to middle Eocene interval from the ODP Hole 762C, located on the Exmouth Plateau in the mid-latitude eastern Indian Ocean. This new dataset includes bulk carbonate δ13C and δ18O records, as well as bulk chemical composition of the sediments. By combining δ13C data with previously published magneto-biostratigraphic records, we revised the age model based on the newly identified hyperthermal event layers.Description of files:Supporting Table S3 : Bulk δ13C and δ18O data of ODP Hole 762C.Supporting Table S4 : Major and trace element data of ODP Hole 762C

In this study, we examined marine carbonate sediments of the late Paleocene to middle Eocene interval from the ODP Hole 762C, located on the Exmouth Plateau in the mid-latitude eastern Indian Ocean. This new dataset includes bulk carbonate δ13C and δ18O records, as well as bulk chemical composition of the sediments. By combining δ13C data with previously published magneto-biostratigraphic records, we revised the age model based on the newly identified hyperthermal event layers.Description of files:Supporting Table S3 : Bulk δ13C and δ18O data of ODP Hole 762C.Supporting Table S4 : Major and trace element data of ODP Hole 762C

This dataset includes the 40Ar/39Ar ages, major and trace element compositions, and Sr, Nd, and Pb isotopic ratios of the petit-spot basalts in the western Pacific region. The results of a mass balance-based melting model are also provided. These results 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 Hawaiian North Arch and Samoan petit-spot-like rejuvenated volcanoes, that have similar trace element composition to petit-spot basalts. This dataset is updated version of that previously published.

This dataset includes the 40Ar/39Ar ages, major and trace element compositions, and Sr, Nd, and Pb isotopic ratios of the petit-spot basalts in the western Pacific region. The results of a mass balance-based melting model are also provided. These results 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 Hawaiian North Arch and Samoan petit-spot-like rejuvenated volcanoes, that have similar trace element composition to petit-spot basalts.

Chemical and mineral compositions of volcanic rock, hydrothermal ferromanganese oxide and sandstone from the Daini-Nishi-Yamato Seamount in the Sea of Japan. The samples were obtained by a dredge operation during the KT85-15 cruise. The chemical compostion of the samples were measured by using ICP-MS and XRF. The mineral compostion of the samples were analyzed by using powder XRD.

Chemical and mineral compositions of volcanic rock, hydrothermal ferromanganese oxide and sandstone from the Daini-Nishi-Yamato Seamount in the Sea of Japan. The samples were obtained by a dredge operation during the KT85-15 cruise. The chemical compostion of the samples were measured by using ICP-MS and XRF. The mineral compostion of the samples were analyzed by using powder XRD.

A compilation of bulk chemical composition data of pelagic clay around Minamitorishima Island in the western North Pacific Ocean. Original data were published in the cited articles (shown in Data source column). This is a supplementary dataset for "High-dimensional chemostratigraphy of pelagic clay in western North Pacific Ocean revealed via unsupervised clustering approach" by Yasukawa et al.

A compilation of bulk chemical composition data of pelagic clay around Minamitorishima Island in the western North Pacific Ocean. Original data were published in the cited articles (shown in Data source column). This is a supplementary dataset for "High-dimensional chemostratigraphy of pelagic clay in western North Pacific Ocean revealed via unsupervised clustering approach" by Yasukawa et al.