/* DATA DESCRIPTION: Citation: Choi, Sarang; Park, Jung-Woo; Im, Sunghwan; Kim, Wonnyon; Choi, Sun Ki: Whole-Rrock major oxide geochemistry and titrated ferrous iron (Fe2+) dataset of hydrothermally altered serpentinites and metasomatites from the Onnuri Oceanic Core Complex [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.996098 (dataset in review), In: Choi, S et al.: Geochemical, Mineral Chemical, and Petrological Dataset of Serpentinites and Talc-Rich Metasomatites from the Onnuri Oceanic Core Complex, Central Indian Ridge [dataset bundled publication]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.996097 (dataset in review) Abstract: Whole-rock major element concentrations (wt.%), loss on ignition (LOI), and titrated ferrous iron (FeO) measurements were used to establish total iron oxidation states (Fe³⁺/Fe_total). Samples were collected from seafloor detachment surfaces of the Onnuri Oceanic Core Complex, Central Indian Ridge, during the 2019 and 2022 R/V ISABU dredge operations (RD1912, RD1913, RD2208). The aim was to characterize the bulk-rock geochemical transition, hydration states, and chemical redox fluctuations associated with the pervasive replacement of background serpentinites into talc-rich suites. Pulverized rock powders (400 mesh) were analyzed at Actlabs (Canada). Major oxide abundances were determined by lithium metaborate/tetraborate fusion followed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), whereas ferrous iron (FeO) contents were independently quantified using cold acid digestion (V₂O₅-HF) and subsequent potassium dichromate colorimetric titration. Keyword(s): Bulk-rock geochemistry; Ferrous iron titration; ICP-OES; Iron oxidation state; Major oxides; Metasomatic zonation; Redox baseline Coverage: MEDIAN LATITUDE: -11.420718 * MEDIAN LONGITUDE: 66.401321 * SOUTH-BOUND LATITUDE: -11.428260 * WEST-BOUND LONGITUDE: 66.378405 * NORTH-BOUND LATITUDE: -11.413095 * EAST-BOUND LONGITUDE: 66.421243 MINIMUM DEPTH, sediment/rock: 0 m * MAXIMUM DEPTH, sediment/rock: 0 m Event(s): RD1912_DREG * LATITUDE START: -11.413095 * LONGITUDE START: 66.418228 * LATITUDE END: -11.414573 * LONGITUDE END: 66.421243 * ELEVATION START: -2162.0 m * ELEVATION END: -2045.0 m * METHOD/DEVICE: Dredge (DRG) * COMMENT: Geomorphology: Detachment fault surface. Lithology: Diabase, Gabbro, Serpentinite RD1913_DREG * LATITUDE START: -11.428260 * LONGITUDE START: 66.378405 * LATITUDE END: -11.426827 * LONGITUDE END: 66.381727 * ELEVATION START: -3133.0 m * ELEVATION END: -2984.0 m * METHOD/DEVICE: Dredge (DRG) * COMMENT: Geomorphology: Detachment fault surface. Lithology: Serpentinite RD2208_DREG * LATITUDE: -11.420833 * LONGITUDE: 66.407000 * ELEVATION: -2160.0 m * METHOD/DEVICE: Dredge (DRG) * COMMENT: Geomorphology: Detachment fault surface. Lithology: Diabase, Serpentinite, Talc-rich metasomatite, Breccia Parameter(s): Event label (Event) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) DEPTH, sediment/rock [m] (Depth sed) * GEOCODE * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) Lithology/composition/facies (Lithology) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) Sample number (Sample no) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) Silicon dioxide [%] (SiO2) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * METHOD/DEVICE: ICP-OES, Inductively coupled plasma - optical emission spectrometry * COMMENT: wt. % Aluminium oxide [%] (Al2O3) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * METHOD/DEVICE: ICP-OES, Inductively coupled plasma - optical emission spectrometry * COMMENT: wt. % Iron oxide, Fe2O3 [%] (Fe2O3) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * METHOD/DEVICE: ICP-OES, Inductively coupled plasma - optical emission spectrometry * COMMENT: wt. %, total Titanium dioxide [%] (TiO2) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * METHOD/DEVICE: ICP-OES, Inductively coupled plasma - optical emission spectrometry * COMMENT: wt. % Magnesium oxide [%] (MgO) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * METHOD/DEVICE: ICP-OES, Inductively coupled plasma - optical emission spectrometry * COMMENT: wt. % Calcium oxide [%] (CaO) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * METHOD/DEVICE: ICP-OES, Inductively coupled plasma - optical emission spectrometry * COMMENT: wt. % Sodium oxide [%] (Na2O) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * METHOD/DEVICE: ICP-OES, Inductively coupled plasma - optical emission spectrometry * COMMENT: wt. % Potassium oxide [%] (K2O) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * METHOD/DEVICE: ICP-OES, Inductively coupled plasma - optical emission spectrometry * COMMENT: wt. % Manganese oxide [%] (MnO) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * METHOD/DEVICE: ICP-OES, Inductively coupled plasma - optical emission spectrometry * COMMENT: wt. % Phosphorus pentoxide [%] (P2O5) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * METHOD/DEVICE: ICP-OES, Inductively coupled plasma - optical emission spectrometry * COMMENT: wt. % Loss on ignition [%] (LOI) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * COMMENT: wt. % Total [%] (Total) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * COMMENT: wt. % Iron 2+ oxidation state (OS FeO) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) Iron 3+ oxidation state (OS Fe2O3) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) Iron 3+/Iron total (Fe3+/Fetotal) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) Magnetite [%] (Fe3O4) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * COMMENT: wt. %, iron partitioning between magnetite and silicate minerals Ratio (Ratio) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * COMMENT: bulk rock Fesilicate/Fetotal; iron partitioning between magnetite and silicate minerals Ratio (Ratio) * PI: Choi, Sarang (https://orcid.org/0000-0003-4942-8625, csr7824@gmail.com) * COMMENT: bulk rock silicate Fe3+/Fetotal; iron partitioning between magnetite and silicate minerals License: Creative Commons Attribution 4.0 International (CC-BY-4.0) (URI: https://creativecommons.org/licenses/by/4.0/) (License comes into effect after moratorium ends) Status: Curation Level: Enhanced curation (URI: https://wiki.pangaea.de/wiki/Curation_levels) Size: 280 data points */ Event Depth sed [m] Lithology Sample no SiO2 [%] (wt. %) Al2O3 [%] (wt. %) Fe2O3 [%] (wt. %, total) TiO2 [%] (wt. %) MgO [%] (wt. %) CaO [%] (wt. %) Na2O [%] (wt. %) K2O [%] (wt. %) MnO [%] (wt. %) P2O5 [%] (wt. %) LOI [%] (wt. %) Total [%] (wt. %) OS FeO OS Fe2O3 Fe3+/Fetotal Fe3O4 [%] (wt. %, iron partitioning betw...) Ratio (bulk rock Fesilicate/Fetotal;...) Ratio (bulk rock silicate Fe3+/Fetot...) RD1912_DREG 0 Serpentinite RD1912-04 40.18 0.88 7.63 0.01 38.41 0.06 0.09 0.01 0.08 <0.01 12.76 99.81 2.7 4.63 0.61 2.75 0.63 0.57 RD1912_DREG 0 Serpentinite RD1912-12 40.80 1.09 8.12 0.02 37.49 0.40 0.08 0.02 0.09 <0.01 11.95 99.68 3.3 4.45 0.55 3.10 0.61 0.47 RD1912_DREG 0 Serpentinite RD1912-13 38.23 1.15 7.76 0.02 37.71 0.77 0.09 0.01 0.09 <0.01 12.17 97.67 3.1 4.32 0.56 3.58 0.52 0.46 RD1912_DREG 0 Serpentinite RD1912-16 38.79 1.69 8.14 0.03 37.16 0.29 0.10 0.04 0.10 <0.01 13.77 99.81 2.7 5.14 0.63 3.30 0.58 0.61 RD1913_DREG 0 Serpentinite RD1913-02 41.51 1.61 7.49 0.04 37.00 1.19 0.19 0.04 0.09 <0.01 10.96 99.80 2.9 4.27 0.57 2.82 0.61 0.51 RD2208_DREG 0 Serpentinite RD2208-10 38.64 0.92 7.39 0.01 39.85 0.09 0.08 0.01 0.09 0.03 13.64 100.80 1.5 5.72 0.77 4.94 0.31 1.00 RD2208_DREG 0 Serpentinite RD2208-11 40.54 1.56 7.04 0.03 37.14 0.72 0.15 0.03 0.08 0.02 11.71 99.01 3.4 3.26 0.46 2.65 0.61 0.33 RD2208_DREG 0 Serpentinite RD2208-39 38.25 0.76 7.74 0.02 38.95 0.04 0.12 0.01 0.06 0.04 14.38 100.40 1.5 6.07 0.78 4.31 0.42 0.95 RD1913_DREG 0 Talc-serpentinite RD1913-01 44.67 0.77 7.21 0.01 35.79 0.22 0.11 0.02 0.08 <0.01 11.06 99.58 3.2 3.65 0.51 0.88 0.87 0.48 RD2208_DREG 0 Talc-rich metasomatite RD2208-04 57.25 1.38 6.28 0.03 26.31 2.17 0.22 0.02 0.06 0.02 5.25 98.99 4.7 1.06 0.17 0.02 1.00 0.17 RD2208_DREG 0 Talc-rich metasomatite RD2208-12 54.34 2.41 7.31 0.04 28.50 2.23 0.24 0.02 0.08 <0.01 5.79 101.00 5.5 1.20 0.16 0.02 1.00 0.16 RD2208_DREG 0 Talc-rich metasomatite RD2208-13 57.89 1.39 5.38 0.02 28.48 0.57 0.22 0.02 0.05 0.02 5.81 99.86 2.6 2.49 0.46 0.64 0.88 0.43 RD2208_DREG 0 Talc-rich metasomatite RD2208-38 57.17 1.65 6.87 0.02 26.89 1.06 0.22 0.02 0.06 0.02 5.86 99.85 4.7 1.65 0.24 0.05 0.99 0.24 RD2208_DREG 0 Talc-rich metasomatite RD2208-43 57.01 1.71 7.24 0.03 26.58 0.53 0.22 0.02 0.06 0.03 5.74 99.18 5.6 1.02 0.14 0.16 0.98 0.13