Description: This dataset contains the rawdata of a microthermometric study of fluid inclusions in hydrothermal precipitates and 87Sr/86Sr composition of their host sulfate minerals. The samples were recovered at Brothers volcano, originate from the NW Caldera and the Upper Caldera vent sites and were retrieved during RV Sonne cruise SO253 in December 2016/January 2017 and during RV Thompson cruise TN350 in March 2018. The fluid inclusion dataset contains 〉400 measurements of ice melting temperatures, 〉340 measurements of homogenization temperatures and includes a detailed descriptions of the measured fluid inclusions. The 87Sr/86Sr dataset contains Thermal Ionization Mass Spectrometry (TIMS) measurments of 5 single crystal and 6 bulk samples of the fluid inclusion (sulfate) samples or material taken in direct adjacency.

Description: Calculated end-member compositions of hydrothermal fluids (for samples that have at least ≥ 85 % end-member) from Haungaroa, Brothers Upper Caldera and NW Caldera Wall, Kermadec intraoceanic arc. Ambient background seawater concentrations are given for comparison.

Description: Rare Earth Element and yttrium (REY) concentrations measured with ICP-MS in hydrothermal fluids from the Kermadec intraoceanic arc. Seawater from 1000 m water depth, values for SW are * 100 (SW data from Alibo and Nozaki (1999; doi:10.1016/S0016-7037(98)00279-8)).

Description: Comparison of Brothers hydrothermal fluid composition collected by de Ronde et al. (2011; doi:10.1007/s00126-011-0345-8) with data collected during this study. In this study, only samples taken with IGT and Major samplers with end-member concentrations greater than 50% are shown. The three samples from the Upper Caldera Site are not included within this data set.

Description: Overview of all fluid samples collected during SO253 along the Kermadec intraoceanic arc together with parameters that were analyzed directly onboard.Fe were determined by a visual Fe CHEMets© field kit.

Description: Major, minor and trace element concentrations measured with ICP-OES, ICP-MS and data for SO42- in hydrothermal fluids from the Kermadec intraoceanic arc.

Description: This dataset provides the rawdata of an extensive microthermometric study of fluid inclusions in hydrothermal precipitates recovered at Brothers volcano. Samples originate from the NW Caldera and the Upper Caldera vent sites and were retrieved during RV Sonne cruise SO253 in December 2016/January 2017 and during RV Thompson cruise TN350 in March 2018. The dataset contains 〉400 single measurements of ice melting temperatures, 〉340 measurements of homogenization temperatures and includes a detailed descriptions of the measured fluid inclusions.

Description: This dataset provides 87Sr/86Sr in hydrothermal precipitates recovered at the Brothers volcano. Samples originate from the NW Caldera and the Upper Caldera vent sites and were retrieved during RV Sonne cruise SO253 in December 2016/January 2017 and during RV Thompson cruise TN350 in March 2018. All samples were analyzed using Thermal Ionization Mass Spectrometry (TIMS). The dataset contains measurements of 87Sr/86Sr in single crystals of anhydrite or barite and measurements of 87Sr/86Sr in sulfate bulk samples composing of anhydrite and/or barite.

Description: Little is known about the effects that subducting an oceanic large igneous province (LIP) has on the petrogenesis of submarine arc volcanoes and their geochemical composition. The southern Kermadec arc represents a rare example where an LIP—the Hikurangi Plateau—is currently subducting and where its effect on mantle composition, element recycling and arc volcanism can be studied. We present mineral chemistry and whole-rock major and trace element, and Sr–Nd–Pb isotope data from samples recovered from the southern Kermadec arc volcanoes Rumble II East and Rumble II West, together with shipboard gravity and magnetic measurements. The Rumble II volcanoes (including a volcanic cone ∼10 km further west) form an ∼23 km long arc–backarc transect located ∼250 km north of New Zealand above the subducting Hikurangi Plateau. Although only a short distance apart, rocks from the two volcanoes have different mineral and whole-rock geochemical compositions. Lavas from Rumble II East are predominantly basaltic and contain primitive olivine phenocrysts (≤Fo91), high-Mg# clinopyroxene (≤96) and anorthitic plagioclase (≤An97). Geochemically these lavas are very diverse and cover a spectrum from low Th/Yb (〈0·15) at high Ba/Th (〉1014) to higher Th/Yb (〉0·15) at lower Ba/Th (〈844). This spectrum, together with 206Pb/204Pb and 143Nd/144Nd in the range of 18·74–18·83 and 0·51309–0·51298 respectively (at similar to slightly elevated 87Sr/86Sr), suggests a mantle wedge that has undergone previous melt extraction and significant fluid addition from the subducting Pacific Plate and that contains sediment and HIMU-type Hikurangi Plateau components. The geochemistry of the sediment–HIMU-type components is exemplified in an olivine pyroxenite (e.g. 206Pb/204Pb = 20·02; 87Sr/86Sr = 0·70516; 143Nd/144Nd = 0·5126). We propose that the olivine pyroxenite formed through melt or fluid–rock metasomatism and represents the first direct evidence of a near Moho arc mantle rock that shows the imprint from a subducting HIMU-type (Hikurangi) seamount. Conversely, lavas from Rumble II West and the cone ∼10 km to the west are generally more silica rich than Rumble II East lavas and mainly contain plagioclase with less ortho- and clinopyroxene + olivine phenocrysts. The low Ba/Th (〈470) and 206Pb/204Pb (〈18·74), a range of 143Nd/144Nd (0·51297–0·51307) and elevated Th/Yb (0·13–0·39) in these lavas can best be explained by minor sediment input into a less depleted mantle wedge. In addition, the geochemical composition of the Rumble II West lavas does not require involvement of a Hikurangi component, placing a spatial limit on Hikurangi material influencing regional melt generation beneath the backarc. Supported by a gravity model requiring two distinct magma chambers, the different geochemical compositions of Rumble II East and West lavas are inconsistent with a shared magma plumbing system. The different geochemical compositions of lavas from the two Rumble II volcanoes furthermore demonstrate that across-arc geochemical heterogeneities can occur within a few kilometres and may originate from both a geochemically heterogeneous mantle wedge and Moho transition layer, recording inherited geochemical heterogeneities beneath the volcanoes.