Mineralogical and geochemical characterisation of iron-sulfur deposits from the Manus Basin (SW Pacific) sampled during SONNE cruise SO216 in 2011

Abstract

In this dataset, seven inactive massive sulfide chimneys, collected in the Manus Basin (Bismarck Sea, Papua New Guinea, SW Pacific) during SONNE cruise SO216 in 2011, are characterized with respect to mineralogical and geochemical composition as well as age. The samples originate from the PACManus (Snowcap, Fenway, Satanic Mills, Solwara 6, Solwara 8) and SuSu Knolls (North Su) hydrothermal vent fields that emit highly sulfidic fluids and feature poly-metallic sulfide chimneys and mounds. They were collected by the ROV QUEST (Marum Bremen) with the ROV's hydraulic arm. Ore petrology was performed on polished thin sections and shows that the chimneys were mainly composed of chalcopyrite (CuFeS₂), pyrite/marcasite (FeS₂), sphalerite (Zn(Fe)S), and bornite (Cu₅FeS₄) with a suite of other minor to rare minerals. The bulk geochemistry of the samples was determined on representative samples (several tens to hundreds of grams) by a combination of methods including ICP-OES, ICP-MS and Instrumental Neutron Activation. Some samples show elevated As-and Pb-concentrations (up to 3.2 wt.% As; up to 2.0 wt.% Pb), which is also reflected in the presence of tennantite and galena as well as other sulfosalts in thin sections. Five of the seven collected inactive chimney samples were dated using the ²²⁶Ra/Ba method. The youngest, yet clearly inactive sample was StM-R2 (Satanic Mills; 0 y ± 160 y) followed by Fw-R1 (Fenway; 1400 y ± 160 y), Sol8-R1 (Solwara 8; 1800 y ± 160 y) and Sol6-R1 (Solwara 6; 2093 y ± 267 y). The oldest dated chimney was NSu-R7 (North Su; 3183 y ± 236 y). The chimney samples were part of a study, in which 16S rRNA gene based community profiling of active (n=6) and inactive (n=7) sulfide chimneys from the Manus Basin (SW Pacific) was conducted. The diversity information in combination with radiometric dating was used to select a subset of inactive sulfide chimneys of different age for functional analyses on metagenomic (n=4) and metaproteomic (n=1) level

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