de.pangaea.dataset666862 und dataset PANGAEA

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https://www.pangaea.de/ information pointOfContact 2026-05-01T05:00:49Z https://doi.pangaea.de/10.1594/PANGAEA.666862 2003-01-01 publication https://doi.org/10.1594/PANGAEA.666862 Bach, Wolfgang

wbach@uni-bremen.de

https://orcid.org/0000-0002-3099-7142 information author Roberts, Stephen author Vanko, David A author Binns, Raymond A author Yeats, Chris J author Craddock, Paul R https://orcid.org/0000-0003-4702-0204 information author Humphris, Susan E author PANGAEA

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https://www.pangaea.de/ information publisher tableDigital Supplement to: Bach, Wolfgang; Roberts, Stephen; Vanko, David A; Binns, Raymond A; Yeats, Chris J; Craddock, Paul R; Humphris, Susan E (2003): Controls of fluid chemistry and complexation on rare earth element contents of anhydrite from the PACMANUS subseafloor hydrothermal system, Manus Basin, Papua New Guinea. Mineralium Deposita, 38(8), 916-935, https://doi.org/10.1007/s00126-002-0325-0 Ocean Drilling Program (ODP) leg 193 successfully drilled four deep holes (126 to 386 m) into basement underlying the active dacite-hosted Pacmanus hydrothermal field in the eastern Manus Basin. Anhydrite is abundant in the drill core material, filling veins and vesicles, cementing breccias, and occasionally replacing igneous material. We report rare-earth element (REE) contents of anhydrite from a site of diffuse venting (Site 1188) which show extreme variability, in terms of both absolute concentrations (e.g., 0.08–28.3 ppm Nd) and pattern shape (LaN/SmN=0.08–3.78, SmN/YbN=0.48–23.1, Eu/Eu*=0.59–6.1). The range of REE patterns in anhydrite includes enrichments in the middle and heavy REEs and variable Eu anomalies. The patterns differ markedly from those of anhydrite recovered during ODP Leg 158 from the TAG hydrothermal system at the Mid-Atlantic Ridge which display uniform LREE-enriched patterns with positive Eu anomalies, very similar to TAG vent fluid patterns. As the system is active, the host-rock composition is uniform, and the anhydrite veins appear to relate to the same hydrothermal stage, we can rule out predominant host-rock and transport control. Instead, we propose that the variation in REE content reflects waxing and waning input of magmatic volatiles (HF, SO2) and variable complexation of REEs in the fluids. REE speciation calculations suggest that increased fluoride and possibly sulfate concentrations at Pacmanus may affect REE complexation in fluids, whereas at TAG only chloride and hydroxide complexes play a significant role. The majority of the anhydrites do not show positive Eu anomalies, suggesting that the fluids were more oxidizing than in typical mid-ocean ridge hydrothermal systems. We use other hydrothermal fluids from the Manus Basin (Vienna Woods and Desmos), which bracket the Pacmanus fluids in terms of acidity and ligand concentrations, to examine the dependence of REE complexation on fluid composition. Geochemical modeling reveals that under the prevailing conditions at Pacmanus (pH=3.5, T=250–300 °C), Eu oxidation state and the relative importance of fluoride versus chloride complexing are very sensitive to small variations in oxygen fugacity, temperature, and pH. Patterns with extreme mid-REE enrichment may reflect speciation effects (free-ion abundance) coupled with crystal chemical control. We conclude that the great variability in REE concentrations and pattern shape is likely due to variable fluid composition and REE complexation in the fluids. completed Bach, Wolfgang

wbach@uni-bremen.de

https://orcid.org/0000-0002-3099-7142 information principalInvestigator ODP Ocean Drilling Program theme 1995-01-01 creation PANGAEA

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https://www.pangaea.de/ information pointOfContact copyright copyright CC-BY-3.0: Creative Commons Attribution 3.0 Unported textTable und geoscientificInformation 151.669783333333 151.669783333333 -3.72813333333333 -3.72813333333333 2000-11-18T00:00:00 2000-12-30T00:00:00 48.59 364.0 DEPTH, sediment/rock physicalMeasurement m m Sample code/label thematicClassification DSDP/ODP/IODP sample designation Lanthanum physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Cerium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Praseodymium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Neodymium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Samarium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Europium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Gadolinium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Terbium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Dysprosium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Yttrium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Holmium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Erbium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Thulium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Ytterbium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg Lutetium physicalMeasurement ICP-MS, Thermo Finnigan, Element 2 mg/kg mg/kg text/tab-separated-values unknown https://doi.pangaea.de/10.1594/PANGAEA.666862?format=textfile download dataset The data set was checked for completeness, correctness, and consistency of metainformation. Validity of used methods was checked and - if applicable - precision and range of data. EVENT LABEL: 193-1188 * LATITUDE: -3.728133 * LONGITUDE: 151.669783 * DATE/TIME START: 2000-11-18T00:00:00 * DATE/TIME END: 2000-12-30T00:00:00 * ELEVATION: -1640.4 m * PENETRATION: 745.3 m * RECOVERY: 53 m * LOCATION: Bismarck Sea * CAMPAIGN: Leg193 * BASIS: Joides Resolution * METHOD/DEVICE: Composite Core 69 cores; 380.3 m cored; 365 m drilled; 13.9% recovery 2000-11-18T00:00:00