Mineralogical and geochemical variation in hydrothermal sulfides from Vienna Woods field, Manus Basin, Papua New Guinea:
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Mineralogical and geochemical variation in hydrothermal sulfides from Vienna Woods field, Manus Basin, Papua New Guinea: constraints on their evolution RAY Durbar1*, BANERJEE Ranadip1, MAZUMDER Aninda1, PAROPKARI Anil L.1, MUKHOPADHYAY Subir2, BALAKRISHNAN Srinivasan3 1 CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India 2 Department of Geological Sciences, Jadavpur University, Kolkata 700032, India 3 Department of Earth Sciences, Pondicherry University, Puducherry 605014, India
Received 5 June 2017; accepted 29 September 2017 ©The Chinese Society of Oceanography and Springer-Verlag GmbH Germany, part of Springer Nature 2018
Abstract
Polymetallic sulfides from two hydrothermal chimneys and talus deposit from the Vienna Woods field of Manus Basin were studied for mineralogy, elemental composition, and S-isotope ratio to understand their evolution. The factors including the nature of source fluid, mineral paragenesis, and related geochemical processes have been discussed. Mineralogy and elemental concentration of Cu and Fe-rich large chimney at the central part of this hydrothermal field was completely different from the smaller Zn-rich peripheral chimney and Fe-rich talus deposit, suggesting the variable degree of alterations generate physico-chemically different source fluids responsible for these hydrothermal structures. Similarly, S-isotope ratios also indicate chemically diverse fluids and different modes of precipitation were involved in their evolution. Distinct mineral zonings and associated elemental and isotopic compositions within individual deposit confirm paragenetic shifts were involved during their growth process. Key words: Manus Basin, hydrothermal chimney, talus, geochemistry, mineralogy Citation: Ray Durbar, Banerjee Ranadip, Mazumder Aninda, Paropkari Anil L., Mukhopadhyay Subir, Balakrishnan Srinivasan. 2018. Mineralogical and geochemical variation in hydrothermal sulfides from Vienna Woods field, Manus Basin, Papua New Guinea: constraints on their evolution. Acta Oceanologica Sinica, 37(4): 22–33, doi: 10.1007/s13131-018-1194-4
1 Introduction The western part of the Pacific Plate has a number of convergent segments, marking the boundaries of more than 75% marginal basins found on the earth today (Tamaki and Honza, 1991). Some of these marginal basins developed due to seafloor spreading behind the magmatic arcs and are well known for seafloor hydrothermal activities. Over the last two decades several explorations in these marginal basins have shown that this region has wide variation in hydrothermal activities and associated ore deposits (Ishibashi and Urabe, 1995). In the Manus Basin, evidence of hydrothermal activity was first recorded in 1985–1986 with deep tow camera which photographed a variety of vent fauna within the Manus Spreading Center (Both et al., 1986). Later, many active and extinct hydrothermal fields (e.g., Vienna Woods, Solwara, PACMANUS, NE Pual, DESMOS and SuSu Knoll) were found at different parts of this basin (Tufar, 1990; Auzende et al., 1996, 2000; Li
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