Acidic and sulfate-rich hydrothermal fluids from the Manus back-arc basin, Papua New Guinea

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doi: 10.1130/0091-7613(1997)025<0139:AASRHF>2.3.CO;2
Authors:Gamo, Toshitaka; Okamura, Kei; Charlou, Jean-Luc; Urabe, Tetsuro; Auzende, Jean-Marie; Ishibashi, Junichiro; Shitashima, Kiminori; Chiba, Hitoshi; Binns, Ray A.; Gena, Kaul; Henry, Katell; Matsubayashi, Osamu; Moss, Roger; Nagaya, Yoshiharu; Naka, Jiro; Ruellan, Etienne
Author Affiliations:Primary:
University of Tokyo, Ocean Research Institute, Tokyo, Japan
IFREMER, Plouzane, France
Geological Survey of Japan, Ibaraki, Japan
Central Research Institute of Electric Power Industry, Chiba, Japan
Kyushu University, Fukuoka, Japan
Corporate Authors:ManusFlux Cruise, Shipboard Scientific Party
Volume Title:Geology (Boulder)
Source:Geology (Boulder), 25(2), p.139-142. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613
Publication Date:1997
Note:In English. With GSA Data Repository Item 9708. 34 refs.; illus., incl. sketch maps
Summary:Hot (±88-120°C) and acidic (pH≤2.1) hydrothermal fluids rich in sulfate were discovered venting in the DESMOS caldera (depth = 1926 m), eastern Manus back-arc basin, Bismarck Sea, surrounded by Papua New Guinea. The abundant sulfate (≥32.8 mM, higher than the seawater value of 28 mM) with elemental sulfur deposition around the vents, and remarkably low δD(H2O) and δ34S(H2S) values (-8.1 per mil and -5.6 per mil, respectively), are suggestive of the incorporation of a magmatic fluid and the disproportionation of the exsolved SO2 from a magma body. The DESMOS fluid may be similar in origin to the acidic sulfate-chloride hot springs associated with subaerial volcanic activity. In contrast to the typical hydrothermal end member Mg concentration of 0, the DESMOS fluids are rich in Mg (46-52 mM), probably because of Mg dissolution by acid attack upon magnesium silicate minerals.
Subjects:Acidic composition; Back-arc basins; Basins; Deep-sea environment; Geochemistry; Hydrothermal vents; Marine environment; PH; Sea water; Submarine volcanoes; Sulfate ion; Volcanoes; Australasia; Bismarck Sea; Manus Basin; Pacific Ocean; Papua New Guinea; South Pacific; Southwest Pacific; West Pacific; DESMOS hydrothermal field
Coordinates:S034130 S034130 E1515200 E1515100
Abstract Numbers:97M/2813
Record ID:1997020219
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
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