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
Other:
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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