Geology and mineralogy of massive sulfide ores from the central Okinawa Trough, Japan

Halbach, Peter; Pracejus, Bernhard; Maerten, Andreas

doi:10.2113/gsecongeo.88.8.2210

Cited by 192 publications

(105 citation statements)

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“…27.6a, b). The Izena Hole is situated along the southwestern continuation of a chain of Quaternary volcanoes of the Ryukyu arc , while its location can also be considered as the eastern end of the Aguni rift graben segment (Halbach et al 1993). The Izena Hole is a rectangular shaped depression about 6 Â 3 km.…”

Section: Hakurei Hydrothermal Field In the Izena Holementioning

confidence: 99%

“…Sphalerite and galena were the principal minerals, which are accompanied by pyrite, marcasite, chalcopyrite, tetrahedrite-tennantite, barite, amorphous silica and anglesite. Halbach et al (1993) distinguished five ore types from the collected samples; (i) Zn-Pbrich sulfide ore, massive sulfide composed of sphalerite, galena, pyrite, and chalcopyrite; (ii) Ba-Zn-Pb sulfide ore, consists of a matrix of euhedral to anhedral barite with sphalerite and tennantite-tetrahedrite; (iii) Massive Zn-Cu-rich sulfide slabs, dominated by sphalerite and chalcopyrite, but contain pyrite, marcasite, covellite, realgar, galena and a Ag-Cu-sulfide; (iv) Fe-rich replacement ore, which represents fragments of mature chimneys and (v) Zn-Pb-rich impregnation ore consists of thin stringers and veinlets filled with coarse-grained sulfides in strongly altered siliceous host rocks.…”

Section: Jade Hydrothermal Field In the Izena Holementioning

confidence: 99%

“…(Lawrie and Miller 2000). Alphabetical symbols represent a name of a hydrothermal field where samples were collected, G: Daiyon-Yonaguni Knoll field , M: Hatoma Knoll field (Okamoto et al 2002), J: Jade site in the Izena Hole (Halbach et al 1993), K: Iheya North Knoll field (Ueno et al 2003) By drilling into the flank part of the active hydrothermal mound (NBC mound) at Site C0016, a variety of mineralization styles were successfully recovered Yeats et al 2012). Blocks of massive and semi massive sulfide were obtained from the first core (0-9 mbsf).…”

Section: Style Of Mineralization Below the Active Hydrothermal Fieldmentioning

confidence: 99%

“…Fouquet et al (1991) proposed seafloor massive sulfide deposits in a back-arc setting showed more resemblance to the Kuroko-type deposits compared with those in the midocean ridge. Halbach et al (1993) studied in detail mineralogy of sulfide ore samples collected from the Jade field in the Okinawa Trough, and concluded that the seafloor sulfide deposit is a modern analogue of the Kuroko-type deposits, based on strong similarities in the mineralogical and chemical composition of the polymetallic (zinc and lead enriched) sulfides present. Several researchers followed this idea in their reports for description of hydrothermal mineralization (e.g., Nakamura et al 1989).…”

Section: Introductionmentioning

confidence: 99%

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Hydrothermal Activity in the Okinawa Trough Back-Arc Basin: Geological Background and Hydrothermal Mineralization

Ishibashi

Ikegami

Tsuji

et al. 2014

Subseafloor Biosphere Linked to Hydrothermal Systems

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The Okinawa Trough is a back-arc basin behind the Ryukyu trench-arc system and located along the eastern margin of the Eurasian continent. Sulfide and sulfate mineralization associated with hydrothermal activity has been recognized in ten hydrothermal fields in the Okinawa Trough. Hydrothermal mineralization recognized in these fields is commonly represented by coexisting occurrence of zinc-and lead-enriched polymetallic sulfides and abundant sulfate minerals. The mineralogy and geochemical signatures present has led researchers to suggest these areas may be a modern analogue for the formation of ancient Kuroko-type volcanogenic massive sulfide (VMS) deposits. Recent seafloor drilling during IODP (Integrated Ocean Drilling Program) Expedition 331 documented the subseafloor structure of a hydrothermal system at the Iheya North Knoll. Mineral textures and hydrothermal assemblages present in the drilled cores obtained from a hydrothermal mound in the proximal area are consistent with Kuroko-type mineralization. Based on geochemical studies, the intra-field diversity of mineralization commonly recognized in the Okinawa Trough can be explained by subseafloor phase separation of the hydrothermal fluid, which reflects shallow water depth (from 700 to 1,600 m). The subseafloor phase separation may. play an important role to accumulate metal elements beneath the seafloor. Based on geophysical and geological studies, the Okinawa Trough is considered a back-arc basin in the rifting stage. Such a tectonic setting is characterized by development of normal faulting in brittle continental crust and frequent intrusion of a magma, which can be expected to provide favorable environment for development of a hydrothermal system Keywords

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Section: Hakurei Hydrothermal Field In the Izena Holementioning

confidence: 99%

Section: Jade Hydrothermal Field In the Izena Holementioning

confidence: 99%

Section: Style Of Mineralization Below the Active Hydrothermal Fieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hydrothermal Activity in the Okinawa Trough Back-Arc Basin: Geological Background and Hydrothermal Mineralization

Ishibashi

Ikegami

Tsuji

et al. 2014

Subseafloor Biosphere Linked to Hydrothermal Systems

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“…Hydrothermally altered rocks have been extensively studied but mostly in the context of ore formation and characterization (Aiuppa et al, 2006;Allen and Hahn, 1994;Halbach et al, 1993;Horton et al, 2001;Huston et al, 1995;Ostwald 3 and England, 1977). In addition, several authors have examined the geochemistry of toxic elements, such as As and some heavy metals, in contact with hydrothermally altered rocks at mine pit lakes (Davis and Ashenberg, 1989;Davis et al, 2006;Eary, 1998;Levy et al, 1997;Savage et al, 2009;Tempel et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Mobilization and speciation of arsenic from hydrothermally altered rock containing calcite and pyrite under anoxic conditions

Tabelin

Igarashi

Yoneda

2012

Applied Geochemistry

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The effects of water residence time and anoxic conditions on the mobilization and speciation of arsenic (As) in a calcite-and pyrite-bearing altered rock excavated during a road-tunnel project has been evaluated using batch and column laboratory experiments. Higher infiltration rates (i.e., shorter water residence times) enhanced the leaching of As due to the higher pH values of the effluents and more rapid transport of dissolved As through the columns. The concentration of As in the effluent also increased under anoxic conditions regardless of the water residence time.This enhanced leaching of As under anoxic conditions could be attributed to a significant pH increase and decreased Fe oxyhydroxides/oxides precipitation compared to similar experiments done under ambient conditions. Processes that controlled the evolution of pH and the temporal release mechanisms of As under anoxic conditions were identical to those previously observed under ambient conditions: the dissolution of soluble phases, pyrite oxidation, co-precipitation and/or adsorption/desorption reactions. Speciation of As in the column experiments could partly be attributed to the pH-dependent adsorption of As species onto Fe oxyhydroxides/oxides precipitates. Moreover, apparent equilibriums of the total As and arsenite (As[III]) concentrations were delayed under anoxic conditions in both batch and column experiments.

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Lithium isotopic systematics of submarine vent fluids from arc and back‐arc hydrothermal systems in the western Pacific

Araoka

Nishio

Gamo

et al. 2016

Geochem Geophys Geosyst

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The Li concentration and isotopic composition (d 7 Li) in submarine vent fluids are important for oceanic Li budget and potentially useful for investigating hydrothermal systems deep under the seafloor because hydrothermal vent fluids are highly enriched in Li relative to seawater. Although Li isotopic geochemistry has been studied at mid-ocean-ridge (MOR) hydrothermal sites, in arc and back-arc settings Li isotopic composition has not been systematically investigated. Here we determined the d 7 Li and 87 Sr/ 86 Sr values of 11 end-member fluids from 5 arc and back-arc hydrothermal systems in the western Pacific and examined Li behavior during high-temperature water-rock interactions in different geological settings. In sediment-starved hydrothermal systems (Manus Basin, Izu-Bonin Arc, Mariana Trough, and North Fiji Basin), the Li concentrations (0.23-1.30 mmol/kg) and d 7 Li values (14.3& to 17.2&) of the end-member fluids are explained mainly by dissolution-precipitation model during high-temperature seawater-rock interactions at steady state. Low Li concentrations are attributable to temperature-related apportioning of Li in rock into the fluid phase and phase separation process. Small variation in Li among MOR sites is probably caused by low-temperature alteration process by diffusive hydrothermal fluids under the seafloor. In contrast, the highest Li concentrations (3.40-5.98 mmol/kg) and lowest d 7 Li values (11.6& to 12.4&) of end-member fluids from the Okinawa Trough demonstrate that the Li is predominantly derived from marine sediments. The variation of Li in sediment-hosted sites can be explained by the differences in degree of hydrothermal fluid-sediment interactions associated with the thickness of the marine sediment overlying these hydrothermal sites. Key Points:First Li isotopic report on submarine vent fluids from arc and back-arc hydrothermal systems Li in vent fluids can be explained mainly by dissolution-precipitation model during seawater-rock and seawater-sediment interactions Variation in Li due to diffusive hydrothermal fluid and the degree of hydrothermal fluid-sediment interaction

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Geology and mineralogy of massive sulfide ores from the central Okinawa Trough, Japan

Cited by 192 publications

References 0 publications

Hydrothermal Activity in the Okinawa Trough Back-Arc Basin: Geological Background and Hydrothermal Mineralization

Hydrothermal Activity in the Okinawa Trough Back-Arc Basin: Geological Background and Hydrothermal Mineralization

Mobilization and speciation of arsenic from hydrothermally altered rock containing calcite and pyrite under anoxic conditions

Lithium isotopic systematics of submarine vent fluids from arc and back‐arc hydrothermal systems in the western Pacific

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