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

Ishibashi, Jun Ichiro; Ikegami, Fumihiko; Tsuji, Takeshi; Urabe, Tetsuro

doi:10.1007/978-4-431-54865-2_27

Cited by 76 publications

(97 citation statements)

References 72 publications

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“…Thick (~1000 m) sequences of organic-rich terrigenous sediments sourced from the Yangtze and Yellow rivers overlie basement lithologies . Due to volcanism and rifting, the VAMP area is characterized by anomalously high heat flow (Yamano et al, 1986) and contains several hydrothermal fields (Glasby and Notsu, 2003;Ishibashi et al, 2015). From 5 north to south these include the Minami-Ensei Knoll, Iheya North Knoll (Fig.…”

Section: Regional Geologymentioning

confidence: 99%

“…Hole, CLAM site of the Iheya Ridge, the JADE and Hakueri hydrothermal fields of the Izena Hole (also known as the Izena Cauldron) (Ishibashi et al, 2015).…”

Section: ) Yoronmentioning

confidence: 99%

“…1b). Approximately ten hydrothermal mounds aligned north to south are associated with active venting and sulfide/sulfate mineralization (Ishibashi et al, 2015; (Ueno et al, 2003). Some samples also include arsenopyrite, tetrahedrite [Cu 12 (As,Sb) 4 S 13 ], tennantite [Cu 3 (As,Sb) 4 ], freslebenite [PbAgSbS 3 ], native arsenic, realgar [AsS] and/or covellite [CuS] (Ueno et al, 2003).…”

Section: Hydrothermal Activity At Iheya Northmentioning

confidence: 99%

“…In particular, the research findings of expeditions to the Trans-Atlantic Geotraverse [TAG], Manus Basin and Juan de Fuca Ridge have provided important insights into the nature of fluid rock interaction and fluid mixing in the development of seafloor hydrothermal systems in different tectonic settings (Barriga et al, 2000;Fouquet et al, 1997;Humphris et al, 1995Lackschewitz et al, 2004;Mottl et al, 1994;Paulick and Bach, 2006;Roberts et al, 2003;Teagle et al, 1998;Webber et al, 2011). This work has been complemented by countless other scientific and industry-funded cruises to hydrothermal fields worldwide (Connelly et al, 2012;de Ronde et al, 2005;Glasby et al, 2008;Hannington et al, 2005 and references therein; Ishibashi et al, 2015;McConachy et al, 2005;Petersen et al, 2014;Yeats et al, 2014;Webber et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…1), and this location has since become the most intensely investigated of all hydrothermal fields within the middle Okinawa Trough, Japan (Aoyama et al, 2014;Chiba et al, 1996;Glasby and Notsu, 2003;Ishibashi et al, 2015;Kawagucci et al, 2013;Masaki et al, 2011;Shao et al, 2015;Takai et al, 2011;Tsuji et al, 2012). During 2010, IODP Expedition 331 drilled five sites at Iheya North.…”

Section: Introductionmentioning

confidence: 99%

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Actively forming Kuroko-type volcanic-hosted massive sulfide (VHMS) mineralization at Iheya North, Okinawa Trough, Japan

Yeats

Hollis

Halfpenny

et al. 2017

Ore Geology Reviews

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show abstract

Section: Regional Geologymentioning

confidence: 99%

“…Hole, CLAM site of the Iheya Ridge, the JADE and Hakueri hydrothermal fields of the Izena Hole (also known as the Izena Cauldron) (Ishibashi et al, 2015).…”

Section: ) Yoronmentioning

confidence: 99%

Section: Hydrothermal Activity At Iheya Northmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Actively forming Kuroko-type volcanic-hosted massive sulfide (VHMS) mineralization at Iheya North, Okinawa Trough, Japan

Yeats

Hollis

Halfpenny

et al. 2017

Ore Geology Reviews

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Magnetic anomalies associated with abundant production of pyrrhotite in a sulfide deposit in the Okinawa Trough, Japan

Honsho

Yamazaki

Ura

et al. 2016

Geochem Geophys Geosyst

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We report here results from a deep‐sea magnetic survey using an autonomous underwater vehicle over the Hakurei hydrothermal site, in the middle Okinawa Trough. Magnetic inversion revealed that the Hakurei site is associated with well‐defined high‐magnetization zones distributed within a broad low‐magnetization zone. Results from rock magnetic measurements, performed on sulfide ore samples obtained by drilling, showed that some samples possessed extremely high natural remanent magnetization (NRM) (as much as 6.8–953.0 A/m), although most of the measured samples had much lower NRM. These high‐NRM samples were characterized by high Königsberger ratios (101−103), indicating much larger NRM than induced magnetization, and contained pyrrhotite as the only magnetic mineral. This suggests that NRM carried by pyrrhotite is the source of the observed magnetic anomalies. The wide range of NRM intensity was considered to be due to a highly heterogeneous distribution of pyrrhotite, because pyrrhotite was commonly identified in both the high‐NRM and low‐NRM samples. Pyrrhotite production may have been occasionally drastically increased, with highly magnetic ores formed as a result. Rapid burial of active vents may result in the creation of an extensive reducing environment under the seafloor, which is favorable to pyrrhotite production, and may also prevent oxidation of pyrrhotite by isolating it from seawater. Because the magnetization intensity of sulfide ores was highly variable, it would not be straightforward to estimate the quantity of ore deposits from the magnetic anomalies. Nevertheless, this study demonstrates the usefulness of magnetic surveys in detecting hydrothermal deposits.

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Crustal structure of the southern Okinawa Trough: Symmetrical rifting, submarine volcano, and potential mantle accretion in the continental back‐arc basin

et al. 2017

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Back‐arc basins are a primary target to understand lithospheric evolution in extension associated with plate subduction. Most of the currently active back‐arc basins formed in intraoceanic settings and host well‐developed spreading centers where seafloor spreading has occurred. However, rift structure at its initial stage, a key to understand how the continental lithosphere starts to break in a magma‐rich back‐arc setting, is poorly documented. Here we present seismological evidence for structure of the southern Okinawa Trough, an active rift zone behind the Ryukyu subduction zone. We find that the southern Okinawa Trough exhibits an almost symmetric rift system across the rift axis (Yaeyama Rift) and that the sedimentary layers are highly cut by inward dipping normal faults. The rift structure also accompanies a narrow (2–7 km wide) on‐axis intrusion resulted from passive upwelling of magma. On the other hand, an active submarine volcano is located ~10 km away from the rift axis. The P wave velocity (Vp) model derived from seismic refraction data suggests that the crust has been significantly thinned from the original ~25 km thick arc crust and the thinnest part with 12 km thickness occurs directly beneath the rift axis. The velocity model also reveals that there exists a thick layer with Vp of 6.5–7.2 km/s at lower crustal levels and may indicate that mantle materials accreted at the bottom of the crust during the crustal stretching. The abrupt crustal thinning and the velocity‐depth profile suggest that the southern Okinawa Trough is at a transitional stage from continental rifting to seafloor spreading.

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

Cited by 76 publications

References 72 publications

Actively forming Kuroko-type volcanic-hosted massive sulfide (VHMS) mineralization at Iheya North, Okinawa Trough, Japan

Actively forming Kuroko-type volcanic-hosted massive sulfide (VHMS) mineralization at Iheya North, Okinawa Trough, Japan

Magnetic anomalies associated with abundant production of pyrrhotite in a sulfide deposit in the Okinawa Trough, Japan

Crustal structure of the southern Okinawa Trough: Symmetrical rifting, submarine volcano, and potential mantle accretion in the continental back‐arc basin

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