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Sakai
Name Alias(es):
Iheya Small Ridge
Iheya Ridge
Vent Sites:
Clam field (= Clam Site) (includes Calyptogena site and Pyramid chimney)
Hitoshi
Noho (?) (= pNoho)
Activity:
Maximum Temperature:
338
Max Temperature Category:
Latitude:
27.5481
Longitude:
126.9895
Location on map:
Ocean:
Region:
National Jurisdiction:
Maximum or Single Reported Depth (mbsl):
1600
Minimum Depth (mbsl):
1300
Tectonic setting:
Full Spreading Rate (mm/a):
28.8
Host Rock:
basalt, high-K andesite, dacite, sediment
Deposit Type:
NotProvided
Notes on Vent Field Description:
Sakai field includes Clam, Hitoshi, and Noho (?) (direction: N to S & shallower to deeper); position in database and max temp 280 C at Hitoshi site 27°32.886'N, 126°59.371'E (Cruise Report NT15-13, 2015); maximum temperature 338 C for pNoho on ROV Hyper-Dolphin Dive 1772 in Miyazaki et al. (2017); for Clam site: Ishibashi et al. (2015): "temperature was recorded as 220 C in 1988. Venting was ceased in 1990, and since then, dive studies have not been conducted in this field"; Calyptogena site did not have shimmering water, Pyramid site 200 m N of Calyptogena had clear smokers 100-220 C;
Notes Relevant to Biology:
Calyptogena okutanii, Neolepas-type scalpellid barnacles, tubeworms; fauna less abundant at Pyramid than Calyptogena
Year and How Discovered (if active, visual confirmation is listed first):
1988 submersible Shinkai 2000; 1987 plume only
Discovery References (text):
[Tanaka et al. (1989) Shinkai 2000 diving surveys in the east of Iheya Small Ridge of the central Okinawa Trough. JAMSTECR Deep-Sea Res. 267-281 (in Japanese with English abstract)];
(plume only) Ishibashi et al. (1988) Geochemical evidence for hydrothermal activity in the Okinawa Trough. Geochemical Journal 22: 107-114;
Other References (text):
Ohta, S. and Kim, D. (2001) Submersible Observations of the Hydrothermal Vent Communities on the Iheya Ridge, Mid Okinawa Trough, Japan. J. Oceanogr. 57: 663-677;
Halbach et al., Econ. Geol., 88, 2210-2225, 1993;
Ishibashi, J., et al. (2015) Hydrothermal Activity in the Okinawa Trough Back-Arc Basin: Geological Background and Hydrothermal Mineralization. pp. 337-359 in Ishibashi, J. et al. (eds) Subseafloor Biosphere Linked to Hydrothermal Systems. Springer. doi:10.1007/978-4-431-54865-2_27;
R/V Natsushima & ROV Hyperdolphin Cruise Report NT15-13, 2015 Summer Tour of deep-sea hydrothermal ventfields in mid Okinawa Trough and investigation of their geochemical and (micro)biological diversity, July 27, 2015 from Kumamoto – August 6, 2015 to Kagoshima, Japan Agency f or Marine-Earth Science and Technology (JAMSTEC), http://www.godac.jamstec.go.jp/catalog/data/doc_catalog/media/NT15-13_all.pdf (accessed on: 2019/03/20);
Miyazaki, J., et al. (2017) WHATS-3: An Improved Flow-Through Multi-bottle Fluid Sampler for Deep-Sea Geofluid Research. Front. Earth Sci., 5, https://doi.org/10.3389/feart.2017.00045;
Nakamura, K., et al. (2015) Water column imaging with multibeam echo-sounding in the mid-Okinawa Trough: Implications for distribution of deep-sea hydrothermal vent sites and the cause of acoustic water column anomaly. Geochem. J., 49, https://doi.org/10.2343/geochemj.2.0387;
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