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Bayonnaise Knoll caldera

Vent Sites: 
Hakurei ore deposit
National Jurisdiction: 
Depth (m)
Maximum or Single Reported Depth: 
Minimum Depth: 
Tectonic setting: 
Host Rock: 
dacitic to andesitic caldera with lava dome
Deposit Type: 
Notes on Vent Field Description: 
hydrothermal field around SE caldera floor 500x700m, sulfide chimneys; Tanahashi et al. (2006): "first discovery of Kuroko-type ore deposit in the Izu-Bonin back-arc rift;" from Neptune Minerals website: "In April 2008, Neptune lodged a further 405 applications totalling 1,395 km2 in the Izu-Bonin Arc. The applications cover 6 highly prospective areas within the Izu Back-arc Basin adjacent to Neptune’s existing applications areas over Bayonnaise, Myojin and Myojinsho Knolls – all host to well-researched SMS mineralisation."; note: spreading rate apparently not appropriate here because this is a nascent back-arc rift
Notes Relevant to Biology: 
Year and How Discovered (if active, visual confirmation is listed first): 
2003 temperature anomalies, but camera survey observed inactive vent deposits
Discovery References (text): 
[Iizasa, K et al (2004) A first extensive hydrothermal field associated with Kuroko-type deposit in a Silicic Submarine caldera in a Nascent Rift Zone, Izu-Ogasawara (Bonin) arc, Japan. OCEANS'04 MTTS/IEEE: 991-996]
[Tomizawa, N et al (2004) Exploration for a hydrothermal sulfide deposit in a submarine caldera, Izu-Ogasawara arc. OCEANS'04 MTTS/IEEE: 997-1003]
[Tanahashi, M et al (2006) A large hydrothermal sulfide deposit discovered in the Bayonnaise knoll, Izu-Bonin back-arc rift. Shigen Chishitsu 56: 185-196 (Japanese)]
Watanabe, H., pers. comm., 2009: "Dr. K. Iizasa in AIST conducted a cruise of R/V Natsushima and ROV HyperDolphin"
Other References (text): 
Tanahashi, M. et al. (2008) Myojin Rift, Izu–Bonin Arc as the Modern Analog of Hokuroku Basin, Northeast Japan: Geotectonic Significance of the New Hydrothermal Deposit in the Back-Arc Rift. Resource Geology 58: 301–312.