basalt, high-K andesite, dacite, sediment
Notes on Vent Field Description:
Southernmost Part of Okinawa Trough; caldera (800 m diam) with > 10 vents in field 300 x 500 m; chimney more than 30-m tall; hydrothermal fluids > 300 C; total area of hydrothermal sites estimated about 16,800m2; also known for "blue smoker" observed on 2006 cruise (http://www.jamstec.go.jp/jamstec-e/PR/0701/0123/index.html); Lee (1999): " Seven out of the 68 identified volcanoes have shown an active hydrothermal venting from the high-frequency EK500 records"
Notes Relevant to Biology:
mussels, crabs, shrimp; no Calyptogena clams or vestimentiferan tubeworms as of Kojima (2002) review
Year and How Discovered (if active, visual confirmation is listed first):
1999 submersible Shinkai 2000
Discovery References (text):
[K. Fujikura et al. (2001) Report on the investigation of hydrothermal vent ecosystems by the crewed submersible ‘Shinkai 2000’ on the Dai-yon (No. 4) Yonaguni Knoll and the Hatoma Knoll, the Okinawa Trough. JAMSTEC J. Deep Sea Res. 19: 141-154 (in Japanese with English abstract)]
Lee, C.-S. (1999) Active collision and backarc extension in the southernmost part of the Okinawa Trough. EOS, American Geophysical Union Transactions, 80, 46, AGU Fall Meeting abstract #T51B-06.
Other References (text):
Tsuchida et al. (2000) Preliminary report of a biological, geological, and geochemical survey on hydrothermalism at the Hatoma and Minna Knolls. JAMSTEC J. Deep-Sea Res. 17: 35-42
Watanabe, K (2001) Mapping the hydrothermal activity area on the Hatoma Knoll in the southern Okinawa Trough. JAMSTEC Journal of Deep Sea Research 19: 87-94 (in Japanese with English abstract)
Kishida, K. et al. (2004) Tungsten enriched in submarine hydrothermal fluids. Earth and Planetary Science Letters 222: 819-827.