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Name Alias(es): 
South Backarc
MGDS_FeatureID lowest in hierarchy: 
Vent Sites: 
Snail (= Fryer)
Y (= Yamanaka)
Maximum Temperature: 
Location on map: 
Maximum or Single Reported Depth (mbsl): 
Minimum Depth (mbsl): 
Tectonic setting: 
Full Spreading Rate (mm/a): 
Volcano Number (if applicable): 
Host Rock: 
Deposit Type: 
Notes on Vent Field Description: 
southern Mariana Trough; the position and maximum depth in this database is for Snail site; Yamanaka site at 12.9403N, 143.6080E, 2830 m; Wheat et al. (2003): "Two styles of venting were identified within an 80 m by 70 m area. Higher temperature venting was located in cracks among extinct mounds that were 2-5 m high and wide and are nearly monomineralic (sphalerite) in composition. Maximum temperatures of 248 degrees C were recorded 30 cm into these cracks, which were covered with abundant large provannid snails, Alvinoconcha hessleri, and crabs. In contrast, lower temperature diffuse venting (77 degrees C) emanated from mounds that have a porous structure that is composed of amorphous iron oxide and opal. These mounds are covered with microbial mats, which exhibit a high degree of biomass..."; J. Ishibashi (pers. comm.), for Yamanaka site: "Only very weak shimmering around 20 deg C was observed"; Baker et al. (2005): "Plumes between 12 55' and 12 58'N rose ~200 m, with the maximum NTU and Eh anomalies centered between 2700 and 2750 m"; located in the U.S. Marianas Trench Marine National Monument; WHOI YouTube video accessed 24 April 2015,
Notes Relevant to Biology: 
snails (including Alvinoconcha hessleri), crabs, shrimp; see list of species in Kojima and Watanabe (2015)
Year and How Discovered (if active, visual confirmation is listed first): 
2003 ROV Jason II; 2003 plume only
Discovery References (text): 
Wheat, C. G., et al. (2003), Hydrothermal venting in the southernmost portion of the Mariana backarc spreading center at 12°57′N, Eos Trans. AGU, 84(46), Fall Meet. Suppl., Abstract V32A-0920
(plume only) Baker, E.T. et al. (2005) Hydrothermal activity on near-arc sections of back-arc ridges: results from the Mariana Trough and Lau Basin. Geochem. Geophys. Geosyst. 6: Q09001, doi:10.1029/2005GC000948.
Other References (text): 
Kojima, S., and Watanabe, H. (2015) Vent fauna in the Mariana Trough. Chap. 25 in Subseafloor Biosphere Linked to Hydrothermal Systems, eds. Ishibashi, J., et al., doi:10.1007/978-4-431-54865-2_25.