Europa

depth approximate; initially called "Mid-Cayman Rise, shallower site" in Version 2.0, then listed as synonym for "Von Damm" in Version 2.1, then as of cruise FK008 (OASES 2013) considered separate from Von Damm with activity inferred/unconfirmed; "the highest dissolved methane concentrations of the trip - by about a factor of two " (http://oases-expedition.blogspot.com/2009/11/down-to-wire.html); near submersible Alvin dive #625 in 1976 (18 22.8N, 81 48.4W, depth 2228 m); German et al. (2010): "because the methane-rich Europa plume signals originate close to the summit of Mt. Dent—a long-lived detachment surface—a more likely explanation may be that they are associated with serpentinization of ultramafic rocks and, hence, more closely related to low-temperature Type 3 venting as reported previously from Lost City"; cruise FK008 (OASES 2013) report: Dive N052, "extending SW away from the Von Damm Spire, at the end of the dive) revealed consistent evidence for two discrete sources of venting entering the ocean at two distinct depth/density horizons. One of these could clearly be traced back to the Von Damm spire’s summit but the other, deeper, appeared to exhibit strongest plume signals to the West, away from the Von Damm site, consistent with the presence of some additional source of venting which, because it was deeper in the water column but was strongest over shallower terrain, need not be indicative of a high temperature system"; although some references categorize as back-arc spreading center, here we categorized as mid-ocean ridge because the tectonic setting is pull-apart basin in transform fault zone;