Notes on Vent Field Description:
southern Mariana Arc; elliptical caldera 6-10km across, featureless caldera floor at 1500m depth; Stern et al. (2008): "small area of low temperature diffuse venting was discovered on dive HD-483a near the base of the southeastern caldera wall", "The basal andesitic section was affected by intense hydrothermal alteration and sulphide stockwork mineralization, which – because the overlying basalt-rhyolite section is not altered or mineralized – seems to pre-date caldera collapse. This was the root zone of a robust hydrothermal system, the sea floor expression of which has not been found (and might not exist if hydrothermal activity occurred while WRV was an island)."
Notes Relevant to Biology:
Year and How Discovered (if active, visual confirmation is listed first):
2005 ROV Hyper-Dolphin; 2003 plume only; 2004 ROV ROPOS did not observe venting
Discovery References (text):
(plume only): Embley, R et al (2004) Explorations of Mariana Arc volcanoes reveal new hydrothermal systems. EOS, Trans. AGU 85(4): 37, 40
(ROV) Stern, R et al (2008) Evolution of West Rota Volcano, an extinct submarine volcano in the southern Mariana Arc: Evidence from sea floor morphology, remotely operated vehicle observations and 40Ar–39Ar geochronological studies. Island Arc 17: 70-89.