IAB, minor BABB, med-K andesite
Notes on Vent Field Description:
chimneys and surficial polymetallic sulfide deposition; "Clark volcano has a double cone summit at a water depth of 875 meters. The shallowest cone has a near-summit hydrothermal vent field with five-meter tall venting chimneys with smaller structures around the periphery. Water temperatures of 200°C" Malahoff (2008); de Ronde et al. (2014): "hydrothermal activity today is largely manifest by widespread diffuse venting, with temperatures ranging between 56 and 106 C. Numerous, small (30 cm high) chimneys populate the summit area, with one site host to the ~7-m-tall “Twin Towers” chimneys with maximum vent fluid temperatures of 221 C"
Year and How Discovered (if active, visual confirmation is listed first):
2005 submersible Pisces V; 1999 plume only
Discovery References (text):
(plume only) de Ronde, CEJ et al. (2001) Intra-oceanic subduction-related hydrothermal venting, Kermadec volcanic arc, New Zealand. Earth Planet. Sci. Lett. 193: 359-369
New Zealand American Submarine Ring of Fire 2005 (NZASRoF'05) cruise report: http://oceanexplorer.noaa.gov/explorations/05fire/logs/leg2_summary/media/srof05_cruisereport_final.pdf
Other References (text):
Malahoff, A. (2008) Opportunities and challenges in polymetallic sulfide mining in the Kermadec Ridge and back arc basins. IGC Oslo abstracts, session MRD-03 Recent developments on marine mineral deposits.
de Ronde, C.E.J., et al., 2014, The anatomy of a buried submarine hydrothermal system, Clark volcano, Kermadec arc, New Zealand. Econ. Geol. 109, 2261-2292.