LTH, silica, barite deposits
Notes on Vent Field Description:
amorphous silica, barite, and clays cementing volcaniclastic basalt fragmentals (offset on active spreading center); inactive in systematic survey on Arculus cruise SS07/2008, but de Ronde et al. (2003) plot a hydrothermal site at Peggy Ridge, and Ishibashi and Urabe (1995) say oxygen isotopes suggest temp. > 100 C; Arculus et al. (2008) cruise report (http://www.cmar.csiro.au/datacentre/process/data_files/cruise_docs/SS200807sum.pdf) with additional support from Teck-Cominco: "We did not detect any distinctive isolated hydrothermal plumes associated with either the Peggy Ridge or the LETZ, but a widespread diffuse transmission anomaly several hundred metres thick generally deeper than about 2000m and averaging around 2250m depth was noted;" Note: Nautilus Minerals has tenements in Fiji EEZ on northern and southern parts of Central Spreading Ridge and Hunter Ridge (North Fiji Basin) and Peggy Ridge (Lau Basin)
Notes Relevant to Biology:
Year and How Discovered (if active, visual confirmation is listed first):
1975 or earlier rock samples only; inactive in systematic survey on Arculus cruise SS07/2008
Discovery References (text):
[(deposit only) Bertine & Keene, Science, 188, 150-152, 1975].
Other References (text):
Ishibashi, J. and Urabe, T. (1995) Hydrothermal activity related to arc-backarc magmatism in the western Pacific. pp. 451-495 in Backarc basins: Tectonics and magmatism, ed. Taylor, B., Plenum Press, New York
de Ronde et al. (2003) Hydrothermal fluids associated with seafloor mineralization at two southern Kermadec arc volcanoes, offshore New Zealand. Mineralium Deposita 38: 217–233, DOI 10.1007/s00126-002-0305-4.