LTH, fe-oxide, silica, Fe silicate (nontronite) deposits; Fe oxide mats can be quite thick (e.g., 1m)
Notes on Vent Field Description:
Hawaiian Hotspot, Hawaiian Islands; vent site depths: 960-980 Pele's, 1230-1250 Kaupo's, 1300 Ikaika, 4800 Mir; active low-temperature vents with abundant Fe oxide and amorphous silica precipitates; Pele's Vents are in southwest portion of the summit; large earthquake swarm in 1996, prior to 1996 only low temp (<30 C) observed, after 1996 200 C venting observed in newly formed collapse pit; "first documentation of high-temperature sulfides from the hydrothermal system of an ocean island volcano" (Davis and Clague 1998); note: 1999 Shinkai Dive 514 did not observe hydrothermal activity at MIR Vents mapped in 1991 (http://pubs.usgs.gov/ds/2006/171/data/cruise-reports/1999.pdf): "Yellow stains indicating previous low temperature hydrothermal events were observed near the base of the fault scarps"; WHOI YouTube video accessed 24 April 2015, https://www.youtube.com/watch?v=KOH1J4UvjIw&index=3&list=PL1CGd4Scv4GJsaaFRzItk-btFI757bH8f
Notes Relevant to Biology:
alvinocarid shrimp, pogonophorans, extensive bacterial mats, "conspicuous absence of large benthic animals"
Year and How Discovered (if active, visual confirmation is listed first):
1985 bottom photography R/V Hakuho Maru; 1987 submersible Alvin
Discovery References (text):
[Malahoff et al. (1982) Geology and chemistry of hydrothermal deposits from active submarine volcano Loihi, Hawaii. Nature 298: 234-239, doi:10.1038/298234a0]
[Horibe et al (1983) Off-ridge submarine hydrothermal vents: Back-arc spreading centers and hotspot seamounts. Eos 64: 724]
Sakai et al., Geochem. J., 21, 11-21, 1987, Hydrothermal activity on the summit of Loihi Seamount, Hawaii
Karl, D. et al. (1989) Hydrothermal and microbial processes at Loihi Seamount, a mid-plate hot-spot volcano. Deep-Sea Res. A 36: 1655-1673.
Other References (text):
[(for Mir Vents) Malahoff, A. (1992), Unstable geological processes: Loihi submarine volcano, Eos Trans. AGU, 73(43), Fall Meet. Suppl., 513]
Davis & Clague, Geology, 26, 399-402, 1998, Changes in the hydrothermal system at Loihi Seamount after the formation of Pele's pit in 1996
Malahoff et al. (2006) A decade of exploring a submarine intraplate volcano: Hydrothermal manganese and iron at Lo’ihi volcano, Hawai’i. G3 7: Q06002, doi:10.1029/2005GC001222.