MORB, serpentinite, gabbro
Notes on Vent Field Description:
the source of venting was pinpointed over 3 cruises from 1992-1994 (FAZAR, HEAT, BRIDGET); serpentinized peridotite; 360 C, low pH (2.8) fluids; in MOMAR area, which is designated for long-term monitoring efforts; at least 10 high temperature (365 C) black smokers in a field approximately 100 m by 250 m in area; ultramafic-hosted vent field exposed by large-scale faulting; enriched concentrations of H2, CH4, Fe, and chloride in high-temperature vent fluids; reported in 2007 as MPA in OSPAR Network (Portugal extended continental shelf); ridge-transform intersection; transform fault (NT06); Petersen lists as MOR, off-axis; Aballea et al. (1998) ranked hydrothermal activity as "likely" in southern AMAR segment (published just prior to discovery); German et al. (1996):"The largest anomaly detected ... was located close to 36 18’N ...in the offset between the AMAR (Alvin Mid Atlantic Ridge) and AMAR Minor segments - the Rainbow hydrothermal area."
Notes Relevant to Biology:
low species diversity; dominated by bresiliid shrimp (Rimicaris), as compared to mussel-dominated Lucky Strike vent field
Year and How Discovered (if active, visual confirmation is listed first):
Discovery References (text):
(Plume only) CR German et al. (1996) The Rainbow hydrothermal plume, 36°15'N, MAR. Geophys Res Lett 23(21): 2979-2982
(plume only) German et al, Earth Planet. Sci. Lett. 138, 93-104, 1996, Hydrothermal exploration near the Azores Triple Junction: tectonic control of venting at slow-spreading ridges?
(Visual Confirmation) Y Fouquet, et al., 1997. Discovery and first submersible investigations on the Rainbow hydrothermal field on the MAR (36°14 N). Eos Trans. Am. Geophys. Union 78 (46): 832
Fouquet et al. (1998) FLORES diving cruise with the Nautile near the Azores – First dives on the Rainbow field: hydrothermal seawater/mantle interaction. InterRidge News 7(1), p. 24-28
(plume only) Chin et al., Earth Planet. Sci. Lett. 162, 1-13, 1998, Detection of hydrothermal plumes on the northern Mid-Atlantic Ridge: results from optical measurements.
Other References (text):
(plume only) Aballea et al., Deep Sea Res., 45, 1319-1338, 1998, Manganese distribution in the water column near the Azores Triple Junction along the Mid-Atlantic Ridge and in the Azores domain
HN Edmonds and CR German (2004) Particle geochemistry in the Rainbow hydrothermal plume, Mid-Atlantic Ridge. Geochim Cosmo Acta 68(4): 759-772
Dyment et al. (2009) Detailed investigation of hydrothermal site Rainbow, Mid-Atlantic Ridge, 36°13’N: Cruise MoMARDream. InterRidge News 18: 22-24.
Ribeiro, M.C. (2010) The ‘Rainbow’: The First National Marine Protected Area Proposed Under the High Seas. The International Journal of Marine and Coastal Law 25, 183-207.