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Alarcon Rise, Ja Sit

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Notes on Vent Field Description: 
southernmost spreading center in Gulf of California, a northern segment of the East Pacific Rise; 300 C on ROV Doc Ricketts Dive 399; Clague et al. (2012): "Mapping data also reveal the presence of about 110 apparent hydrothermal chimney structures as tall as 18 m, scattered along roughly the central half of the Rise. Subsequent ROV dives observed 70 of these structures and found active venting at 22 of them in two areas within the large sheet flow on the inflated portion of the ridge. Fluid temperatures exceed 300 C"; MBARI website, accessed 11 May 2015,, on-axis "near the fissure of the most recent lava flow at this ridge segment"
Notes Relevant to Biology: 
Clague et al. (2012): "extensive vent communities that superficially resemble those at [EPR] 21 N with robust clumps of Riftia pachyptila and fields of mostly dead Calyptogena magnifica"
Year and How Discovered (if active, visual confirmation is listed first): 
2012 ROV Doc Ricketts
Discovery References (text): 
Clague, D., et al. (2012) Geology of the Alarcon Rise Based on 1-m Resolution Bathymetry and ROV Observations and Sampling. American Geophysical Union, Fall Meeting 2012, abstract #T44A-04.
Other References (text): 
Marlow, J. (2012) How to discover deep-sea hydrothermal vents. Wired magazine, accessed online 5 May 2015: