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Monowai Caldera

Name Alias(es): 
Orion Seamount Caldera
MGDS_FeatureID lowest in hierarchy: 
Vent Sites: 
Mussel Ridge
Maximum Temperature: 
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Maximum or Single Reported Depth (mbsl): 
Minimum Depth (mbsl): 
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Volcano Number (if applicable): 
Host Rock: 
Deposit Type: 
Notes on Vent Field Description: 
Monowai (= Orion) Seamount, southern Tofua Arc (STA); Global Volcanism Program 242050 Monowai Seamount includes both cone and caldera as single database listing; however, here we are listing Monowai Caldera and Monowai Cone separately, based on Leybourne et al. (2012): "Hydrothermal plume mapping has shown at least three major hydrothermal systems associated with the caldera and cone: (1) the summit of the cone, (2) low-temperature venting (<60°C; Mussel Ridge) on the southwestern wall of the caldera, and (3) a deeper caldera source with higher temperature venting that has yet to be observed... We believe the Monowai volcanic center is host to a robust magmatic-hydrothermal system, with significant differences in the style and composition of venting at the cone and caldera sites."; Monowai Caldera is just north of Monowai Cone; plume hit during NZAPLUME III expedition
Notes Relevant to Biology: 
Tunnicliffe et al.: "Lithodid crabs are abundant in the mussel beds"; discovery of vents in Monowai caldera: "The extensive biomass of Mussel Ridge was a surprise to us. " (
Year and How Discovered (if active, visual confirmation is listed first): 
2005 with submersibles PISCES IV and PISCES V and ROV RCV-150; 2004 plume only
Discovery References (text): 
New Zealand American Submarine Ring of Fire 2005 Kermadec Arc Submarine Volcanoes, NOAA VENTS Cruise Report compiled by Merle, Embley and Chadwick.
Other References (text): 
Graham et al. (2008) Structure and petrology of newly discovered volcanic centers in the northern Kermadec-southern Tofua arc, South Pacific Ocean. JGR 113(B8): B08S02.1-B08S02.24
Tunnicliffe et al. (2009) Survival of mussels in extremely acidic waters on a submarine volcano. Nature Geoscience 2: 344-348.
Leybourne et al. (2012) Submarine Magmatic-Hydrothermal Systems at the Monowai Volcanic Center, Kermadec Arc. Economic Geology, 107, 1669-1694, doi:10.2113/econgeo.107.8.1669.