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Mothra Field

Name Alias(es): 
MGDS_FeatureID lowest in hierarchy: 
Vent Sites: 
Faulty_Towers (includes Giraffe Chimney)
Maximum Temperature: 
Location on map: 
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Maximum or Single Reported Depth (mbsl): 
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Full Spreading Rate (mm/a): 
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Deposit Type: 
Notes on Vent Field Description: 
Kelley et al. (2001): "The 500-m-long Mothra hydrothermal field is the largest venting site in areal extent on the Endeavour segment of the Juan de Fuca Ridge near western valley wall. Within this field, there are at least five actively venting sulfide complexes, spaced 40 to 200 m apart along a trend of 020. The clusters are composed of multiple steep-sided pinnacles that rise up to 24m above the seafloor. Most of the sulfide structures are awash in diffusely venting fluids (30–200 C) that support rich and diverse macrofaunal and microbial communities. Isolated black smoker chimneys vent up to 320 C fluids"; Glickson et al. (2006): "Water column temperature anomalies were initially detected in 1986, and subsequent hydrocasts in 1988, 1991, and 1995 refined the position of the hydrothermal plume, leading to the field's discovery in 1996. In 1997 and 1998, the Edifice Rex sulfide recovery expedition mapped two sites of focused hydrothermal flow and collected four large sulfide chimneys from the central part of the field"; area of Canadian marine protected area. Kelley (2012): composed of six clusters of chimneys reaching up to 24 m in height, spaced ~600 m along strike and ~200 m across strike. >tens of active and inactive chimneys, typically tall, slender and lacking pronounced flanges, numerous sites of diffuse flow. Smokers not perturbed by 1999-2000 events though diffuse flow was affected. A centred position has been provided by Ocean Network Canada based on their observations.
Notes Relevant to Biology: 
Year and How Discovered (if active, visual confirmation is listed first): 
1996 ROV ROPOS; 1986 plume only
Discovery References (text): 
Juniper et al. (1996) Report on ROPOS submersible observations on the R/V Thomas G. Thompson cruise: 12-27 August 1996. InterRidge News 5(2): 25-26
Delaney, J.R., et al., 1997, The Endeavour Hydrothermal System I: Cellular circulation above an active cracking front yields large sulfide structures, "fresh" vent water, and hyperthermophilic archae, RIDGE Events, vol. 8, No. 2, 11-19.
Other References (text): 
Kelley et al., Geology, 29, 959-962, 2001, Geology and venting characteristics of the Mothra hydrothermal field, Endeavour segment, Juan de Fuca Ridge
Glickson, al. (2007) Geology and hydrothermal evolution of the Mothra Hydrothermal Field, Endeavour Segment, Juan de Fuca Ridge, Geochem. Geophys. Geosyst., 8, Q06010, doi:10.1029/2007GC001588.
Wankel, S.D. et al, 2011. Influence of subsurface biosphere on geochemical fluxes from diffuse hydrothermal fluids. Nature Geoscience 4, 461–468 (2011) doi:10.1038/ngeo1183.
Kelley, D. et al (2012). Endeavour Segment of the Juan de Fuca Ridge. Oceanography, Special Issue on Ridge 2000 Program Research, Vol 25, No.1, Mar 2012, 44-61