Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls
We have reviewed available visual information from the seafloor, and recently acquired microbathymetry for several traverses across the Lucky Strike segment, to evaluate the distribution of hydrothermal activity. We have identified a new on-axis site with diffuse flow, Ewan, and an active vent structure ∼1.2 km from the axis, Capelinhos. These sites are minor relative to the Main field, and our total heatflux estimate for all active sites (200–1200 MW) is only slightly higher than previously published estimates. We also identify fossil sites W of the main Lucky Strike field. A circular feature ∼200 m in diameter located on the flanks of a rifted off-axis central volcano is likely a large and inactive hydrothermal edifice, named Grunnus. We find no indicator of focused hydrothermal activity elsewhere along the segment, suggesting that the enhanced melt supply and the associated melt lenses, required to form central volcanoes, also sustain hydrothermal circulation to form and maintain large and long-lived hydrothermal fields. Hydrothermal discharge to the seafloor occurs along fault traces, suggesting focusing of hydrothermal circulation in the shallow crust along permeable fault zones.
Escartin J., Barreyre T., Cannat M., Garcia R., Gracias N., Deschamps A., Salocchi A., Sarradin Pierre-Marie, Ballu V. (2015). Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls. Earth And Planetary Science Letters. 431. 173-185. https://doi.org/10.1016/j.epsl.2015.09.025, https://archimer.ifremer.fr/doc/00281/39241/
Escartin Javier, Cannat Mathilde, Deschamps Anne (2021). Microbathymetry from AUV and ROV Surveys (MOMARETO'06, MOMAR'08-Leg1 and BATHYLUCK'09 cruises) along the Lucky Strike ridge segment (Mid Atlantic Ridge). SEANOE. https://doi.org/10.17882/80574
Escartin Javier (2009). EWAN hydrothermal site (Mid-Atlantic Ridge south of Lucky Strike): Seafloor photomosaic (black and white, VICTOR 6000, 2009). SEANOE. https://doi.org/10.17882/77405