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Implementation of an observatory strategy in the Lucky Strike vent field The MOMAR (“Monitoring the Mid-Atlantic Ridge”) project has been developed to promote a coordinated and multidisciplinary long-term study of hydrothermal environments at the Mid-Atlantic Ridge (MAR) near the Azores (35°N to 40°N). Javier Escartin*, Pierre Marie Sarradin**, Céline Rommevaux-Jestin* & Mathilde Cannat* * Institut de Physique du Globe Paris ** Ifremer Brest Hydrothermal circulation at mid-ocean ridges is a fundamental process that controls the transfer of energy and matter from the interior of the Earth to the crust, hydrosphere and biosphere. QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Humphris and McCollum, Oceanus, 41 (2), 1998 Ridge spreading rate & Hydrothermal Circulation: Fast vs. Slo w ? ? The MOMAR project: a contribution to understanding the causal links among magmatic, tectonic, hydrothermal, biochemical and biological processes at slow spreading ridge environments The MOMAR Area • Slow-spreading Mid-Atlantic Ridge (12 mm/yr half-rate) • In proximity to the Azores • 36°to39°N - consists of several ridge segments: good targets for establishing integrated studies at regional scale, segment scale, and individual vent sites MOMAR hydrothermal sites: 4 known sites, 3 hydrothermal environments - Peridotite hosted, high T, end of segment at discontinuity - Rainbow - Peridotite hosted, diffuse low T, end of segment - Saldanha - Basalt-hosted, high T, center of segment - Menez Gwen and Lucky Strike MOMAR hydrothermal sites: 4 known sites, 3 hydrothermal environments - Peridotite hosted, high T, end of segment at discontinuity - Rainbow - Peridotite hosted, diffuse low T, end of segment - Saldanha - Basalt-hosted, high T, center of segment - Menez Gwen and Lucky Strike Lucky Strike : a large hydrothermal vent field (2km/1km) at summit of rifted central volcanoe Lucky Strike Lucky Strike is the selected MOMAR site for integrated & multiscale long-term monitoring of ridge hydrothermal processes and ecosystems Lucky Strike Lucky Strike : a large hydrothermal vent field (2km/1km) at summit of rifted central volcanoe Lucky Strike More than 40 identified high-T & low-T vents …. A remarkable diversity of species…. A Marine Protected Area in the portuguese ZEE. Vent ecosystem dynamics in the MOMAR area Dispersal Propagule input Hydrothermal Ecosystem Hydrothermal Fluxes Biological Interactions Magmatic Tectonic Events Photosynthetic seasonal input microbiology Lucky Strike observatory design I 2006-2009 Light ASSEM buoy design Time series sampling Long term chemical monitoring EM monitoring II 2009- AUV for rapid response Long term visual monitoring EM monitoring Lucky Strike end of site survey phase 2005-2006 Seafloor mapping and imaging Volcanoe scale on bottom gravity survey Segment scale seismic reflection & refraction cruise Upcoming Cruises: EXOMAR (2005, Godfroy): Bio/ecological studies of MOMAR sites SISMOMAR (2005, W. Crawford): 3D seismic structure of the LS segment and central volcano: Porosity of the segment and central volcano Presence of fluids and heat sources Velocity structure for microseismicity studies GRAVILUCK (2005/2006, V. Ballu): Geodesy and seafloor gravity. Observatory design phase I (Long-term monitoring of seafloor vertical deformation and gravity) MOMARETO (2006, Sarradin): Ecosystem studies. Observatory design phase I (Visual and chemical monitoring of vent habitats). Further implementation of Phase I and Phase II observatory design: MoMAR is an international, InterRidge sponsored program with european leadership. MoMAR holds frequent workshops (last to date in Lisbon, april 2005). It is supported by national funding agencies and marine institutes in France, the US, Portugal, the UK, with active involvment of individual scientists in other european countries. It benefits from EC support through the STREP and MCRTN schemes. It is a component of the ESONET “european seafloor observatory network”. MoMAR welcomes participation of interested scientists and engineers. For more information & contacts : www.momar.org