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AT25-04: Hydrogeologic, Geochemical, and Microbiological Experiments in Young Oceanic Crust of the Northeastern Pacific Ocean Using Subseafloor Observatories S. Cooper1, A. T. Fisher2, and NSF co-PIs3 1 Consortium for Ocean Leadership 2 Earth and Planetary Sciences Department and Center for Dark Energy Biosphere Investigations University of California, Santa Cruz 3 K. Becker, J. Clark, J. Cowen, C. G. Wheat OET Nautilus Workshop University of Rhode Island, ISC 6–9 May 2013 Most of the seafloor is hydrogeologically active… modified from Ge et al. (2003); Fisher (2005) Seafloor hydrogeology influences... …the physical state and evolution of the crust and mantle, including volatile cycling at subduction zones; …the chemical evolution of the oceans; …heat loss and the thermal evolution of Earth; and …development and evolution of remarkable biological communities, both on and within the crust. Focus of this expedition: seafloor hydrothermal circulation The upper oceanic crust is a globalscale aquifer A permeable aquifer… Overview of CORK subseafloor observatories Created by Stephanie Keske, IODP Expedition 327 Department of Visualization, Texas A & M University Post-drilling CORK servicing with ROV Hydrogeology, Geochemistry, Microbiology Following IODP Expedition 327, CORK servicing accomplishing by ROV in Summer 2011 (very successful!) • Deploy long-term well-head OsmoSampling systems to collect fluids, run microbiology incubation experiments • Extract, collect, filter, analyze samples from well-heads using active pumping systems • Deploy flowmeter and open large-diameter valve to allow measured free-flow of hydrothermal fluids, create pressure perturbation, collect samples • Expedition AT25-04 (Summer 2013) is designed to "wrap up" initial phase of single-hole and multi-hole experiments through sampling, data downloads, perturbation of experimental systems CORK Observatory System in Operation! Planning for 2013 (AT25-04) and beyond… Download pressure data ROV Jason Exchange flowmeter Exchange OsmoSamplers Recover GeoM sled Large EOC effort planned (5-6 participants) Summer 2013 Education, Outreach, Communication IODP 327, AT18-07, AT25-04 pore Orcutt et al. (2011) • Numerous web conferences (schools, museums) • EOC and scientist blogs • Adopt-a-Microbe program • Podcasts, videos, photography • Curriculum development, museum displays • High-band-width "telepresence" with OET/URI! Acknowledgements Collaborators: Collaborators from ODP Leg 168, IODP Expeditions 301 and 327, numerous R/V Atlantis expeditions during 2004-11+… Funding, leadership: Thank you! Ship operators, crew, techs: Seafloor hydrothermal circulation is… …the passage of warm (or hot) water through rock of the oceanic crust; …generally a result of heating from below, although it can also occur immediately adjacent to newly-erupted magma; …partly responsible for making the ocean "salty"; …thought likely to have occurred very early in Earth history and may occur on other planetary bodies in our solar system. This presentation explores large-scale, ridge-flank hydrothermal systems (in contrast to "black smokers") Ridge-flank hydrothermal systems are subtle but important… …far from the magmatic and thermal influence of seafloor spreading; …fluid temperatures are often ~5-30°C, so systems are hard to detect; …driving force is heat rising slowly from deep inside the Earth, not active volcanism; …result in huge fluid flows, chemical impacts less well understood; …may help to support vast, subseafloor ecosystems (thermal and other conditions are optimal). Eastern Flank of the Juan de Fuca Ridge Hydrogeology, Geochemistry, Microbiology Focus on active ridge-flank processes to address these questions: • What are the magnitude and nature (distribution, extent of channeling) of permeability in crustal fluid-rock systems, variations, scaling (temporal, spatial)? • What are the magnitudes and directions of driving forces, fluid fluxes, and associated solute, heat , and microbial transport? • What are the magnitude and nature of storage properties, variations with fluid pressure, scaling (temporal, spatial)? • What are relations between fluid flow, vertical and horizontal compartmentalization, microbiological communities, seismic properties, alteration, structure, and primary crustal lithology? • How large are distinct fluid reservoirs, what are fluid residence times and fluid velocities, and how do these respond to transient events and processes (tides, seismic events)? Center for Dark Energy Biosphere Investigations (C-DEBI) Site Primary Review, 2013: Juan de Fuca Ridge Flank fieldFisher, locations modified from Fisher, Tsuji et al. (2011) New borehole observatories installed in 2010 IODP Expedition 327: Site 1362 Instrument and sampling bays Center for Dark Energy Biosphere Investigations (C-DEBI) Microbiologist for scale Site Review, 2013: Fisher, Juan de Fuca Ridge Flank First controlled measurement of water, solute particle velocity! Started Summer 2010 IODP Exp. 327 modified from Fisher et al. (2011)