Design and deployment of borehole observatories and experiments during IODP Expedition 336, Mid-Atlantic Ridge flank at North Pond

Abstract

During Integrated Ocean Drilling Program (IODP) Expedition 336 to North Pond on the western flank of the Mid-Atlantic Ridge (8 Ma crust) in the late fall of 2011, borehole observatories were installed in IODP Holes U1382A and U1383C and Deep Sea Drilling Project Hole 395A. These borehole observatories are designed for long-term (multiyear) coordinated hydrogeological, geochemical, and microbiological monitoring and experimentation to understand the nature of life, fluid flow, and fluid-rock interactions in young and cool oceanic crust. Additional related activities during Expedition 336 included recovery of an instrument string that was deployed within an earlier generation of a circulation obviation retrofit kit (CORK) observatory in Hole 395A and preparation of IODP Hole U1383B, which was drilled, cased, and left open during Expedition 336, for a future deployment of a borehole observatory. A streamlined CORK observatory was deployed in Hole U1383B during a remotely operated vehicle–supported cruise in April 2012. An additional CORK servicing cruise is scheduled for 2013. Here, we summarize the observatory project goals and provide an overview of the design, construction, and deployment of these CORKs and related instrumentation during Expedition 336. We also summarize the project goals, design, and construction for the CORK-lite installation in Hole U1383B and discuss plans for its deployment. CORK servicing plans for 2012 and 2013 also are presented.

Abstract

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