Articles | Volume 13
Sci. Dril., 13, 4–11, 2012
Sci. Dril., 13, 4–11, 2012

  01 Apr 2012

01 Apr 2012

IODP Expedition 327 and Atlantis Expedition AT 18-07: Observatories and Experiments on the Eastern Flank of the Juan de Fuca Ridge

A. T. Fischer1, T. Tsuji2, K. Petronotis3, C. G. Wheat4, K. Becker5, J. F. Clark6, J. Cowen7, K. Edwards8, H. Jannasch9, the IODP Expedition 327, and Atlantis Expedition AT18-07 Shipboard Paries A. T. Fischer et al.
  • 1Earth and Planetary Sciences Department and Institute for Geophysics and Planetary Physics, University of California at Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
  • 2Graduate School of Engineering, Kyoto University, C1-1-110 Kyotodaigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan
  • 3Integrated Ocean Drilling Program, Texas A&M University, 1000 Discovery Drive, College Station, TX 77845-9547, USA
  • 4Global Undersea Research Unit, P.O. Box 475, Moss Landing, CA 95039, USA
  • 5Rosenstiel School of Marine and Atmospheric Science, University of Miami, Division of Marine Geology and Geophysics, 4600 Rickenbacker Causeway, Miami, FL 33149-1098, USA
  • 6Department of Earth Science and Program of Environmental Studies, University of California Santa Barbara, 1006 Webb Hall, Santa Barbara, CA 93106-9630, USA
  • 7Department of Oceanography, University of Hawaii at Manoa, 1000 Pope Road, Marine Sciences Building, Honolulu, HI 96822, USA
  • 8Center for Earth Sciences, University of Southern California, 3651 Trousdale Parkway, Los Angeles, CA 90089-0740, USA
  • 9Monterey Bay Aquarium Research Institute, 7700 Sandholt Road, Moss Landing, CA, 95039, USA

Abstract. Integrated Ocean Drilling Program (IODP) Expedition 327 (summer 2010) was designed to resolve the nature of fluid-rock interactions in young, upper volcanic crust on the eastern flank of the Juan de Fuca Ridge. Expedition 327 drilled, cased and cored two new basement holes, conducted hydrogeologic experiments, and installed subseafloor borehole observatories (Circulation Obviation Retrofit Kits, CORKs). These CORKs were intended to allow borehole conditions to recover to a more natural state after the dissipation of disturbances caused by drilling, casing, and other operations; provide a long-term monitoring and sampling presence for determining fluid pressure, temperature, composition, and microbiology; and facilitate the completion of active experiments to resolve crustal hydrogeologic conditions and processes. Expedition 327 was followed (summer 2011) by R/V Atlantis Expedition AT18-07, with the remotely-operated vehicle (ROV) Jason, to service these CORKs, collect subseafloor pressure data, recover and deploy autonomous fluid and microbial samplers, collect large volumes of borehole fluids, and initiate a cross-hole hydrogeologic experiment using an electromagnetic flow meter. In addition, Atlantis Expedition AT18-07 refurbished an old CORK that could not be replaced during IODP Expedition 327, completing a critical part of the three-dimensional observation network that is currently being used to monitor a large-scale, directional formation response to long-term fluid flow from the crust.