Scheduled Cruises in 2004

Summary of a cruise on margins research (US.044)

Location and cruise identifier :   Costa Rica Subduction Zone, East Pacific - OCE0118478

Research ship :   Atlantis

Sails :   27th February 2004 from : Puntarenas COSTA RICA

Docks :   7th March 2004 in : Puntarenas COSTA RICA

Duration :   14 days

Principal Scientist/Investigator :   Miriam Kastner

Laboratory :   SIO

Other investigators :   

E-mail contact for further information :   

Website :   NSF Margins Award - here.

Scientific objectives :   This project will continuously monitor the pressure, fluid chemistry, and hydrology in two instrumented boreholes at the Costa Rica subduction zone, using long-term observatories (CORK and ACORK) installed during ODP Leg 203. The field program will 1) deploy pressure gauges and data loggers, OsmoSamplers, and osmotic flow meters in 3 CORKed boreholes along a transect across the deformation front of the subduction zone and 2) retrieve the OsmoSamplers, data stored in the data loggers and deploying new OsmoSamplers and pressure gauges, with the submersible Alvin. The fluid stored in the OsmoSamplers will provide a continuous 1.3 year record of fluid conditions collected at in situ conditions at weekly resolution, in three distinct hydrogeologic systems. The first flow system is the upper oceanic crust of the incoming Cocos Plate, the second is the return of a deeply sourced fluid along the decollement and the third is in the underthrust sediment section driven by compaction dewatering. By documenting the nature of these hydrogeologic systems it will be possible to better understand the effects of fluid flow at convergent margins on the shallow thermal structure and fluid content of the downgoing plate, the physical properties of the subduction zone interface, deformation style and transport of elements to the oceans.