SAMPLING STRATEGYSampling guidelines and policy are available at the following Web site URL: http://www-odp.tamu.edu/publications/policy.html. The Sample Allocation Committee (SAC; composed of co chiefs, staff scientist, and ODP curator on shore and curatorial representative on board ship) will work with the entire scientific party to formulate a formal leg-specific sampling plan for shipboard and postcruise sampling. Modification of the strategy during the leg must be approved by the co chiefs, staff scientist, and curatorial representative on board ship.
The minimum permanent archive will be the standard archive half of each core. All sample
frequencies and sizes must be justified on a scientific basis and will depend on core recovery, the
full spectrum of other requests, and the cruise objectives. Some redundancy of measurement is
unavoidable, but minimizing the duplication of measurements among the shipboard party and
identified shore-based collaborators will be a factor in evaluating sample requests.
As Leg 205 will reoccupy sites cored during Leg 170, only minimal coring will be conducted. At Site 1039R, we will initiate RCB coring from ~50 m above the gabbro sill to provide overlap between Leg 170 and Leg 205 coring results as well as to document pore fluid profiles. RCB cores will be continuously taken through the gabbro sill, the basal sediment section below it, and a minimum of 100 m into basaltic basement. At Site 1040R, cores will be taken from ~180 to 420 mbsf to obtain samples from the upper fluid conduit (thrust), décollment, and uppermost underthrust sequence.
We anticipate extensive whole-round sampling to document pore fluid chemistry profiles, sediment strength, stress and consolidation, and permeability, as well as, potentially, microbiological experiments. In the Site 1039R basement cores, we anticipate developing a coordinated sampling strategy, possibly including the creation of large composite samples, to ensure that multiple analyses can be performed on splits of the same sample.
For parts of the section cored at Site 1039R, there will only be one copy of the section available for core description and sampling. In some critical intervals there may be considerable demand for samples from a limited amount of recovered core material. These intervals may require special handling, a higher sampling density, or reduced sample size. A coordinated sampling plan may be required before critical intervals are sampled.
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