SAMPLING STRATEGY
Sampling guidelines and policy are available at the following web site URL: http://www- odp.tamu.edu/publications/policy.html. The sample allocation committee or SAC (co-chiefs, staff scientist, and ODP curator onshore and curatorial representative on board ship) will work with the entire scientific party to formulate a leg-specific sampling plan for shipboard and postcruise sampling. Modification of the sampling strategy during the leg must be approved by the co-chiefs, staff scientist, and curatorial representative on board the ship.In some critical intervals (i.e., LPTM, Eocene/Oligocene, Oligocene/Miocene, Eocene impact events) there may be considerable demand for samples from a limited amount of cored material. These intervals may require special handling, a higher sampling density, reduced sample size, or continuous core sampling by a single investigator. A coordinated sampling plan may be required before critical intervals are sampled.
During Leg 199, we hope to be able to sample at <5-k.y. resolution to obtain records of biological and physical oceanography at temporal resolutions adequate to resolve orbital forcing cycles. Given low regional sedimentation rates (~1-3 cm/k.y.), the high temporal resolution sampling required, and the operational reality of obtaining deeply buried sections across a transect of water depths indicates that in special circumstances we may require high sample density and volume to achieve the primary paleoceanographic, paleoclimatic, and paleomagnetic cruise objectives. Sample volumes must be large enough to ensure adequate numbers of planktonic and benthic foraminifers for biostratigraphic and stable isotopic/trace element studies and will depend on the exact nature of the sediment recovered. This is not meant as a blanket statement for heavy sampling of all cores. In fact, every effort will be made to stay within sample guidelines by first attempting to assemble consortia scientists to develop plans to attack these problems with the most efficient use of samples and/or by encouraging scientists to work on time slices or a subset of sites (as high-resolution sampling of all core at all sites will result in an unreasonably large number of samples to be analyzed by any individual scientist for the scientific results).
Because there are only a limited number of people available for sampling at sea and to minimize sediment waste, we plan to conduct low-resolution sampling at sea and save most of the high-resolution sampling for a postcruise shore-based sampling party. Low-resolution sampling will be carried out onboard ship to conduct shipboard description/characterization of the sediments, to facilitate pilot studies, to identify sections requiring high-resolution postcruise sampling, and to provide samples for studies that do not require a high temporal resolution. High-resolution sampling at sea will typically be limited to provide sufficient samples to work on until the shore-based sampling party takes place. All shipboard scientists will participate in shipboard sampling according to a shift schedule.
Most high-resolution sampling will be done approximately four months postcruise at a
sampling party at the Gulf Coast Core Repository (Texas A&M University). However, the
SAC may decide to sample the upper few cores on the ship because high-porosity sediments
could be disturbed during transport to the core repository. Samples that need to be frozen or
sealed for shore-based analysis also must be taken on board.