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doi:10.2204/iodp.sp.322.2009

Sampling and data sharing strategy

NanTroSEIZE expeditions are part of a single coordinated science program

To maximize the science return, Expedition 322 will strive to achieve consistency in approach and cooperation with previous Stage 1 expeditions, as well as Expedition 319. This applies to all research activities including shipboard analysis, use of scientific terminology, measurement protocol, and sample requests for onshore research. There are three key points related to overall research planning (described below).

Specialty coordinators

Unlike traditional, stand-alone IODP expeditions, unusual amounts of coordination and collaboration must occur among science parties across NanTroSEIZE expeditions. Specialty Coordinators will be responsible for facilitating these essential collaborations and maintaining consistent protocols and terminologies. The NT-PMT has identified six specific research areas that require special effort over the project's duration:

1. Lithology and sedimentary petrology,

2. Structural geology,

3. Geotechnical properties and hydrogeology,

4. Geochemistry,

5. Core-log-seismic integration, and

6. Paleomagnetism and biostratigraphy.
   

Specialty Coordinators will provide technical and scientific guidance to each science party and facilitate cross-expedition collaborations among the science parties to achieve NanTroSEIZE objectives. Shipboard scientists should expect frequent communications with their relevant Specialty Coordinators before, during, and after the expedition.

Community samples

As usual, individual scientists will collect samples for shipboard analyses and their postcruise research. In addition, however, we intend to collect substantial numbers of "community" archive samples, especially whole rounds. In some cases, these community samples will augment and/or provide redundancy for those requested by shipboard scientists. The goal is to preserve samples for a wide range of overall science objectives over the duration of the NanTroSEIZE project. This strategy, for example, will enable additional analyses of critical intervals once those zones are identified from initial shore-based laboratory tests.

Sample clusters

To ensure achievement of overall NanTroSEIZE scientific objectives, it will be essential to colocate suites of essential data types. This must be done with appropriate and consistent sample spacing throughout each hole. During Expedition 322, sample clusters will be located immediately adjacent to all whole-round intervals extracted for pore water geochemistry and geotechnical/hydrogeology tests. The clusters may include subsamples for carbon-carbonate, bulk powder XRD, microfabric, clay-mineral XRD, moisture and density, grain size analysis, and bulk chemistry by X-ray fluorescence. Most of those analyses will be completed onboard the Chikyu.

Research plan proposals (sample and data requests)

Shipboard and shore-based researchers should refer to the IODP Sample, Data, and Obligations Policy (www.iodp.org/program-policies). This document outlines the policy for distributing IODP samples and data and defines the obligations that sample and data recipients incur.

A research plan covering all samples and data, including those from potential contingency sites, is required well in advance of the expedition, which is scheduled to start in September 2009. Scientists must submit their research plans using the sample material curation system at smcs.iodp.org. We expect all of the individual expedition participants to honor expedition-specific as well as cross-expedition objectives and priorities. Such requests are also welcome from shore-based participants.

Access to data and core samples for specific research purposes, both during the expedition and during the subsequent 1 y moratorium, must be approved by the Sample Allocation Committee (SAC) for the expedition. The moratorium period will extend 1 y from the completion of the expedition, or if a significant postcruise sampling party is required, 1 y following the completion of the sampling party.

The SAC is composed of Co-Chief Scientists, Expedition Project Manager, the IODP curator on shore, and the curatorial representative in place of the shipboard curator. The six Specialty Coordinators will also contribute to this process as project-wide representatives of their respective disciplines. Because proposed Site NT1-01A could be drilled during Expedition 319 (as a contingency operation), the SACs from Expeditions 319 and 322 will be merged to evaluate requests for those samples.

Based on research (sample and data) requests submitted, the SAC will work with the scientific party as well as other Stage 2 SACs and Specialty Coordinators, if necessary, to formulate a formal expedition-specific sampling and data-sharing plan for shipboard and postcruise activities. Coordination of a whole-round sampling map will be particularly important and will include both personal samples and community samples. This map will be subject to frequent core-to-core adjustments depending on the actual material/data recovered and collaborations that may evolve between scientists before and during the expedition. Other modifications to the sampling plan during the expedition require the approval of the SAC.

All sample frequencies and sizes must be justified on a scientific basis and will depend on core recovery, the full spectrum of other requests, the expedition objectives, and project-wide NanTroSEIZE objectives. Success will require substantial amounts of cross-expedition collaboration, integration of complementary data sets, and consistent methods of analysis.

When critical intervals are recovered, there may be considerable demand for samples from a limited amount of cored material. These intervals (e.g., highly deformed fault zone) may require special handling, a higher sampling density, reduced sample size, or continuous core sampling for a set of particular high-priority research objectives. The SAC may require an additional formal sampling plan before critical intervals are sampled.

All sampling to acquire ephemeral data types or to achieve essential sample preservation will be conducted during the expedition. Sampling for individual scientists' postcruise research may be conducted during the expedition or may be deferred to postcruise. Following Expedition 322, cores will be delivered to the IODP Core Repository at Kochi Core Center, Japan.

Cruise-specific sampling

The unique nature of the NanTroSEIZE project requires some adaptation of existing IODP policies and procedures. As scientists develop their individual research plans for core samples and data, they should refer to this expedition's scientific objectives (see above), the three Stage 1 expeditions (Kinoshita et al., 2008; Ashi et al., 2008; Kimura et al., 2008), the Expedition 319 Scientific Prospectus (Araki et al., 2009), as well as the overarching Stage 1 Scientific Prospectus (Tobin and Kinoshita, 2006a).

We anticipate an extensive sampling program to achieve research objectives within most disciplines. When possible, our goal will be to make as many measurements as possible on common (or nearly co-located) samples, thus reducing the amount of material removed from the core and maximizing our ability to correlate different data types. These sample clusters (e.g., pore water, carbon-carbonate, moisture and density, bulk XRD, clay XRD, and bulk chemistry) will also improve our collective ability to complete and interpret complementary postcruise analyses. Substantial whole-round core sampling will be conducted to obtain appropriate samples for ephemeral shipboard analyses and to appropriately preserve samples for postcruise research. Such whole-round samples are especially important for geotechnical, hydrogeologic, and rock mechanics tests (e.g., permeability, consolidation, triaxial, ring-shear, etc.). Because different laboratories employ different protocols and have different capabilities and limitations (e.g., elevated temperature, stress ranges, and strain rates), there are no rigorous standardized approaches for many of the critical measurements. This, combined with a need for comprehensive characterization of core materials over the broadest possible range of experimental conditions, requires a coordinated sampling approach. Further, experience shows that it is impossible to identify all of the critical sampling intervals ahead of time (i.e., before the cores are split). Therefore, not only will whole-round samples be extracted for individual scientist's research, we will also build a community archive. The community whole-round specimens will be stored at the repository (Kochi) and released to scientists only after they file appropriate sample requests. These samples will be used primarily to ensure that there are no critical gaps in sample characterization both with respect to spatial sample distribution and scientific data types generated, for interlaboratory calibration, redundancy, and quality assurance (QA)/quality control (QC).

Community labs for postexpedition analyses

Whereas many analyses can and will be conducted at sea, others require state-of-the-art instrumentation that is only available onshore. We are particularly concerned about stable isotopic measurements that depend on dedicated instruments not found at all universities and government laboratories. For example, we expect to collect pore waters to measure at least Sr, B, Li, O, H, Cl, and C stable isotopic compositions. It is doubtful that any individual scientist has the on-site capability to make all of the measurements listed above. Issues regarding QA/QC become significant. To get the most consistent and reliable data for all Stage 1 expeditions, the NT-PMT proposed that all samples for each category of geochemical analysis go to a single laboratory. Several laboratories (to be determined) will have to be involved. For example, one laboratory might measure O, H, and C isotopes while another might measure Cl isotopes or Li. The choice of a particular laboratory (and analytical technique) will be reached by consensus of the inorganic geochemists who sail on the Stage 2 expeditions, mediated by the Specialty Coordinator for Geochemistry and approved by expedition SACs. We anticipate that data generated from each laboratory will be shared by all members of the Expedition 322 scientific party for use as defined by the approved research plans. Similarly, shore-based collaborators who are part of the community team will be granted access to the results of shipboard geochemical analyses at the earliest convenience (i.e., as site reports are completed). This strategy was implemented successfully during the postexpedition phase of NanTroSEIZE Stage 1.

Data sharing between expeditions

Data sharing across expeditions is normally accommodated through a formal data/sample request; that is, scientists from one expedition can apply as a shore-based scientist for shipboard data/samples from a completed or planned expedition. In this context, all Expedition 322 scientists are encouraged to submit a request for data/samples from other IODP expeditions, including Expedition 319, if they are interested in conducting postcruise research that furthers the science objectives of those expeditions. In the case of NanTroSEIZE, it is also possible that drilling or scientific objectives will overlap across two or more expeditions to such an extent that the expeditions will be considered one expedition in terms of shipboard data and samples. In these cases, data can be shared without a separate data/sample request. This may occur, for example, for scientific or logistical reasons during preexpedition planning or during the expedition if contingency sites are drilled that overlap with a planned expedition. The decision as to whether an expedition is a stand-alone expedition in terms of data/samples or is part of a suite of expeditions is made by the NT-PMT in consultation with the SAC and Co-Chiefs of the involved expeditions.

As a specific example, if proposed Site NT1-01A is drilled during Expedition 319 but partially or wholly analyzed during Expedition 322, the science parties of Expeditions 319 and 322 will be merged in order to best address the common theme of characterizing subduction inputs. In this scenario, scientists participating in either expedition will have full access to all samples and data from both expeditions, and sample requests will be reviewed and evaluated jointly by the two expedition SACs. This is somewhat different than most previous IODP expeditions but will follow the precedent and procedures defined during NanTroSEIZE Stage 1 drilling (e.g., Ashi et al., 2008; Kimura et al., 2008).

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