Responsibilities of Shipboard Scientists
Each scientist participating in an IODP cruise has a number of general responsibilities with respect to contributing to the overall objectives of the cruise as summarized below. In addition, details about specific job assignments are addressed in the subsequent section.
Each participant is required to familiarize himself/herself with the scientific objectives and operational strategies of the expedition as outlined in the cruise prospectus.
Precruise Sample and Data Request
Each participant is required to submit an expedition-specific research plan (sample and data request) that contains an outline of their proposed postcruise research. This is typically submitted ~3–4 months before the expedition. This request will be used to allocate core samples and data, and coordinate and define all participant’s postcruise research.
Special Lab Needs
Scientists must alert IODP as early as possible if special equipment, supplies, lab space, etc., are needed. Additional details about specific labs and shipboard instrumentation can be found at http://iodp.tamu.edu/labs/ship.html. Contact the IODP staff scientist if you are unsure about lab facilities or requirements. Contact the IODP Staff Scientist if you are unsure about lab facilities or requirements.
Shipboard scientists collect, analyze and compile data conforming to IODP procedures and format established for each laboratory station and job description. Work shifts typically are 12 hours a day, 7 days per week for the duration of the expedition. All data collected during an expedition shall be input into the specified databases and shall be documented in the Expedition Report. All data collected during a cruise are the property of the entire shipboard party for one year postcruise or following shore-based sampling. After this 1-year moratorium, all data and samples become public.
Shipboard scientists produce scientific reports in the form of site chapters for the Expedition Report (ER) volume and present their findings to the other participants in shipboard science meetings. They also assist the Co-chiefs in writing summary reports such as the Weekly Report, Site Summary Report, and Expedition Summary chapter for the ER. Authorship of cruise reports is collective; individuals contribute according to their job assignment and scientific expertise.
Sampling of the cores on the ship is performed by all members of the scientific party. Scientists are routinely assigned core-sampling shifts (not more than 2 hours/day) during their normal work shift. When a core is ready for sampling, the assigned sampling shift takes all the samples designated for shipboard sampling by the Sample Allocation Committee (SAC), under guidance of the shipboard curator. For high recovery cruises, participants are also strongly encouraged to take part in postcruise sampling parties, when samples cannot be obtained onboard, if travel funding is available.
At the end of the cruise, all shipboard scientists are encouraged to complete cruise evaluations. These evaluations guide IODP in upgrading laboratory equipment and procedures and in improving life on board ship.
Scientists who sail on the expedition incur the obligation to analyze samples as proposed in their research plans (sample and data request) and publishing data and results. Details of this obligation are described in the IODP Sample, Data and Obligations Policy, which is available at http://www.iodp.org/program-policies/.
Scientist Job Descriptions
Participants are invited to serve in particular jobs that need to be completed to ensure scientific success of the cruise. The optimal mix of expertise is determined by the expedition objectives and by the Co-chief Scientists, the JOIDES Resolution Science Operator (JRSO) Expedition Project Manager/Staff Scientist, and the JRSO Supervisor of Science Support. An individual’s scientific expertise is taken into account as much as possible during job assignments. However, a one-to-one relationship between an individual’s expertise and objectives and the required job may not always exist. In such cases, shipboard scientists should be aware that they first serve the overall expedition objectives as outlined in the prospectus in the most effective way possible before they pursue their individual scientific interests during the cruise.
Core describers may have expertise in a wide variety of fields including sedimentology, petrography, petrology, or structural geology (http://iodp.tamu.edu/labs/ship/Cdeck_description.html). Core description can involve the following tasks:
- macroscopic visual description of section halves are entered in a core description database via a custom spreadsheet application and support staff help generate standard graphic summary reports for cores (sediments) or sections (igneous rocks);
- microscopic observations from smear slides and/or thin sections are entered using the same custom spreadsheet application and support staff help generate form-type reports for each thin section;
- description and measurement of deformational structures are also entered using the same custom spreadsheet application and some of the observations can be included in the standard graphic and thin section form reports;
- acquisition of digital images, diffuse color reflectance, and magnetic susceptibility using automated core loggers. In some cases, this may also be done by individuals in the petrophysics position;
- preliminary interpretation of formation (depositional), alteration (diagenetic), and/or deformational processes;
- selection of samples, in consultation with other scientists, for shipboard carbonate (coulometry), mineralogy (x-ray diffraction; XRD), or elemental (ICP-OES; pXRF) analysis;
- analysis of XRD data, if the appropriate expertise exists, which may also be done by one of the geochemists.
The stratigraphic correlator position is essential on cruises where complete stratigraphic sections are a primary expedition objective. Complete stratigraphic sections are achieved by coring multiple holes at a site. Completion of a Core Composite depth below Sea Floor (CCSF) depth scale in near-real time guides coring operations and ensures complete recovery of the sediment section. A spliced section comprising the best core intervals from multiple holes typically is created and used for sampling postcruise. For maximum efficiency, two correlators are needed to cover 24 hours and to guarantee feedback within hours or minutes. Correlation is achieved using software of choice, such as Correlator or Excel. The job typically includes operation of the Whole-Round Multi Sensor Logger (WRMSL) and Natural Gamma Ray Logger (NGRL). Other data acquired after the sections are split may be needed to improve correlation such as color reflectance logs, RGB series sampled from the section half images, macroscopic descriptions, paleomagnetic logs, or even biostratigraphic information.
Micropaleontologists provide age data and a biostratigraphic age model for each site. This mainly is done using core catcher samples as soon as possible after a core is recovered. Additional samples may be examined to provide as complete a biostratigraphic characterization of the cored section, or of critical intervals, as possible within the time available. Full assemblage analysis is not required on the ship; rather, identification of useful microfossil datums for constructing age-depth plots and sedimentation/accumulation rate curves is the primary emphasis. Paleoenvironmental or bathymetric data, principally from benthic foraminifers, may also be important on certain cruises. Slides, mounting media, and maceration chemicals are available for all major microfossil groups. See the paleontology web page at http://iodp.tamu.edu/labs/ship/Cdeck_paleontology.html and http://iodp.tamu.edu/labs/ship/Cdeck_microscopy.html for additional details.
A reference library with texts, journals, and reprints is available to help shipboard paleontologists identify microfossils. Because of limited shipboard space, the library is not comprehensive and micropaleontologists should check with IODP before the cruise to confirm reference availability.
Micropaleontology Reference Collections from DSDP and ODP cores are available at a number of institutions worldwide. Scientist may visit these collections before sailing http://iodp.tamu.edu/curation/mrc.html.
Paleomagnetists conduct paleomagnetic measurements and reduction of data to intensities and direction of magnetization to provide a magnetostratigraphy for each site. Paleomagnetists also provide absolute orientation data for orientation of deformational structures measured in the core, if appropriate. Some additional rock magnetic properties can be acquired on the ship, which is particularly useful if the magnetic properties are (partly) ephemeral (post-recovery dissolution, reduction, or oxidation of magnetic minerals). For detailed information, see the paleomagnetics web page (http://iodp.tamu.edu/labs/ship/Cdeck_paleomagnetism.html) and Technical Note 34 (http://www-odp.tamu.edu/publications/pubs_tn.htm).
Petrophysics: Physical Properties, Downhole Measurements
Scientists invited as petrophysics (PP) specialists collect, interpret and present physical properties data acquired from core samples and from downhole measurements. The shipboard tasks are shared and/or split among the petrophysics lab group members based the expedition scientific objectives, coring operations, as well as the individual’s scientific expertise and that of the entire science party. These tasks may focus only one (e.g., Physical Properties or Downhole Measurements) or both (e.g., Physical Properties/Downhole Measurements).
Physical Properties of Core Samples
- operation of whole-round multisensor logger (WRMSL) including gamma ray attenuation bulk density, magnetic susceptibility, and P-wave velocity measurements;
- operation of natural gamma radiation logger (NGRL);
- operation and/or data presentation and interpretation of section half multisensory logger (SHMSL), including magnetic susceptibility and core reflectance;
- moisture content and grain density on core samples;
- P-wave velocity on section halves and/or core samples;
- thermal conductivity on core sections or section halves, if appropriate;
- vane shear strength on section halves if warranted by the cruise objectives
Note that the core describer group typically operates the SHMSL for practical reasons, and PP specialists present and interpret the data in the context of other physical properties. Also, when stratigraphic correlation specialists are sailing, they assist in, or take complete responsibility of, WRMSL and NGRL operation, and the PP specialists present and interpret the data in the context of other physical properties measurements.
PP specialists ensure that calibrations and control measurements are carried out according to protocol and ensure quality of the data. For detailed information, see the physical properties lab web page (http://iodp.tamu.edu/labs/ship/Cdeck_petrophysics.html) and Technical Note 26 (http://www-odp.tamu.edu/publications/pubs_tn.htm).
The following measurements may be acquired:
- formation temperature measurements using a core barrel memory tool;
- a suite of wireline logs, typically including two basic tool strings: (1) triple combo (gamma ray attenuation, bulk density, neutron porosity, electrical resistivity, magnetic susceptibility, and natural gamma radiation); (2) FMS-sonic (micro-resistivity imaging; sonic data). The triple combo may be configured differently, potentially into two strings, depending on expedition requirements. Furthermore, vertical seismic profiles (check shots) are sometimes acquired using an additional tool string containing a geophone.
Formation temperature and wireline logs (and in special cases, Logging While Drilling logs) are acquired by the JRSO staff and Schlumberger logging engineer, respectively. The shipboard tasks of the PP specialists consist of assisting with data acquisition if required, and to interpret and present the data for the Expedition reports. All PP specialists participate in the integration of core and downhole data, and if available, the seismic survey data. This may include construction of synthetic seismic profiles. For detailed information on shipboard downhole measurements capabilities see http://iodp.tamu.edu/tools/logging/index.html.
Geophysics, Core-Log-Seismic Integration
Depending the expedition objectives, scientists can also be tasked with other roles that may involve petrophysics. These may include scientists that focus solely on linking the core/log to precruise seismic data (Core-Log-Seismic Integration) or other geophysical experiments (Geophysics).
The primary responsibility of organic geochemists is to monitor cores for hydrocarbon content. They advise the Operations Superintendent and scientific party when hydrocarbon levels in cores may constitute a potential safety or pollution hazard. They also provide data concerning organic matter characterization, elemental composition of organic matter, and carbonate carbon content.
Inorganic geochemists conduct chemical analyses on interstitial water, and/or solid sediment, or rock samples. For detailed information, see the chemistry lab web page (http://iodp.tamu.edu/labs/ship/Fdeck_chemistry.html) and ODP Technical Notes 15, 29, and 30 (http://www-odp.tamu.edu/publications/pubs_tn.htm).
Major responsibilities of the shipboard microbiologist include the following:
- conduct onsite contamination tests by using highly sensitive tracers (perfluorocarbons and/or fluorescent microspheres) added to the drilling fluid or core barrel to evaluate extent of contamination of cores by the drilling process;
- conduct sampling for shipboard and shorebased microbiological analyses;
- analyze thin sections of sediments or rocks for preliminary interpretations on contamination and bacterial activity;
- start cultures and incubation of samples using different media;
- may participate in the chemical analysis of interstitial waters.
For additional information on the microbiological lab and testing protocols from Technical Note 28, see http://iodp.tamu.edu/labs/ship/Fdeck_microbiology.html and (http://www-odp.tamu.edu/publications/pubs_tn.htm).
On occasion, experts may sail to perform more specialized measurements, which may include:
- downhole hydrologic (packer) or other geotechnical experiments;
- installation of borehole experiments (e.g., CORKs, seismometers, etc.).