Exp. 364 Sampling and Measurement Plan

Offshore sampling and measurements plan

The following sampling and measurements plan is subject to amendment according to the scientific needs/interests of the Science Party and/or operational constraints. Routine measurements and core flow will be undertaken in line with the IODP-Mission Specific Platform (MSP) standard measurements procedures. Please see here for details on Offshore Core Curation and Measurements.

Priority will be given to the following measurements while offshore:

A mobile core curation laboratory container will be on board the drilling platform. Curation personnel on board will have delegated responsibility in the absence of the ESO Curation Manager and IODP Curator for the Bremen Core Repository and MSPs, Dr. Ursula Röhl. A sufficient number of core storage containers will be present on the drilling platform. There will be no splitting of the cores at sea and the majority of scientific analyses will be carried out during the Onshore Science Party (OSP) in Bremen (scheduled to start 21st September 2016).

Core description
Core catcher (CC) samples will be collected and split on board at intervals dictated by the length of the core barrels used (1.5 m or 3 m). The working half of the sample will be used for initial structural, petrophysical and sedimentological description. A small subsample will be taken for micropaleontological/biostratigraphic descriptions. If no core catcher sample is recovered, a sample from the lower end of each core will be taken for shipboard analysis. Thin section billets will be taken in representative sections for preparation in advance of the OSP.

Inorganic Geochemistry
In suitable lithologies, pore-water samples (e.g. squeezers and/or rhizone moisture samplers) will be taken on a routine basis. Pore water will be extracted immediately from cores and ephemeral properties (e.g. salinity, pH, alkalinity and ammonia) will be analyzed. Sample splits for onshore analysis (e.g. cations, sulfide, 13C) will be prepared and preserved whilst offshore.
The detailed sampling strategy is defined by the requests of the expedition microbiologists. After initial core curation, whole round samples for microbiology will be taken. Appropriate shipboard collection and preservation of sub-samples for post-cruise microbiological studies will be carried out under the most sterile possible conditions. Samples of mud will be taken from the outer surface of the core (where it has been in contact with the liner) for contamination testing.

Core logging
Temperature-equilibrated cores will be measured on the drilling platform in a containerized laboratory utilizing a standard multi-sensor core logger (MSCL). The MSCL will collect gamma density, P-wave velocity (where acoustic coupling is possible), non-contact electrical resistivity and magnetic susceptibility data. QA/QC checks will be carried out offshore, including repeat logging of calibration standards to monitor sensor precision and accuracy.

Downhole logging
Super-slimline logging tools will be deployed to collect downhole logging data. Priority will be given to the following measurements:
• Through-pipe: spectral gamma ray.
• Open hole (by toolstring): electrical resistivity; spectral gamma ray; total gamma ray + P-wave sonic velocity + magnetic susceptibility; total gamma ray + acoustic borehole imaging and VSP (2.5 m spacing).

Other downhole logging measurements (to be acquired in open hole) will be included in the logging program, depending on hole conditions, operational progress and preliminary scientific results. Options available for Expedition 364 include: hydrogeological measurements (fluid conductivity, pH, eH and temperature), caliper, optical borehole imaging and flow meter.

Onshore sampling and measurements plan

The OSP will be undertaken at the IODP Bremen Core Repository and laboratory in combination with access to the laboratories at MARUM and the Department of Geosciences, University of Bremen.
The following facilities will be available to the expedition scientists at the IODP Bremen Core Repository/MARUM:

  • Core splitting: an archive half will be set aside as per IODP policy.
  • Core description: ESO will provide a system that is IODP standard and also provide access to a Corewall viewing system. For data entry, ESO will employ an Offshore DIS system that is compatible with others being used in IODP.
  • Digital line-scan imaging: on a multisensor track system (archive half).
  • Thin section and smear slide preparation: as requested — preparation, description, and interpretation.
  • Inorganic geochemistry: whole-rock and pore fluid chemistry; inductively coupled plasma–optical emission spectrometry (ICP-OES), X-ray fluorescence (XRF) and total carbon (TC) / total organic carbon (TOC) content (LECO CS analyzer) / carbonate content.
  • Biostratigraphy: facilities to wash and sieve samples, microscopes incl. options for taking photographs
  • X-ray diffraction analysis (XRD): bulk mineralogy (e.g., carbonate mineralogy, etc.).
  • Paleomagnetic measurements: natural remnant magnetism (NRM) with stepwise demagnetization (2G longcore cryogen magnetometer) on U-channels (pass through) or samples (robot system which feeds up to 100 adapted sample cubes).
  • Petrophysical measurements:
    Natural gamma ray logging on whole cores (prior to the OSP).
    Thermal conductivity on whole cores (prior to the OSP).
     Physical properties of discrete samples : P-wave velocity and moisture and density properties (MAD) including: wet bulk density; grain density; porosity; and void ratio. Following IODP procedure: core samples will be oven-dried; the dried sample volume quantified using a Quantachrome penta-pycnometer; and masses measured using a high-precision balance.
    Color reflectance measurements (Minolta spectrophotometer).
    X-ray CT scanning (before/after the OSP on special request and on selected core sections only).
  • Core sampling: A detailed sampling plan will be devised at the completion of the offshore phase and after the scientists have submitted their revised sample requests.

Please also refer to the online tutorial. For an overview of core flow during the OSP