Next Section | Table of Contents
doi:10.2204/iodp.sp.302.2004
APPENDIX I : MEASUREMENTS PLAN
Arctic Coring Expedition (ACEX)
ESO Sampling and Measurement Plan
This plan is subject to amendment according to the scientific needs and interests of the Scientific Party of the expedition
Offshore sampling and analysis (Figure A1)
Core curation
A mobile core-curation laboratory container onboard the drill ship will be used to catalogue and maintain a database of recovered core. Two temperature-controlled core-storage containers will be on the drillship, with additional storage available on the Oden should more core be collected than anticipated.
Micropaleontology
Core catcher samples will be collected on the drill ship and transferred to the Oden where the paleontologists and a technician will be based. The experienced technician is being contracted from the University of Stockholm, and there is suitable laboratory space for preparation. Microscopes will be provided as follows: the University of Stockholm (6), Bremen (2) and one other scientist (1). The following groups of microfossils will be studied:
- Nannofossils
- Diatoms
- Silicoflagellates, ebridians
- Foraminifera
- Ostracods
- Radiolarians
- Dinoflagellates, spores, pollen
Organic geochemistry
A sniffer device will be used to check for the presence of gas as part of the drilling safety procedure. This sniffer detects H2S, CO2 and C1–C4, and will provide quantitative data which will be logged, and from which C1:C2 ratios can be determined. Headspace gas samples will also be collected for GC analysis both offshore and onshore.
Two samples will be taken; one for offshore analysis, the second will be refrigerated for analysis onshore. We will seal two 5mL sediment samples in dry 20 mL vials.
Inorganic geochemistry
Several ephemeral properties in pore-water require that pore water should be extracted immediately from a core, and, depending on the parameter, might be specially treated in order to conserve it for later analyses. The pore waters may be sampled after core logging provided the logging is carried out sufficiently rapidly so that the quality of the pore-water is not compromised. Pore-water sampling will not be carried out in the A hole, but will begin in the B hole.
ESO propose a simple procedure for the proper preservation of interstitial water and some measurements of ephemeral parameters. This is a minimal scheme since both lab space and manpower are strictly limited, particularly on the Vidar Viking.
Actions on Vidar Viking:
Whole round samples will be taken (beginning with the B-hole) after core logging, provided that the logging can be completed in about 20 to 40 minutes. Whole-round samples will be taken on a selected basis at an interval of approximately one every 2nd core depending on core recovery. If recovery allows, the upper 60 m (approximately) of the record will be sampled more frequently.
- Pore-water sampling with pore-water squeezers (20 to 40 ml); the squeezers will be installed in the core curation container.
- If time is available, in addition to the squeezers, a pore-water sampling with the new generation of “Rhizone pore water samplers” will be tested on this cruise, at least for the less indurated sediments of the record. Rhizone samplers are 2.5 mm in diameter and 5 cm in length; they can be inserted into the sediment from the cut face of core segments, or alternatively through tiny holes drilled into the liner like those for temperature measurement. The samples are collected in 10 mL vacuum tubes designed for medical use and requiring a minimum of experience and maintenance. http://www.geochemie.uni-bremen.de/koelling/rhizon.html
- Splitting and conservation of pore-water sample (if it turns out that this cannot be done on the Vidar Viking due to limited space, this work will be done onboard the ice breaker Oden). Subject to further discussion among the Co-chiefs and chemists.
- Analysis of alkalinity/pH on pore-water samples (titration with HCl).
- Analysis of salinity on pore-water samples (refractometer).
- Cool storage of all samples until they are transferred to the Oden.
Actions on Oden:
- Splitting and conservation of pore-water sample only if it turns out that this cannot be done on the Vidar Viking due to space constraints.
- Analysis of chloride (Cl-) on pore water samples (to be discussed if this can be postponed to onshore).
- Analysis of ammonia (NH4) on pore-water samples. Subject to further discussion.
- Cool storage of all samples at 4°C or –20° C depending on scientific requirements.
- Preparation of material needed on the Vidar Viking
Microbiology
Whole-round samples will be taken at an interval of approximately 1 per 20 m contingent on core recovery. The sample will be placed in a tri-laminate bag and transferred to the Oden for microbiological preparation (normally within 12 hours). Onboard Oden, where a microbiology laboratory will be set up, the whole core will be split into four sub-samples:
- Stored cool for anaerobic cultivation.
- Frozen at –80 ° C for DNA and biomarker analyses.
- Preserved in formalin for biomass estimates.
- Measured onboard for H as a proxy for rate determinations.
The use of biodegradable polymer mud will often be used during drilling to maintain a stable borehole. Samples of the mud used will be taken periodically for later analysis.
Offshore petrophysics measurements
Downhole logging
The logging program is focused on recovering basic petrophysical parameters to supplement the core data.
It is planned to wireline log the deepest hole at each site using the following equipment:
- Triple Combo comprising the spectral natural gamma-ray tool (NGT), accelerator porosity sonde (APS), hostile environment litho-density sonde (HLDS), dual induction resistivity tool (DIT-E) and a caliper for determining borehole diameter and thus hole conditions.
- Formation MicroScanner (FMS)/sonic (borehole compensated sonic tool [BHC]) combination comprising the FMS which provides oriented, high-resolution, 3D images of the borehole wall, acoustic velocity (BHC) and natural gamma ray for matching tool string passes.
Core logging
Cores will be logged on the Vidar Viking in a modified 20 ft container, housing a single MSCL track comprising magnetic susceptibility (x2 loops), density, velocity and resistivity sensors. The single core-logger system will include a full spares kit.
In Hole A, a full (or best sensor configuration) suite of physical properties will be logged on lab temperature equilibrated cores. In subsequent holes, to allow real-time direction of the coring, core sections will be logged immediately (not temperature equilibrated) using magnetic susceptibility and/or density. Data are output to the splicing software (accessible from both Vidar Viking and Oden) to keep the splice synchronized with the coring. The addition of a second magnetic susceptibility loop (both loops take a measurement at the same time, thereby reducing the measurement time) allows collection of susceptibility data at a significantly increased rate.
Points to note are:
- If core recovery rates are fast, then as we near the bottom of hole A it may be necessary to run only magnetic susceptibility and density on non temperature equilibrated cores, in order to get all hole A cores logged before the B hole is spudded.
- It is proposed that, provided access to cores is possible (which is believed will be the case), during the transit following operations out to the ice edge, all cores logged under non temperature equilibrated conditions, will be temperature equilibrated and logged in the petrophysics container using the full sensor suite.
All the temperature-equilibrated core log data acquired at sea will provide QC/QA checks when compared to repeat measurements planned for Bremen.
Discrete sample index properties
A reduced (compared with ‘normal’ ODP procedures) set of discrete sample index property measurements will be made at sea, by taking samples from core-section ends at an interval of one every four cores in Hole A and one every two cores in subsequent holes. Following ODP procedure, core samples will be weighed, oven-dried, the dried sample volume quantified using a pycnometer, and masses using acceleration corrected balance(s). The quality of these measurements is ultimately dependent upon resolving the ship movement problems, an issue complicated for these measurements as they will be undertaken on Oden, while it will be involved in ice management (breaking) duties. In the event that this problem cannot be satisfactorily resolved the discrete constant volume samples will be stored in watertight jars for subsequent onshore measurements.
Onshore sampling and analysis (Figure A2)
Location
The onshore Science Party will be undertaken at the existing ODP Core Repository and Laboratory at Bremen Docks (extended by renting another floor in the building for office space and, e.g., micropaleontology lab) in combination with access to the laboratories at the Department of Geosciences, the Research Center for Ocean Margin (RCOM), and the Center for Marine Environmental Research (MARUM).
Planned analysis and available facilities
The following list of facilities or analyses briefly describes the succession of planned working steps. Depending on the core recovery and time available, two shifts might be introduced, especially as it is to be expected that the Scientific Party for this expedition will be relatively large (28 participants in total).
- CORE SPLITTING
An archive half will be set aside as per IODP policy
- COLOR REFLECTANCE MEASUREMENTS
- PHOTOGRAPHY AND/OR DIGITAL IMAGING (line scan camera on MSCL).
- CORE DESCRIPTION
ESO are working in co-operation with TAMU to generate a system that is at least equivalent to the ODP standard. For data entry, ESO will employ an Offshore DIS system that is entirely compatible with others being used in IODP.
- SMEAR SLIDES PREPARATION
- CORE SAMPLING
A detailed sampling plan will be devised at the completion of the offshore phase.
- SOME MICROSCOPES (plus hood for sample preparation if acids needs to be applied)
- PALEOMAGNETICS
U channels will be collected during the Onshore Party for analysis at scientists’ laboratories; analyses to be completed for distribution to science party within 2 months of the end of Onshore Party.
- OPTIONAL - INORGANIC GEOCHEMISTRY.
Analyses on pore water and sediment/hard rock, needs to be discussed with Scientific Party. Access to geochemical lab can be provided (on university campus), e.g., for analysis of pore water and sediment main and trace elements (ICP-OES, ED-XRF), carbonate content and total organic carbon (LECO).
- OPTIONAL – X-RAY DIFFRACTION ANALYSIS (XRD)
Bulk mineralogy on selected samples, to be discussed with Scientific Party.
Core logging
It is anticipated that EPC personnel and a number of the Science Party (stratigraphic correlators and physical properties specialists) will arrive in Bremen early and complete whole core logging activities before arrival of the remainder of the Science Party.
Discrete sample index properties
Discrete intervals will be sampled from the core working half to complete the index property measurements (water content, porosity; bulk density, grain density, dry density). Following ODP procedure, core samples will be oven-dried, the dried sample volume quantified using a Quantachrome Penta-Pycnometer, and masses using a high-precision balance. Comparison of results with those made at sea will provide QC/QA checks on the preservation of the ephemeral physical properties.
Other
Once cores have equilibrated to room temperature, thermal conductivity will be measured. Falling cone penetrometer WF21600 for the determination of liquid and plastic limits, plasticity index, and shear strength will also be available.