COMPILED REPORTS OF THE
U.S. ICE CORE RESEARCH WORKSHOP
2.3 GISP II: FIELD AND LABORATORY ANALYSIS
(Moderator: P. M. Grootes)
The logical order of various property analyses and whether sampling and analysis should occur in the field or in the laboratory were discussed. The choice depends on:
(i) How sensitive the property is to core relaxation and microfracturing which
starts immediately when a core segment is brought up.
(ii)The need for controlled and clean sampling conditions. These are not usually found in a core processing trench.
(iii)The possibility that a paleoenvironmental record can be derived in the
field that can focus sampling for other core properties.
It is technically feasible to measure dD and d180 in the field. For d180 existing mass spectrometer technology can be used-, a system for real time measurements of dD in the field is under development. However, stable isotope measurements in the field are expensive. Their stratigraphic task is better fulfilled by other analyses. Limited C02 content measurements can be made in the field.
Core stratigraphy can be obtained in Holocene ice by continuous sampling and analysis of:
Electrical conductivity (ECM)
Particulates by laser light scattering
It was felt that a combination of at least three of these techniques will provide a reliable record of environmental change that can be used to guide further sampling. Below the Holocene, only the particulates may still be useful. Isotope verification through direct d180/dD measurements becomes desirable.
Analyses requiring immediate field sampling were identified as:
Gases (He, Ne, CC14)
Field processing must not alter the integrity of the core and it was decided that sampling for the above properties and for stable isotopes can be done in such a way.
Concern arose that a full sampling program by P.I.'s in the field may slow drilling progress, create logistical problems, and be expensive. A preference was expressed for minimal core processing, as listed above, by a mostly technical staff. The bulk of the core would then be shipped to a central U.S. core processing and storage location. A U.S. "field season" would be declared later to sample the core for the various properties. Cost estimates for the two options (processing in the field with possible storage of remaining core at an accessible site in the Greenland ice versus processing and storage of such core at a central U.S. site, maybe a new PICO) will be developed.
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