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Marine
sediment cores are the fundamental data source for information on seabed
character and recent sedimentation. Research into global climatic change,
slope stability, oil exploration, pollution assessment and control, surveying
for laying telecommunication cables and offshore pipelines, coastal development
and the siting of seafloor structures by government and commercial concerns
all relay on data obtained from marine sediment samples.
Initial
description of sediment cores depends on the recognition of characteristic
sedimentary structures and sediment types. Identification of sediment type
commonly depends on the analysis of smear slides, and this often forms
the main investigative technique in the practical description of marine
sediments. Training in core description is rarely given during undergraduate
geoscience courses, and to geologists, trained on terrestrial sediments
and used to the conventional thickness of thin sections, some minerals
may appear unfamiliar when seen in smear slides.
Financial
constraints on cruise manning today also means that inexperienced staff
and students often replace more costly but experienced personnel and core
describers. As a result the graphic logs accompanying cores entering marine
core repositories can be of uneven quality and few repositories have the
resources to redescribe cores.
Since
1977, several American institutions that maintain core repositories have
collaborated to set up the 'Index of Marine Geological Samples' (http://www.ngdc.noaa.gov/mgg/curator/curator.html)
in order to provide information on the contents of their collections to
help researchers locate marine sediment and rock material for further analysis.
Currently, eighteen institutions or programmes contribute to the database
which can be searched online, including three from Europe (British Ocean
Sediment Core Repository, Southampton (UK); Alfred Wegener- |
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Institute
for Polar and Marine Research, Bremerhaven (Germany); and GEOMAR Research
Centre for Marine Geosciences, Christian Albrechts University, Kiel (Germany)).
Curators from contributing institutions meet every two years to discuss
common issues of interest and share experiences in core curation, analysis
and associated data management. Problems associated with uneven quality
core descriptions and the desirability of making training material available
for new core describers were raised in discussion at both the 1998 Curator's
Meeting at the Ocean Drilling Program, College Station, Texas, and at the
2000 Meeting at Oregon State University, Corvallis.
It
was suggested that it would be very useful to set up a curatorial reference
website on core and sediment description, with the ultimate aim of producing
a training CD-ROM - an interactive guide to deep sea sediments and their
practical description. The CD-ROM would |
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