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a
water core, a real sediment core in a standard liner; a synthetic core
in a standard liner, and an Aluminium stepped bar for split cores. It was
also noted that different core diameters and core liner material will require
their own standards. Other suggestions for improving MST data: resaturating
the core with distilled water, especially to sands that drain easily; removing
section endcaps if the core is not soupy; maintaining good acoustic coupling;
letting cores warm to room temperature before taking measurements.
It was also noted that section lengths as measured by the MST data logger
frequently differed from that measured by describers. It was agreed that
the length of the core should be determined by the MST logger and recognized
that all depth measurements are relative.
There is great interest in digital
imaging, both as a scientific tool and an aid to core curation. From the
curators point of view, images from digital cameras are fast and inexpensive
but not yet of archival quality. There are questions regarding the permanence
of digital images, whether the digital format will be readable in the future,
and how to obtain and print out images with true colors. The consensus
of the group was that printed photographs are still the most permanent
archival record and their continued use should be encouraged.
As a scientific tool, quantifying the
red, green and blue lines of digital images shows great promise. The GEOTEK
line scan camera with its 1000pixel line CCD eliminates distortion longitudinally.
The 1.7f stop lens is very fast but for dark cores there is such a small
depth of field that the focus is lost. It is also very sensitive
to vibrations which may preclude its use at sea.
Researchers at Oregon State University
have used an Epson digital camera, generating electronic data by importing
the JPEG file into Matlab and processing out text files. The blue component
of the CCD array drifted too much to generate usable data; the red and
green lines were more stable. This digital camera is too automated and
for scientific work more manual control is needed. For all digital imaging,
the calibration of black and white is key to reproducible data. Ideally,
a scheme for maintaining a white calibration for each camera shot should
be used (e.g. a beam splitter). The zero calibration is equivalent to black,
but is this the ambient light surrounding the core or is it the total absence
of light?
The NGDC's mission is to promote the
free exchange of data. Carla Moore presented "the state of the Data Base"
at NGDC. Over the last twelve months, there have been 25,011 hits on the
curators pages during 14,300 user sessions by 4,896 unique hosts, averaging
69 hits per day. Identifiable US addresses constitute slightly over 51%
of users, unidentified IP and network addresses account for roughly 32%
of users, with the rest coming from 33 different countries.
There are 101,904 samples represented
in the Index to Marine Geological Samples database as of September 15,
2000, with an additional 2,863 samples in review. An unusually large amount
of data has been received and processed during the last two years. There
were 5,826 samples received in 1999 and 10,476 samples in 8 months of 2000
compared to 709 samples in 1998. It was agreed that the database should
be augmented with references, i.e. a core should refer back to a program,
thesis, publication, or actual physical location.
Concern was expressed over the potential
loss of data to the scientific community when IMAGES is completed as it
is a program and not a physical institute. Since cores taken within the
IMAGES program are housed at multiple repositories, these facilities should
submit data pertaining to these cores to NGDC, and the NGDC database should
reference the different storage locations. |
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