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| HOME > CHIKYU >
CHIKYU SCIENCE AND TECHNOLOGY > Science the Earth
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| How does D/V CHIKYU reveal the Earth and life? We introduce the onboard research such
as borehole observation and sample research process. |
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| Onboard analysis of D/V CHIKYU |
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The cylindrical rock and sediment samples taken from the deep
Earth is called “Core” and it is a key to find the figure of the Earth, however, the core is a “living
materials” and its nature changes every moment due to environment difference. D/V CHIKYU equips
with the onboard laboratory for competent, complex and quick analysis. |
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The 9 meters long core samples moved from the drill floor through
catwalk are cut into sections of 1.5 meters in length. Each core section is provided an ID barcode (indicating
the expedition number, drill hole number, core number, and section number). These data are stored in
the database. |
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It measures CT value of whole core and construct inner view
of the core, before the core is distracted its physical property and structure by cut to half. To measure
inner heterogeneity of the core, this device provides more information for using sample more efficiently
and effectively. |
| Quality Analysis and Quality Control (QA/QC) |
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In the study of microbiology and geochemistry, gases and fluids
are important samples as well as solid core. Therefore, high quality gas / fluid sampling is required.
The QA/QC Sampling Room enables non-contaminated sampling in anaerobic atmosphere. |
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Subsurface microorganisms are living in a low temperature and
anaerobic environment, which can be killed or mutated by long-time exposure in the aerobic environment
under room temperature. Microbiology Lab. provides various equipments for sampling and storage for subsurface
microorganisms such as anaerobic glove box, freezer (under -80 degree C) and incubator. |
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Split a 1.5 meters long whole core into working and archive
halves. Working half is for distributed to researchers as discrete samples for on-board and onshore analyses.
Archive half is for stored in a core case for permanent archiving after description and non-destructive
physical property measurements (density, magnetic susceptibility...etc.). |
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Discrete samples taken from the working half core are purified
for each analysis by centrifugal separation and/or filtering. |
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High precision residual magnetization measurement of the core
is done in a magnetic shield room, for age determination and paleo-environmental research. |
| Paleontology / Petrology Lab. |
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Microscopic observations are done for paleontological / petrological
studies such as fossil age determination, paleo-environment, petrogenesis and crustal environment. |
| Various geochemical analyses are done for rocks, sediments
and interstitial water such as ICP-AES/MS analyses, ion-chromatography (gas, liquid). |
| Data Integration --- J-CORES |
| All data including core analytical results, core images (including
X-ray CT scan images), downhole logging data, and mud logging data are stored in the workstation situated
in the Data Integration Center where secondary processing, integration, visualization and imaging are
done. |
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20ft containers are used to refrigerate cores and can store
up to 8,000 meters in length of half-split core. |
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The geological layers are observed not only by a recovered
geological sample (core sample), but also by a special observation equipment run down by a wire-line
from the vessel into the borehole. Permeability, mineral composition, quantity of thermal flow are measured
by using sound wave (seismic wave), radiation, electromagnetism. The equipment can also output a color
image of borehole and sample formation fluid. In situ and real time data are acquired continuously compared
to the core sample. The high resolution image (resolution is about 5mm) makes it possible to catch the
indistinct crack on the geological layer and the subtle change of the rock recording the past climatic
change. |
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An example of a borehole-wall image processed
by a computer. It was acquired by FMI (Formation Micro Imager) which makes the high resolution color
image by using resistance.
(c) Schlumberger |
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| Long-term Downhole Monitoring System |
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The long term borehole monitoring system observing crustal
change is developed. In the future, earth observation network will be prepared by linking several observation
boreholes by cables on the sea floor. It will contribute to our society such as disaster prevention.
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