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| Titel |
Characteristics of correlation between climate and environmental elements from past 700,000 years in Dome Fuji ice core, Antarctica |
| VerfasserIn |
H. Motoyama, Dome Fuji Ice Core Project members |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250061982
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| Zusammenfassung |
| Two deep ice cores (DF1: 2503m and DF2: 3035m) at Dome Fuji, Antarctica have the
in-depth information of global environmental change from present to the past 700,000 years.
We made the data set of major ion concentration, dust concentration and stable isotope ratio
which were analyzed 10cm sample every 50cm from 2400m to 3035m using the DF2 core.
The age of this depth was covered from 300,000 to 700,000 years before. Using the DF1 core,
major chemical species were carried out using 7-10cm ice samples cut out of the 50
cm-long spaced from 0.5 to 2.5m. All data was averaged by every 5 m or every
1,000 years. The correlations between climate and environmental elements were
calculated.
The indexes of climate and environment are the following elements; MSA-,
Cl-, NO3-, SO42-, H+ (calculated from pH), Na+, NH4+, K+, Mg2+, Ca2+,
ss-Na+, nss-Cl-, nss-SO42-, nss-K+, nss-Mg2+, nss-Ca2+, δD, δ18O, d-excess,
dust, pH and electrical conductivity. There is a feature in correlation respectively
by the climatic stage. δD or δ18O which becomes the index of the temperature
and the environmental elements (for example, Na+ and Mg2+) indicate the strong
negative correlation, but its degree is different depending on the climatic stages. In
particular, environmental changes around Mid-Brunhes event (i.e. 430kyrBP) were
examined.
Ice core drilling reached just near the bedrock in ice sheet. Liquid water which existed
around the basal ice was soaked into the borehole. Its water was frozen and was picked up
with drill machine. Characteristics of ion concentrations near the bedrock (i.e, from 3000m to
3035m) were reported.
There was no big change in δ18O , δD and d-excess profiles in deeper part. Dust and
nssCa2+ concentrations did not show the conspicuous change between 3000m to 3034m.
They became high concentrations under 3034m. The concentration of Na+, SO42-, NO3-
became small but Cl- became large from 3020m to 3033.5m. The concentrations of all ion
components were suddenly decreased from 30033.5m.
The borehole measurement was carried out in January 2011. The items of borehole
measurements were; borehole diameter, ice temperature and liquid temperature, liquid
pressure, inclination of vertical borehole. The interesting vertical profiles of ice temperature
and borehole diameter were observed. We discuss the characteristics of basal ice and
subglacial water. |
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