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| Titel |
Late Quaternary sediment deposition of core MA01 in the Mendeleev Ridge, the western Arctic Ocean: Preliminary results |
| VerfasserIn |
Kwang-Kyu Park, Sunghan Kim, Boo-Keun Khim, Wenshen Xiao, Rujian Wang |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094341
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| Publikation (Nr.) |
 EGU/EGU2014-9748.pdf |
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| Zusammenfassung |
| Late Quaternary deep marine sediments in the Arctic Ocean are characterized by brown
layers intercalated with yellowish to olive gray layers (Poore et al., 1999; Polyak et al., 2004).
Previous studies reported that the brown and gray layers were deposited during interglacial
(or interstadial) and glacial (or stadial) periods, respectively. A 5.5-m long gravity core MA01
was obtained from the Mendeleev Ridge in the western Arctic Ocean by R/V Xue Long
during scientific cruise CHINARE-V. Age (~450 ka) of core MA01 was tentatively
estimated by correlation of brown layers with an adjacent core HLY0503-8JPC
(Adler et al., 2009). A total of 22 brown layers characterized by low L* and b*,
high Mn concentration, and abundant foraminifera were identified. Corresponding
gray layers are characterized by high L* and b*, low Mn concentration, and few
foraminiferal tests. Foraminifera abundance peaks are not well correlated to CaCO3
peaks which occurred with the coarse-grained (>0.063 mm) fractions (i.e., IRD)
both in brown and gray layers. IRDs are transported presumably by sea ice for the
deposition of brown layers and by iceberg for the deposition of gray layers (Polyak et
al., 2004). A strong correlation coefficient (r2=0.89) between TOC content and
C/N ratio indicates that the major source of organic matter is terrestrial. The good
correlations of CaCO3 content to TOC (r2=0.56) and C/N ratio (r2=0.69) imply that
IRDs contain detrital CaCO3 which mainly originated from the Canadian Arctic
Archipelago. In addition, high kaolinite/chlorite (K/C) ratios mostly correspond
to CaCO3 peaks, which suggests that the fine-grained particles in the Mendeleev
Ridge are transported from the north coast Alaska and Canada where Mesozoic and
Cenozoic strata are widely distributed. Thus, the Beaufort Gyre, the predominant
surface current in the western Arctic Ocean, played an important role in the sediment
delivery to the Mendeleev Ridge. It is worthy of note that the TOC and CaCO3 peaks
are obviously distinct in the upper part of core MA01, whereas these peaks are
reduced in the lower part of the core. More study on these contrasting features is in
progress.
References
Adler, R.E., Polyak, L., Ortiz, J.D., Kaufman, D.S., Channell, J.E.T., Xuan, C., Grottoli,
A.G., Sellén, E., and Crawford, K.A., 2009. Global and Planetary Change 68(1-2),
18-29.
Polyak, L., Curry, W.B., Darby, D.A., Bischof, J., and Cronin, T.M., 2004. Palaeogeography,
Palaeoclimatology, Palaeoecology 203, 73-93.
Poore, R., Osterman, L., Curry, W., and Phillips, R., 1999. Geology 27, 759-762. |
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