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| Titel |
Biotic response of benthic foraminifera to ~4 ka cooling event in the Nakdong River delta of the southeast Korea |
| VerfasserIn |
Hiroyuki Takata, Boo-Keun Khim, Daekyo Cheong, Seungwon Shin |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147386
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| Publikation (Nr.) |
 EGU/EGU2017-11545.pdf |
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| Zusammenfassung |
| It has been reported that the cooling event at 4 ka caused climatic deterioration in the
world, which is closely associated with the decline/development of the civilizations
(e.g., Kawahata et al., 2009). In particular, various climate events at about 4 ka
have been reported in the East Asian margin such as the decline pattern of total
sulfur content in Lake Tougou-ike (southwest Japan) (Kato et al., 2003), and the
enhanced precipitation and freshwater event in northeast China (Hong et al., 2005)
and South Korea (Lim et al., 2015). We investigated fossil benthic foraminiferal
faunas at two borehole cores (ND-01: landward site and ND-02: seaward site) drilled
at the Nakdong River delta in the southeastern coast of Korea, in order to reveal
whether the paleoclimate changes across 4 ka occurred in the southeast Korea. The
planktonic/total foraminiferal ratio (P/T ratio) and MDS axis 1, representing the faunal
composition, show temporal decline at 4 ka at core ND-01, despite no marked
change at core ND-02. In contrast, MDS axis 2, which is negatively related to the
dominance of Haynesina sp. A (an opportunistic species in organic-rich condition of
neritic environments), at core ND-01 shows positive shift across 4 ka. These biotic
changes are interpreted as the increase of river water discharge with rainfalls by
East Asian summer monsoon and the weakening of northwestly winds possibly
with East Asian winter monsoon. Thus, despite insufficient, benthic foraminifera in
the Nakdong River delta likely experienced the paleoclimate change across 4 ka. |
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