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| Titel |
An absolutely dated high-resolution stalagmite record from Lianhua Cave in central China: Climate forcing and comparison with Wanxiang Cave and Dongge Cave records over the past 2000 years |
| VerfasserIn |
Hong-Chun Li, Jian-Jun Yin, Chuan-Chou Shen, Horng-Sheng Mii, Ting-Yong Li |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250104054
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| Publikation (Nr.) |
 EGU/EGU2015-3475.pdf |
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| Zusammenfassung |
| A 33-cm long aragonite stalagmite (LHD-1) from Lianhua Cave has been dated by
MC-ICPMS 230Th/U method on 41 horizons. Very high U contents (1~6ppm) and low Th
contents yield excellent 230Th/U dates which provide reliable chronology of the stalagmite on
sub-decadal time scale over the past 3350 years. A total of 1716 samples have been measured
for δ18O and δ13C, spanning annual resolution over the past 1820 years. The stalagmite δ18O
is not only influenced by the “amount effect”, but also affected by the moisture
source. Enhanced the tropical monsoon trough under strong EASM brings higher
spring quarter rainfall with isotopically light monsoonal moisture in the cave site,
resulting in lighter stalagmite δ18O. On decadal or longer time scales, increased solar
activity produces warmer condition and stronger summer monsoon which lead to wet
climates. On interannual-to-decadal scales, the Walker Circulation under El Niño
conditions during cold periods will shift toward the central Pacific and result in
weakening of EASM. Under such a circumstance, dry climates will be prevailed in the
study area. Based on the δ18O and δ13C records, we have deciphered climatic and
vegetation changes of the study area in decadal scales. The highly precise dated
LHD-1 record has been compared with previous published Wanxiang Cave and
Dongge Cave records. Although some similarities can be found, there are major
discrepancies among the three well-dated records, especially during AD 500-700
and AD 1300-1600. In additional, the major weak monsoon periods defined in
the Wanxiang Cave record during late Tang Dynasty, late Yuan Dynasty and late
Ming Dynasty are not supported by the LHD-1 record. The heaviest δ18O peaks
(more than five continuous heavy values) over the past 2000 years appeared around
AD 1990-2003, 1657-1662, 1220-1228, 663-669, 363-370, and 1082-1090 (in the
order of heavy to light). None of these periods occurred Chinese dynasty collapse. |
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