 |
| Titel |
Magnetic susceptibility as a high-resolution climate proxy in lacustrine sediments of the Qaidam paleolake (NE Tibetan Plateau) throughout the Quaternary |
| VerfasserIn |
Christian Herb, Erwin Appel, Andreas Koutsodendris, Silke Voigt, Jörg Pross, Weilin Zhang, Xiaomin Fang |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250088563
|
| Publikation (Nr.) |
 EGU/EGU2014-2680.pdf |
|
|
|
|
|
| Zusammenfassung |
| Magnetic proxies in lacustrine archives play an important role as they are acquirable in
high resolution due to short measurement times. One premise for building a link
between magnetic properties and climate variation is to investigate what is controlling
their changes. The magnetic record of drill core SG-1 (940-m-long) in the Qaidam
Basin, in particular magnetic susceptibility (Ï), is a good example for the value
of magnetic properties concerning climate change. SG-1 was obtained from the
Chahansilatu sub-basin in the western, presently hyper-arid Qaidam Basin and contains late
Pliocene-Quaternary lacustrine sediments. Potential humidity sources in that region
during the past were primarily the Westerlies but also the East Asian monsoon. Time
markers for depth-time transformation of drill core SG-1 were previously acquired by
magnetostratigraphic and optical stimulated luminescence (OSL) dating, indicating a time
span from 2.8 to 0.1 Ma. Relating the high-amplitude variation of the Ï record to orbital
forcing and applying extensive time series analysis, a more detailed depth to time
transformation is achieved. To assess the climate sensitivity of Ï, the Ï record is compared
with other magnetic parameters and with palynological results. The pollen ratio
Artemisia/Chenopodiaceae (A/C) shows a good anti-correlation with Ï values,
except of the interval around ~1.5 Ma. Thus, for core SG-1 high and low Ï values
predominantly document dryer and less dry conditions, respectively. Our observations reduce
the possible mechanisms leading to the observed Ï variation to two interfering
scenarios: low-temperature oxidation (LTO) in the sedimentary source area and
a change of the catchment area. As a bottom line of this study, the updated time
frame of drill core SG-1 and the comparison of Ï with other magnetic properties
and palynological results lead to a well-dated, high-resolution record of humidity
fluctuations during the late Pliocene-Quaternary on the NE fringe of the Tibetan Plateau. |
|
|
|
|
|
|