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| Titel |
Dependence of the cyclization of branched tetraethers on soil moisture in alkaline soils from arid–subhumid China: implications for palaeorainfall reconstructions on the Chinese Loess Plateau |
| VerfasserIn |
H. Wang, W. Liu, C. L. Zhang |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 23 ; Nr. 11, no. 23 (2014-12-08), S.6755-6768 |
| Datensatznummer |
250117715
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| Publikation (Nr.) |
 copernicus.org/bg-11-6755-2014.pdf |
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| Zusammenfassung |
| The use of branched glycerol dialkyl glycerol tetraethers (bGDGTs) in
loess–palaeosol sequences (LPSs) has shown promises in continental
palaeotemperature reconstructions. Thus far, however, little is known about
the effect of soil moisture on their distributions in the water-limited
Chinese Loess Plateau (CLP). In this study, the relationships between
environmental variables and the cyclization of branched tetraethers (CBT)
were investigated in arid–subhumid China using 97 surface soils in the CLP
and its vicinity, as well as 78 soils with pH > 7 which have been
previously published. We find that CBT correlates best with soil water
content (SWC) or mean annual precipitation (MAP) for the overall data set.
This indicates that CBT is mainly controlled by soil moisture instead of
soil pH in alkaline soils from arid–subhumid regions, where water
availability is a limiting factor for the producers of bGDGTs. Therefore, we
suggest that CBT can potentially be used as a palaeorainfall proxy on the
alkaline CLP. According to the preliminary CBT–MAP relationship for modern
CLP soils (CBT = −0.0021 × MAP + 1.7, n = 37, r = −0.93),
palaeorainfall history was reconstructed from three LPSs (Yuanbao, Lantian,
and Mangshan) with published bGDGT data spanning the past 70 ka. The
CBT-derived MAP records of the three sites consistently show
precession-driven variation resembling the monsoon record based on
speleothem δ18O, supporting CBT as a reasonable proxy for
palaeorainfall reconstruction in LPS. The direct application of CBT as a
palaeorainfall proxy in corroboration with the bGDGT-based temperature proxy
may enable us to further assess the temperature/hydrological association for
palaeoclimate studies on the CLP. |
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