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| Titel |
Decoupled evolution of temperature and precipitation in western Germany during the Last Interglacial reconstructed from a precisely dated speleothem |
| VerfasserIn |
Denis Scholz, Dirk Hoffmann, Christoph Spötl, Peter Hopcroft, Augusto Mangini, Detlef K. Richter |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250041637
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| Zusammenfassung |
| We present high-resolution stable oxygen and carbon isotope (δ18O and δ13C) as well as
trace element profiles for stalagmite HBSH-1 from Hüttenbläserschachthöhle, western
Germany. The chronology was established by MC-ICPMS 230Th/U-dating, and the high
U-content of the stalagmite allowed determination of very precise 230Th/U-ages although
using very small sample sizes. The beginning and end of individual growth phases of the
stalagmite could, thus, be determined very accurately.
Stalagmite HBSH-1 grew during the penultimate interglacial (MIS 7), the Last
Interglacial (MIS 5) and the Holocene. The major part of the sample (40 cm) grew between
130 and 80 ka providing a climate record with decadal to centennial resolution for this period.
The record shows three growth interruptions during MIS 5 coinciding with Greenland
Stadials 25, 24 and 22, as recorded in the NGRIP ice core (North Greenland Ice Core Project
members, 2004). The end of the MIS 5 growth phase coincides with GS 21. This
shows that stalagmite growth in this area is a very sensitive proxy for northern
hemisphere cooling. Correlation of the absolutely dated stalagmite record with
Greenland ice cores may provide a tool to improve the chronology of the Greenland
Stadials.
The δ18O profile of stalagmite HBSH-1 shows a distinct similarity during MIS 5 with the
NGRIP ice core and a sea surface temperature record from the Iberian Margin (Martrat
et al., 2007). This suggests that stalagmite δ18O mainly reflects past temperature
variability.
Stalagmite HBSH-1 consists of aragonite rather than calcite, which is probably
a result of pronounced prior calcite precipitation in the epikarst above the cave
(Fairchild and Treble, 2009). In this case, the δ13C signal rather reflects changes in past
precipitation than temperature. The δ13C record of HBSH-1 shows three pronounced
negative peaks during MIS 5, in agreement with the three MIS 5 warm phases,
MIS 5e, 5c and 5a. During the Last Interglacial, however, the evolution of δ18O
and δ13C, and thus temperature and precipitation, is opposite. Whereas the δ18O
signal suggests the warmest temperatures around 125 ka followed by a gradual
decrease, the δ13C signal indicates wetter conditions towards the end of the Last
Interglacial.
The decoupling of temperature and precipitation during this time period is also seen in a
series of snapshot simulations performed using a fast coupled ocean-atmosphere general
circulation model. This behaviour can be explained by the influence of varying solar
insolation patterns (in response to changing orbital configuration) on atmospheric dynamics
and the resulting influence on storm activity in the region.
References
Fairchild, I. J. and Treble, P. C., 2009. Trace elements in speleothems as recorders of
environmental change. Quaternary Science Reviews 28, 449-468.
Martrat, B., Grimalt, J. O., Shackleton, N. J., de Abreu, L., Hutterli, M. A., and Stocker,
T. F., 2007. Four climate cycles of recurring deep and surface water destabilizations on the
Iberian Margin. Science 317, 502-507.
North Greenland Ice Core Project members, 2004. High-resolution record of Northern
Hemisphere climate extending into the last interglacial period. Nature 431, 147-151. |
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