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| Titel |
Reconstructing last 2000 years of temperature variation from Pyrenean caves
(N Spain) |
| VerfasserIn |
Ana Moreno, Miguel Bartolomé, Carlos Pérez, Carlos Sancho, Isabel Cacho, Heather Stoll, Antonio Delgado-Huertas, R. Lawrence Edwards, Hai Cheng |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250131612
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| Publikation (Nr.) |
 EGU/EGU2016-12040.pdf |
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| Zusammenfassung |
| The Central Pyrenees, and particularly the protected area known as Ordesa and Monte
Perdido National Park, is a high-altitude karstic region rich in cavities with active drips and
present precipitation of carbonates. Although not generally very abundant, there are
speleothems growths in several of those cavities. We present here (1) a three-year seasonal
monitoring survey to isolate the environmental parameters influencing isotopic composition
of farmed carbonate and (2) the last 2000 years isotopic record resulting from compiling
seven stalagmites from three different caves. In temperate regions such as the NE Iberian
Peninsula is difficult to discern the influences on δ18O variation in speleothems since
temperature, amount of precipitation or even source effect are usually acting simultaneously.
Main results after three years monitoring period indicate a strong dependence on air
temperature through its influence on rainfall δ18O, although a small amount effect is not
discarded. The good overlapping during the observational period of δ18O from
actively growing modern stalagmites and air temperature in the area supports this
dependence and provides a reliable proxy for the temperature evolution along last
millennia.
The stalagmites belong to three different caves (Seso, Gloces and B-1 caves) but still
present a very coherent isotopic signal allowing us to discard local effects (diagenetic
imprint, non-equilibrium fractionation) and to produce a stacked record with decadal
resolution. Interpreting this signal as regional temperature variation divides the
temporal sequence in five main periods, in consonance with historical stages. Thus, a
continuous decrease in temperature characterized the end of the Roman period
(0-500 AD). Lower temperatures are dominant during “Dark Ages” (500-1000
AD) that increase during the Medieval Climate Anomaly (MCA, 1000-1400 AD).
Following this warm period, the cold signal during the Little Ice Age is very well
replicated in several speleothems, even for short events lasting less than a decade. The
warming that identifies the Industrial Era (from 1850 AD to present day) is also well
document.
This reconstruction is in striking similarity with other high-resolution records in Europe
and, particularly, with global temperature reconstructions for last 2000 years. In addition, the
fact that the δ18O signal presented here is so well replicated in speleothems from
different caves gives strong support to our interpretation and opens the door to further
research on Pyrenean speleothems as exceptional archives of thermal oscillations. |
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