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| Titel |
Climate variability inferred from physical principles of stalagmite growth - the case of GIB04a modern Gibraltar stalagmite |
| VerfasserIn |
D. Romanov, D. Mattey, G. Kaufmann |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250025810
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| Zusammenfassung |
| The knowledge about the basic physical and chemical processes governing the stalagmite
growth has increased significantly during the last years. A very detailed instrumental climate
record has been compared with the basic climatic parameters reconstructed from a stalagmite
(Gib04a) collected from a carefully selected site in the New St. Michaels Cave on the
Gibraltar Peninsula (Mattey D., Lowry D., Duffet J., Fisher R., Hodge E., Frisia S., 2008, A
53 year seasonally resolved oxygen and carbon isotope record from a modern Gibraltar
speleothem: Reconstructed drip water and relationship to local precipitation., Earth
and Planetary Science Letters, 269, 80-95). The authors demonstrate a very good
correlation between the known and the recovered signal for the period between 1951 and
2004. We use the climatic and isotope data recorded between 2004 and 2008 at
the same stations as input parameters for a numerical simulation and model the
stalagmite growing at this location. Our “numerical stalagmite” resembles the shape of
the collected one very closely. Both stalagmites have the same equilibrium radius,
and very similarly shaped growth layers. Also the modeled amplitude of the δ13C
variation along the laminae is close to the one of Gib04a. In a further step we invert
growth rate and equilibrium diameter of Gib04a using the procedure outlined in
Kaufmann G., Dreybrodt W., 2004, Stalagmite growth and paleo-climate: an inverse
approach., Earth and Planetary Science Letters, 224, 529-545, and try to reconstruct the
record between 1953 and 2004 from the morphology of Gib04a. We obtain a good
agreement for the diameter, the temperature and the drip rate. On the other hand
the predicted values for the PCO2 in the soil are much higher than the measured
ones.
These results show that our model is able to predict stalagmite growth, morphology and
isotope profiles successfully even for time scales in the order of years, but it also shows that
further efforts are necessary to describe the processes in the karst layer above the cave and
their influence on the speleothems. |
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