Project (DFG - Funded Temporary Position for Principal Investigator):
Annual-resolution temperature and precipitation reconstruction for Central Europe using Holocene stalagmites
High resolution palaeoclimate reconstruction provides important information for the understanding of our climate system. The most prominent climate archives providing annual resolution are tree-rings, but some speleothems also show annual laminae and have a large potential for past climate reconstruction with an annual resolution. Whereas tree-rings mostly record the climate signal of the summer months, annually laminated speleothems can conserve climate information of different seasons and, in particular, of the winter season.
In the framework of the current project, three different types of annual lamination have been observed in the stalagmites from Zoolithencave (southern Germany): visible, fluorescent, and element laminae. Both lamina thickness and elemental variability have been shown to be proxies for past precipitation variability. Furthermore, preliminary annual-resolution d18O and d13C records for the last 200 years have been determined in a recent stalagmite from Zoolithencave. The d18O values show a significant correlation with instrumental winter temperature highlighting the great potential of these samples for annual-resolution winter temperature reconstruction. Thus, the stalagmites from Zoolithencave are ideal for annual-resolution reconstruction of both past temperature and precipitation variability.
The aim of the renewal project is to create annually resolved temperature (for last 3000 years, based on annual-resolution d18O values) and precipitation (for the entire Holocene, based on annual-resolution lamina thickness and elemental records) reconstructions. An additional stalagmite from Zoolithencave will be sampled in order to fill the gaps in the current chronology. This will result in a continuous record of visible and elemental laminae covering the entire Holocene, as well as a continuous record of d13C and d18O values for the last 3000 years, both with a replication of one to four records. Annual-resolution temperature and precipitation records of this length are not available yet for Central Europe.
The resulting proxy records will mainly reflect past winter climate. Comparison with other high resolution climate records, such as tree-ring chronologies, which record spring/summer climate conditions, will, thus, provide information on climate variability during different seasons. Furthermore, the resulting records will enable the detection of short-term extreme climate events.