Overview - Cluster F - Time Frame
|Speaker: Prof. Dr. J. Rethemeyer|
In order to reconstruct and understand the often complex human-environment interaction during the spread of modern humans, it is necessary to develop robust models in which the archaeological, biological and terrestrial archives are correlated to each other, as precisely as possible, in terms of age sequences and geochemical properties. Cluster F provides a wide range of state-of-the-art dating techniques, namely:
- Radiocarbon 14C AMS dating and initial 10Be and 26Al dating (F1),
- Thermo and Optically Stimulated Luminescence (TL and OSL) and Electron Spin Resonance (ESR) dating (F2),
- Uranium-Thorium (U-Th) dating (F4).
Notwithstanding the fact that 14C, TL / OSL, ESR and U-Th dating have been successfully used in the past to establish age control for geoarchaeological and geological archives, various methodological issues require further investigation. The projects of Cluster F deal with calibration issues particularly in difficult materials or time periods and aim at improving the accuracy and precision of the individual methods using samples from reference-sites. All of these projects can be used as support for other CRC investigations in Clusters A-D. Vice versa, the framework of the CRC provides the opportunity to work on specific case studies, to allow necessary validation. Joint processing of archaeological and terrestrial archives offers many possibilities for combining the specific advantages of different dating methods, both in terms of the achieved analytical accuracy and precision, as well as in relation to systematic dating offsets, which are otherwise notoriously difficult to identify. Such close cooperation during the initial planning phases, simultaneous fieldwork (on-site), joint laboratory studies, and common publications is a central component of the planned CRC.
Another key issue of the CRC is the recognition of human impact from sediments. Black carbonic remnants (BC), the so-called black carbon, provide an ideal but long neglected indicator for doing this. BC, a component of charcoal, is a preferred reference, as it consists of black carbon that is presumed to be stable and little contaminated by recent organic matter. Hence, especially the joint application of dating tools and specific BC marker methods will provide a unique opportunity to successfully link the work of archaeologists, geomorphologists, geochronologists and palaeoecologists (F3). For example, BC traces fires beyond the limits of radiocarbon dating at ca. 50 ka; these events can be fixed by OSL or TL dating of associated sediments or stone tools. Exciting new data for archaeology may derive from flint dating beyond the 14C limit and from the ESR dating of teeth.
Thus, the aims of Cluster F comprise: (1) constructing homogeneous data sets to provide chronologies of regional and supra-regional validity for all CRC projects, (2) improving dating accuracy and calibration by systematically comparing radiocarbon dating and data from the family of trapped charge dating techniques (TL, OSL, ESR) and (3) introducing and expanding the use of BC as a maker of human impact.
With the co-existence of an internationally well-established Radiocarbon Dating Laboratory at the Institute of Prehistoric Archaeology and the new 6 MV AMS facility for cosmogenic nuclides to be fully established in Cologne by 2011/12 (F1), the equally renowned Laboratories for Luminescence and Electron-Spin-Resonance (ESR) Dating in the Department of Geography (F2), and the U/Th laboratory to be set up at the Institute of Geology and Mineralogy in 2008/09 (F4), the University of Cologne has a unique position in Germany with respect to geoarchaeological dating facilities. Jointly with compoundspecific datings and analyses of terrestrial biomarkers at the University of Bonn (F3), this scientific platform offers a favourable starting-point for approaching the wide variety of questions that can be expected for the CRC.