Laboratory of Quaternary Geochronology
Contact: Anatoli Molodkov
Since the mid-1970s the laboratory has been engaged in research in the field of luminescence, and since the early1980s – in research in the field of ESR dating of mollusc fossils. As a result, new versions of ESR/OSL techniques have been developed in the recent years for age determinations of marine, freshwater and terrestrial mollusc shells and enclosing deposits.
Marina Osipova is operating the electron spin resonance (ESR) ERS-221 type spectrometer - one of the main facilities in the Research Laboratory for Quaternary Geochronology
Now the Tallinn Research Laboratory for Quaternary Geochronology (RLQG) is one of the very few in the Western and Central European countries as well as in the former Soviet Union, which can provide at least three up-to-date Radiation Exposure Dating Methods – Electron-Spin-Resonance (ESR), Thermally- and Optically- (infrared-light) Stimulated Luminescence (TL, OSL). A new promising optically stimulated afterglow (OSA) method is currently under development. Together they are applicable over a time range from about hundred years to almost a million years on various naturally occurring minerals: biogenic carbonates, such as terrestrial, freshwater and marine mollusc shells, corals (by ESR), and minerals (quartz and feldspar) common in aeolian (e.g., sand dunes, loess) and waterlain (e.g. fluvial, lacustrine, marine) deposits (by TL and OSL). Combined use of the above-mentioned methods is enormously valuable because it can provide an independent age estimation for Quaternary deposits and cross check often urgently needed to estimate the reliability of the dates obtained.
ESR/OSL are described as Radiation Exposure Dating Methods because each is used to determine the total radiation dose absorbed by a mineral since it was last exposed to a “clock-resetting” event. For luminescence dating of sediments the clock-resetting event is the exposure to sunlight which sediment grains undergo during transport and the process of sedimentation. The ESR signal is not affected by exposure to ordinary light. The “clock-resetting event” in ESR is the creation of a mineral, e.g. the growth of shell skeleton by molluscs. After burial shell is acting as natural radiation dosimeter.
The main trend of the research activity, the laboratory has long been engaged in, is the feldspar-based IR-OSL and mollusc-based ESR-study of Quaternary sedimentary dynamics and environmental changes in the Northern Eurasia (including the high-Arctic) region. The major goal of the work is to establish the periodicity and chronology of the main Quaternary events and their relationship with changes in the level of marginal seas and inland bodies of water, to create a climato-chronostratigraphic framework for North Eurasian Pleistocene to provide regional and interregional correlations and the linkage between marine and terrestrial data sets.
The research in the field of Mid- Late Pleistocene ESR/IR-OSL-geochronology combined with sedimentology, palynology, diatom analysis, etc., remains to be a highly important tool for chronostratigraphic studies on the vast territories of Eurasian north, especially when the age of the sample is greater than the 40-50,000 year limit of radiocarbon dating.
In addition to our own research projects, we offer also a dating service for luminescence and resonance dating of archaeological, environmental and geological contexts. This includes infrared optically stimulated luminescence (IR-OSL) dating of sediments and electron-spin-resonance (ESR) dating of freshwater, terrestrial and marine mollusc shells. The prices for
ESR/IR-OSL dates depend on the nature and number of samples. Please contact the RLQG for further details.