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Quaternary stratigraphy and sea level changes have been extensively investigated in many areas of the Mediterranean. However, numerical dating of coastal deposits and the associated paleoenvironmental information are limited for the coasts of Cyprus, principally based on radiometric and radiation-exposure geochronological techniques on fossils which bear a range of limitations and uncertainties. As such, optically stimulated luminescence (OSL) dating techniques are deemed to be the most suitable in direct dating of the coastal sediments of Cyprus. In the southeastern Cyprus, coastal dunes (aeolianites) now forming elongated ridges appear as morphological features running parallel to the current shoreline presenting an indicator of sea level and climate changes of great paleoenvironmental significance. We present our first chronological results for the exposed aeolianites and underlying littoral deposits formed along the southeastern coastal Cyprus ranging from 78.4 ± 9.9 to 56.2 ± 7.4 ka. The post-infrared-infrared stimulated luminescence (pIR-IRSL) revealed that dune formation took place during the marine isotope stages (MISs) 3, 4, and possibly 5a. Late Holocene reworking is proposed for a distinctively isolated dune with an age of ~1.3 ka ago. This study also showed that pIR-IRSL dating of feldspars may be a reliable alternative to quartz OSL dating when the quartz luminescence characteristics are unsuitable. [ABSTRACT FROM AUTHOR]

Abstract Accurate determination of the environmental radiation dose-rate is crucial for dosimetric dating methods. Two approaches for dose-rate estimation are currently employed: (1) calculating and summing up individual dose-rate components, including propagation of uncertainties and (2) simulating the radiation field and calculating the absorbed dose using a Monte Carlo approach. Here we compare dose-rate estimation using the two aforementioned approaches, applied to six sedimentary quartz samples with differing radionuclide concentrations, chemical composition, grain-size distribution and water content and to one heterogeneous archaeological sample. For approach (1) two web-based, freely accessible calculators, "Dose-Rate calculator" (DRc), "Dose Rate and Age Calculator" (DRAC) and a bespoke spreadsheet were used. For approach (2) DosiVox, a Geant4 Monte Carlo simulation toolkit was employed which allows the definition of material properties such as chemical composition, density and porosity in addition to radionuclide concentrations and water content in a three dimensional geometry. The sensitivity of dose rate to material properties, usually assumed to be constant over the burial time scale, was also tested. The results obtained using the three dose-rate calculators for sedimentary quartz samples are consistent within uncertainties, mainly because the conversion and correction factors are all taken from the same references. Comparing these results with those obtained from DosiVox simulations show grain-size dependent dose-rate differences, caused by the charge build-up and attenuation of the irradiated grain-size fraction. Moreover, it reveals that the effect of porosity and moisture on dose rate is grain-size dependent. For the heterogeneous archaeological sample the total dose rate determined by a calculator is inaccurate for the alpha- and too precise for the beta dose-rate. We conclude that the standard approach to dose-rate estimation is robust and that DosiVox is an important diagnostic tool for samples originating from complex environments. Highlights • Dose rates (DR) from sedimentary and archaeological samples were determined using two approaches. • Three commonly used dose-rate calculators were employed, as well as Monte Carlo simulation using DosiVox. • DR are consistent within uncertainties confirming robustness of the commonly used approach but calculated uncertainties vary between techniques. • Monte Carlo simulations reveal the impact of heterogeneous sedimentary environment on the DR accuracy. [ABSTRACT FROM AUTHOR]