Charcoal and wood remains for radiocarbon dating Upper Pleistocene loess sequences in Eastern Europe and Central Siberia

The present paper concerns long Upper Pleistocene loess sequences from Eastern Europe with multiple Upper Palaeolithic occupations, rich in charcoal, as well as loess sequences from Central Siberia with abundant wood remains. These complementary records have allowed establishing a high-resolution climatic sequence integrating 24 interstadial episodes between ca 42.5 and 10 kyr BP. Here, we discuss the methodology of dating used to fix the chronological framework of this climatic sequence, based on a set of 240 available radiocarbon dates, mainly produced on charcoal and wood remains.Special attention is paid to the strategy of sampling charcoal and wood material in strict accordance with stratigraphy, as well as to the preparation process in the laboratory for extraction, cleaning, identification and selection of the best fragments to date. Careful stratigraphic drawing and detailed positioning of the samples for each geological layer are also considered in order to clarify the relationship of the obtained dates with respect to any sedimentary, pedological or archaeological event to be dated. The reliability and accuracy of the dates obtained from loess sequences are further controlled by the internal consistency with regard to stratigraphy. Palaeoenvironmental implications are also discussed. (C) 2010 Elsevier B.V. All rights reserved.