A NEW 14C DATA SET OF THE PY608W-PC SEDIMENT CORE FROM LAKE PUMOYUM CO (SOUTHEASTERN TIBETAN PLATEAU) OVER THE LAST 19 KYR

A new continuous sediment core (PY608W-PC; 3.8 m length) for reconstruction of climatic and environmental changes in the southeastern Tibetan Plateau was taken from the eastern part of Lake Pumoyum Co in August 2006. Sediment layers of the lower part of PY608W-PC (380-300 cm depth) were composed mainly of relatively large plant residues (up to similar to 3 cm in length) with an admixture of fine sand and sandy silt. The large plant residues disappeared at 300-290 cm depth in core PY608W-PC and were replaced by silt-silty clay. The large plant residues from the lower part of PY608W-PC could be aquatic, because the plant residues were extremely enriched in C-13 (up to -3.0 parts per thousand, -5.6 +/- 2.3 parts per thousand on average). On the other hand, the plant residue concentrates (PRC fractions) from the upper part of the core (290-0 cm in depth) could be terrestrial C-3 plants (delta C-13 = -21.8 +/- 1.7 parts per thousand on average). Radiocarbon dating was performed on the large plant residues and PRC fractions from the PY608W-PC sediment core, which represented the chronology from similar to 19,000 cal BP to present.