Variation in carbon isotopic composition over the past ca. 46,000Â yr in the loess-paleosol sequence in central Kazakhstan and paleoclimatic significance

We present a high resolution record of δ13Corg variation from two loess sequences in central Kazakhstan. The variation shows that the vegetation was persistently dominated by C3 plants over the past ca. 46,000 yr. The δ13Corg signature was most likely an indicator of moisture and the moisture variation in central Kazakhstan was associated with the precipitation in Western Europe. The δ13Corg indicated that moisture variation exhibited five stages: decreasing during stage 1 (ca. 46,000-ca. 31,500 yr BP), increasing during stage 2 (ca. 31,500-ca. 25,500 yr BP), again decreasing during stage 3 (ca. 25,500-ca. 19,000 yr BP), fluctuating along a constant line during stage 4 (ca. 19,000-ca. 5000 yr BP) and increasing during stage 5 (last ca. 5000 yr). Our comparison demonstrated a general similarity between the δ13Corg-indicated moisture variation in central Kazakhstan and the reconstructed precipitation variation in Western Europe. The similarity implies that the moisture of the past ca. 46,000 yr in central Kazakhstan has been controlled or modulated by westerlies that brought water vapor from the North Atlantic not only to Western Europe but also to central Kazakhstan.