Speleothem-derived Asian summer monsoon variations in Central China, 54-46 ka

The oxygen isotope signature (delta O-18) of stalagmite SI3 collected from Shizi Cave in north-east Sichuan Province provides an Asian Summer Monsoon (ASM) record in Central China for the period 54-46 ka. The SI3 delta O-18 record clearly shows a negative delta O-18 excursion centred around 49.4 ka, which was reported in Hulu Cave in East China but not identified in the speleothem records from South-west China. As a whole, this record displays a higher coherence with the two Hulu records from East China than with the speleothem delta O-18 records from South-west China, suggesting that at 54-46 ka, Central China was influenced more by the East Asian Summer Monsoon than by the Indian Summer Monsoon. It also displays a significant negative delta O-18 excursion at 47.5-46.6 ka, which is not clearly documented in two other speleothem delta O-18 records previously reported from South-west China. This suggests that details of the Greenland interstadial 12 warrant further investigations in future in monsoonal China. The SI3 delta O-18 record displays more significant centennial-scale variations than the other four speleothem delta O-18 records from East and South-west China, which may be due to the fact that the study site is closer to the north-west boundary of the ASM and more sensitive to variations of the ASM than East and South-west China. Copyright (C) 2011 John Wiley & Sons, Ltd.