资源环境科技发展态势分析平台

As a unique continental archive, speleothem has been widely used in reconstructing paleoclimate change. However, the interpretation of Chinese speleothems delta O-18 has remained a subject of debate. Recently, a Community Atmosphere Model version 3 (CAM3) study indicated that the stalagmite delta O-18 from eastern China reflected the Indian summer monsoon (ISM) intensity rather than the East Asian summer monsoon (EASM) intensity during Heinrich events. Here, we present a high-resolution speleothem delta O-18 record from Xianglong Cave in Shaanxi province, China, covering the period of 25.5-10.9 ka BP. The XL15 record shows similar variations with ice core record from Greenland and other climate records from China and India on millennial scale, including Heinrich 2 (H2), Heinrich 1 (H1), Bolling-Allerod (BA) and Younger Dryas (YD) events, supporting the connection between the Asian monsoon and northern high latitude climate. The delta O-18 amplitude of our record is larger than or similar to the stalagmite delta O-18 records from India during these events. In addition, differences of stalagmite delta O-18 in eastern China and the ISM region were observed on glacial-interglacial as well as decadal timescales. That means the ISM is not the sole controlling factor of Chinese stalagmite delta O-18 during Heinrich events. When subtracting the Indian stalagmite delta O-18 series from our XL15 record during H1 period, we found a significant negative correlation with sea surface temperature (SST) record of Western Pacific Warm Pool (WPWP). Consequently, our study suggests that the Chinese stalagmite delta O-18 is controlled by both the ISM and EASM on orbital-, millennial-, and decadal timescales.