基于重庆地区黑风洞石笋HF01的~(230)Th年代数据、灰度数据、氧同位素数据和Fe含量数据,重建了长江中上游地区全新世季风变化历史。结果显示石笋HF01的灰度值主要响应东亚季风变化,石笋灰度序列能够记录东亚全新世季风气候变化历史,即全新世早中期东亚夏季风增强,在6 ka B.P.以后季风逐渐减弱。石笋HF01的灰度序列清晰地记录了一系列的Bond事件,显示石笋灰度值对气候环境变化敏感,是可靠的气候环境信息载体;也进一步证明东亚季风不仅受太阳辐射驱动,还受高纬地区千年尺度的气候变化影响。石笋HF01灰度序列功率谱所呈现的55 a周期与太平洋数10 a尺度涛动(PDO)的50~70 a周期一致,45、25、23、22、18、12 a周期接近于太阳活动周期,说明在数十年至百年尺度上东亚季风可能受太平洋涛动和太阳活动的共同影响。
英文摘要:
Heifeng Cave(28°50'-29°20'N, 107°00'-107°20'E; 1 980 m above sea value) is located at the north slope of the Jinfo Mountains, and the climate here is controlled by Asian monsoon system, with abundant rainfall and high temperature in summer. Stalagmite HF01 was collected from Heifeng Cave, the research area in this paper. Based on the ~(230)Th dating results, grey scale data, oxygen isotope data and trace elements data, the grey scale time series of the stalagmite HF01 grown during the Holocene is established. Results suggest that the grey scale of stalagmite HF01 is controlled by the East Asian monsoon variability. The main trend of Holocene climate change is: in the early and middle Holocene, the summer monsoon of North Hemisphere increase gradually, and in late Holocene decreased continually; this change of stalagmite HF01 is reflected from both the evolution of delta~(18)O value and the grey scale of stalagmite. The grey scale of HF01 stalagmites responses to 8 cold events of the North Atlantic record, indicating that the grey scale of stalagmite is closely associated with variations in past climates and environments. Using the spectral analysis of Redfit 37, the main cycles of stalagmite records from grey scale are 55 a, 45 a, 40 a, 33 a, 25 a, 23 a, 22 a, 18 a, 16 a, 14 a and 12 a. The 55 a cycle may be related to the Pacific Decadal Oscillation(PDO), and 45 a, 25 a, 23 a, 22 a, 18 a, and 12 a cycles agree well with the solar activity, suggesting that the Pacific Decadal Oscillation(PDO)and solar activity changes may be partly responsible for centennial-decadal changes in East Asian monsoon.