High - Resolution Records Of The Shennongjia Cave In The East Asian Monsoon Climate During The Last Interglacial

The Last Interglacial is the most recent one near to the Holocene whose climatic boundary conditions are simlar, so it is extremely important to explore the evolution and difference between the last interglacial and the Holocene climate, which is quite useful to research the evolution and formation mechanism of modern climate under the natural conditions, thereby the future climate prediction will turn into possibility.The research stalagmite named YX108in the article was collected from Yongxing Cave of Shennongjia, in Hubei Province. And the1840mm stalagmite is characterized by clear and continuous annual layers. Based on the six U/Th absolute dates,1701annual layers,1837isotope data of the YX108, high precision and resolution time series from122.483～120.786ky BP have been firstly reconstructed. And the oxygen and carbon isotope time series is consistent with the trend of65°N summer insolation, which indicates that the last interglacial climate change in the region as a whole is controlled by changes in solar radiation. In the decade-centennial scale, both oxygen and carbon isotope curves record seven weak monsoon events, which also can be catched by stalagmite D3in Dongge Cave. However, the istope profiles evolve differently in the climate transition phase, such as the chang in the carbon profile laging behind the oxygen one for about74y, which indicates vegetation changes response but lag to climate change. The laminae thickness and gray curves of YX108show significant peak to valley characteristics, suggesting that both have the same drive mechanism.And then, comparing the last interglacial oxygen isotope record in Yongxing Cave of Shennongjia to the Holocene one in Dongge Cave of Libo, it is found that there are some similar and some different features in overall trends, oxygen isotope average value, shock characteristics and Weak monsoon events records. Firstly, in the general trend, both showed a downward trend, but trend in YX108is more obvious than that in DA; Secondly, in the oxygen isotope average value, both records are negative, but the YX108records is more negative than DA. Thirdly, the last interglacial YX108recod and Holocene DA both show the high frequency oscillation characteristics, while the oscillation frequency of Yongxing is highe. Finally, the two curves both record weak monsoon events, and there is a good correspondence. These comparative results show that solar radiation, greenhouse gases and so on, are the main climate background affecting interglacial climate different change.The spectral analysis on the carbon and oxygen isotopic composition, laminae thickness and gray curves of YX108show the climate in Shennongjia has the significant and similar solar activity cycle (11～13,9,15～20,23～26,31～41,147,162and212yr), illustrating that solar activity is the main controlling factor to drive the last interglacial climate change in decadal scale.