The Stalagmite Record Of The Cave Environment Evolution In The MIS11 Stage

Compared with the climate fluctuations on the orbital scale,the internal oscillation law of the short-scale climate system directly relates to the major environmental problems in the current survival and development of human society.The coupling mechanism between internal drive and solar radiation has become a hot spot in the current research of paleoclimatology.Based on the limited paleoclimate carriers,There are relatively few studies on millennium scale events during MIS11.Here we present a typical Asia summer monsoon record of a stalagmite(LS33)from Luoshui Cave,constrained by 15 U/Th data and 721 ?18O and ?13C isotopic subsamples and trace elements,to reconstruct the Asian summer monsoon climate evolution with a 70-year average resolution-during the MIS11 stage(435.99-365.12 ka BP).Compared with the same area ?18O records of the Sanbao and Jinfo Caves,the long-term evolution trend and millennium scale events of the three caves show good correspondence,indicating that large area scale atmospheric circulation to control the Asian summer monsoon intensity,and the LS33 stalagmite ?18O records reflect changes in Asian summer monsoon intensity.Altholgh the stalagmites ?13C record has complex responsiveness,it has certain potential in the reconstruction of the quaternary climate change.Compared the ?13C with the ?18O record,we found that the two curves show distinctly different characteristics in the evolution trend,high-frequency oscillation and orbital-scale periodic cycle.On the contrary,?13C is consistent with the LR04 ice volume curve,indicating that the ?13C is controlled by the changes of global temperatures rather than precipitation on the orbital scale.The The strong coupling relationship between ?18O and ?13C records indicates that the oxygen and carbon isotopes may be controlled by the same climate driving factor when they are removed the signal of orbital scale.It supports the view that ?13C may represent soil CO2 yield under the influence of soil effective humidity on the millennium scale.We extend the link between the millennium scale event and the internal driving mechanism of the Earth to MIS11 internal MIS11a and MIS11c.Comparing with other Paleoclimate records,it is found that the weak monsoon event recorded by stalagmite?18O during MIS11a seems to have a certain correspondence with the Antarctic EDC ice core record,supporting the anti-phase relationship between the northern and southern hemispheres.At the same time,using Matlab wavelet analysis and EEMD analysis method,the results show that the millennium scale period is more obvious during MIS11a,such as 2ka,3?4ka,and 6ka with weak signal.There are lka and 2?4ka cycles in the MIS11c,which are consistent with the Greenland ice core record and the analysis period of the North Atlantic ice drift debris event.It indicates that the millennial monsoon events may be affected by the internal driving factors of the climate system(such as global ice volume)under the background of solar radiation at different external periods.Further comparing the residual data of Sambao,LS26 and LS33 stalagmite ?18O record with Sima simulation results for 440,000 years,our results support the simulation results of Sima:medium ice condition or inter-ice order to ice level conversion process,sea-ice is slowly and fully exchanged,and the DO event occurs.It shows that the ice content inside the earth has a regulatory effect on the evolution of the monsoon millennium scale events recorded by stalagmites.