Chinese-Interstadial 24 Event Characteristics In A Stalagmite From Northern Guizhou Province

Millennial and sub-millennial climatic variability is observed during the past glacial-interglacial cycles retrieved from ice-core and sedimentary proxy records. MIS 5, a period at 130-70 kyr B.P. of relative small ice sheet extent, was characterized by remarkable long and low-frequency GIS event compared to MIS 3.However, it remains uncertain about the behaviors of the Chinese Interstadials (CIS) events sub-cycle variability and its the linkages with the northern high latitudes during this period.Sanxing Cave (107°11'E,27°22'N,720 m a.s.l.) with a depth of?2 km, is located in Tiechang Town,-70 km southeast of Zunyi City, Guizhou Province, southwest China. This region is strongly influenced by the Asian summer monsoon (ASM) with the peak monsoon precipitation in the summer (JJA) and the dry season in winter (DJF). The annual average precipitation is?1000 mm and the mean temperature is 13.5?. Cave temperature is 12.8?(In April 2010). This region is dominated by the subtropical broadleaf evergreen and deciduous mixed forests.We tested 7 high-precision 230Th ages,194 oxygen isotope data points,78 rare earth elements and yttrium (REE discussed without Y or REY with Y) in the stalagmite (SX15a), using an Inductive Coupled Plasma Sector Field Mass Spectrometry method.6 REE concentrations in surface soil and 3 in bed rock.The following conclusions can be drawn:(1) From 230Th ages and oxygen isotope data points, the stalagmite from Sanxing Cave (SX15a) reveals the precipitation history of the ASM from 110.2 to 103.3 ka B.P. (relative to AD 1950). The high-resolution ?18O record reveals the detailed process of Chinese Interstadials (CIS) event 24. Our records indicate an abruptly negative shift from-8.2‰ to -10.0‰ at 107.7±0.6 ka and a positive shift from -9.7‰ to -8.5‰ at 105.4±0.5 ka. The duration of this event is about 2.3±0.5 ka. So far, this is the most accurate duration.(2) Comparing the total REY with the stalagmite oxygen isotope record in same period,the two records have a consistency feature. In Marine Isotopic Stage 5d (MIS 5d) period, REY content is relatively low and ?18O values are modifier, climate is cold and aridity. During MIS 5c, REY content is high, ?18O values are negative, climate is warm and humid. In MIS5d/5c conversion period, REY and ?18O both showed abrupt characteristic.(3) In the period of CIS 24, our high resolution ?18O record reveals four sub-millennial scale events with enhanced ASM, which are in close correlation with sub-cycles recorded in the equivalents of Greenland ice cores. Further, REY and ?18O also have a good correspondence to the sub-millennial fluctuation of GIS24 event, these feature indicate that the total amount of REY can response to climate change sensitively.(4) We show for the first time that the sub-millennial scale climatic events of CIS 24 occurred more or less synchronously between ASM and North high latitude, indicating that the North high latitude climate exert an important influence in the ASM at the conditions with a relatively small ice volume.