The Climate Change Record From MIS-3a Of The Xialu Peat In The Northern Leizhou Peninsula

The studied area of Xialu peat bog is located in the northern Leizhou Peninsula of the South China Sea, it is the south limit of the sub-tropic areas and the north limit of the tropic areas, where is intersect site of eastern southeast monsoon and southwest monsoon and sensitive to climate change. Based on the century resolution analysis of different environment proxies such as decayhumification(DH), total organic carbon (TOC), organic matter(OM) and magnetic susceptibility, probe into paleoclimatic and paleoenvironmental changes between 35000 and 7500 years before the present(B. P.) in the northern Leizhou Peninsula. The results indicate that the climate evolution can be divided into three stages as follows:The climate and environment since 35000a B.P. had experienced a series of cold-warm and dry-moisture changes. According to the interpretation of the proxies and regional comparison, this paper identifies three characteristic climatic periods in the past 35000a B. P.: (1) 35000～26000aB. P. the paleoclimatic condition was predominated by warm and humid; at the former periods the paleoclimate was mainly hot and humid but cool and humid in the later phase, it maybe gradually transferred to MIS-2. (2) 26000～10000aB. P., The paleoenvironment was controlled by cold and dry. It also can be divided into three sub-stages by the characteristic in this period; it was found the Last Glacial Maximum (LGM) about 18000aB. P. and the Younger Dryas(YD) Event about 11000aB. P. from the profile. (3) 10000～7500aB. P. was last Deglaciation changed to the early Holocene, at first, the paleoclimate showed warm and humid condition, but got cold-dryness later. It maybe the record of 8.2kaBP cold event in low latitude regions.It can be found the obvious cycle periods such as 1439a, 760a, 702a, 651a and 520a by the red-noise spectra analysis from Xialu peat profile. We found that the dominant periodicities are similar to the solar activity periods and the Thermohaline Circulation(THC). Then it can infer the possible main causes and dynamic mechanism of paleoclimatic change in Leizhou Peninsula may closely associate with solar activity.Through a comparative anaylysis of highly resolved palaeoclimate proxy record between the GRIP ice core, Hulu cave stalagmiteδ¹⁸O from Nanjing, North Atlantic sedinment record, GISP2 ice core and geochemistry of Xialu curves, we found our results are comparable with the North Atlantic Ocean Ice Rafted Debris(IRD) events from Heinrichl to Heinrich4, Younger Dryas and the Dansgaard-Oeschger(D-O) cycle warmer events ISNo.1 to ISNo.6 which can relfect rapid climate change in short time scale since the last glacial stage, and these changes are clearly affected by the climate oscillation of the North At]antic Ocean. it is showed that the climatic and environmental changes of the Leizhou Peninsula Area are consistent tendency with these changes of other places, meanwhile, it is already clear that the climatic changes is global significance.