大青山调角海子地区全新世低温波动研究

A STUDY ON THE LOW TEMPERATURE FLUCTUATIONSSINCE THE HOLOCENE IN DIAOJIAOHAIZI LAKE AREA,DAQINGSHA MOUNTAINS, INNER MONGOLIA

根据调角海子剖面寒冻现象的野外观察与测量、室内测年分析及孢粉分析等资料，对调角海子地区全新世低温波动进行了探讨，并与邻近地区的多种研究资料进行了对比。经初步研究认为，大青山调角海子地区一万年以来的低温波动主要有６次，时代分别为９１００ａＢＰ～８８００ａＢＰ、８０００ａＢＰ～７８００ａＢＰ、７０００ａＢＰ～６９００ａＢＰ、６０００ａＢＰ～５８００ａＢＰ、５３００ａＢＰ～４７００ａＢＰ和３１００ａＢＰ～２４００ａＢＰ，除第２、４次为弱低温波动，可能仅限于大青山地区外，其余均具有较为广泛的区域意义；每次低温波动的极端低温期较短，可能只有５０年～６０年；低温波动时年气温只比现在下降了１℃～３℃。

ased on field observation and measurement of periglacial phenomena, radiocarbon dates and sporopollen analysis of the samples from the Diaojiaohaizi section, this paper has inquired into the low temperature fluctuations in the Holocene in Daqingshan Mountains. The researches in the paper come into the conclusions as follows:(1) There are six times low temperature fluctuations in the Holocene including those in 9100 aBP～8800 aBP, 8000 aBP～7800 aBP, 7000 aBP～6900 aBP, 6000 aBP～5800 aBP, 5300 aBP～4700 aBP, and 3100 aBP～2400 aBP. They have extensive regional significance except the 2nd and the 4th fluctuations which are relatively weak and confined to Daqingshan Mountains.(2) Comparing the sand wedge developing conditions of three stages in the Holocenc in Diaojiaohaizi section with the sand (ice) wedge developing conditions in Qinghai-Xizhang Plateau and the environmental conditions in the southern boundary of modern perennial frozen earth area in northeastern China, this paper hold that the annual temperature of the cold stages if the Holocene was only 1℃～3℃ lower than that of today, which is different from the conclusions of other researchers.(3) The characteristics of the sand wedge in Diaojiaohaizi section indicated that the extreme low temperature interval in the cold stages if the Holocene was short, which was only 50～60 years. However, the low temperature intervel indicated by vegetation, paleosoil and archaeological materials was relatively long, which was generally 100～700 years. This is clearly due to the sensitive difference of those proxy data.