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中国南方更新世红土是古气候环境变化研究非常重要的载体之一,红土微生物类脂分子是其古气候环境研究的有效指标,但其在红土中的古气候意义需要更进一步的挖掘和明确.选取处于气候变化敏感地带并且已有很好年代学基础的安徽宣城红土剖面进行详细的野外调查和系统的样品采集,利用改善后的碱式水解法提取红土微生物类脂分子,通过对比分析、比较印证等方法对其中的甘油二烷基链甘油四醚(glycerol dialkyl glycerol tetraethers,简称GDGTs)进行系统研究.宣城剖面GDGTs分布特征显示:剖面下部各指标呈旋回性变化、而上部相对稳定,表明形成初期环境比较动荡,而后期成土环境相对稳定;土壤pH为7.0~8.0,推测其物源主要来源于北方干旱区或长江中下游干涸河滩沉积;BIT指标反映宣城地区在130ka BP左右气候极为干旱.结果表明,红土中微生物类脂物GDGTs能够定量、高分辨率地重建安徽宣城的古气候环境,具有重要的研究意义.
Lateritic Pleistocene in South China is one of the most important carriers for the study of paleoclimate and environmental change. The clay molecules of laterite are effective indicators of paleoclimatic and environmental studies, but their paleoclimatic significance in lateritic soils needs to be further excavated and clarified. A detailed field investigation and systematic sample collection were carried out in the Xuancheng laterite section of Anhui Xuancheng, which is sensitive to geo-climate change and has good geochronology. The improved alkaline hydrolysis method was used to extract soil microbial lipid molecules. By comparative analysis, Compared with confirmation and other methods to glycerol dialkyl glycerol tetraethers (glycerol tetraethyl tetraethers GDGTs) were systematically studied.The Xuancheng profile GDGTs distribution characteristics: the lower section of the cross-section indicators cyclical changes, while the upper part is relatively stable, Indicating that the initial environment was relatively turbulent, while the late soil forming environment was relatively stable. The soil pH ranged from 7.0 to 8.0, suggesting that its source mainly came from the northern arid region or the dry riverbank sediments in the middle and lower reaches of the Yangtze River. The BIT index reflects that the Xuancheng region is around 130ka BP The climate is extremely arid.The results show that GDGTs in the laterite soil can be quantitative and high score Xuancheng rate reconstruct the ancient climate and environment has important significance.