论文部分内容阅读
环化指数(CBT)/甲基化指数(MBT)是近年来根据支链四醚膜类脂(GDGTs)提出的定量化重建土壤pH和陆地年平均大气温度(MAAT)的生物标志物指标.本文通过对高寒若尔盖草原泥炭柱状样中GDGTs含量的测定,利用CBT/MBT指标定量化重建了其近150年来的泥炭pH和MAAT的变化.近150年来四川若尔盖草原泥炭pH和MAAT大致经历了3个变化阶段:1851~1927年pH基本没有变化,MAAT缓慢降低1℃;1927~1979年pH快速降低0.6,MAAT大幅降低2.5℃;自1979年以来pH和MAAT大幅升高0.8和5℃.计算温度与当地气象站记录的近45年来年平均温度具有相似的升温趋势和平均值,并且近150年来计算的MAAT和在该地区利用树木年轮计算的温度具有相似的变化趋势,表明泥炭沉积中GDGTs相关指标在高分辨重建陆地古环境的适用性和应用潜力.
Cyclization Index (CBT) / Methylation Index (MBT) is a biomarker index for quantitatively reconstituting soil pH and terrestrial mean atmospheric temperature (MAAT) based on branched tetraetherified membrane lipids (GDGTs) in recent years. In this paper, the changes of peat pH and MAAT in the past 150 years have been quantitatively reconstructed by using the CBT / MBT index to determine the content of GDGTs in the peat-column samples of the Alpine Zoige steppe. During the period of change, there was almost no change in pH between 1851 and 1927, a slight decrease in MAAT by 1 ° C, a rapid decrease in pH by 0.6 from 1927 to 1979, and a drastic reduction in MAAT by 2.5 ° C; a significant increase in pH and MAAT by 0.8 and 5 ° C since 1979. The temperatures recorded by the local weather stations recorded similar warming trends and averages over the past 45 years, and similar trends were calculated for the MAAT calculated over the past 150 years and the tree age for the region, indicating that the peat deposition Applicability and potential of GDGTs related indicators in high resolution reconstructed terrestrial paleoenvironment.