摘要
对渭南阳郭黄土剖面So～L_2层段作了总有机碳(TOC)和Rock—Eval热解烃分析.建立了TOC气候变化曲线及其变化周期,与其它气候指标进行了对比.揭示了黄土剖面中与气候变化有关的两种烃类,推导并验证了古湿度公式,计算了各层段的湿度分布及其演变趋势.
The samples collected from Weinan loess section (L2-So) have been analysed by TOC(total organic carbon) and Rock-Eval.The curve of TOC with depth has been set up and compared well with other climatic markers. The main periods of TOC variation of the last 0. 14 Ma are 67. 08 Ka and 18. 29 Ka, which is near with the period of the variation of sunshine, showing that the TOC vari-ation may be controlled by the variation of 65°N sunshineThe distribution of pyrolysis hydrocarbon and its parameters have been researched in detail in the section. It shows that there are two kinds of hydrocarbon associated with cli-matic change. One is called biological reduce hydrocarbon (pHC2-1) which is in the range of Tmax 350℃ ~500℃, and associated with atmospheric water. The other is called car-bonate inclusion hydrocarbon (pHC2-2) which is in the range of Tmax 500~600℃ and formed by evaporation and associated with dry climate.The formula calculating humidity has been deduced: Qg = pHC2-1/(pHC2-1 + pHC2-2). The range of humidity of the section is 47%~77% and the reducing order is S1-3>S1-2>>O>S1-1>L1-4>L1-1>L1-3>L1-5. And the trend of the humidity is still in-creasing today.
出处
《地理科学》
CSSCI
CSCD
北大核心
1996年第2期97-105,共9页
Scientia Geographica Sinica
基金
国家重大基金
有机地球化学重点实验室的赞助
关键词
黄土
有机质
气候演变
地球化学
烃类
干酪根
Weinan loess section
Organic matter
Climatic evolution
Humidity
