黄土地区气候演变的有机地球化学标志  

ORGANIC GEOCHEMISTRY MARKERS OF CLIMATIC EVOLUTION IN LOESS REGION OF CHINA

作　　者：贾蓉芬[1] 赵林[1] 刘友梅[1] 文启忠[1] 

机构地区：[1]中国科学院广州地球化学研究所,广州510640

出　　处：《地理科学》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

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.

关 键 词：黄土 有机质 气候演变 地球化学 烃类 干酪根 

分 类 号：P618.130.4[天文地球—矿床学]