极地冻土区浅表土壤烃类组成特征及指示意义

漠河盆地是我国主要极地冻土分布区,通过在漠河盆地西北部冻土区进行地球化学方法试验,浅表土壤中检出酸解烃和吸附烃两种烃类气体,其中吸附烃含量较高,甲烷平均值为12.48μL/L,最高值达49.93μL/L,酸解烃相对偏低.烃类三维荧光光谱显示凝析油特性,为热解成因气,表明深源气体不断迁移到地表表现出地球化学微观信息,结合该地区冻土、温压等条件,指示冻土区深部具有油性气和天然气水合物的存在.

Characteristics and indicative significance of hydrocarbon composition in shallow soil of polar permafrost region

Mohe basin is the main permafrost distribution area in China.The performance of experimental geochemical prospecting methods in the northwestern permafrost area of Mohe basin detected acidolysis hydrocarbon and adsorbed hydrocarbon in shallow soil,and the adsorbed hydrocarbon has relatively high value,with the average methane value being 12.48μL/L and the maximum value being 49.93μL/L,whereas acidolysis hydrocarbon has relatively low content.The results of three-dimensional fluorescence spectra show that hydrocarbon gas exhibits characteristics of condensate oil,which is pyrolysis gas,indicating that the deep source gas migrates to the surface and manifests microscopic geochemical information.Combined with the permafrost,temperature and pressure conditions,it is shown that the deep permafrost area probably has oil gas and natural gas hydrate.