摘要
沉积有机质可溶有机组分的碳同位素组成具有母质继承效应,同时受热力和生物降解作用等因素的影响。利用M AT 252同位素质谱仪分析了塔里木盆地塔北、塔中地区寒武系—奥陶系碳酸盐岩中可溶有机组分的碳同位素组成,发现它们的1δ3C值普遍发生了逆转。饱和烃组分明显富集13C,其1δ3C值的分布区间为-29.7‰^-26.2‰,平均值为-28.5‰,而沥青质组分明显富集12C,其1δ3C值的分布区间为-37.8‰^-27.1‰,平均值为-31.9‰,并且大部分样品的可溶有机组分的1δ3C值出现饱和烃>芳烃>非烃>沥青质的完全反序分布特征。综合分析认为该区寒武系—奥陶系碳酸盐岩中可溶有机组分碳同位素的逆转分布特征主要与热力作用及漫长的热演化史有关,而这种可溶有机组分碳同位素组成完全反序分布模式可以作为沉积有机质在高演化阶段的一个重要的地球化学标志。
Carbon isotopic compositions of the soluble organic components for the sedimentary organic matter have the inherited effect of parent materials,which can be affected by the thermal and the biodegradation factors. In this paper,the carbon isotopic compositions of the soluble organic components for the Cambrian and Ordovician carbonate rocks collected from Tabei and Tazhong Areas in Tarim Basin were analyzed by MAT252 Isotope Mass Spectrometer. The results show that their carbon isotopic compositions have apparently reversed distribution. The sat urated hydrocarbons,with δ^13C values ranging from -29.7‰ to -26. ‰（average -28.5‰）, obviously enriched in ^13C. However,the asphahenes, with δ^13C values ranging from -37.8‰） to -27.1‰（average --31.9‰）,obviously enriched in ^12C. The distribution of δ^13C values of the sol- uble organic components is as follows： saturated hydrocarbons〉aromatics：〉non-hydrocarbons〉 asphaltenes. This appearance of carbon isotopic reversed distribution,based on the previous studies and the geological setting, is regarded to result from the heating effects and the long-term thermal evolution,and it may be an important geochemical characteristics for the sedimentary organic matter in high evolution stage.
出处
《矿物岩石》
CAS
CSCD
北大核心
2006年第4期69-74,共6页
Mineralogy and Petrology
基金
国家重点基础发展规划项目(编号:2001CB209102)
关键词
塔北
塔中地区
采武系
奥陶系碳酸盐岩
可溶有机组分
碳同位素逆转
饱和烃
Tabei and Tazhong Areas
Cambrian and Ordovician carbonate rocks
soluble organiccomponents
carbon isotopic reversed distribution
saturated hydrocarbons
