Abstract In order to understand the influence of the diagenetic water medium on the hydrogen isotope of sedimentary n-alkanes, thermal simulation experiments were carried out involving the initial peat under the addition of alkaline saltwater, acidic freshwater and peat alone condition. The generated n-alkanes were analyzed in terms of molecule composition and hydrogen isotopic composition of individual n-alkanes. The results show that the addition of water had a significant effect on n-alkane nC21−/nC22+ ratio, ACL value and Pr/Ph ratio. The n-alkanes display significant heavier hydrogen isotopic composition from the alkaline saltwater added experiments, but obvious lighter hydrogen isotopic composition from the acidic freshwater added experiments. The difference of the average δD value of n-alkanes between the saltwater and freshwater experiments ranged from 6‰ to 73‰, and maximum difference occurred from the experiments of 350 °C. The exchange of inorganic hydrogen in water and organic hydrogen was more intensive in the acidic freshwater experiments than that in the alkaline saltwater experiments. The average δD value of n-alkanes generated under the participation of saltwater and freshwater media appear to be higher heavier along with the increase in experimental temperature. Also, the average δD value of n-alkanes generated from the saltwater added experiments was always higher than that from the freshwater added experiments. The correlations among the δD composition of n-alkanes generated under different condition were established. These results provide information to understand of the genesis of sedimentary n-alkanes formed under the participation of diverse diagenetic water media at various stages of maturity.

中文翻译：

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成岩水介质对沉积正构烷烃及其氢同位素影响的实验模拟研究

摘要 为了解成岩水介质对沉积正构烷烃氢同位素的影响，对初始泥炭在碱性盐水、酸性淡水和单独泥炭条件下进行了热模拟实验。根据单个正烷烃的分子组成和氢同位素组成分析生成的正烷烃。结果表明，水的加入对正构烷烃的nC21-/nC22+比值、ACL值和Pr/Ph比值有显着影响。从添加碱性盐水的实验中，正构烷烃显示出明显更重的氢同位素组成，但从添加酸性淡水的实验中显示出更轻的氢同位素组成。盐水和淡水实验之间正构烷烃的平均δD值差异在6‰至73‰之间，最大差异出现在350℃的实验中。在酸性淡水实验中，水中无机氢和有机氢的交换比在碱性盐水实验中更强烈。随着实验温度的升高，在盐水和淡水介质的参与下生成的正构烷烃的平均δD值似乎更高。此外，添加盐水的实验产生的正构烷烃的平均 δD 值总是高于添加淡水的实验。建立了不同条件下生成的正构烷烃的δD组成之间的相关性。