Abstract

The results of lithological, petrographic, and C–O isotope studies of various types of the diagenetic and postdiagenetic carbonate cement in silty mudstones, as well as coeval limestones, in postglacial deposits of the Dal’nyaya Taiga Group (Patom Basin, Siberia) are presented. Evidence of methane generation but not its anaerobic oxidation has been obtained. High δ¹³C (up to 14.9‰) values of the earliest carbonate cement generations in mudstones from the Barakun and Ura formations are related to extreme isotopic fractionation during the biogenic methanogenesis. The absence of isotopic signatures of the anaerobic oxidation of methane indicates its isolation during the subsequent reactions, suggesting the accumulation of gas hydrate compounds inside the sedimentary layers. Analysis of the distribution and correlation of δ¹⁸0 and δ¹³C in the authigenic and sedimentary carbonates provides new arguments in favor of link of the Ediacaran global δ¹³C trend with epochs of the predominant accumulation of gas hydrate hydrocarbon compounds inside the deep-sea sedimentary strata and their subsequent anaerobic oxidation.

中文翻译：

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Dal'nyaya Taiga群（西伯利亚Patom盆地下Vendian）沉积物中甲烷生成的碳同位素证据。

摘要

Dal'nyaya Taiga群（西伯利亚Patom盆地）后冰期沉积物中粉质泥岩和同年龄的石灰岩中各种类型的成岩和成岩碳酸盐水泥的岩性，岩石学和C-O同位素研究结果如下：呈现。已获得甲烷生成的证据，但尚未获得其厌氧氧化的证据。高的△ ¹³来自Barakun和Ura地层的泥岩中最早的碳酸盐水泥世代的C（高达14.9‰）值与生物成甲烷作用中的极端同位素分馏有关。甲烷厌氧氧化的同位素特征的缺乏表明其在随后的反应中被隔离，表明气体水合物化合物在沉积层内的积累。的δ的分布和相关性的分析¹⁸ 0和δ ¹³在自生和沉积碳酸盐下在赞成埃迪卡拉全球δ链路提供了新的参数¹³ Ç趋势与深孔内的气体水合物的烃化合物的主要积累的历元海沉积层及其随后的厌氧氧化。