Abstract Is natural radioactivity a significant agent of hydrocarbon gas generation from sedimentary organic matter? Laboratory gamma radiation of dead crude oil (no solution gas) yields wet hydrocarbon gases depleted in 13C: δ13C CH4 (−75‰ to −65‰), δ13C C2H6 (−52‰ to −45‰), δ13C C3H8 (−42‰ to −37‰) and δ13C n-C4H10 (−35‰ to −32‰). Although laboratory irradiation dose rates are orders of magnitude higher than those in geological settings, radiolytic transformations occur at total radiation doses equivalent to those in natural geological settings over many millions of years. Radiolysis generates wet gases with isotopic signatures that might be interpreted as “biogenic” if only the methane carbon isotope ratio is considered. We examine situations where such gases may be quantitatively significant.

中文翻译：

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辐射分解是地圈中 13C 耗尽天然气的来源

摘要 天然放射性是沉积有机质生成烃气的重要因素吗？死原油（无溶解气）的实验室伽马辐射产生在 13C 中耗尽的湿烃气体：δ13C CH4（-75‰ 至 -65‰）、δ13C C2H6（-52‰ 至 -45‰）、δ13C C3H8（-42‰）至-37‰）和δ13C n-C4H10（-35‰至-32‰）。尽管实验室辐照剂量率比地质环境中的辐射剂量率高几个数量级，但在数百万年的总辐射剂量下发生的辐射分解转变与自然地质环境中的辐射剂量相当。如果仅考虑甲烷碳同位素比率，辐射分解会产生具有同位素特征的湿气体，这些气体可能被解释为“生物成因”。我们研究了这些气体在数量上可能具有重要意义的情况。