This research presents an integrated approach to organic petrographical and geochemical characteristics of the Upper Permian Newcastle Coal Measures outcropping in the northern Sydney Basin, southeast Australia. Twenty-seven coal, coaly mudstone and mudstone samples were collected and analyzed by using organic petrography (maceral composition and vitrinite reflectance) techniques, Rock–Eval pyrolysis, bitumen extraction and gas chromatography - mass spectrometry (GC–MS). The obtained results indicate that the samples exhibit promising gas-prone source rock potential and contain a predominantly terrestrial in origin organic matter, with limited contribution by marine organisms. The prevalence of terrestrial organic matter is inferred by the presence of collotelinite and sporinite macerals in most of the samples and the ternary plot of C27, C28 and C29 regular steranes. Further, the low C27/C29 ratio, the cross-plots of C27/(C27 + C29) regular steranes vs. Pr/Ph ratio, the C27/C29 vs. Pr/Ph and the C24 tetracyclic/C26 tricyclic terpane ratio point also to the terrestrial origin of the organic matter. The obtained values of vitrinite reflectance, Tmax, OEP27–31 and CPI25–33, along the cross plots of 20S/(20S + 20R) versus ββ/(ββ + αα) suggest that the samples are immature and were subjected to a low burial depth. The examined samples indicate accumulation in a delta-plain environment of deposition, under fluctuating oxic/anoxic conditions, in a humid climatic zone that is characterized by dry periods, interrupting the longer-termed humid climatic regime. This research adds knowledge on the source rock potential in the northern Sydney Basin and on the environmental and climatic setting of a time interval just prior to the major Permian - Triassic climatic crisis.

中文翻译：

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上二叠统冈瓦纳煤的岩石学和地球化学特征：澳大利亚北悉尼盆地纽卡斯尔煤层


本研究提出了一种综合方法，研究了澳大利亚东南部悉尼盆地北部上二叠纪纽卡斯尔煤系露头的有机岩石学和地球化学特征。收集了 27 个煤、煤质泥岩和泥岩样品，并使用有机岩相学（镁质成分和镜质体反射率）技术、Rock-Eval 热解、沥青萃取和气相色谱-质谱 （GC-MS） 进行分析。获得的结果表明，样品表现出有希望的易溶气源岩潜力，并且主要包含陆地起源的有机物，海洋生物的贡献有限。陆地有机质的普遍性是通过大多数样品中存在胶硼石和孢子石斑块以及 C27、C28 和 C29 规则甾烷的三元图来推断的。此外，低 C27/C29 比率、C27/（C27 + C29） 规则甾烷与 Pr/Ph 比率、C27/C29 与 Pr/Ph 比率以及 C24 四环/C26 三环萜烷比率也指向有机物的陆地来源。沿着 20S/（20S + 20R） 与 ββ/（ββ + αα） 的交叉图获得的镜质体反射率、Tmax、OEP27-31 和 CPI25-33 的值表明样品是不成熟的，并且受到低埋深。检查的样品表明，在波动的氧化/缺氧条件下，在以干燥期为特征的潮湿气候区，在三角洲平原沉积环境中积累，中断了长期的潮湿气候状况。这项研究增加了对悉尼盆地北部烃源岩潜力以及二叠纪-三叠纪重大气候危机之前某个时间间隔的环境和气候设置的了解。