【摘要】 二叠系长兴和茅口灰岩中大量产出的固体沥青可能主要来源于紧邻的龙潭煤层。沥青富含芳烃。在饱和烃中富含高分子量正烷烃,长链类异戊二烯烷烃,甾烷以 C₂₉为主,还检出三种 C₂₄四环萜烷。更多还原

【Abstract】 Solid bitumens are concentrated in the forms of vein, or irregular spots, or fine grained dispersion within the limestones of Permian Maokou and Changxing groups in Nantong area, Sichuan Pron., China. It is proposed through "oil-source rock correlation" by biomarkers and stable carbon isotope ratios that the various kinds of bitumens were directly derived mainly from the adjacent coal bed No. 6 of Permian Longtan Group, of which hydrogen-rich vitrinite is abundant in coal materals, in Yanshitai Coal Mine ares. These bitumens and the coal bed are rich in n-alkanes of high-molecular weight and long chain acyclic isoprenoid alkanes in saturate fraction, and possess the predominant C29 component in steranes. In addition, they have low hopane/sterane ratios below unit, and contain C19-C29 tricyclic terpanes and C29-30 4-methyl steranes, which means a microbial contribution. The difference of biomarkers between these bitumens and the coal bed is in C24 tetracyclic terpanes. There are three C24 tetracyclic terpanes detected in these solid bitumens, however only a common 17, 21-secohopane is found in the coal bed, two other ones which are possibly secotriterpanes with characteristic mass fragments, e.g. m/z:109, 123, 191 (major peak), 315 (M - 15), 330 (M+)are not existed in the coal bed. Therefore, other sources besides the Longtan coal bed can not be excluded for these solid bitumens.更多还原