Solid bitumen is ubiquitous in the Sinian Dengying Formation dolomite, a crucial gas reservoir in the Sichuan Basin. We use biomarkers and Re–Os geochronology, coupled with burial-thermal evolution history to trace the source and formation timing of the solid bitumen, and to reconstruct the petroleum system evolution in the Dengying Formation of the Beiba Dome, northern Sichuan Basin. The bitumen reflectance (Rb) values of solid bitumen range from 1.92 to 3.95%, with the solid bitumen showing no fluorescence, indicating that the solid bitumen in the Dengying Formation dolomite has a high thermal maturity, which consequently belongs to pyrobitumen formed by thermal cracking of crude oil. The isoprenoids and terpanes indicate that the solid bitumen was sourced from a marine shale deposited under a reducing environment. The C₂₇–C₂₉ regular sterane distribution of the solid bitumen is consistent with the Lower Cambrian Guojiaba Formation (Є₁g) organic-rich shale, indicating that the solid bitumen was derived from the Є₁g shale, rather than dolomite or shale within the Dengying Formation. The burial-thermal evolution history indicates that initial oil generation began in the Late Cambrian to the Early Silurian. Since the Early Permian, the Є₁g organic-rich shale re-entered the oil generation window, and formed a giant paleo-oil accumulation during the Late Triassic. Thermal cracking of crude oil occurred from the Late Triassic to the Early Cretaceous forming the extensive solid bitumen. The Re–Os isotopes of solid bitumen yield two similar isochron ages of 128.1 ± 7.3 Ma and 126.2 ± 8.0 Ma, which represents the timing of thermal cracking termination, i.e. the final timing of dry gas generation. This work highlights that the Re–Os geochronology has great potential to constrain the absolute timing of evolution of the petroleum system.

四川盆地重要的天然气储层震旦系灯影组白云岩中普遍存在固态沥青。我们使用生物标志物和Re-Os年代学，再结合埋藏-热演化史来追踪固体沥青的来源和形成时间，并重建川北贝巴穹顶灯影组的石油系统演化。固体沥青的沥青反射率（Rb）值介于1.92％至3.95％之间，固体沥青无荧光，表明灯影组白云岩中的固体沥青具有较高的热成熟度，因此属于热裂解形成的焦岩原油。类异戊二烯和萜烯表明固体沥青来自还原性环境中沉积的海相页岩。C₂₇ -C ₂₉的固体沥青的常规甾烷分布与下寒Guojiaba组（Є一致₁ G）富含有机物页岩，这表明固体沥青从Є衍生₁克页岩，而不是在白云石或页岩灯影组。埋藏-热演化历史表明，最初的石油产生始于寒武纪晚期至志留纪早期。由于早二叠，所述Є ₁富含有机质的页岩重新进入了生油窗口，并在三叠纪晚期形成了巨大的古油堆积。原油的热裂解发生在三叠纪晚期至白垩纪早期，形成了广泛的固体沥青。固体沥青的Re-Os同位素产生两个相似的等时年龄，分别为128.1±7.3 Ma和126.2±8.0 Ma，这代表了热裂解终止的时间，即干燥气体产生的最终时间。这项工作突显了Re-Os年代学在限制石油系统演化的绝对时机方面具有巨大潜力。