Achieving accurate chronostratigraphical correlation between late Cambrian sections in North China and sections from elsewhere in the world has been a long‐standing problem, largely owing to a lack of preserved or identified biostratigraphical marker fauna. Here, we examine trilobite occurrences, the sequence of facies and lithological change, and carbon and oxygen isotopes from the carbonate sequence of the Jiulongshan section, Shandong Province. Whereas regionally comparable sections are commonly unconformable coincident with the Kushan–Chaumitien formation boundary, we report the Steptoean Positive Isotopic Carbon Excursion (SPICE) event from an uninterrupted section recording a regressive–transgressive palaeoenvironmental fluctuation. Further, we place the onset and rise of the SPICE event within a high‐resolution, trilobite biostratigraphical framework, reporting, for the first time, Fenghuangella laevis from Shandong Province. Although correlating trilobite biostratigraphical relationships from China to the rest of the world has long been burdened by the endemism of Chinese taxa, the base of the Fenghuangella biozone corresponds with the base of the globally recognized Glyptagnostus reticulatus biozone, thus better demarcating the base of the Paibian Stage in North China.

Pore structure heterogeneity affects the porosity and permeability variation of tight sandstone, thereby restricting sandstone gas production. In total, 11 sandstone samples were taken as a target in the northwest margin of the Junggar Basin. Then, scanning electron microscope and high-pressure mercury injection tests are used to study the distribution of a pore and fracture system in the target sandstone. On this basis, single and multifractal models are used to quantitatively characterize the heterogeneity of pore structure, and the applicability of the classification model in characterizing the heterogeneity of the pore-fracture structure is explored. The results are as follows. (1) The target samples are divided into two types, with the mercury removal efficiency of type A samples ranging from 44.6 to 51.8%, pore size mainly distributed between 100 and 1000 nm, and pore volume percentage ranging from 43 to 69%. The mercury removal efficiency of type B samples ranges from 14 to 28%, and pore diameter distribution is relatively uniform. (2) Different fractal models represent different physical meanings. The calculation results of sponge and thermodynamic fractal models indicate that the heterogeneity of pore structure distribution in the type B sample is significantly stronger than that in type A, which is inconsistent with the conclusions of the Sierpinski model. This is because the aforementioned two models characterize the complexity of pore surface area, while the Sierpinski model characterizes the roughness of pore volume. The comparison shows that there is a significant correlation between the thermal dimensionality value DT and the volume percentage of macropores and mesopores. Therefore, the thermodynamic model can better quantitatively characterize the heterogeneity of macropore and mesoporous pore distribution. (3) The results indicate that higher pore volume range is mainly influenced by mesopores and macropores. From the relationship curve between mercury removal efficiency and single fractal dimension, it can be seen that mercury removal efficiency is greatly affected by distribution heterogeneity of the lower value area of pore volume, and it has no obvious relationship with distribution heterogeneity in the lower value area of the pore volume.

In this paper, coal samples from multiple regions on the eastern margin of the Ordos Basin in the North China Craton were selected as the subject of study. All the samples are selected based on their ash content. Then, micropore volume and heterogeneity of the pore size distribution of deep coal seams are studied by using low-temperature liquid nitrogen and high-pressure methane adsorption experiments. Then the factors influencing methane adsorption capacity as constrained by ash content are studied. The results are as follows: (1) The coal samples can be divided into two categories based on ash content: high-ash and medium-to-low-ash. The micropore structure distribution curve for medium-to-low-ash coal exhibited a four-peak distribution, and that of high-ash coal also showed a four-peak distribution. (2) Micropore volume and heterogeneity of micropore distribution are controlled by thermal evolution. Conversely, for high-ash coal, the micropore volume and heterogeneity are constrained by ash content; the micropore volume decreases and heterogeneity increases with rising ash content. (3) The methane adsorption capacity of medium-to-low-ash coal was higher than that of high-ash coal. A critical pore size range of 0.3~0.6 nm for controlling methane adsorption was found. Within this range, an increase in pore size distribution heterogeneity leads to a decrease in adsorption capacity.