The Kalatag mineralization belt is an important metallogenic belt of polymetallic mineral deposits in the northern part of eastern Tianshan, and its age and tectonic setting are still controversial. We identified a set of Devonian volcanic rocks hosted in the Early Palaeozoic package of dominantly marine sediments with a small amount of terrestrial rocks. This study presents petrological, U–Pb geochronology, and geochemical data for the volcanic rocks. The ages of the rhyolite (407.2 ± 1.9 Ma) and basaltic andesite (380.4 ± 2.8 Ma) suggests that the Kalatag belt is a Devonian volcanic succession. These rocks consist mainly of marine calc–alkaline lava, tuff, pyroclastic rocks, and minor terrestrial basaltic andesite. The lavas are characterized by the enrichment of light rare earth elements and strongly depleted in Nb and Ta, typical of island arc magmatic rocks. The volcanic rocks probably originated from the partial melting of the mafic lower crust which was modified by subducted slab-related fluids. During their ascent through the crust, these volcanic rocks underwent variable extents of fractional crystallization (rhyolites) and crustal contamination (basaltic andesites). Combined with the results of previous studies, we suggest that the Devonian rocks formed in an island arc related to the northward subduction of the Northern Tianshan Ocean with a crustal thickness of ~35–40 km.

With the development of mineral resources, the inevitable creation of numerous abandoned mines has impacted environmental resources. Numerous studies have been conducted on the restoration and management of individual abandoned mines. However, there has been no systematic study on the overall ecological restoration planning of abandoned mine clusters. Hence, there is an urgent need to research restoration planning strategies, focusing on the characteristics of abandoned mines and their environmental impacts. In this study, abandoned mines in Toli County, Xinjiang, were selected as the case. The K-means clustering analysis method was employed to study the spatial distribution of abandoned mines, selecting longitude, latitude, and road access as analytical factors. Based on spatial location attributes, three groups of abandoned mines were identified. The Analytic Hierarchy Process (AHP) was used to study the ecological importance evaluation model in Toli County, selecting eight evaluation factors including vegetation, precipitation, and population density, and dividing the ecological importance levels of various sectors to establish a three-stage restoration project. The Principal Component Analysis (PCA) method was used to assess the hazards of abandoned mines, selecting distance, land type, area, and ecological impact as influencing factors and determining the management sequence of abandoned mines within each project. The results show that (1) longitude, latitude, and road indices help to mitigate geographical obstacles such as mountains and rivers, ensuring a high degree of continuity in abandoned mine areas; (2) the AHP reveals that the combined weight of population density, gross domestic product, and vegetation index exceeds 80%, which are key factors affecting the priority of ecological restoration; and (3) the application of PCA provides a scientific basis for the hazard assessment and management of abandoned mines, prioritizing those close to densely populated areas and with larger areas. The significance of this study lies in providing a systematic method for ecological restoration planning of abandoned mines, as well as offering important references for future research and practice in related fields.

Amid the rapid development of the digital economy and China’s carbon-peaking and carbon-neutrality goals, digital transformation has emerged as a critical pathway for petroleum enterprises to improve quality and efficiency. However, the mechanisms linking digital transformation to operational efficiency in the petroleum industry remain insufficiently understood. Using an unbalanced panel of 45 Chinese A-share-listed petroleum firms over the 2008–2024 period, this study examines the direct effect of digital transformation on operational efficiency, the mediating roles of factor-utilization efficiency and technological innovation capability, and the moderating effects of ownership and firm size. The results show that digital transformation is significantly and positively associated with operational efficiency. Among its dimensions, digital applications exert the strongest enabling effect, whereas the digital-achievements dimension may suppress operational efficiency in the short run. The relationship also operates through two mediation channels: technological innovation capability transmits the effect significantly for both efficiency measures, whereas factor-utilization efficiency transmits it significantly for total asset turnover only. By contrast, the moderating effects of ownership and firm size are not statistically significant in the current estimates: the interaction terms of digital transformation with state ownership and with firm size are insignificant for both efficiency measures. These findings clarify how digital transformation affects operational efficiency in petroleum enterprises and provide evidence for designing more effective digital transformation strategies in the energy sector.