The northern Alxa orogenic belt, located in the middle segment of the Central Asian Orogenic Belt, is a junction between the North China Craton, Tarim Craton and Mongolian microcontinents. However, its Permo-Carboniferous tectono-palaeogeographic evolution has not been well established. In this study, new zircon U–Pb–Hf isotopic data for the Permo-Carboniferous clastic rocks were used to address the above issue. Based on our dating work and fossil assemblages, we confirmed that the Amushan, Maihanhada, Aqide and Haersuhai formations were formed in the late Carboniferous to early Permian, early to middle Permian, middle Permian and late Permian periods, respectively. The Amushan Formation sandstone in the Zhusileng area contains abundant Palaeozoic zircons (with age peaks at 440 Ma, 475 Ma and 539 Ma) and some Precambrian zircons. These zircon ages and the southeast transgressive direction suggest the provenance to be the local Zhusileng–Hangwula block and the nearby Yagan continental margin. The zircon age pattern with a high proportion of detrital zircons much older than the depositional time and no detrital zircons close to the depositional time suggest an extensional basin depositional setting. The clastic rocks of the Maihanhada, Aqide and Haersuhai formations inherited the source for the Amushan Formation, with a greatly increased input of Permo-Carboniferous volcanic rocks with post-collision or intraplate chemical affinity. Accordingly, a Permo-Carboniferous extensional stage was suggested. Finally, a tectono-palaeogeographic model was reconstructed for the northern Alxa orogenic belt, evolving from a late Carboniferous transgression with crustal extension to early to middle Permian rapid basin filling and a late Permian marine regression.

The Weihe Basin is an intracontinental rift basin in central China that provides an ideal location for studying the interactions between regional tectonics and monsoonal climate change. In this paper, we present detrital zircon U–Pb ages from sediments from Core LYH drilled in the northern margin of the basin. We use these to illuminate changing sediment transport processes, provenance and palaeo-environments during the Quaternary. The sediments are dominated by zircon age groups of 100–400 Ma and 400–550 Ma, and three secondary age peaks at 700–1100 Ma, 1700–2100 Ma and 2400–2600 Ma. Multidimensional scaling plots support the conclusion that the Central Loess Plateau and the Luo River are the dominant sources of sediments to the core site. Before c. 1.06 Ma, the Qinling Mountains and the Wei River, as well as the Yellow River, had minor influence on the sedimentation at the core site. These results are consistent with the existence of a palaeolake prior to 1.06 Ma, which allowed sediments supplied to the south and east edge of the basin to be reworked to the northern side of the Weihe Basin. Subsequently, the Luo River has provided a steady source of sediments to the northern Weihe Basin.