Provenance analysis of Nanying'er Group in the eastern Hexi corridor belt and its geological significance

The study of the Late Triassic provenance system and basin features in the eastern transitional zone of the corridor has been relatively weak and poorly understood. This study conducted a systematic source analysis of the Upper Triassic Nanying'er Group in the Jingtai area of the eastern transition zone of the corridor using methods such as detrital zircon geochronology and geochemistry. Based on this, detrital zircon geochronology data from neighboring contemporaneous strata were collected for regional comparison, providing a reliable basis for a comprehensive understanding of the original basin features of the corridor transition zone of Ordos Basin. The whole rock geochemical results obtained in this study indicate that its main source is the felsic source area. The results of detrital zircon geochronology indicate that the detrital zircons of the Upper Triassic Nanying'er Group in the Jingtai area of the corridor transition zone mainly exhibit two main age distribution ranges: Late Paleozoic (peak age of 270.1 Ma) and Early Paleoproterozoic (peak age of 1 832 Ma), as well as a small amount of Neoproterozoic and Late Paleoproterozoic-Early Neoproterozoic ages. Based on a comprehensive comparison of the potential provenance areas in the surrounding areas, it is believed that the provenance in the Jingtai area of the corridor transition zone mainly comes from the Alxa block in the north, and a small amount of provenance may also be provided by the northern edge of the North China Plate in the northeast. The regional comparison results indicate that the corridor transition zone of Ordos Basin mainly received material sources from the Alxa block, the northern edge of the North China Plate, the North Qilian Orogenic Belt, and the Qinling Orogenic Belt in the Late Triassic. However, the material source systems in different regions have significant differences. The material sources in the corridor transition zone are mainly from the Alxa block and the North Qilian Orogenic Belt, while the internal material sources in the Ordos Basin are mainly from the northern edge of the North China Plate and the Qinling Orogenic Belt.