Collisional orogeny processes in the Qinling Orogenic Belt during the Late Permian to Early Triassic: Evidence from detrital zircon geochronology in the south of North China

Abstract

The Qinling Orogenic Belt serves as a critical geological record documenting the closure of the eastern Paleo-Tethys Ocean during the Late Paleozoic to Early Mesozoic. This study investigates sandstone petrology and detrital zircon geochronology from Late Permian to Early Triassic strata in the south of North China Basin to conduct a provenance analysis. Petrographic data showed that all sample fall into a recycled orogenic provenance. Two detrital zircon samples from the Late Permian Shiqianfeng Formation exhibit two prominent age groups of Late Paleozoic-Early Mesozoic and Paleoarchean-Paleoproterozoic. Additionally, the sample from the upper part of the strata reveals secondary age groups of Early Paleozoic and Meso-Neoproterozoic. Detrital zircon samples from the Liujiagou and Heshanggou formations exhibit a similar age spectrum, encompassing the Late Paleozoic-Ealy Mesozoic, Early Paleozoic, Meso-Neoproterozoic, and Paleoarchean-Paleoproterozoic age groups. Combined detrital zircon ages with the paleogeography and paleocurrent data, we suggest that these sediments predominantly originated from the Southern North China Block and the North Qinling Belt. The uplift of the Qinling Orogenic Belt resulted from the initial collision between the North and South China blocks. Notably, the contributions from the North Qinling Belt increased progressively in younger strata, indicating a continuous enhancement in the uplift process. Further investigations into detrital zircon age data from time-equivalent strata distributed along south of the North China reveal a progressive westward propagation of uplift over time. Thus, our findings suggest that the uplifting pattern of the Qinling Orogenic Belt is consistent with the oblique collision model between the North and South China blocks.