Abstract

While previous studies have reported a link between provenance changes and the tectonic-paleogeographic evolution of basins in the North China Craton (NCC) and the Qinling Orogenic Belt during the late Palaeozoic, the mechanisms of the provenance transition and tectonic-paleogeographic evolution of the southeastern margin of the NCC and its adjacent basins remain unclear. To investigate the tectonic processes that were responsible for the provenance changes, we conducted a detailed study of the Carboniferous-Permian successions sampled from a drill hole in the Huainan Coalfield, such as sandstone petrology, U-Pb geochronology of detrital zircon grains in sandstones using LA-ICP-MS, and Lu-Hf isotope analysis. The Qt-F-L plots suggest that except for the provenance of the Benxi Formation, which was mainly continental arc, the overlying Formations (Taiyuan, Shanxi, Xiashihezi, and Shangshihezi) were predominantly derived from volcanic-magmatic arc, indicating a shift in sediment source from a recycled orogenic belt for the Carboniferous units to a volcanic-magmatic arc for the Permian units. The ZTR values in the overlying Formations are significantly higher than that in the Benxi Formation, reflecting an increase in mineral maturity and longer transport pathways. Detrital zircon age patterns and E Hf(t)-age plots suggest zircon ages in the Benxi Formation are predominantly Neoproterozoic to Mesoproterozoic, whereas those in the overlying Formations are mainly Late Palaeozoic, with overall negative E Hf(t) values, reflecting clear changes in the source. The tectonic evolution model of the NCC during the late Palaeozoic was reconstructed using the above analyses and the existing paleogeographic framework of the area. In the late Carboniferous, subduction of the Mianlue Ocean plate beneath the Qinling Orogenic Belt started and led to uplift and erosion of the North Qinling Orogenic Belt, resulting in a north-south elevation gradient in the North China region. In the early to middle Permian, accelerated subduction of the Paleo-Asian oceanic plate led to rapid uplift of the northern flank of the NCC, forming the Yinshan-Yanshan and Xingmeng orogenic belts. The significant influx of distal sediments and cyclicity of sedimentary provenance in the Huainan region record the uplift and erosion of the Qinling Orogenic Belt, and reconstruction of these changes is crucial for a comprehensive understanding of the late Palaeozoic sedimentary processes and tectonic-paleogeographic evolution of North China.

DOI: http://dx.doi.org/10.1002/gj.70440