Channel evolution in the lower reach of paleo Fen River; evidence from detrital apatite petrochronology and zircon geochronology

This study provides a comprehensive analysis combing multi-element (Sr, Y, Th, U, and rare earth elements (REE)) geochemistry and U-Pb geochronology of single-grain apatite, alongside zircon U-Pb ages, from channel sand deposits of the paleo Fen River, collected at the Chaizhuang and Weijiazhuang sites, corresponding to sediments from the Late Pleistocene and late Middle Pleistocene, respectively. The results unveil that the analyzed apatites originated from a varied assemblage of source rocks, encompassing mafic-ultramafic rocks, intermediate to felsic I-type plutons, highly fractionated S-type granites and pegmatites, as well as assorted metamorphic rocks. U-Pb age dating of detrital zircons and apatites identifies three predominant age peaks at 2.4 Ga, 2.2 Ga, and 1.8 Ga, consistent with known tectonothermal episodes within the North China Craton (NCC). The similarity in U-Pb age spectra for both zircon and apatite, along with comparable apatite geochemical characteristics across both the Chaizhuang and Weijiazhuang sections, indicate stable provenance with little to no change from the late Middle Pleistocene to the Late Pleistocene. This continuity in provenance signatures suggest an absence of shift in drainage patterns or sediment sources, indicating that the current location and pattern of Fen River lower reach drainage was not formed at least by then. Consequently, it is inferred that the detrital material composing the paleo Fen River sediments during this period predominantly originated from the NCC. Supplementary material: https://doi.org/10.6084/m9.figshare.c.7258187