Provenance and Tectonic Setting of Formation of Quaternary Sedimentary Successions from the Songhua River, Northeast China

Abstract

Drilling has been conducted to investigate the petrogeochemistry of the Late Pleistocene Guxiangtun Formation and Holocene Wenquanhe Formation in Northeast China. Both Guxiangtun and Wenquanhe Formations are fluvial facies, which are composed mainly of quartz and feldspar, with minor mica and clay minerals. To understand the provenance and tectonic setting of these sediments, geochemical analyses of fifteen selected samples from the drill core have been carried out. Compared to the composition of the upper continental crust (UCC), the sediments exhibit higher SiO2, similar TiO2 and K2O, and lower Fe2O3, MgO, MnO, CaO, and Na2O contents. The bivariant plot of Th/Sc versus Zr/Sc ratios indicates the contribution from recycled sedimentary provenance for our studied sediments; furthermore, the low to medium degree of weathering of these sediments is commonly indicated by the chemical index of alteration (CIA) of 52. The discriminant function diagram using major elements shows a mixed provenance of the sediments, including quartzose sedimentary and felsic igneous rocks. According to the Fe2O3+MgO vs. K2O/Na2O plot and Th–Sc–Zr/10 diagram, the sediments under the investigation fall mostly within the active continent margin field.