Search Results (2)

A total of 388 surface sediment samples taken from the northern South China Sea (SCS) continental shelf were analyzed to characterize the signature of their rare earth elements (REEs). The average REEs concentration was 192.94 μg/g, with a maximum of 349.07 μg/g, and a minimum of 32.97 μg/g. The chondrite-normalized REEs pattern exhibits a remarkably light REEs accumulation, a relatively flat heavy REEs pattern, and a negative Eu anomaly. We subdivided the study area into three zones using the characteristics of REEs and statistical characteristics. Zone I: continental shelf off western Guangdong Province. Here, the sediment provenance is mainly river-derived from the Pearl River, Taiwanese rivers, and those in the adjacent area. Zone II: Qiongzhou Strait and Leizhou Peninsula. Here, the sediment provenance consists of the Qiongzhou Strait and the Hainan Island. Zone III: Hainan Island and SCS slope sediments are dominated. The REEs compositions are mainly controlled by source rock properties, hydrodynamic conditions, and an intensity of chemical weathering. We reconstructed the sediment dispersal and transport route using the REEs compositions, grain size, and other geochemical characteristics throughout the study area. Full article

Sediment geochemistry is affected by sediment granularity and chemical partition, which may greatly influence the accuracy of sediment source identification. In this study, we analyzed Ca, Co, Zr, V, Cr, Ti, Sc, Th, and Al in the sediments of major rivers and a Holocene core along the eastern coast of China to reveal the constraints on sediment geochemistry related to granularity and chemical partition and to try and identify the sources of the sediments present in the core. The results reveal that the element concentrations have a significant positive correlation with Al concentration in all these riverine sediments. There are significant differences in the element contents of the bulk sample and the residual sediment leached with acid, including in their ratios. The ratios of Cr/Th–Sc/Th, which is often used for provenance discrimination, reveal that uncertainty of provenance discrimination will increase if the impact of sediment granularity and chemical phase on the index system is not considered. We applied this geochemical approach for provenance on a Holocene core of the East China Sea using Cr/Th–Al, Sc/Th–Al, Ti/Zr–Al, and Cr/Th–Sc/Th with the same granularity as the residue sediments. Based on this approach, we identified the core sediments to have had a large component derived from the western Taiwanese rivers since the mid-Holocene. This study sheds light on the sediment geochemistry used to identify the provenance of marginal seas with multiple rivers entering them. Full article