Abstract
The provenance study of the sediments from Qinghai Lake is of great significance for the understanding of geological and climatic evolution processes of the Tibet Plateau on the one hand and for evaluating the controlling factors of the sediment components on the other hand. The samples were collected from five rivers, foreshore, beach, beach bar, and aeolian sand dune in the Qinghai Lake. The bulk geochemical composition, petrography, and mineralogy features of the samples are analyzed. The results show that: 1) Qinghai Lake sediments experienced low-intensity chemical weathering from the source areas to the deposition sites and were affected by some recycled detrital materials and 2) the source rocks for the sediments include felsic rocks (granite, granodiorite, and felsic volcanic rocks), carbonate, metamorphic rocks (marble and meta-volcanic rocks), and clastic rocks with the felsic source rocks to have the most important impact on the chemical compositions of the sediments. The geochemical indicator of Al2O3/TiO2 reflects that the provenance of fine-grained sediments from the center of Qinghai Lake is more mafic than the coarse-grained sediments from the margin of the Qinghai Lake, suggesting that the hydraulic sorting of grain size probably plays an important role in the geochemical compositions of the sediments. The mafic elements were probably preferentially enriched in muds.
Highlights
Qinghai Lake is the largest inland closed salinized lake, located at the Northern Tibet Plateau (Figure 1A)
Eight sand samples were collected from the Erlangjian beach bar to the southeast of the lake, eight sand samples were collected from the beach of Niaodao, and six sand samples were collected from the aeolian sand dune to the northeast of the lake (Figure 1B)
Fifteen samples from the Erlangjian (ELJ) beach bar and Niaodao (ND) beach were ground into 200 mesh (
Summary
Qinghai Lake is the largest inland closed salinized lake, located at the Northern Tibet Plateau (Figure 1A). The formation of Qinghai Lake was closely associated with the uplift of the Tibet Plateau. The thicknesses of the sediments in the southern and northern depressions of Qinghai Lake are over 700 and 560 m (An et al, 2006). The uninterrupted sediments are sensitive to the changes of climate and tectonic, making Qinghai Lake a natural laboratory for the study of climate and tectonic evolution of the Tibet Plateau. The basement structures, the geochemical and mineral compositions of the drilled core and bottom sediments, and water chemical ions of Qinghai Lake were investigated (Zhang et al, 1994; Liu et al, 2002; Jin et al, 2009, 2015; Xiao et al, 2012; Zhang et al, 2019; Song et al, 2020). The sediments from the margin of Qinghai Lake are ideal materials to trace the source rocks of Qinghai Lake and to evaluate the influence of the hydraulic sorting
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