Geochemistry and Petrography of the Sediments From the Marginal Areas of Qinghai Lake, Northern Tibet Plateau, China: Implications for Weathering and Provenance

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.

Differential Responses of Plant Primary Productivity to Nutrient Addition in Natural and Restored Alpine Grasslands in the Qinghai Lake Basin

“…As the main alpine grassland area of Qinghai province, the Qinghai Lake Basin (QLB) is a distinctive geographical unit within the QTP. The ecosystem's internal fragility, coupled with external environmental and land-use changes, makes the alpine grasslands in QLB highly sensitive to human activities and ongoing climate change (Cui and Li, 2015 ; Tao et al, 2021 ). Therefore, studying the relationships among the environment, ecology, and agriculture/pasture development embedded within climate change scenarios is essential.…”

Separation, reserve estimation and radioactivity responsibility of the economic heavy minerals of East El- Arish black sand, North Sinai, Egypt

“…The elements Zr and Hf are frequently used in sediment source discrimination 46 – 48 . The Zr/Hf ratio ranges 11 to 21 lower than the chondritic value of ~ 30.…”

Provenance Indication of Rare Earth Elements in Lake Particulates from Environmentally Sensitive Regions

“…In this study area, Qinghai Lake and the recharging rivers mainly comprise felsic rocks (granite, granodiorite, and felsic volcanic rocks), carbonate rocks, metamorphic rocks (dacite and metavolcanic rocks), and clastic rocks. Of these, the felsic hydrocarbon source rocks have the most significant influence on the chemical composition of the sediments [18].…”

“…Subsequently, they studied the depositional environment of the sediments in the area using radioactive elements [17]. More recently, Tao et al [18] conducted an analysis of REEs concentrations in sediments near Qinghai Lake, complemented by petrological and mineralogical methods, to study the provenance in the region.…”