Elemental interactions between pore water and lake sediments with their environmental significance: a case as Holocene sediments in Guozha Co, northwestern Tibetan Plateau

Elements in lake sediments and lake water were commonly used in the reconstruction for the paleoenvironment and paleoclimate, and also enriched into mineral deposit, such as lithium deposit. However, previous studies seldom distinguish the elements in porewater and minerals, and also seldom considered water–sediment interaction and how the elements of different properties migrated and enriched during the drying climate. This study investigated the major and trace elements of the porewater, and the carbonate and silicate minerals in a 407–cm-long core from Guozha Co, a brackish lake on the northwestern Tibetan Plateau. Our results indicated that (a) Ca and Sr were predominantly present in carbonate minerals, while Na, K, Mg, Li, were primarily preserved in silicate minerals. (b) the elements of porewater were closed with those of silicate minerals; (c) Na water , Na acid , Li water , and Li acid were more sensitive to drying climate than the others; (d) Identifying Mg/Ca, Sr/Ca and Li/Ca sources is better, rather than directly using the whole sample data to discuss environmental changes. (e) Mg water /Li water were much lower than those of Mg acid /Li acid and Mg residue /Li residue . Low temperature favors the movement of Li in aqueous solution and carbonate minerals. This is useful for the lithium extraction from brines.