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Reconstruction of the paleoaltitude history of the Tibetan Plateau is critical for understanding the linkage between tectonics and its effect on regional and global climate change. Presently, most of the paleoaltitude studies are concentrated on the southern and southeastern part of the Tibetan Plateau, and few studies have been conducted in the central‐northern part. In this paper we focused on the Wudaoliang Formation in the Tuotuohe Basin, central to northern Tibetan Plateau, to reconstruct paleoaltitude based on carbonate oxygen isotopes. The carbonate samples are primary or have experienced an early stage of digenesis. Based on the thermodynamic and empirical model results, the paleoaltitude of the Wudaoliang Formation is found to be around 2700–3260 m (average of 2980 ± 280 m) in the early Miocene (∼24 Ma). Integrating paleoaltitude results from Wudaoliang Basin and our results, we conclude that crustal shortening and tectonic activity were strong during the late Eocene to late Oligocene‐early Miocene and relatively weak during the early Miocene in the central‐northern Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Hydrogen isotopic compositions (δD) of fatty acids (FAs) in lake sediments have been widely used in palaeoenvironmental reconstruction, but investigations on FA δD values in algae and submerged plants from natural lakes are still limited, greatly hampering the application and interpretation of their δD values in lacustrine environments. Here, we systematically investigated δD values of short-chain (C 14 –C 18 ), mid-chain (C 20 –C 24 ), and long-chain (C 26 –C 30 ) FAs in four algae and submerged macrophytes, two algal genera Chara and Cladophora and two angiosperm genera Potamogeton and Ruppia , that commonly occur in six lakes on the north-eastern Tibetan Plateau. We obtained the following results: (i) C 20 –C 30 FAs in each algal and submerged plant sample have similar variation patterns in δD values, suggesting that δD values of C 20 –C 30 FAs have consistent responses to their source water δD. In C 4 -like taxa ( Potamogeton , Ruppia , and Chara ), the C 16 and C 26 FAs have minor differences in their δD values, while in the C 3 -like Cladophora , δD values of C 16 FAs are significantly more negative (avg. –48 ± 7‰) than that of the C 26 FAs. We propose that different photosynthetic mechanisms in these algae and submerged plants account for the different inter-molecular δD variations between C 16 and C 26 FAs; (ii) δD values of C 26 FAs in the carbonate-coated alga Chara are significantly correlated with the δ 18 O values of carbonate encrustations – such a co-variance suggests that in addition to lake water, other factors may also influence both lipid synthesis and carbonate encrustation building up in Chara , leading to a significantly positive apparent hydrogen isotope fractionation factors (ε FA-W ) between C 26 FAs of Chara and lake water; (iii) δD values of C 26 FAs from Potamogeton , Ruppia and Cladophora are correlated well with lake water δD values ( R 2 = 0.84, p  < 0.001, n = 19), suggesting that the δD values of long-chain FAs potentially record δD variations of lake water with the apparent hydrogen isotope fractionation factors (ε FA-W ) of C 26 FAs ranging from −153‰ to −134‰. Our results highlight the impact of different photosynthetic pathways on the inter-molecular difference of FA δD values in algae and submerged plants and illustrate both the potential and the challenge of applying their FA δD values as a palaeo-hydrology proxy. [ABSTRACT FROM AUTHOR]

Eolian dust activity studies on the arid Central Asia (ACA), one of the world's largest dust sources, are of great importance to the global climatic system. Grain size distributions (GSDs) can provide information on sediment sources, transport processes and sedimentary environments. As a result, GSD is the most frequently applied proxy in reconstruction of past eolian dust activities of the ACA using lake sediments. The GSD dataset for a core spanning the last ~850 years from Kuhai Lake on the northeastern Tibetan Plateau was unmixed by end-member analysis (EMA) for reconstruction of past eolian dust activities on the southeastern margin of the ACA. The results suggest that EM 2 and EM 3, which were added together to form an eolian dust activity proxy, represent the proximal eolian suspension and saltation loads, respectively. The fractional abundances of EMs suggest that siliciclastic materials in the studied core were mainly from eolian contributions. The occurrence of enhanced eolian dust activities within the cold Little Ice Age period together with the GSDs of EM 2 and EM 3 indicate that eolian dust activities on the southeastern margin of the ACA were basically governed by the Siberian High-produced Asian Winter Monsoon over the last millennium. At decadal to centennial scales, enhanced eolian dust activities generally correspond to warm periods with high total solar irradiance (TSI). Increased temperatures as the result of high TSI would have caused larger increases in evaporation than in precipitation, and hence deteriorated vegetation cover and increased dust sources availability. • Eolian dust activity of the arid Central Asia was studied using a core of Kuhai Lake. • The HALS-NMF parametric algorithm of end-member analysis was applied. • Siliciclastic materials in the studied core are mainly from eolian contribution. • Eolian dust activity at centennial scale was governed by Siberian High. • Eolian dust activity at decadal scale was governed by total solar irradiance. [ABSTRACT FROM AUTHOR]

As a transitional region between arid and semi-arid areas, and the climatic junction where the Asian summer monsoon and the Westerlies interact strongly, the climatic pattern of northeastern Tibetan Plateau has always been the focus of paleoclimate research. In this study, the changes in the lake depth of Lake Qinghai on the northeastern Tibetan Plateau were reconstructed from analyses of biomarkers in sediment records from the center of the lake and aeolian deposits on its southern bank. On millennial scale, the lake depth showed a fluctuating upward trend from the minimum depth at 15.6 ka to the maximum depth at 5.9 ka, revealing an overall warming-wetting pattern since the last deglaciation. Compared to the typical monsoon-dominated areas, the relatively humid late Holocene of Lake Qinghai appears to have been related to a weakened evaporation on the long-term trend. We show that on a long-term scale, precipitation may control the rate of changes in lake depth. This reasonably explains the asynchrony of precipitation and lake depth over the northeastern Tibetan Plateau during the mid-Holocene. • Reconstruct lake depth change using P aq records in lacustrine and terrestrial records. • Precipitation controlling the rate of lake depth change. • Precipitation decreased and lake depth rising slowed in the mid-Holocene. [ABSTRACT FROM AUTHOR]