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As the Third Pole of the Earth and the Water Tower of Asia, the Tibetan Plateau (TP) nurtures large numbers of glacial lakes, which are sensitive to global climate change. These lakes modulate the freshwater ecosystem in the region but concurrently pose severe threats to the valley population by means of sudden glacial lake outbursts and consequent floods (GLOFs). The lack of high-resolution multi-temporal inventory of glacial lakes in TP hampers a better understanding and prediction of the future trend and risk of glacial lakes. Here, we created a multi-temporal inventory of glacial lakes in TP using a 30-year record of 42,833 satellite images (1990–2019), and we discussed their characteristics and spatio-temporal evolution over the years. Results showed that their number and area had increased by 3285 and 258.82 km2 in the last 3 decades, respectively. We noticed that different regions of the TP exhibited varying change rates in glacial lake size; most regions show a trend of expansion and increase in glacial lakes, while some regions show a trend of decreasing such as the western Pamir and the eastern Hindu Kush. The mapping uncertainty is about 17.5%, which is lower than other available datasets, thus making our inventory reliable for the spatio-temporal evolution analysis of glacial lakes in the TP. Our lake inventory data are publicly published, it can help to study climate change–glacier–glacial lake–GLOF interactions in the Third Pole and serve as input to various hydro-climatic studies. [ABSTRACT FROM AUTHOR]

We present herein detailed images of the Moho depth and V p/ V s ratio along ANTILOPE-1 profile beneath the western Tibetan Plateau derived from receiver function analysis. Along the ANTILOPE-1 profile, a rapidly northward-dipping Moho extends from ∼50 km below the Himalaya to ∼80 km across the Indus–Yarlung suture, shallowing to ∼66 km under the central Lhasa terrane. The Moho depth shows a dramatic increase from ∼66 km north of the Bangong–Nujiang suture to ∼93 km beneath central Qiangtang terrane where it reaches the maximum depth observed along this profile before steeply rising to ∼73 km. We interpret both the 15 and 20 km offsets of Moho depth occurring beneath the central Lhasa and central Qiangtang terranes as being related to the northern frontiers of the decoupled underthrusting Indian lower crust and lithospheric mantle, respectively. The Moho remains at a depth of ∼70 km with a slight undulation beneath the northern Qiangtang and Songpan–Ganzi terranes, and then abruptly shallows to ∼45 km near the Altyn Tagh Fault. The ∼25 km Moho offset observed at the conjunction of the Tarim Basin and the Altyn Tagh mountain range suggests that the crustal shortening is achieved by pure shear thickening without much underthrusting. The average crustal V p/ V s ratio changes from 1.66 to 1.80 beneath the Himalaya, the Lhasa terrane and the Tarim Basin indicating a felsic-to-intermediate composition. However, higher V p/ V s ratios between 1.76 and 1.83 (except for a few outlying low values) are found beneath the Qiangtang and Songpan–Ganzi terranes, which could be attributed to the joint effects of the more mafic composition and partial melt within the crust. The Moho depth and V p /V s ratio exhibit complex N–S variations along this profile, which can be attributed to the joint effects of Indian lower crust underthrusting, the low-velocity zone of the mid-upper crust, crustal shortening and thickening, and other involved dynamic mechanisms. [ABSTRACT FROM AUTHOR]

Leucogranites play a significant role in understanding crustal thickening, melting within continental collisional belts, and plateau uplift. Field investigations show that Miocene igneous rocks from the Hoh Xil Lake area mainly consist of two-mica leucogranites and rhyolites. We studied the Bukadaban two-mica leucogranites and the Kekao Lake, Malanshan and Hudongliang rhyolites by zircon U-Pb, muscovite and sanidine Ar/Ar geochronology, and whole-rock geochemical and Sr-Nd isotopic analysis. Results yielded crystallization and cooling ages for the Bukadaban leucogranites of 9.7±0.2 and 6.88±0.19 Ma, respectively. Extrusive ages of the Kekao Lake and Malanshan rhyolites are 14.5±0.8 and 9.37±0.30 Ma, respectively. All rocks are enriched in SiO (70.99%-73.59%), AlO (14.39%-15.25%) and KO (3.78%-5.50%) but depleted in FeO (0.58%-1.56%), MgO (0.11%-0.44%) and CaO (0.59%-1.19%). The rocks are strongly peraluminous (A/CNK=1.11−1.21) S-type granites characterized by negative Eu anomalies ( δEu=0.18−0.39). In also considering their Sr-Nd isotopic compositions (Sr/Sr=0.7124 to 0.7143; ε Nd (9 Ma) =−5.5 to −7.1), we propose that these igneous rocks were generated through dehydration melting of muscovite in the thickened middle or lower crust of northern Tibet. Melting was probably triggered by localized E-W stretching decompression in the horse tails of Kunlun sinistral strike-slip faults. Reactivation of the Kunlun strike-slip faults, accompanied by emplacement of leucogranite and eruption of rhyolite in the Hoh Xil Lake area, indicates that large-scale crustal shortening and thickening in northern Tibet mainly occurred before 15 Ma. In addition, these findings suggest that the northern Tibetan Plateau attained its present elevation (∼5000 m) at least 15 Ma ago. [ABSTRACT FROM AUTHOR]