The Wuyu Basin is bounded by the Gangdese Mountains to the north and the Yarlung Tsangpo River to the south, and is a representative basin to study the Cenozoic tectonism of the southern Tibet. The sedimentary strata in the Wuyu Basin include the Paleocene-Eocene Linzizong Group volcanics and the Oligocene Rigongla Formation (Fm.) volcanics, the Miocene lacustrine sediments of the Mangxiang Fm. and Laiqing Fm. volcanics, the late Miocene-Pliocene Wuyu Fm., and the Pleistocene Dazi Fm. Five sandstone samples from the Mangxiang Fm., Wuyu Fm. and Dazi Fm. and one modern Wuyu reiver sand sample were collected for detrital zircon U-Pb dating using the LA-ICP-MS method. Detrital zircon U-Pb ages in the Mangxiang Fm. show a large cluster at 45-80 Ma; those in the Wuyu Fm. show a large cluster at 8-15 Ma and a subsidiary cluster at 45-70 Ma; those in the Dazi Fm. show three large clusters at 45-65 Ma, 105-150 Ma and 167-238 Ma; and those in modern Wuyu river show a large cluster at 8-15 Ma and a subsidiary cluster at 45-65 Ma (Figure 1). Late Cretaceous-early Eocene zircons in all samples are consistent with the most prominent stage of magmatism of the Gangdese Mountains; the 8-15 Ma zircons in the Wuyu Fm. and modern Wuyu river are consistent with the magmatism of the Laiqing Fm.; and the Triassic-Jurassic zircons in the Dazi Fm. are consistent with the magmatism of the central Lhasa terrane. The results of detrital zircon U-Pb ages and sedimentary facies analyses in the Wuyu Basin indicate that the southern Tibetan Plateau suffered multi-stage tectonism-magmatism since the India-Asia collision: (1) Paleogene Linzizong Group-Rigongla Fm. volcanics; (2) tectonism-magmatism at ~15 Ma ended the lacustrine sediments of the Mangxiang Fm. and resulted in volcanism of the Laiqing Fm.; (3) tectonism at ~8 Ma resulted in the volcanic rocks of the Laiqing Fm. becoming one of the main provenances for the overlying Wuyu Fm.; (4) the Wuyu Basin formed braided river and received sediments from the central Lhasa terrane to its north at ~2.5 Ma. The geomorphic pattern of the southern Tibet has gradually formed since the Quaternary.
MENG Qingquan MENG Qingquan
The Cenozoic strata developed within and around the Tibetan Plateau, contain fruitful information on the tectonic evolution, paleoenvironment and paleoclimate changes. It's very significant on revealing the history of the uplift and deformation of the Tibetan Plateau and its relevant effects on the regional and even global environment and climate. This data set contains several well developed sections, which have been identified by the systematic geological survey. Depending on the tools (e.g. GPS, geological compass) in the fieldwork, we have finished the geological measurements and descriptions of these sections as well as the relevant geological maps. It includes a 90-m loess deposit of the Duikang section in the Linxia basin, several fluvial and lacustrine deposits (such as the 1890-m Dayu section in the Lunpola basin, the 300-m Shuanghe section in the Jianchuan basin, the 252-m Caijiachong section in the Qujing basin) and a 932-m saline lacustrine deposit with gypsolyte of the Jiangcheng section in the Simao basin. This data set provides a solid geological foundation for the following researches on stratigraphic chronology, tectonic evolution, paleoenvironment and paleoclimate, and so forth.
FANG Xiaomin , FANG Xiaomin, YAN Maodu, ZHANG Weilin, ZHANG Dawen
Dating data of debris flow and dammed lake sediments in complex mountainous areas from 2019 to 2021. The data collection sites are complex mountainous areas prone to debris flow in the eastern and southern edges of the Qinghai Tibet Plateau. The experimental analysis is mainly completed in the salt lake chemical analysis and testing center of Qinghai Salt Lake Research Institute of Chinese Academy of Sciences and the analysis and testing center of Chengdu Mountain Institute of Chinese Academy of Sciences. The instruments used include RIS ø TL / OSL – Da – 20 automatic luminescence instrument, etc. The age data set of debris flow sediments in typical complex mountainous areas is established, the formation age of debris flow sediments in complex mountainous areas is quantitatively studied, and the ancient debris flow disaster activity history in complex mountainous areas is determined.
HU Guisheng
Paleo-shorelines are widely developed in the lakes of the Tibetan Plateau (TP), which record the history of paleo-lake level changes. The development age of the mega-lake represented by the highest paleo-shoreline is controversial. The age of the shoreline or the mega-lake can be obtained by measuring the burial age of the shoreline sand in the sedimentary strata of the paleo-shoreline by using the optical stimulated luminescence (OSL) dating technology. This data includes the OSL ages of the highest paleo-shorelines of three lakes in the northwestern TP. The dating is based on the K-feldspar pIRIR method developed in recent years, which effectively solves the problem that the quartz OSL signal is not suitable for dating in the study area. This data can provide key information for the evolution history of the mega-lakes on the TP.
ZHAO Hui, ZHANG Shuai, SHENG Yongwei
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