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
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 Paleogene marine strata in southern Tibet are well developed and rich in foraminifera and other marine fossils. Based on the study of macroforaminifera taxonomy and Stratigraphy in the West Tethys domain (mainly the Mediterranean region), western scholars established the Paleocene Eocene macroforaminifera biostratigraphy in 1998. Compared with Tibet in the East Tethys domain, the development of macroforaminifera in the Paleocene in the Mediterranean region is relatively poor. Therefore, the accuracy of biostratigraphy based on sittis foraminifera is low. In this study, detailed profile survey and high-density sample collection of lower Paleogene carbonate sedimentary strata in guru area, southern Tibet are carried out to supplement and improve the biostratigraphy of macroforaminifera in southern Tibet on the basis of macroforaminiferal taxonomy research; Based on biostratigraphy and carbon isotope stratigraphy, a high-resolution chronostratigraphic framework is established. A total of 7 profiles were measured in this study, and the profiles are located between 89 ° 11 ′ ~ 89 ° 13 ′ E and 28 ° 3 ′ ~ 28 ° 7 ′ n; The elevation range is 4643 ~ 5380 M. Based on the observation of rock slices in the laboratory, the age of the measured strata is preliminarily judged. P2 section is a limestone sequence overlying the late Cretaceous strata, representing the earliest Paleocene sedimentation in the study area; P1 section is a set of very thick limestone deposits of lower Paleocene; Section E2 is the top of Paleocene, close to the Paleocene / Eocene boundary; The ages of sections E1, E3, E3s and E4 are roughly early Eocene; The grayish green marl and red shale at the top of section E4 represent the latest marine strata in the study area. We plan to conduct detailed taxonomic and stratigraphic studies on foraminifera in these sections to establish high-resolution large foraminifera biostratigraphy; At the same time, we also need to analyze the changes in composition and abundance of macroforaminifera, and further explore the evolution process of macroforaminifera in early Paleogene. For the sandstone strata in the section, we need to conduct detrital zircon U-Pb isotope analysis, the obtained age and biostratigraphic data confirm each other, and further explore the paleogeographic evolution process under the influence of India Eurasia collision.
ZHANG Qinghai
On the basis of satellite image recognition, this data set catalogues and photographs the debris flow disaster chain and landslide disaster chain observed in the Himalayas and its surrounding areas; And fill in the data form, scientific examination log file and distribution map. Discipline scope of this data set: information and system science related engineering and technology - > systematic application of information technology - > geographic information system. This data mainly determines the location and type of disaster and disaster chain through field investigation, and then arranges it into tables and generates original data such as vector data and scientific research logs. The field scientific research areas include Nyingchi, Shannan, Bomi, Basu, Shigatse, Ali and other areas of the Tibet Autonomous Region, and the South-North rift areas such as Yadong, Nyalam, Chentang village, Jilong and Pulan of the South Asia channel.
DENG Hongyan
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