Abstract:
This paper summarizes the composition and age characteristics of the Precambrian and Paleozoic lithostratigraphy in the central to southern Qinghai-Tibet Plateau in six regions: the North Qiangtang area, the South Qiangtang area, the Gangdise area, the Zhongba area, the Himalaya and the Qamdo area. It summarizes the lithological and geochronological characteristics of 117 lithostratigraphic units, meanwhile, preliminarily sorts out the problems in stratigraphic division and correlation, so as to provide basic geological information for the pre-Mesozoic geological evolution of Qinghai-Tibet Plateau. The Qiangtang was considered that most of the Precambrian basement designated by predecessors no longer has typical metamorphic or crystalline basement characteristics. The northern Qiangtang area (with limited information) may have a relatively stable basement. Lower Paleozoic in northern Qiangtang area only includes part of the Ordovician and Silurian, and the Upper Paleozoic may be unconformity above the Lower Paleozoic; late Early Devonian, middle Late Devonian, Late Carboniferous and possibly the whole Permian develop successively. The basement in southern Qiangtang area is of unknown nature. The Lower Paleozoic in southern Qiangtang area is only exposed in the form of "residual block" in the Mayigangri mountain. And its Upper Paleozoic has different styles in the West and East: Rutu county area in the western has more stable sedimentary characteristics, while the Shuanghu area in the Eastern may be a subduction accretion complex of "matrix + block". In Gangdise area, except Lhasa block (central part) and Nerong block, the basement of other areas is unknown. A set of "bimodal" volcanic rocks developed from the end of Neoproterozoic to Cambrian in Gangdise area. The Ordovician may be unconformity above the pre-Ordovician in Gangdise area, and from Ordovician to Permian, marine (or transitional) deposits developed. The strata of Zhongba block can be clarified into Upper Sinian - Cambrian schist and Ordovician - Devonian metamorphic carbonate, Carboniferous - Permian from bottom to top. The Himalayan region has a relatively stable Precambrian crystalline basement, and the Paleozoic deposited a set of marine strata from Middle Ordovician to Late Permian. There may be Precambrian in Qamdo area, but further work is indeed. Lower Ordovician and Silurian are only sporadically exposed, and except for the disconformity contact between Lopingian and Guadalupian, the marine sedimentary strata are relatively developed in Qamdo area.