Cretaceous integrative stratigraphy, biotas, and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

The Cretaceous Period is a vital time interval in deciphering the evolutionary history of the Neo-Tethys Ocean and the convergence of different plates and blocks across the Qinghai-Tibetan Plateau. A detailed stratigraphic framework and paleogeographic patterns are the basis for understanding the evolution of the Neo-Tethys Ocean and the formation of the Qinghai-Tibetan Plateau. Here, the Cretaceous stratigraphy, biota, paleogeography, and major geological events in the Qinghai-Tibetan Plateau are analyzed to establish an integrative stratigraphic framework, reconstruct the paleogeography during the Cretaceous Period, and decode the history of the major geological events. The Cretaceous rocks of the Qinghai-Tibetan Plateau and its surrounding area are predominantly marine deposits, with a small amount of interbedded marine-terrestrial and terrestrial conponents. The Indus-Yarlung Tsangpo Suture Zone was responsible for the deposition of deep marine sediments dominated by ophiolite suites and radiolarian silicalite. To the south, the Tethys Himalayas and Indus Basin received marine sediments of varying depths and lithology; to the north, the Xigaze and Ladakh forearc basins are also filled with marine sediments. The Lhasa Block, Karakorum Block, western Tarim Basin, and West Burma block consist of shallow marine, interbedded marine-terrestrial, and terrestrial sediments. The Qiangtang Basin and other areas are dominated by terrestrial sedimentation. The Cretaceous strata of the Qinghai-Tibetan Plateau and its surrounding areas are widely distributed and diversified, with abundant foraminifera, calcareous nannofossils, radiolarians, ammonites, bivalves, and palynomorphs. On the basis of integrated lithostratigraphic, biostratigraphic, geochronologic, and chemostratigraphic analyses, we proposed herein a comprehensive stratigraphic framework for the Cretaceous Period of the eastern Neo-Tethys. By analyzing the Cretaceous biota of different biogeographic zones from eastern Neo-Tethys and its surrounding areas, we reconstructed the paleobiogeography of different periods of eastern Neo-Tethys. The Cretaceous paleogeographic evolution of the Qinghai-Tibetan Plateau and its surrounding areas can be divided into three phases: (1) gradual breakup of the Indian Plate from the Australia-Antarctica continent and the early collision phase of the Lhasa-Qiangtang blocks (145–125 Ma); (2) northward drift of the Indian Plate and the collision phase of the Lhasa-Qiangtang bl