Cretaceous：A key transition period of the plate tectonic evolution in China and its adjacent areas

Abstract：The Asian continent (mainland China and its adjacent areas) is a composite one formed by multi-stage accretion and collision of a number of microcontinents (cratons) and blocks of different origins. The Hercynian-Indosinian cycle and Neo-Tethyan cycle played a decisive role in its formation. At the end of the Jurassic and the beginning of the Cretaceous, the Neo-Tethys ocean (which is called the Mid-Tethys by some people) closed ａｎｄ the embryonic Asian continent occurred. At the end of the Cretaceous, the Neo-Tethys ocean was consumed and the Asian continent originated；therefore the Cretaceous was an important transition period of the plate tectonic evolution of China and its adjacent areas. This paper discusses this transition in the contexts of the transitions of geodynamic system and tectonic framework, appearance of the NE-trending neogenic structures and diversity of orogeny. This transition is mainly manifested by the transformation of north-south differentiation to east-west differentiation in the region during the Cretaceous. The western part is characterized by the tectonic inheritance, while in the eastern part the neogenic structures played the main role. Geomorphologically, the region was high in the east and low in the west in the Early Cretaceous, while the present-day geomorphologic feature of being high in the west and low in the east began to appear at the end of the Cretaceous. The “basin-and-range” system also began to change significantly in the Cretaceous, which suggests that the margin of the East Asian continent was disintegrated progressively in response to its creep and dispersion toward the Pacific plate, and then the tectonics in the interior of the continent became increasingly complex. This case study further indicates that we must adhere in the tectonic concept of mobilism and reconstruct the regional tectonic evolution with the idea of dynamic evolution.