TECTONIC EVOLUTION OF THE EAST QINLING MOUNTAINS, CHINA, IN THE PALEOZOIC - A REVIEW AND NEW TECTONIC MODEL

East Asia is a composite assemblage built up from various plates, and the Qinling Mountains are prominent among the orogenic belts dividing these plates. Because of its complex and prolonged history, interpreta tion of the geology of the Qinling Mountains has led to a variety of t ectonic models. We review and summarize recently published data and pr evious work and develop a new tectonic model for the eastern part of t his mountain range. Four tectonic zones are recognized from north to s outh: the Lesser Qinling, the North Qinling, the Central Qinling and t he South Qinling zones. The Lesser and North Qinling zones are interpr eted as a late Proterozoic to early Palaeozoic passive continental mar gin bordering the North China Block. The Central Qinling, separated fr om the Lesser/North Qinling zone by a suture zone, mainly consists of volcanic arcs and a high-grade metamorphic complex. The South Qinling zone forms part of the northern margin of the Yangtze Block and has a long (latest Proterozoic to Middle Triassic) depositional history as r evealed by its sedimentary cover. Available data do not support the hy pothesized existence of a major suture divide between the Central and the South Qinling zones, These two zones seem to have collectively for med an early Palaeozoic destructive continental margin on the northern edge of the Yangtze Block, with the Central Qinling as an island-are system and the South Qinling as a wide, highly attentuated marginal ba sin. Late Ordovician to Early Silurian collision between the North Chi na and the Yangtze Block built up the Palaeozoic orogenic belt in the northern part of the Qinling and gave rise to the embryonic East Asian continent. Yet the South Qinling was transformed to a remnant basin a nd remained undeformed until the Late Triassic when the palaeo-Tethys collision to the south of the Yangtze Block drove the Yangtze Block to move northeastwards. Deformation in a transpressive regime during thi s late event largely reconstructed the Qinling belt and hence further complicated its tectonics.