Paleozoic metamorphism in the Qinling orogen, Tongbai Mountains, central China

The collision of the Sino-Korean and Yangtze blocks to form a significant part of China is recorded in the Qinling, Tongbai, and Dabie Mountains. Radiometric ages of the ultrahigh-pressure metamorphic rocks in the South Qinling orogenic belt suggest that subduction and collision took place during the Triassic Period. Our new 40Ar/39Ar geochronology of units in the North Qinling orogenic belt confirms that high-grade metamorphism and deformation took place also during the Silurian-Devonian and Carboniferous Periods. These results imply that the amalgamation of eastern China was a multistage process extending over at least 200 m.y.