A new model that dates the collision of the North China Block with the South China Block more recently than had been previously thought by most geologists has been proposed by scientists at the University of California, Santa Cruz (UCSC). The model, which was proposed by Xixi Zhao and Robert Coe, shows that the North China Block and the South China Block collided at a single point about 200 million years ago near what is now Shanghai, during the Early Triassic Period.
Most other geological interpretations show that the blocks joined in Permian or earlier times. The South China Block then rotated about 70° relative to the North China Block, bringing the two blocks into contact along a 1200-mile border. An inland sea was eliminated by the collision, and the Qin-Ling Mountains were pushed up along the current boundary.