THE TECTONIC RELATIONSHIP BETWEEN THE QINLING MOUNTAINS AND TONGBAI-DABIE MOUNTAINS WITH NOTES ON THE TECTONIC EVOLUTION OF THE HEHUAI BASIN
秦岭与桐柏-大别山的构造关系——兼论河淮盆地的构造演化

Abundant microfossils have been found in the Nanwan Formation of the former Xinyang Group, which is consistant with the Devonian Liuling Group in the Qinling Mountains in age and sedimentary-structural characteristics. Also, abundant Early Paleozoic microfossils and a few corals have been discovered in the Erlangping Group, whose sedimentary sequence represents the process from sea-floor spreading to subduction of the ocean basin. The tectonic zones of the Qinling Mountains and the Tongbai-Dabie Mountains may link up one another, and the main suture zone is situated along Danfeng-Xinyang-Shucheng. It is the Guishan Formation of! the former Xinyang Group that is the strongly deformed pre-Devonian tectono-stratigraphic unit distributed in the main suture zone. The result of the systematic, isotopic dating clearly shows that the Qinling Mountains are a Caledonian, Variscan, Indosinian, and Yanshanian polycyclic composite orogen. The Sinian to Triassic sequence on the southern edge of the Sino-Korean platform has recorded the evolution of the Qinling orogen in different aspects of its process. The Cretaceous-Tertiary Hehuai basin was generated owing to the combined effect of the Tethys and Pacific Ocean dynamic systems.