秦岭与桐柏-大别山的构造关系——兼论河淮盆地的构造演化

原信阳群南湾组中已发现丰富的微古生物化石,其地质时代和沉积-构造特征与秦岭的泥盆系刘岭群一致;二郎坪群中已发现丰富的早古生代微古生物化石和少量珊瑚化石,其沉积序列基本显示了由海底扩张到洋盆消减的全过程。秦岭与桐柏-大别山各构造带之间可以彼此衔接,主缝合带位于丹凤-信阳-舒城-线。原信阳群龟山组就是沿主缝合带分布的前泥盆纪强应变构造地层体。同位素年代学的系统研究结果,充分反映出秦岭是一个加里东、华力西、印支、燕山多旋回复合造山带。中朝准地台南缘震旦-三叠系的沉积序列从另一个侧面反映了秦岭造山带的演化过程。白垩-第三纪河淮盆地是在特提斯与太平洋动力学体系联合作用下形成的。

THE TECTONIC RELATIONSHIP BETWEEN THE QINLING MOUNTAINS AND TONGBAI-DABIE MOUNTAINS WITH NOTES ON THE TECTONIC EVOLUTION OF THE HEHUAI BASIN

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.