秦岭造山带结构与演化若干问题的再认识

本文详细论述了北秦岭与商丹带、南秦岭、勉略带和太白－佛坪－汉南带的组成、结构特征；重新划分和阐述了秦岭造山带的构造单位及其发展演化。提出秦岭是由五类岩石地层地质体按非线性、混沌动力学的关系组合在一起并拼贴、镶嵌、叠置、堆垛而成的综合构造体，是南北与东西共存的构造格局。其经历了太古宙－古元古代陆核或古陆块增生或拼贴的发展阶段，中－新元古代板块构造体制发展阶段，震旦纪－三叠纪板内海相沉积盆地与造山带转换的发展阶段．印支期以来陆相沉积盆地和造山带转换的抽拉－逆冲岩片构造(或抽拉构造)体制的发展阶段。

RECONSIDERATION OF SOME PROBLEMS ABOUT THE STRUCTURE AND EVOLUTION OF THE QINLING OROGENIC BELT

New data of the Qinling- Dabashan orogenic belt has been applied to discuss the composition and structure characteristics of the North Qinling, Shangdan tectonic belt, South Qinling, Mianlue tectonic belt and Taibai- Fuping- Hannan tectonic belt. Some new views on the distribution features of Qinling mixtite located in the North Qinling, the volcanic rocks of Erlangping Group and the geologic age of Danfeng Group were also proposed. We believe that: ① the Shangdan tectonic belt is not a plate junction, but a contact boundaiw surface of various geologic bodies; ② the South Qinling tectonic belt is mosaicked and pieced together by Shanglan- Wudang block, Shanzhaxun-Ankang belt and Fuping block in a east-west direction; ③ the Mianlue ophiolite belt is not the plate junction of the Phanerozoic, but a ultrabasic rock belt of the last stage of the Proterozoic, which was broken and involved with the tectonic melanes latter; Based on the new discovery that the metamorphic crystalline rock belt extended in north-south directionin Longbao, Taibai, Fuping and Hannan, the Qinling orogenic belt could be divided into two different parts, i.e., the East Qinling belt and the West Qinling belt. The Qi1ian orogenic belt is not extended to the North Qinling. The north-south direction structures are very important in the Qinling orogenic belt. Combining the geophysics data, we redivided the tectonic units and the evolution stages of the Qinling orogenic belt and suggest that the Qinling is a synthetic tectonic body pieced tog ether, mosaicked, layered and piled up by five kinds of rocks in monlinear and chaodynamic way. The north south tectonics coexist with the east west tectonics. It has gone through the Archaean to Paleoproterozoic continental nucleus growing stage, the Mesoproterozoic to Neoproterozoic plate tectonic developing stage, the Sinian to Triassic sea basin transforming to orogenic belt developing stage and the continental basin transforming to the orogenic belt developing stage in drawing-out-thrusting tectonic system since the Indosinian.