Geological Evolution of Qinling Orogen

The Qinling Orogen has been formed by the collision between South China and North China continents. It includes four tectonic units southward termed Huaxiong Block, North Qinling Accretion Belt, South Qinling Fold Belt, and Songpan Fold Belt. It witnessed a >3-Ga geologic evolution including significant orogenic events corresponding to the assembly and breakup of the Kenor, Nuna, Rodinia, Gondwana, and Pangaea supercontinents. Unique tectonic location, longtime evolution, and complex geological processes endow the Qinling Orogen with various mineral systems including, Mo deposits. Four important but controversial issues are clarified in this chapter: (1) the Early Precambrian crystalline basement in southern North China Craton is the mosaic amalgamation of multiple terranes or blocks that independently developed before 2.05 Ga. (2) The Xiong’er and Xiyanghe groups coevally developed in the continental arc and continental rift, respectively. (3) Triassic Qinling Orogen was analogous to the present Mediterranean Sea, accommodating transition from oceanic plate subduction to continental collision, but not a post-collisional extension. (4) The Yanshanian Orogeny in Qinling Orogen was a tectonic transition from syn-collisional, through post-collisional to intracontinental orogenies, resulting in crustal uplift, granitic magmatism, and hydrothermal mineralization. It was affected by the far-field impact from the Pacific plate subduction since ~130 Ma.