Abstract
Two major Early Paleozoic orogens exist in East China, the North Qinling-North Tongbai and Wuyi-Yunkai orogens, which used to be regarded as two independent systems controlled by distinct plate tectonic processes. The North Qinling-North Tongbai orogen consists predominantly of subduction- and collision-related rock assemblages, whereas the Wuyi-Yunkai orogen is made up chiefly of collision-related foreland fold-thrust systems. It is demonstrated that the two seemingly unrelated orogens are actually two components of an immense single orogen that is here named the Fuxi-Nüwa orogen. We stitch together a complete picture of the Fuxi-Nüwa orogen based on a holistic treatment of Early Paleozoic tectonics in East China. It is surmised that the Fuxi-Nüwa orogen was created by initial continental promontory-intraoceanic arc point collision and final complete collision of the North China block with West Cathaysia. The orogen was then torn apart in the Carboniferous, with the Wuyi-Yunkai orogen gradually moving away along a crustal-scale sinistral shear zone. Our proposed tectonic panorama offers satisfactory explanations for many perplexing questions that have plagued geologists for decades, such as the tectonic driver for the Kwangsian orogeny in West Cathaysia, mechanisms for ultra-high-pressure metamorphism and exhumation of the eclogized continental rocks in the North Qinling, simultaneousness of Silurian high-flux magmatism in the North Qinling-North Tongbai and Wuyi-Yunkai orogens, broad absence of Silurian-Early Devonian strata, and causes for Mid-Late Devonian marine inundation over West Cathaysia. Discovery and restoration of the Fuxi-Nüwa orogen will reshape our understanding of tectonic evolution of the Proto-Tethyan regimes, and necessitate reassessment of potentials of oil-gas resources in East China.