The Shangnan pluton is located close to the northern side of the Shangdan fault belt, which has strongly deformed and recorded information of tectonic evolution of the Qinling orogenic belt and the Shangdan fault belt. On the basis of field investigation, a comprehensive study by means of microstructure analysis, estimation of deformation temperature, calculation of differential stress and the strain rate, kinematic vorticity measurement, geochronological analysis and geochemical analysis are conducted on the Shangnan pluton in this paper. Results show that the Shangnan pluton was formed at 422.1±5.9 Ma with similar geochemical??characteristics??to the adakite, and has experienced left-lateral ductile shearing in later period. The formation temperature, differential stress and strain rate of the mylonite are 450 ℃～530 ℃, 22.27～35.99 MPa and 1.03232×10-14 s-1～3.81394×10-14 s-1 respectively. Based on the previous research results, it is believed that the Shangnan pluton was formed by partial melting of a thickened lower crust which was deformed accompanying the left-lateral strike-slip activity of the Shangdan fault belt in the later period.
Yang Tingyu Li Jiahao Ren Shenglian Lan Ruixuan Chen Shouwen. Structural deformation and geochemical??characteristics of the Shangnan pluton in the North Qinling and its geological significance[J]. Chinese Journal of Geology, 2019, 54(3): 1000-1015.