Rotation and Uplift of the Taoxi Dome and Its Implication for the Evolution of Wuyi Terranes in Cathaysia Block

Abstract

The Taoxi dome stands out as a rotated-circular structure on maps of the Wuyi terrane, south China. The origin and tectonic activity analysis of the Taoxi dome is a window to understand the tectonic framework and aggregation process of the Wuyi terranes in the Cathaysia block. Our field observations demonstrated that two major phases of deformation, counterclockwise rotation and dome uplift, were recorded in the Taoxi dome. Geochronological data indicated that the counterclockwise rotation was initiated at about 422 Ma as a result of a sinistral slide collision between the North Wuyi terrane and the South Wuyi terrane along the Nanping–Ninghua tectonic belt during the Caledonian. Zircon dating ages of the intrusions developed in the Taoxi dome suggested that the Taoxi dome had undergone at least two strong upheavals and the uplift of the Taoxi dome was active during the periods 229–222 Ma and 158–100 Ma. Geochemical data indicated that the intrusions developed in the Taoxi dome had characteristics of high silica (SiO2 > 70 wt.%) and belonged to the A2-type granites, which suggest that the Taoxi dome was long governed by a tectonic setting of post-collisional or anorogenic magmatism since the Caledonian. The strong movement of the Caledonian rotation and coeval strike-slip movement in the Wuyi terranes suggests that a slide rotation may have been a major characteristic in response to the rifting process of micro-terranes during the late Paleozoic in the Cathaysia block.