Structural geometry and kinematic processes at the intracontinental Daloushan mountain chain: Implications for tectonic transfer in the Yangtze Block interior

Abstract

The Daloushan mountain chain, located in the centre of the upper Yangtze continental block, is considered to represent the locus of the tectonic shortening resulting from the eastward growth of the Tibetan Plateau and NW-thrusting of the Xuefeng Orogen. Structural data and apatite fission-track ages have been used to decipher the geometry and the kinematic evolution of the Daloushan. The latter is subdivided into two domains: the eastern domain, governed by west- to NW-verging thrusting and deformation with dextral transpression, and a western domain, governed by south-verging thrusting and deformation. Both domains experienced four episodes of deformation, synchronous with the four stages of post-Cretaceous denudation, marked by rapid cooling propagating eastward from 20 to 5 Ma, at a rate of ∼0.1mm/year. In particular, the last two episodes of denudation are closely related to the growth of the Tibetan Plateau. This indicates an intra-continental transfer of tectonic forcing from the Palaeo-Pacific to the Tethys-Himalayan Tectonic Domain across the Daloushan.