Transfer zones within the Longmen Mountains thrust belt, SW China

摘要

The Longmen Mountains thrust belt contains complex structures resulting from multi-phase tectonic movements. Field investigations and interpretations of seismic profiles reveal two important transfer zones in the thrust belt: the Anxian and Guanxian transfer zones. Many thrust and strike-slip faults are found in the shallow part of the transfer zones, and duplexes and detachment structures in the deep part. The Anxian transfer zone is located between the Jiaoziding and Jiudingshan nappes, consisting mainly of the Lower Triassic Feixianguan Formation (T1 f) and Jianglingjiang Formation (T1 j), and Middle Triassic Leikoupo Formation (T2 l). The Guanxian transfer zone is located between the Baoxing and Jiudingshan nappes, consisting mainly of Devonian, Carboniferous, Triassic, Jurassic, and Presinian rocks. This zone contains many thrust faults, strike-slip faults, and duplexes in its deeper part (where early structures have been almost completely overprinted), and many klippens are found at the surface.