Multiple Stages of Strike-slip Movement and the Propagation of the Tan–Lu Fault Zone, East Asia

The approximately 3000 km long Tan–Lu fault zone (TLFZ) in East Asia is the longest continental strike-slip fault zone in the world and exemplifies how such a fault zone forms and propagates on a continental scale. Structural and geochronological data from the TLFZ and surrounding regions indicate that the fault zone originated as NE/SW-striking sinistral ductile shear zones along an oblique continental convergence margin during the Triassic indentation collision between the North China Craton and the Yangtze Block. The Triassic fault zone, with a total length of about 720 km between the Dabie and Sulu orogens, exhibited an apparent sinistral offset of approximately 300 km along the TLFZ. The second stage of sinistral movement occurred in the earliest Late Jurassic, reactivating the pre-existing southern segment and propagating northwards to the southern coastline of present-day Bohai Bay, as well as forming a significant portion of the Dunhua–Mishan fault zone. The third stage of sinistral movement, in the earliest Early Cretaceous, was the most intense strike-slip movement of the Mesozoic, leading to the complete linkage of the TLFZ. This stage included further northward propagation of the southern–middle segment, both southward and northward propagation of the Dunhua–Mishan fault zone, as well as the formation of the entire Yilan–Yitong fault zone. The fourth stage, in the earliest Late Cretaceous, involved the reactivation of the entire TLFZ. Following its Triassic origin due to the indentation collision, the subduction of the Paleo-Pacific Plate and the subduction and closure of the Mongol–Okhotsk Ocean were responsible for the multi-stage sinistral movements from the Late Jurassic to the Cretaceous. The evolution of the TLFZ demonstrates that a continental-scale strike-slip fault zone (>1000 km long) forms through multiple stages of propagation and linkage in dynamic settings of plate convergence.