Search for a command to run...
• DLSTB has undergone three phases of deformation during Meso-Cenozoic. • The first phase occurred in the end Jurassic resulted in NW-SE shortening. • The second phase is NE-SW shortening in the end of Oligocene. • The third one is EW directed shortening in the end of Miocene. The South China Continent (SCC) has experienced multiple phases of intracontinental deformation processes since the Mesozoic, and investigating the intracontinental deformation process of the SCC is helpful for the understanding intracontinental tectonic evolution of the Eastern Asian continent. The Daloushan Tectonic Belt (DLSTB), located within the SCC, composed of a series of Meso-Cenozoic superposed folding structures, holds key information for revealing the intracontinental deformation mechanism of SCC. Detailed structural analyses of representative fold and fault structures indicate that the DLSTB experienced three phases of shortening deformation during the Meso-Cenozoic time. The first phase (D 1 ) is defined by a series of NE-SW striking folds involving the Jurassic and its underlying strata, indicative of NW-SE shortening. Combining the deformation of Jurassic strata, and the regional angular unconformity between the Jurassic and Cretaceous strata, this tectonic event is confined to the end of the Jurassic, and is dynamically linked to the subduction of the Paleo-Pacific Plate. The second phase (D 2 ) is distinguished by a set of NE-SW-directed superimposed folding structures, forming “Type 1” and “Type 2” interference patterns. Based on the regional angular unconformity between the Paleogene and Neogene strata, as well as the regional uplift event during ∼ 28–25 Ma, this phase of deformation is dated to the end of the Oligocene, driven by the collision between the Indian Plate and the Asian continent. The third phase of deformation (D 3 ) features ∼ E-W directed shortening overprinting pre-existing structures. Combining the angular unconformity within the Upper Neogene strata and the regional uplift episode at ∼ 8–5 Ma in and around the Tibetan Plateau, this phase of deformation is constrained to the end of Miocene. Dynamically, the third phase of deformation was related to the eastward expansion of Tibetan Plateau. The polyphase of superimposed deformation of the DLSTB, induced by multi-directional and multi-phase of shortening, demonstrate that the intracontinental deformation of the East Asian continent was primarily controlled by inherited tectonic structures and far‐field effects of subduction along the convergent plate margins.
Published in: Geoscience Frontiers
Volume 17, Issue 4, pp. 102298-102298