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Orogenic growth, characterized by formation and forward propagation of fold‐thrust belts and foreland basins, is predicted by wedge models of thrust systems. The growth of the Nanpanjiang fold‐thrust belt and foreland basin system of the Indosinian orogenic belt in the southwestern South China remains poorly understood. The development of the Indosinian foreland system remains underappreciated due to few constraints on structural styles, kinematics and ages. Surface cross sections, seismic profiles and detrital zircon data are presented to address the structural styles and evolution of the Indosinian foreland system. The results reveal that the fold‐thrust belt is characterized by fault‐related folds with deeper duplexes and shallower imbricates, which yield a NNE‐SSW regional shortening magnitude of ∼36%. Our new constraints indicate that the Nanpanjiang region experienced multi‐staged thrusting during the Indosinian orogeny (D1). The D11 affected the southernmost southern fold‐thrust belt, producing thick‐skinned thrusts involving Neoproterozoic basement and initiating the Nanpanjiang foreland basin. During the D12, NNE‐verging thick‐skinned thrusting continued and was followed by thin‐skinned thrusting in the northern fold‐thrust belt. Locally preserved foreland basin deposits at the northernmost Nanpanjiang Basin define D13. The progressive D14 co‐axially deformed the residual basin into a wide and gentle syncline. Thus, the progressive D11 to D14 deformation sequence of NNE‐verging in‐sequence thrusting and foreland basin migration describe the kinematic and dynamic relationship between fold‐thrust belt and foreland basin during the Indosinian tectonic event. Indosinian D1 structures were subsequently refolded by the Yanshanian tectonic event (D2), forming N‐ to NE‐striking cleavage and arcuation of D1 fold axes. Key Points: The Nanpanjiang fold‐thrust belt and its associated foreland basin migrated NNE‐ward during the Middle Triassic to Early JurassicIndosinian deformation produced an orogenic wedge with a thick‐skinned hinterland belt, a thin‐skinned foreland belt and shortening of 36%In‐sequence thrusting and foreland‐propagation (237–186 Ma) led to incorporation of the Nanpanjiang foreland basin into the fold‐thrust belt [ABSTRACT FROM AUTHOR]

The Cenozoic evolution of SE Asia is marked by thousands of kilometres extension on the continental margin, including normal faults, half‐grabens, and volcanic rocks, but dating of brittle faults in the shallow crust is difficult because of a lack of synkinematic minerals. The Cenozoic extension in the Youjiang fold‐thrust belt in southwest China is marked by brittle normal faults and half‐grabens filled with Paleogene sediments in the region. Here, we identified a strongly weathered mafic sill that was truncated by normal faults in the fold‐thrust belt and present the age and chemistry of zircons from a weathered sill. The zircons from the sill yielded a mean age of ~35 Ma. Integrating cross‐cutting relationship and zircon U–Pb dating suggest that the Cenozoic extension was initiated later than ~35 Ma in Youjiang fold‐thrust belt in southwest China. Combined with structural analysis and previous fission track data in the region, we suggest that the normal faults in this study provide evidence of surface fault activity of Cenozoic extension in SE Asia caused by retreat of a trench system. Furthermore, this study provides a case study to discuss how to decipher brittle normal faulting using zircon geochronology and structural and textural analysis from the mesoscale to the microscale. [ABSTRACT FROM AUTHOR]