Building Southeast China in the late Mesozoic: Insights from alternating episodes of shortening and extension along the Lianhuashan fault zone

• Published in: Earth-science reviews Vol. 201; p. 103056
• Main Authors: Li, Jianhua, Cawood, Peter A., Ratschbacher, Lothar, Zhang, Yueqiao, Dong, Shuwen, Xin, Yujia, Yang, Hang, Zhang, Peixing
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2020
• Subjects: China; Deformation; Early Cretaceous epoch; evolution; geometry; kinematics; Late Cretaceous epoch; Late Jurassic epoch; Late Mesozoic; Lianhuashan; Magmatism; Paleo-Pacific Plate; South China; South East Asia; subduction; tectonics; South East Asia; China; Magmatism; Deformation; Lianhuashan; South China; Late Mesozoic; Paleo-Pacific Plate
• ISSN: 0012-8252; 1872-6828
• DOI: 10.1016/j.earscirev.2019.103056

Understanding the Mesozoic intraplate structural response of South China inboard of the Paleo-Pacific-South China convergent margin is a key issue in unravelling the continental tectonics of SE Asia. The Lianhuashan fault zone of South China represents a high-strain structure, pivotal for constraining the multi-phased intraplate deformation, strain localization, and partitioning in response to the subduction of the Paleo-Pacific plate. New data—coupled with published work—describes the geometry, kinematics, and age of this fault zone, establishing a multi-stage tectono-thermal history. The first-stage, late Jurassic shortening, involved top-to-the-W thrust-sense shear along ~NE-striking shear zones. The associated regional ~E-W shortening is interpreted to have been related to the advancing, NW-ward subduction of the Paleo-Pacific plate. The second-stage, Early Cretaceous deformation, is poorly documented in the Lianhuashan fault zone but is associated regionally with magmatism and Early Cretaceous basins, formed under ~NW-SE extension. This extension has been correlated with the rollback of the Paleo-Pacific plate. The third-stage, late Early Cretaceous ~NW-SE shortening, produced top-to-the-SE, thrust-sense shear zones. The shortening inverted the extensional basins and caused a lull in the magmatic activity. It possibly originated from the re-initiation of low-angle Paleo-Pacific subduction. The fourth-stage deformation generated the top-to-the-W Wuhua detachment, normal-sense ductile fabrics and distributed shear zones in its footwall, and widespread hanging-wall basins in the Late Cretaceous. This regional ~E-W extension has been associated with the re-initiation of slab rollback. Our work predicts episodes of slab steepening and shallowing in retreating and advancing settings. Changes in the slab geodynamics may have caused the alternating contractional and extensional episodes, as well as the flare-up, lull, and resumption of magmatism during the late Mesozoic evolution of South China. •Structural analyses record a four-stage deformation history of the Lianhuashan fault zone.•The first stage deformation involved top-to-the-west shearing under ~E-W compression.•The second-stage deformation is related to NW-SE extension.•The third stage of NW-SE compression produced top-to-the-southeast thrusting fabrics.•The fourth-stage extension produced the detachment, ductile shear fabrics, and basins.