Lithology, kinematics and geochronology related to Late Mesozoic basin-mountain evolution in the Nanxiong-Zhuguang area, South China

摘要: The Nanxiong red-bed basin and its adjacent Zhuguang granite form a distinctive basin-mountain landform in the Nanling region, South China. Research results suggest that is polyphase composite pluton developed on metamorphic basement of paleo-Tethys-paleo-Asian tectonic regime possesses geometrical kinematic features hot-doming extensional tectonics at middle-upper crustal level, which considered as magmatic complex resulted from collision-orogeny during Indosinian Period, subduction-consuming Early Yanshanian Period intra-continental basaltic underplating deep-seated geodynamics Late Period. Cretaceous-Paleogene asymmetric faulted characterized by fault boundary northern side an uncomformable southern side, deposit center was migrated gradually south to north. Structural coupled zone demonstrate ductile brittle rheological layers show quite coincident sense shear, implying it continuous process deformation followed locally sinistral strike-slip shear middle-crustal level tensional upper-crustal formation granitic doming tectonics. constructed semi-graben system. Lithological geochemical Triassic Jurassic bodies have some similar features: high SiO2, Al2O3, K2O contents, alkalinity index > 2.8, ANKC value 1.1, LREE-enriched pattern with REE marked negative Eu anomalies, enrichment Rb Th, depletion Ba Nb, showing K-rich Al-rich calc-alkaline affinity, evolution Jurassic. Formation system were controlled both granitic-doming regional Development olivine basalt suggests tension action very strong lava eruption. magma-type zircon grains yielded SHRIMP age 96±1Ma, providing reliable geochronological constraint tectono-thermal event