The Jurassic to Cretaceous magmatism in the South China Block (SCB) has important geological significance for its tectonic evolution, particularly, the tectonic regime change. We report here new SHRIMP zircon U-Pb ages, geochemical and Sr-Nd isotopic results from the Early Jurassic magmatic rocks in eastern Nanling region of southern Jiangxi and northern Guangdong provinces, SE China. The SHRIMP zircon U-Pb analyses yield consistent Early Jurassic ages of 193 ± 2. Ma for granodiorite and 196 ± 1. Ma for gabbro-diabase from the Hanhu complex of southern Jiangxi Province. Field observation indicates that the gabbro-diabase coexists with syenite in granodiorite, and that the mafic components infiltrate into the syenite. Combined with the SHRIMP zircon U-Pb ages of 196 ± 2. Ma for granites and 195 ± 1. Ma for gabbros of the Xialan complex of northern Guangdong province, these contemporary ages represent an earliest tectono-magmatic events during the Yanshanian orogeny. These results reveal that there are tectonic extension and the post-collisional and intraplate magmatism events at or before 196. Ma, in contrast to the wide believed quiescent stage (205-180. Ma) of magmatic activity in SE China. The confirmation of these tectono-magmatic events in the eastern Nanling area thus sheds new light on the quiescent stage of magmatic activity in SE China during 205-180. Ma and provides new constraints to understand the Early Jurassic tectonic evolution of SE China.
- Early Jurassic
- Intracontinental lithospheric extension
- Post-collisional and intraplate magmatism
- SHRIMP zircon U-Pb ages