Detrital zircon provenance of the lower Yangtze foreland basin deposits: constraints on the evolution of the early Palaeozoic Wuyi orogenic belt in South China

The Wuyi orogenic belt in South China is one of the early Palaeozoic orogenic belts in the world. To provide new perspectives on its deformation and denudation, seven sandstone samples were collected from the upper Ordovician to Silurian sequence in the adjacent lower Yangtze foreland basin for U-Pb dating of detrital zircon. All of the samples reveal a dominance of zircons with ages of 880-740 Ma that correspond to the Neoproterzoic basement of South China, indicating basement-involved deformation in the Wuyi orogenic belt. A fair number of detrital zircons at 1200-900 Ma represent material recycled from the preorogenic strata. A significant population of c. 458-425 Ma zircons in the Silurian samples recorded contemporaneous orogenic activity and suggest that the synorogenic magmatic and metamorphic rocks had been exhumed. The youngest zircons at 425 Ma provide a maximum depositional age for the top of the foreland basin sequence. This isotopic age, together with constraints from graptolite zones, suggests the tectonic activity of Wuyi orogeny took place from 455 to 425 Ma. Compared with the Appalachian-Caledonian orogenic belt in timing, deformation styles, magmatism and metamorphism, we propose that there is some link between the two orogenic belts.