Detrital zircon and rutile geochronology and provenance of early Permian lithium-rich bauxites in central Yunnan, SW China: Implications for the late Neoproterozoic–Palaeozoic evolution of the South China Block

Abstract

Lithium (Li)-rich bauxites from the lower Permian Daoshitou Formation in central Yunnan, western South China Block, have significant potential for aluminium (Al) and Li exploitation. However, the provenance of these Li-rich bauxites remains uncertain. We conducted a comprehensive in situ U–Pb geochronology and trace element study of detrital zircon and rutile grains from lower Permian Li-rich bauxites and underlying Ediacaran–Carboniferous strata in central Yunnan, SW China, which yields valuable insight into the provenance of the Li-rich bauxites and the location of the South China Block during the break-up of Rodinia and assembly of Gondwana. The detrital rutile and zircon grains from the Li-rich bauxites yield similar age populations to those from Ordovician strata, highlighting the significant contribution of material from the Ordovician strata to the Li-rich bauxites. Detrital rutile grains in the Ediacaran strata have ages of 900–750 Ma, suggesting a source in the Panxi–Hannan metamorphic belt on the western margin of the South China Block. The prolonged duration (∼150 Myr) of this metamorphism implies that the South China Block was located on the margin of Rodinia during the Neoproterozoic. The asynchronous appearance of zircon and rutile populations with ages of 650–500 Ma (Cambrian) and 1050–900 Ma (Ordovician) in the South China Block suggests that the block occupied different positions during these two periods, indicating the northward migration of the block from northwest India to northeast India along the northern margin of East Gondwana during the late Cambrian–Early Ordovician. The successful application of combined detrital zircon and rutile analysis in this study highlights the reliability of this approach in elucidating the sedimentary provenance of deposits and unravelling their tectonic history.