U/Pb LA-SF-ICP-MS dating of detrital zircons in Cretaceous-Tertiary kaolins in the Douala Sub-Basin, Cameroon: A Neoproterozoic provenance

Detrital zircon geochronology is a reliable provenance tool used to trace known zircon age populations from their metamorphic or igneous source to their present location in sedimentary basins. This paper presents U/Pb LA-SF-ICP-MS data of detrital zircons in Cretaceous-Tertiary kaolins in the Douala Sub-Basin in order to determine their provenance. The minimum ages of parent rocks which kaolinised were determined using U-Pb LA-SFICP-MS dating of zircons in the kaolin deposits. Four main zircon populations were identified from radiogenic dating: the 1st between 550 and 650 Ma, the 2nd between 950 and 1050 Ma, the 3rd around 1600 Ma and the 4th between 2800 and 3200 Ma. These four zircon populations belong to the Proterozoic (Neo-, Meso- and Paleoproterozoic) and the Archean. The minimum ages of parent rocks which contained the primary minerals that were kaolinised, reflected by the youngest weighted averages of zircon populations varied between 588 ± 2 Ma and 612 ± 2 Ma, all belonging to the Ediacaran Period (Neoproterozoic), respectively. Ages of zircons in Cretaceous-Tertiary kaolins suggested that the zircons formed during two main tectonic events: the Eburnean orogeny, during which older zircons crystallised and the Pan-African orogeny, during which younger zircons crystallised. The main identified sources of these zircons are the Archean Ntem Complex, the Paleoproterozoic Nyong Group and the Neoproterozoic Yaounde Group.