Emplacement ages of diamondiferous kimberlites in the Wafangdian District, North China Craton: New evidence from LA-ICP-MS U-Pb geochronology of andradite-rich garnet

•U-Pb dating of magmatic andradite yielded an emplacement age of 459.3 ± 3.4 Ma in Wafangdian.•Three discrete episodes recorded in andradites unravel their multiple growth/metasomatic events.•At least two separate pulses of Paleozoic kimberlite magmatism occurred within a single field.•U-Pb system of earlier formed garnets were not disturbed/reset during post-eruptive alteration.