The last Neoproterozoic rift magmatism on the western margin of Yangtze block, South China: New insights of Marinoan onset from low-δ18O magmatic events

•This study first discovered magmatic rocks emplaced on the eve of Marinoan in western margin of the Yangtze block.•Neoproterozoic magmatic rocks with low-δ18O first discovered after 700 Ma in western margin of the Yangtze block.•Emplacement of the magmatic processes temporally overlapped the Marinoan onset.