Microfossil dating of the Brent meteorite crater, southeast Ontario, Canada

Chitinozoans and conodonts have been studied from two drillings in the Brent meteorite Crater, southeast Ontario, Canada. The microfossil faunas are poor and little diverse although diagnostic. The impact event is of early Caradoc age (about 453 Ma), and probably corresponding to upper Black Riveran strata (upper Erismodus quadradactylus conodont Zone), which makes the event somewhat younger than those of early Caradoc age recently described from Baltoscandia. The crater infill ceased at the transition between Black Riveran and Trenton time (uppermost Belodina compressa conodont Zone), and the deposition time of the post-impact sedimentation should then be about 2 Ma. Immediately after the impact event the area was transgressed by the middle Ordovician shelf sea during the end of the Black Riveran–Trenton phase.