Mass extinction events and dinosaurs

At https://phys.org/print443093224.html … not only were dinosaurs eliminated by a catastrophic event at the K/T boundary 66 million years ago but they evolved into a successful species after the Permian mass extinction event 245 million years ago. Now we are being told but dinosaurs were but one of several successful species for around 13 million years – until another extinction event, 232 million years ago. After this event dinosaurs were able to expand very quickly. It is known as the Cernian Pluvial Episode. Whatever the cause was it ended up causing massive volcanic activity in various parts of the world, especially in western Canada where the Wrangellia basalt was laid down. Presumably the reference to pluvial means that there was an invasion by the sea too.