How to pronounce “magmatic” in English

And when geologists dated it, it dated exactly to the time of the end Triassic mass extinction.There's like a perfect-- and this has only been in the last few years, we've had really fine scale radioisotope dating of these giant magmatic sills and eruptions.So this would have covered-- I think it covered something like 3 million, or 5 million, or something like that, square miles of what