We did this before and for there to be impact we would of had J Mungall who is an expert on the formations in Sudbury find shatter cones in the microscopic geology. I am sure if he did find the signs we would know. There may have been an event that contributed to the volcanic intrusions but no sign has been left so far. The entire earth is here from meteor impacts but this ROF shape is not concidered caused by such an event at the time of implacement. It is more of a remelting of a large nickel iron base rock area from underneath into concentrated filling cracks from iceage retreat and maybe hot pods feeding these.