After quite a bit of thought and research, I've demoted Calvin crater, on my impactcraters.us website, to an unconfirmed impact structure. This contradicts the PASSC listing, and I think that the later should be considered the authoritative source. Even so, I am responsible for building my listings according to the best reading of the literature that I can accomplish. I'm posting this specifically to invite argument or disagreement with the decision - or agreement if appropriate. I cannot find, anywhere in the literature, any reference to unambiguous or current widely accepted indicators of a hypervelocity impact event. While the morphology is compelling (and this is, in fact, the guts of the past argument for Calvin), there are many structures with compelling morphology - and this is simply not a valid basis for inclusion with out further evidence. The PASSC database does not typically include such structures. A partial listing of the literature is present on the page, with links to most of the related papers. http://www.impactcraters.us/unconfirmed_impacts/calvin_michigan I'd be grateful if folks pointed out other related literature or challenged/supported my thinking. In short, I'd like a sanity check. If it is more convenient to engage the discussion on the facebook group, feel free. I will follow the question in both places. I have cross-posted this question there: https://www.facebook.com/groups/432433606804823/ Thank you, and best regards, - Robert ______________________________________________
Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
