This sentence is certainly not correct per se. It does not so much matter that the relative pronoun ‘Which’ fails the touch rule. There are four nouns preceding 'which
’, namely World, Formations, Iridium, high levels.
One of them must suggest the cataclysmic impact of a meteor millions of years ago
Either world or formations or iridium can not be the logical referent, since none of them as such can indicate a catastrophic effect. It must then be the plural ‘high levels’
that must be the intended antecedent and thus requires the plural ‘suggest’
rather than the singular ‘suggests’
P.S: May I know why this is classified under absolute phrases?
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