(I assume "Ma" means "mega-agoes".)
(Yes, I looked it up, but my answer is funnier.)
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RT @jdwitts
This is #Zumaia in the Basque region of Spain feat. the K-Pg boundary! Stunning outcrops of 'flysch' in @geoparkea are deep water sediments, with 'rhythmic bedding' caused by orbital cyclicity. The boundary here contains fallout from the #Chicxulub impact event 66 Ma. https://twitter.com/SpagnaInItalia/status/135111037526208…
https://twitter.com/jdwitts/status/1351141091538575361
