Dark Age Arizona

The Triassic, from 252 Mya on, is the Dark Age of the post-Permian. The Earth was a near-dead planet at the onset. Also (I'm now told) we flat have no record of the Norian epoch, a good portion of the second half. This is when Pangaea broke up; and, another one of those mass-extinctions occurred toward the end.

They say we have snapshots from these dozens of millions of years - enough to tell us that three (3) "mountain sized" asteroids hit us. But fragments from a span offer no frame-of-reference to place specific events within it. For that we'd need an unbroken rock core preserving the whole stretch. The Colorado Plateau Coring Project has been on that case.

Paydirt: Petrified Forest National Park, 225-209 Mya.

LIGHT 7/31: In South America anyway, make it 221-209 Mya. We learn here that one reason Arizona / Colorado records are so rotten (at least earlier) is that we have no fossils to mark that era of time, as South America has. These are mostly land-sediments. And there was little life on this land - actually, there's not much life in Arizona to this day. For the inverse, imagine piecing together Pliocene South America from the Atacama.