Cambrian Complaining part 2
Just a brief note to link an illustration of exactly how variable the age correlations for the Cambrian have been over the past 80 years.
http://earth-time.org/evolving_timescale.gif
parallelogram doormat
6 hours ago
3 comments:
Nice! If only it crammed on the details of when the ages changed, vs. when they picked new fossil-appearances to define the eras...
Interesting. I had no idea these dates were so fluid through time.... I now resent our sed/strat guy making us memorize dates even more!
If you're really curious, check out the papers. I suspect that the main problem is correlating the strata. The Neoproterozoic is notorious for not having any ash layers where you need them; I suspect the same was true of the Cambrian for a while. On the other hand, the Cryogenean confusion is what keeps my paychecks coming; if it was easy, I wouldn't be able to keep getting paid for shovelling zircons into the mass spectrometers.
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