Quote:
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Originally Posted by mugaliens
...also as recently as 850 to 635 mya, during the Cryogenian period, during which the Sturtian and Marinoan glaciations occurred, the greatest ice ages known for Earth...
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thanks
mugs -
you triggered a self-correction (ie, shown where I've made an error based on bad memory ... again ... )
Quote:
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Originally Posted by cran
700 Ma BP - the Earth was in a long "cool" era, and many parts were starting to get a lot cooler; it marks the beginning of the second peak of glaciation (the Marinoan) ...
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I'd confused the tillite formation ages (790 and 620) and had 690* in my head - this is well before the Marinoan, and well after the Sturtian; 700 Ma BP is roughly halfway between the peaks - ie,
in the middle of the Cryogenian ...
which makes this:
Quote:
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Originally Posted by cran
ten million years later, things started warming up, and early Ediacarans moved into the neighbourhood ...
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also incorrect by roughly 75 Ma or so ...
all of which throws
AndrewJ's question -
Quote:
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Is there an explanation for the move 700 mya?
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wide open and back into the mix for speculation and discussion ...
*thinking about the 490 C-O transition probably didn't help -
which I'd already confused by losing the Ordovician altogether -
sheesh! ...
I need a better brand of coffee!