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[–] CujoQuarrel 0 points 1 point (+1|-0) ago 

The obvious answer

Aliens

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[–] littul_kitton 0 points 1 point (+1|-0) ago 

The eroding source could change, such as uplift by plate tectonics, by volcanic eruption, or by drying of the source to provide wind-blown dust. The destination could change, by changes in sea levels, filling of a shallow sea so that the sediment level rises above the water level, etc. The chemistry could change, such as deposition of carbonate minerals after a Snowball Earth period ended, or deposition of iron oxides after the Great Oxygenation. Biological changes could occur, such as a change from carbonate life forms (chalk) to silicate life forms (diatomaceous earth), by the evolution of parasites that wiped out the once-prolific crinoids, by evolution of detrivores that now extensively process muds and soils, etc.

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[–] NeedPolyGF [S] ago 

These likely occurred over a very short time-span.

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[–] NeedPolyGF [S] ago  (edited ago)

If anyone wants to see the references, just reply here.

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[–] LinoleumFulcrum ago 

These guys have some raging hard-ons for Archbishop Ussher.

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[–] NeedPolyGF [S] ago 

Clever sarcasm does not refute sound logic.

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[–] 8763506? 1 point 0 points (+1|-1) ago 

A catastrophic flood.

[–] [deleted] 1 point 0 points (+1|-1) ago 

[Deleted]

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[–] 8766013? 1 point -1 points (+0|-1) ago 

I was just researchin yeaterday, but from another angle. Verticle fossils.

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[–] NeedPolyGF [S] 1 point -1 points (+0|-1) ago  (edited ago)

Okay, I'll give everyone till around 11 AM tomorrow (Thu), Central Time, to submit your guesses or knowledge. I'm not suggesting that anyone who has answered so far is right or wrong yet. I hope I don't forget to show up. If I do show up, I'll explain what seems to be the most sensible answer.

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[–] HillbillyGoat 1 point -1 points (+0|-1) ago 

Sunspots