(This topic is by request, in effect):
ETA: (See if you can come up with an "alternative fact"ual explanation on your own without borrowing or cribbing from a comment. ; - )
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crickets
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Dufff’s on-line article on the Chilean Atacama Desert was my introduction to it and the implications for long-term geological change in earth’s surface, and quite hurdle for YEC-cers to jump over.
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Here’s an additional one for the set: aragonite leaching that preserves shell microstructure. With deposits on top that are not leached.
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Can you give us a short lay description of what that’s about?
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Maybe, does this suffice?
Aragonite is the standard crystal structure of calcium carbonate used in making mollusk shells. However, a few groups use calcite (oysters, scallops, and a few similar groups), and a few use some of each (murexes and wentletraps). Echinoderms also mostly use calcite. Over very long periods, aragonite will turn into calcite (and into dust at the same time). Aragonite can also be replaced by larger crystals of calcite or quartz (or any number of other minerals, but calcite and quartz are the most common). Very rarely, this replacement will be sufficiently slow that the original microscopic structures in the shell are transferred to the final mineral.
Induration (turning sediment into limestone) seems to require either hundreds of thousands of years of elevated pressure, or percolating freshwater for a few centuries to millennia. If the latter, it happens from the top of a layer down. As a specific example, the SC Rock Goretown Mine has the following stratigraphy:
a few feet of oxidized, partially leached upper Waccamaw Formation (the yellower layer).
2-10 feet of upper Waccamaw Formation unconsolidated shell-sand (the sloped, paler layer).
unconformity
About 12 feet of very hard (a lot of calcite holding it together), aragonite leached Goose Creek Limestone (the more vertical, darker layer).
unconformity
Pee Dee Formation clayy limestone, which contains dinosaur bones elsewhere (about 3-4 feet below the road here).
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And this all happened in less than 150 days 2348 years ago. Because Jesus, right?
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I wonder if this is truly a gotcha question for YECs (at least hopefully for maybe a few somewhat humble, honest and pensive individuals not too fossilized in their cognitive dissonance from having swallowed the tribe’s false dogma for so long). For those who understand science, it’s just one more compelling piece of evidence (and a delightful and fun one ; - ) from the massive amounts already out there.
(I’m missing seeing you here, @adamjedgar.)
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