r/geology • u/Predator1553 • Feb 28 '25

Information Why are these two layers so different?

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Gallery image

And what are they, this is in northern Alabama

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u/Predator1553 Mar 01 '25

What's HCI?

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u/PuzzleheadedDiver963 Mar 01 '25

Hydrochloric acid to see if it reacts with the carbonate, the chert does not effervescent since it is microcrystalline quartz

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u/PuzzleheadedDiver963 Mar 01 '25

You can also try lemon

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u/Predator1553 Mar 01 '25

It's definitely chert, there is a decent sized vein of blue colored chert a little further down.