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Early Miocene |
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Time: |
23.7 to 16
mya |
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Duration: |
7.7 million years |
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Hundreds of
small, thin coal deposits were formed during this time period in western North America.
Their widespread occurrence suggests that intermittent swampy conditions existed
throughout middle and early late Miocene time (23.7 to 16 million years ago). These very
young coals are not commercial. |
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