One of Earth's biggest mass extinctions caused by rising sea levels in eerie echo of today

Feb 19, 2020
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"In samples of organic-rich black shale, scientists found evidence for oxygen depletion..."

They seem confused. Oxygen depletion is caused by too much organic matter overwhelming dissolved oxygen for aerobic respiration... and leaving organic rich muds.... Not the other way around. That's what happens today in oxygen-minimum zones. The Black Sea?
 
Dec 20, 2022
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"In samples of organic-rich black shale, scientists found evidence for oxygen depletion..."

They seem confused. Oxygen depletion is caused by too much organic matter overwhelming dissolved oxygen for aerobic respiration... and leaving organic rich muds.... Not the other way around. That's what happens today in oxygen-minimum zones. The Black Sea?
So think backwards. Organic-rich black shale was organic-rich mud, which was the remains of the too much organic matter, which depleted the oxygen. So the shale, including its evidence of H₂S, is evidence of the oxygen depletion.
 
Feb 19, 2020
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Yes, but not the cause of the extinction. The authors seem to think that a rapid rise??? in sea level released nutrients from plants on land which went to the ocean and resulted in an algal bloom. And that depleted the oxygen. But the land involved (the Bakkan formation) is a very small portion of the globe so extrapolating that to a global mass extinction would seem to be stretch.