Oxygen came late to ocean depths during Paleozoic
Thallium isotopes show O2 levels rose and fell at the ocean floor long after marine animals appeared and diversified half billion years ago, according to study of ancient marine sediments exposed by river cuts in Canada's Yukon
Thallium isotopes show O2 levels rose and fell at the ocean floor long after marine animals appeared and diversified half billion years ago, according to study of ancient marine sediments exposed by river cuts in Canada's Yukon
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