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Philos Trans R Soc Lond B Biol Sci. 2006 Jun 29;361(1470):903-15.

The oxygenation of the atmosphere and oceans.

Author information

1
Harvard University, Department of Earth and Planetary Sciences, Cambridge, MA 02138, USA. holland@eps.harvard.edu

Abstract

The last 3.85 Gyr of Earth history have been divided into five stages. During stage 1 (3.85-2.45 Gyr ago (Ga)) the atmosphere was largely or entirely anoxic, as were the oceans, with the possible exception of oxygen oases in the shallow oceans. During stage 2 (2.45-1.85 Ga) atmospheric oxygen levels rose to values estimated to have been between 0.02 and 0.04 atm. The shallow oceans became mildly oxygenated, while the deep oceans continued anoxic. Stage 3 (1.85-0.85 Ga) was apparently rather 'boring'. Atmospheric oxygen levels did not change significantly. Most of the surface oceans were mildly oxygenated, as were the deep oceans. Stage 4 (0.85-0.54 Ga) saw a rise in atmospheric oxygen to values not much less than 0.2 atm. The shallow oceans followed suit, but the deep oceans were anoxic, at least during the intense Neoproterozoic ice ages. Atmospheric oxygen levels during stage 5 (0.54 Ga-present) probably rose to a maximum value of ca 0.3 atm during the Carboniferous before returning to its present value. The shallow oceans were oxygenated, while the oxygenation of the deep oceans fluctuated considerably, perhaps on rather geologically short time-scales.

PMID:
16754606
PMCID:
PMC1578726
DOI:
10.1098/rstb.2006.1838
[Indexed for MEDLINE]
Free PMC Article
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