Article abstract


Nature Geoscience 1, 554 - 558 (2008)
Published online: 27 July 2008 | doi:10.1038/ngeo259

Subject Categories: Atmospheric science | Biogeochemistry

Formation of supercontinents linked to increases in atmospheric oxygen

Ian H. Campbell1,2 & Charlotte M. Allen1


Atmospheric oxygen concentrations in the Earth's atmosphere rose from negligible levels in the Archaean Era to about 21% in the present day. This increase is thought to have occurred in six steps, 2.65, 2.45, 1.8, 0.6, 0.3 and 0.04 billion years ago, with a possible seventh event identified at 1.2 billion years ago. Here we show that the timing of these steps correlates with the amalgamation of Earth's land masses into supercontinents. We suggest that the continent–continent collisions required to form supercontinents produced supermountains. In our scenario, these supermountains eroded quickly and released large amounts of nutrients such as iron and phosphorus into the oceans, leading to an explosion of algae and cyanobacteria, and thus a marked increase in photosynthesis, and the photosynthetic production of O2. Enhanced sedimentation during these periods promoted the burial of a high fraction of organic carbon and pyrite, thus preventing their reaction with free oxygen, and leading to sustained increases in atmospheric oxygen.

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  1. Research School of Earth Sciences, The Australian National University, Canberra 0200, Australia
  2. Institute for Study of the Earth's Interior, Okayama University at Misasa, Tottori 682-0193, Japan

Correspondence to: Ian H. Campbell1,2 e-mail: Ian.Campbell@anu.edu.au



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