Details

Autor(en) / Beteiligte

• Partin, C.A.
• Bekker, A.
• Planavsky, N.J.
• Scott, C.T.
• Gill, B.C.
• Li, C.
• Podkovyrov, V.
• Maslov, A.
• Konhauser, K.O.
• Lalonde, S.V.
• Love, G.D.
• Poulton, S.W.
• Lyons, T.W.

Titel

Large-scale fluctuations in Precambrian atmospheric and oceanic oxygen levels from the record of U in shales

Ist Teil von

• Earth and planetary science letters, 2013-05, Vol.369-370, p.284-293

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2013

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The atmosphere–ocean system experienced a progressive change from anoxic to more oxidizing conditions through time. This oxidation is traditionally envisaged to have occurred as two stepwise increases in atmospheric oxygen at the beginning and end of the Proterozoic Eon. Here, we present a study of the redox-sensitive element, uranium, in organic-rich shales to track the history of Earth's surface oxidation at an unprecedented temporal resolution. Fluctuations in the degree of uranium enrichment in organic-rich shales suggest that the initial rise of atmospheric oxygen ~2.4billionyr ago was followed by a decline to less oxidizing conditions during the mid-Proterozoic. This redox state persisted for almost 1billionyr, ending with a second oxygenation event in the latest Neoproterozoic. The U record tracks major fluctuations in surface oxygen level and challenges conventional models that suggest the Earth underwent a unidirectional rise in atmospheric oxygen during the Precambrian. •The [U] of seawater has not been constant throughout geologic time.•The [U] of seawater is linked to changes in oceanic and atmospheric oxygen content.•Secular changes in U demonstrate a drop in O2 after the GOE.