Review article Oxygenation of the Earth’s atmosphereeocean system: A review of physical and chemical sedimentologic responses P.K. Pufahl a, * , E.E. Hiatt b,1 a Department of Earth & Environmental Science, Acadia University, Wolfville, Nova Scotia B4P 2R6, Canada b Department of Geology, University of Wisconsin Oshkosh, Oshkosh, WI 54901, USA article info Article history: Received 22 August 2011 Received in revised form 30 November 2011 Accepted 5 December 2011 Available online 14 December 2011 Keywords: Great oxidation event Earth oxygenation Ocean-atmosphere evolution Bioelemental Chemistry Alteration Sedimentology Diagenesis abstract The Great Oxidation Event (GOE) is one of the most significant changes in seawater and atmospheric chemistry in Earth history. This rise in oxygen occurred between ca. 2.4 and 2.3 Ga and set the stage for oxidative chemical weathering, wholesale changes in ocean chemistry, and the evolution of multicelluar life. Most of what is known about this important event and the subsequent oxygenation history of the Precambrian Earth is based on either geochemistry or “data mining” published literature to understand the temporal abundance of bioelemental sediments. Bioelemental sediments include iron formation, chert, and phosphorite, which are precipitates of the nutrient elements Fe, Si, and P, respectively. Because biological processes leading to their accumulation often produce organic-rich sediment, black shale can also be included in the bioelemental spectrum. Thus, chemistry of bioelemental sediments potentially holds clues to the oxygenation of the Earth because they are not simply recorders of geologic processes, but intimately involved in Earth system evolution. Chemical proxies such as redox-sensitive trace elements (Cu, Cr, V, Cd, Mo, U, Y, Zn, and REE’s) and the ratio of stable isotopes (d 56 Fe, d 53 Cr, d 97/95 Mo, d 98/95 Mo, d 34 S, D 33 S) in bioelemental sediments are now routinely used to infer the oxygenation history of paleo-seawater. The most robust of these is the mass- independent fractionation of sulfur isotopes (MIF), which is thought to have persisted under essentially anoxic conditions until the onset of the GOE at ca. 2.4 Ga. Since most of these proxies are derived from authigenic minerals reflecting pore water composition, extrapolating the chemistry of seawater from synsedimentary precipitates must be done cautiously. Paleoenvironmental context is critical to understanding whether geochemical trends during Earth’s oxygenation represent truly global, or merely local environmental conditions. To make this determina- tion it is important to appreciate chemical data are primarily from authigenic minerals that are diage- netically altered and often metamorphosed. Because relatively few studies consider alteration in detail, our ability to measure geochemical anomalies through the GOE now surpasses our capacity to adequately understand them. In this review we highlight the need for careful consideration of the role sedimentology, stratigraphy, alteration, and basin geology play in controlling the geochemistry of bioelemental sediments. Such an approach will fine-tune what is known about the GOE because it permits the systematic evaluation of basin type and oceanography on geochemistry. This technique also provides information on how basin hydrology and post-depositional fluid movement alters bioelemental sediments. Thus, a primary aim of any investigation focused on prominent intervals of Earth history should be the integration of geochem- istry with sedimentology and basin evolution to provide a more robust explanation of geochemical proxies and ocean-atmosphere evolution. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction One of the most intensely debated topics in the Earth sciences is the oxygenation of the Earth’s atmosphere and oceans, primarily because of their co-evolution with early life (e.g. Kasting, 1993; Catling et al., 2001; Canfield, 2005; Fedonkin, 2009). Spirited discussion began in 1964 with the publication of the “The Origin * Corresponding author. Tel.: þ1 902 585 1858; fax: þ1 902 585 1816. E-mail address: peir.pufahl@acadiau.ca (P.K. Pufahl). 1 Tel.: þ1 920 424 7001; fax: þ1 920 424 0240. Contents lists available at SciVerse ScienceDirect Marine and Petroleum Geology journal homepage: www.elsevier.com/locate/marpetgeo 0264-8172/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.marpetgeo.2011.12.002 Marine and Petroleum Geology 32 (2012) 1e20