Cerium anomaly and Th/U fractionation in the 1.85 Ga Flin Flon Paleosol: Clues from REE- and U-rich accessory minerals and implications for paleoatmospheric reconstruction

Pan, Yuanming; Stauffer, Mel R.

doi:10.2138/am-2000-0703

Cited by 52 publications

(30 citation statements)

References 47 publications

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“…In general terms, geochemical patterns with positive Ce anomalies among other REE can be partly attributed to the nature of parent rocks; in particular, the presence of labile minerals such as monazite (identified as a frequent mineral phase in the studied samples), makes REE release to solution more easy than more weathering-resistant Ce-bearing minerals (Panahi et al, 2000;Caspari et al, 2006). The importance of phosphate complexes in the formation of Ce anomalies is quite consistent with Eh-pH conditions allowing oxidation of trivalent to tetravalent cerium, as documented both in ancient and modern soil environments (Pan and Stauffer, 2000;Panahi et al, 2000). The weathering solution does not mobilize Ce 4+ as easily as the trivalent rare earth elements (especially HREE), that become progressively more depleted relative to cerium), creating a positive anomaly of this element in the more weathered materials (Patino et al, 2003;Caspari et al, 2006).…”

Section: Discussionsupporting

confidence: 73%

“…However, the moderately acid to almost neutral soil reaction of the studied profile (see Section 2.1) suggests that other factors play more important roles in REE fixation than pH (see below). Only Ce shows very significant peaks within the whole REE patterns: this anomalous abundance spike can be explained by the variable behavior of this element on redox changes, as soluble (and easily mobile) Ce 3+ becomes less soluble and more immobile as Ce 4+ in oxidizing environments (Mongelli, 1993;Pan and Stauffer, 2000;Takahashi et al, 2005;Caspari et al, 2006). Cerium frequently occurs in monazite, xenotime and in traces also in feldspars, apatite, zircon (Reimann et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

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Application of laser ablation ICP-MS and traditional micromorphological techniques to the study of an Alfisol (Sardinia, Italy) in thin sections: Insights into trace element distribution

et al. 2009

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Section: Discussionsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Application of laser ablation ICP-MS and traditional micromorphological techniques to the study of an Alfisol (Sardinia, Italy) in thin sections: Insights into trace element distribution

et al. 2009

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“…The REE patterns (Ce/La ratios) of rhabdophane provide direct evidence of an oxygen deficient atmosphere during the late Archean to earliest Paleoproterozoic period. Pan and Stauffer (2000) have shown that ~ 1.85 Ga Flin Flon paleosols have been characterized by positive Ce anomalies, consistent with the observation that both Fe and Mn have been retained in these Flin Flon paleosols (Sreenivas et al, 2004). We have plotted the Ce anomalies in definite paleosols ranging in age from late Archean to Paleoproterozoic in Figure 5, where positive Ce anomalies of > 1.5 are observed only in 1.85 Ga old paleosols.…”

Section: Paleosolssupporting

confidence: 81%

“…The abundances and ratios of REE in Precambrian paleosols have been utilized to understand redox conditions of the atmosphere (Macfarlane et al, 1994;Panahi et al, 2000;Pan and Stauffer, 2000;Murakami et al, 2001;Sreenivas et al, 2001a;Utsunomiya et al, 2003;Nedachi et al, 2005). Rhabdophane, a secondary mineral formed by weathering with almost all Ce as Ce(III), was first found in the Pronto paleosol of Canada (Murakami et al., 2001).…”

Section: Paleosolsmentioning

confidence: 99%

Emerging views on the evolution of atmospheric oxygen during the Precambrian

Sreenivas

Murakami

2005

Journal of Mineralogical and Petrological Sciences

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The oxygenation of the atmosphere produced some irreversible changes in the Earth's history, including evolution of higher biological forms. Several aspects of this important process, such as its timing and causes, have remained subjects of debate. The present review is an attempt to provide an update on issues related to the evolution of atmospheric oxygen during the Precambrian. It is generally believed that the amount of atmospheric oxygen increased during the Paleoproterozoic despite the fact that photosynthesis originated much earlier in the Earth's history. The pattern of Fe retention in paleosols and the record of mass independent fractionation in sulfur isotopes confirm that the transition to more oxidizing conditions took place during the Paleoproterozoic.Various mechanisms, ranging from an increase in the sources of oxygen to a decrease in its sinks, have been envisaged as processes causing the oxygen rise during the Paleoproterozoic. Conventionally, it is believed that the burial of photosynthetic carbon has allowed the establishment of oxygen. However, the transition in mantle oxidation states and the escape of hydrogen during photolysis of methane of biogenic origin have also been suggested as having played an important role in the establishment of free molecular oxygen in the atmosphere hydrosphere system. The coincidence of timing of the oxygen rise and the positive excursions in carbon isotope compositions of carbonate rocks during the Paleoproterozoic suggests an important role for the carbon cycle in atmospheric oxygen evolution.Better quantitative modeling of atmospheric oxygen levels may be essential to allow full comprehension of the timing, causes and consequences of the oxygen rise in the Earth's history. Quantitative modeling is essential as it can lead to an unraveling of the co evolutionary nature of the surface environment and the biosphere of the Earth.

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“…The paleosol studies of Driese et al (1995) and Pan and Stauffer (2000) Mesoproterozoic atmospheric oxygen levels (Planavsky et al, 2014). Therefore, the observed signal for high atmospheric oxygen concentrations at ca.…”

Section: Implications Of Geochemical Datamentioning

confidence: 88%

Geochemistry of Paleoproterozoic Gunflint Formation carbonate: Implications for hydrosphere-atmosphere evolution

Fralick

Planavsky

Burton

et al. 2017

Precambrian Research

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The ~1880 Ma Gunflint Formation has played a critical role in shaping our view of the evolution of the Precambrian biosphere and the redox state of Earth's early oceans.Herein we present a study of the petrology and geochemistry of calcic grainstones and stromatolitic limestones present at the very top of the Gunflint Formation and compare them with underlying ankeritic grainstones that dominate the shore-proximal portion of the basin. Meteoric calcite cements in the upper limestones formed prior to the unit being brecciated and/or buried by debris carried by the blast cloud from the 1850 Ma Sudbury impact event. The intraclastic grains and cements in the limestone are highly enriched in V, Cr, U and REEs, with REE patterns similar to those of modern groundwater. Cr isotopes have a distinctly positive signature in most samples indicating formation of oxidized, hexavalent Cr during subaerial weathering. These redox-sensitive metals were transported in oxygenated groundwater and precipitated where the fluid encountered reducing conditions. In contrast, the underlying ankeritic marine grainstones have REE patterns similar to those of some modern-day venting hydrothermal fluids and earliest Paleoproterozoic seawater. This work suggests that significant levels of oxygen existed in the atmosphere at the time, whereas, even shallow areas of the world ocean remained very oxygen-deficient. The contrast in redox state of anoxic shallow-marine water verses oxic groundwater was probably linked to strong sub-seafloor hydrothermal circulation and extensive upwelling onto shallow shelves, which could have sustained widespread marine anoxia. More broadly, our study highlights the importance of investigating and understanding lateral geochemical gradients, and the flux rates that control them, in shallow paleomarine settings.

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Cerium anomaly and Th/U fractionation in the 1.85 Ga Flin Flon Paleosol: Clues from REE- and U-rich accessory minerals and implications for paleoatmospheric reconstruction

Cited by 52 publications

References 47 publications

Application of laser ablation ICP-MS and traditional micromorphological techniques to the study of an Alfisol (Sardinia, Italy) in thin sections: Insights into trace element distribution

Application of laser ablation ICP-MS and traditional micromorphological techniques to the study of an Alfisol (Sardinia, Italy) in thin sections: Insights into trace element distribution

Emerging views on the evolution of atmospheric oxygen during the Precambrian

Geochemistry of Paleoproterozoic Gunflint Formation carbonate: Implications for hydrosphere-atmosphere evolution

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