Did natural fission of 235U in the earth lead to formation of the supercontinent Columbia?

Abstract

Steady decline in the percentage of 235 U in terrestrial uranium made natural fission impossible after about 1.8 Ga. Fission before 1.8 Ga disturbed the lead isotope system at various places worldwide, such as Oklo, Gabon, and may have caused the first lead isotope paradox. Fission in areas of high uranium concentration may also have generated enough heat to localize sparse Archean and Paleoproterozoic UHT belts. The oldest widespread orogenic systems formed at approximately 2.0e1.8 Ga after fission stopped contributing to the earth's heat flow. These early orogenic systems partly created the supercontinent Columbia. ª 2012, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved.

Continental velocity through Precambrian times: The link to magmatism, crustal accretion and episodes of global cooling

“…Popular models incorporating "supercontinent cycles" and transient supercontinents such as "Columbia" (Rogers andSantosh, 2002, 2009;Zhao et al, 2004;Meert, 2012;Rogers, 2012) and "Rodinia" contrast with the premise of this assessment by envisaging diverse relative movements between the Precambrian cratons. By invoking large relative movements, to have credibility they must use palaeomagnetic poles selected to a very high standard which are well defined in age and positional terms; the resulting datasets are typically very limited (e.g.…”

Geochemistry of metamafic dykes from the Quanji massif: Petrogenesis and further evidence for oceanic subduction, Late Paleoproterozoic, NW China

“…Combination of the affinity of backarc settings for their precursor magma at ~1.85-1.83 Ga and the medium-P/T type metamorphism of the dyke swarms at ~1.82 Ga (Chen et al, 2013a), Liao et al (2014) firstly proposed that an oceanic subduction process was going on before ~1.85 Ga. Our study reveals that the metamafic dykes within the paragneiss suite in the Delingha region carry even stronger signature of subduction-related volcanic arc setting, thus indicative of an oceanic lithosphere subduction process for generation of their precursor magma. These provide further evidence for insight into plate tectonics related to evolution of the Quanji massif at ~1.85 Ga, probably as well as the assembly history of the global Columbia supercontinent (Zhao and Zhai, 2013;Meert, 2012;Mohanty, 2012;Rogers, 2012;Trap et al, 2012;Zhao G C et al, 2004Zhao G C et al, , 2002a.…”

“…The first one occurred at 1.90-1.95 Ga and the second at 1.85-1.80 Ga, respectively (e.g., Chen et al, 2013aChen et al, , 2009Chen et al, , 2007Zhang et al, 2011;Wang, 2009;Lu et al, 2008;. These metamorphism are characterized by medium-P/T type and thus are believed to result from collision of the Quanji massif to other unknown continental blocks or massifs in the NW China (Chen et al, 2013a and references therein), and at the same time, coevally consistent with the timing and natures of the processes involving the amalgamation of the North China Craton, which was linked to the assembly of Columbia supercontinent worldwide (Zhao and Zhai, 2013;Meert, 2012;Mohanty, 2012;Rogers, 2012;Trap et al, 2012;Zhao G C et al, 2004Zhao G C et al, , 2002a. However, little evidence for arc-related tectonic setting has been reported to support oceanic subduction in the previous studies.…”

Re–Os and Sr–Nd–Pb isotope constraints on source of fluids in the Zhifang Mo deposit, Qinling Orogen, China

“…1c; Chen and Fu, 1992). The Taihua Supergroup includes the 3.0-2.55 Ga Beizi, 2.5-2.3 Ga Dangzehe, and 2.3-2.1 Ga Shuidigou Groups (Chen and Zhao, 1997;Xu et al, 2009), and was metamorphosed at amphibolite to granulite facies during 1.95-1.82 Ga coinciding with the global assembly of the Columbia supercontinent (Rogers and Santosh, 2002;Zhao et al, 2004;Wan et al, 2006;Santosh et al, 2007a,b;Rogers and Santosh, 2009;Zhao et al, 2009;Santosh, 2010;Zhai and Santosh, 2011;Rogers, 2012;Zhai and Santosh, 2013;Nance et al, 2014). The Xiong'er Group, unconformably overlying the Taihua Supergroup, is dominated by basaltic andesite, andesite, dacite and rhyolites with minor intermediate to silicic tuff and mafic to felsic sub-volcanic rocks .…”