the Evolution of the Earth's Crust

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INTRODUCTION
The formation of Earth’s crust began during the Hadean eon, shortly after the Chaotian interval of core formation and solidification of the magma ocean (Allegre et al., 2008; Elkins-Tanton, 2008; Rudge et al., 2010). This process initiated with the differentiation of the crust-mantle zones from a bulk silicate Earth (BSE) reservoir, which is thought to have also produced the first continuous terrestrial crust (Allegre et al., 2008). However, whole rock signatures from original Hadean crust have not been preserved in the known geologic record and can only be inferred by isotopic analysis (Tessalina et al., 2010; Rizo et al., 2012). The one continuous trace of this early crust comes in rare detrital zircon grains within sandstone units (Jack Hills) of the Yilgarn Craton in Western Australia (Compston and Pidgeon, 1986; Kemp et al., 2010). Intensive study has surrounded the Jack Hills zircon and has produced various geodynamic models for the early Earth, as well as controversial observations and interpretations (Valley et al., 2002; Harrison et al., 2008). For these reasons, research of the Late Archean igneous complexes has become a primary interest for crustal evolution insight from the Earth’s interior that is otherwise unavailable for study (Smithies et al., 2005; Nebel et al., 2013).
The designation “large igneous province” (LIP) was introduced to embody the range of recognized, immense, crustal emplacements of mafic (Mg,Fe-rich) extrusive and intrusive rock related to the decompression of hot, melting, buoyant mantle ascending from the Earth’s interior (Coffin and Eldholm, 1991). This alteration of mass and energy is also thought to have occurred in specific cycles of geologic time in contrast to normal crustal...

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...of mantle plumes, forming the first persisting oceanic lithosphere as observed in Nebel et al. (2013). This early lithosphere may have been buoyant enough to form cratonic nuclei (Nebel et al., 2014). Subduction is thought to be an essential process in the formation of modern continental crust, yet this early formation model does not involve subduction or the preexistence of continental crust. I conclude that the evolution of crust was a gradual process that may have only required consistent mantle plumes melting and forming original crustal material, which agree with the interpretations of Nebel et al. (2013) though opposing new observations (i.e. Valley et al., 2014) suggest a much cooler Hadean crust. Therefore future models of early crustal formation will be developed from either the presence of cooler (wetter) or hotter (dryer) conditions on Earth’s surface.

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