A multiple-system study of the geochemical evolution of the mantle with force-balanced plates and thermochemical effects

Asthenosphere–lithosphere interaction triggered by a slab window during ridge subduction: Trace element and Sr–Nd–Hf–Os isotopic evidence from Late Carboniferous tholeiites in the western Junggar area (NW China)

“…6a, b), the Hatu samples have intermediate ratios and fall near the primitive mantle along with oceanic plateau basalts such as the Ontong Java and Caribbean Plateaux. Geodynamic models suggest that as much as 20-30% of the Earth's interior may have escaped differentiation (e.g., Brandenburg et al, 2008) and the Hatu basalts have similar isotopic composition to major flood basalt provinces (e.g. Baffin Island, West Greenland, and Ontong Java plateau lavas) that have been proposed to be derived from primitive, albeit non-chondritic, mantle (Jackson and Carlson, 2011;Jackson et al, 2010).…”

Global-scale modelling of melting and isotopic evolution of Earth's mantle: melting modules for TERRA

“…Different elements behave differently during partial melting (via different partition coefficients), so when the techniques of tracking and melting are implemented, the system of segregation and decay can be tracked. We follow the well-studied uraniumthorium-lead system (U-Th-Pb), as has previously been done in a similar way in Christensen and Hofmann (1994), Xie and Tackley (2004a) and Brandenburg et al (2008).…”

“…After that study was published, many followed a similar approach, either tracking preset heterogeneities (e.g. Davies, 2002;Zhong and Hager, 2003;Nakagawa and Tackley, 2004), or having the chemical heterogeneities emerge via melting during the calculation at fixed melting zones (Walzer and Hendel, 1999;Davies, 2002;Huang and Davies, 2007a, b, c), moving melting zones that follow force-balanced plates or imposed plate motions (Brandenburg and van Keken, 2007a, b;Brandenburg et al, 2008), or freely moving melting location via a melting phase diagram (De Smet et al, 1998;Van Thienen et al, 2004;Xie and Tackley, 2004a, b;Nakagawa et al, 2009Nakagawa et al, , 2010.…”

“…Some aspects of the geochemical observations are constraints on mantle dynamics, because the dynamics are partly responsible for the heterogeneity in geochemical observations. Therefore progress can be made by introducing geochemistry to (numerical) mantle convection models (as in Christensen and Hofmann, 1994;van Keken and Ballentine, 1998;Xie and Tackley, 2004a;Huang and Davies, 2007b;Brandenburg et al, 2008).…”

Major and trace element composition of the high 3He/4He mantle: Implications for the composition of a nonchonditic Earth

“…The mantle is ''re-enriched'' when crust, both oceanic and continental, are subducted into the mantle, and the geochemistry of basalts erupted at some oceanic hotspots record the return of these subducted components, as well as deeply seated primitive components, in regions of mantle upwelling and melting Hofmann, 1997;White, 2010]. These enriched and depleted mantle reservoirs are mixed, thereby complicating much of the geochemical history recorded in the mantle [e.g., Brandenburg et al, 2008;van Keken et al, 2004]. While much of the mantle has been processed at mid-ocean ridges and subduction zones, fundamental questions remain: Are there domains in the mantle that have survived, relatively undisturbed since accretion, that might shed light on the composition of the earliest Earth?…”