Combined petrological, geochemical and isotopic modeling of a plume source: Example of Gambier Island, Pitcairn chain

High-precision lead isotopes and stripy plumes: Revisiting the Society chain in French Polynesia

“…8A, we show where basaltic crust and associated sediments recycled into the mantle plot in the e Nd vs. 208 Pb * / 206 Pb * space depending on their recycling age. The calculation procedure is given in Delavault et al (2015) and explained in Supplementary Text S4 where we also list all parameters used in the model. Briefly, the model calculates the present-day Nd and Pb isotopic composition of material recycled into the deep mantle at various times during Earth's history.…”

Recycled Components in Mantle Plumes Deduced From Variations in Halogens (Cl, Br, and I), Trace Elements, and 3He/4He Along the Hawaiian‐Emperor Seamount Chain

“…Samples from the Mangaia OIB have the most extreme 238 U/ 204 Pb signature, which defines the high μ (HIMU) 10.1029/2018GC007959 Geochemistry, Geophysics, Geosystems end-member; however, they appear to be dominated by a peridotite mantle source rather than a recycled pyroxenite source as in the Emperor seamounts (Herzberg et al, 2014). Furthermore, Pitcairn seamount has Br/Cl and I/Cl within the defined mantle range with similar Sr and Pb isotopes to the Hawaiian mantle source (Kendrick, Jackson, et al, 2014), but it contains a significantly lower proportion of recycled material (5%, Delavault et al, 2015) within the mantle source compared to that calculated for the Hawaiian mantle source (15-20%, Sobolev et al, 2007). Therefore, there appears to be an apparent decoupling between the isotopic signatures and the source lithology.…”

Partial melting of secondary pyroxenite at 1 and 1.5 GPa, and its role in upwelling heterogeneous mantle

“…A large number of experimental studies has been dedicated to partial melting of pyroxenites, and their phase relations and melting behavior, including solidus temperature and melt productivity, have been defined for a wide range of temperature, pressure and chemical compositions (e.g., Yaxley and Green 1998;Kogiso and Hirschmann 2001;Hirschmann et al 2003;Pertermann and Hirschmann 2003a;Kogiso et al 2004a;Keshav et al 2004;Médard et al 2006;Sobolev et al 2007;Lambart et al 2009aLambart et al , 2013. Profiting of available experimental data, increasingly sophisticated geochemical models have investigated the role of mixed pyroxenite-peridotite mantle sources in the genesis of mid-ocean ridge basalts (MORBs) and ocean island basalts (OIBs) (e.g., Hirschmann and Stolper 1996;Phipps Morgan 2001;Sobolev et al 2005Sobolev et al , 2007Stracke and Bourdon 2009;Herzberg 2006Herzberg , 2011Shorttle and Maclennan 2011;Guerenko et al 2013;Lambart et al 2012Lambart et al , 2016Shorttle et al 2014;Delavault et al 2015;Brown and Lesher 2016).…”