Abstract The thick mantle lithosphere beneath cratons consists of strongly reduced rocks that have reacted with oxidized melts. These low-silica, incipient melts are rich in CO 2 and H O react surrounding forming an enriched zone at the base lithosphere, which is source region for many diamonds. Here, we reproduce these reactions novel experiments oxidised, hydrous carbonate-rich reduced, deple...

We explore Fe/Mn and Nb/Ta ratios of basalts as potential tracers for differentiating melts of recycled mafic crustal lithologies from peridotitic melts. Trace elements and Fe/Mn ratios of the Mesozoic and Cenozoic basalts from East China were analyzed by ICP-MS. Low Nb/Ta ratios (15.4 ± 0.3 (2r, n = 45)), high Nb and Ta contents (60.1 and 4.01 ppm) and high Fe/ Mn ratios (64.7 ± 1.5 (2r, n = 4...

Oceanic basalts, such as mid-ocean ridge basalts (MORB) and ocean island basalts (OIB), are characterized by large isotopic and trace element variability that is hard to reconcile with partial melting of a peridotitic mantle alone. Their variability has been attributed to the presence of heterogeneities within the mantle, such as recycled crust, metasomatized material or outer core contribution...

Introduction: Komatiites provide several ways of assessing the chemical and thermal evolution of the mantle. Komatiitic liquids are produced from very high degrees of partial melting of the deep mantle, and erupted as extremely fluid lavas. Komatiites are important in the study of the early Earth because they are a significant constituent of the Archean crust. It has been proposed that komatiit...

At subduction zones, crustal material is recycled back into the mantle. A certain proportion, however, is returned to the overriding plate via magmatism. The magmas show a characteristic range of compositions that have been explained by three-component mixing in their source regions: hydrous fluids derived from subducted altered oceanic crust and components derived from the thin sedimentary ven...

Recycled subducted ocean crust has been traced by elevated 187Os/188Os in some studies and by high nickel and low manganese contents in others. Here, we show that these tracers are linked for Quaternary lavas of Iceland, strengthening the recycling model. An estimate of the osmium isotopic composition of both the recycled crust and the mantle peridotite implies that Icelandic Quaternary lavas a...

s CD. BODINIER, J.-L., MENZIES, M. A., SHIMIZU, N., FREY, F. A. & MCPHERSON, E. 2004. Silicate, hydrous and carbonate metasomatism at Lherz, France: contemporaneous derivatives of silicate melt–harzburgite reaction. Journal of Petrology, 45, 299–320. BONADIMAN, C., BECCALUVA, L., COLTORTI, M. & SIENA, F. 2005. Kimberlite-like Metasomatism and ‘garnet signature’ in spinel-peridotite xenoliths fr...

The mantle beneath coastal SE China evolved from enriched to depleted between the Cretaceous and Neogene, although precise timing of this change remains unclear. Here, we focus on a newly discovered Eocene mafic volcanic neck that contains peridotite xenoliths in Fuding area Fujian Province, present new whole-rock Ar–Ar data which indicate flood basalts formed during (ages 38.5 ± 1.2 42.3 2 Ma)...