Heavy Rare Earth Elements and the Sources of Continental Flood Basalts

Abstract Heavy rare earth elements (HREEs) in mafic and ultramafic volcanic rocks are useful recorders of mantle source processes because their ratios not easily modified by differentiation. Here we utilize REEBOX PRO, a simulator adiabatic decompression melting the mantle, to study behavior HREEs formation continental flood basalt (CFB) parental magmas mantle. We simulate partial depleted peridotite, pyrolitic pyroxenite, peridotite-pyroxenite mixtures at potential temperatures 1350–1650°C lithospheric thicknesses 50–150 km, compare results natural data. Many large igneous provinces typified low-Ti high-Ti CFBs with contrasting HREE patterns. Our show that originate mainly from peridotitic sources. Flat mid-ocean ridge basalt-like patterns typical can be generated beneath thick lithosphere (~100 km), given high (>1500°C) garnet is completely consumed source. thus challenge common interpretation flat always indicate shallow sources for CFB magmas. High-Ti require pyroxenite-bearing (≥10%). Contrary view, steep oceanic island quite thin (~50 which due increased stability pyroxenite When applied Karoo province, compatible model where plume penetrates progressively thinning Gondwana lithosphere.