A comprehensive petrological study carried out on Ethiopian mantle xenoliths entrained in Neogene-Quaternary alkaline lavas overlying the continental flood basalt area (Dedessa River-Wollega region, Injibara-Gojam region) and from the southern Main Ethiopian Rift (Mega-Sidamo region) provides an ideal means to investigate mantle evolution from plume to rift settings. Mantle xenoliths from the plateau area (Injibara, Dedessa River) range in composition from spinel lherzolite to harzburgite and olivine websterite, showing pressure-temperature (P-T) equilibrium conditions in the range 1.3-0.9 G Pa and 950-1050°C. These xenoliths show flat chondrite (ch)-normalized bulk-rock rare earth element (REE) patterns, with only few light (L) REE-enriched samples (La N /Yb N up to 7) in the most refractory lithotypes. © 2011 The Geological Society of America. All rights reserved.
Peridotite xenoliths from Ethiopia: Inferences about mantle processes from plume to rift settings
BECCALUVA, Luigi;BIANCHINI, Gianluca;NATALI, Claudio;SIENA, Franca;
2011
Abstract
A comprehensive petrological study carried out on Ethiopian mantle xenoliths entrained in Neogene-Quaternary alkaline lavas overlying the continental flood basalt area (Dedessa River-Wollega region, Injibara-Gojam region) and from the southern Main Ethiopian Rift (Mega-Sidamo region) provides an ideal means to investigate mantle evolution from plume to rift settings. Mantle xenoliths from the plateau area (Injibara, Dedessa River) range in composition from spinel lherzolite to harzburgite and olivine websterite, showing pressure-temperature (P-T) equilibrium conditions in the range 1.3-0.9 G Pa and 950-1050°C. These xenoliths show flat chondrite (ch)-normalized bulk-rock rare earth element (REE) patterns, with only few light (L) REE-enriched samples (La N /Yb N up to 7) in the most refractory lithotypes. © 2011 The Geological Society of America. All rights reserved.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
