Chlorine-rich metasomatic H2O–CO2 fluids in amphibole-bearing peridotites from Injibara (Lake Tana region, Ethiopian plateau): Nature and evolution of volatiles in the mantle of a region of continental flood basalts

The making of an underplate: Pyroxenites from the Ethiopian lithosphere

“…Existing studies of xenoliths derived from the lithospheric mantle in this region suggest that an early subductionrelated metasomatic overprint may be possible (Kaeser et al, 2009;Frezzotti et al, 2010).…”

Evolution of carbon dioxide-bearing saline fluids in the mantle wedge beneath the Northeast Japan arc

“…In olivine, inclusions consist of magnesite and talc, or magnesite, talc, and lizardite, but rarely CO 2 , even in trace amounts (Fig. 4c-e), which can be formed by reaction of CO 2 -H 2 O fluid with the host olivine (Andersen et al 1984;Hirai and Arai 1987;Frezzotti et al 2010). In addition, some inclusions contain what is believed to be hydrous Mg-sulfate (Fig.…”

“…The fluid inclusions found in these peridotite xenoliths may provide us with key information regarding the nature of these metasomatic agents and, more importantly, may even have preserved their original composition. It is important to examine the presence of Cl in the fluids preserved in the fluid inclusions, since the Cl contents of aqueous fluids significantly influence the dissolution of trace elements (Keppler and Wyllie 1991;Keppler 1996;Scambelluri et al 2004a, b;Zajacz et al 2008;Frezzotti et al 2010;Kawamoto et al 2014). Only few papers, however, have reported on the salinity of fluid inclusions in mantle xenolith, such as that for xenoliths from the Ethiopian plateau (Frezzotti et al 2010) and the Pinatubo volcano at the volcanic front in the Luzon arc (Kawamoto et al 2013).…”

Geochemical and Sr–Nd–Pb isotopic compositions of lithospheric mantle: Spinel lherzolites in alkaline basalts from the northwestern Ethiopian plateau

“…Thus, based on the results of the present study, the metasomatism of subcontinental lithospheric mantle beneath the northwestern Ethiopian plateau may be associated with infiltration of hydrous, fluid-rich silicate melt from a sublithospheric source with Sr-Nd-Pb isotopic affinities similar to those of the proposed Afar plume composition Meshesha and Shinjo, 2007). Previous and present studies suggested the metasomatism of the lithospheric mantle beneath northwestern Ethiopia is primarily related to the upwelling Afar plume (e.g., Baker et al, 1998;Beccaluva et al, 2011) with spatial variations in the compositions of the metasomatic agents (Roger et al, 1997(Roger et al, , 1999Conticelli et al, 1999;Ayalew et al, 2003Ayalew et al, , 2009Ferrando et al, 2008;Beccaluva et al, 2009Beccaluva et al, , 2011Frezzotti et al, 2010). Hence, the spatial variations strongly suggest that the lithosphere beneath northwestern Ethiopia is laterally heterogeneous (Ferrando et al, 2008).…”

“…These tectono-magmatic processes consequently induced substantial variations in the thermal structure and chemical composition of the upper mantle beneath Ethiopia and the surrounding regions. The mantle xenoliths hosted in the alkaline basalts of southern Ethiopia (Mega-Megado and Dilo-Goraye: Morten et al, 1992;Bedini et al, 1997;Bedini and Bodinier, 1999;Conticelli et al, 1999;Lorand et al, 2003;Reisberg et al, 2004;Meshesha et al, 2011), the central Main Ethiopian Rift xenoliths and xenocrysts (Debre Zeyte and Butajira: Rooney et al, 2005) and northwestern Ethiopia xenoliths (Injibara, Dedesa and Simien shield volcano: Roger et al, 1997Roger et al, , 1999Conticelli et al, 1999;Ayalew et al, 2003Ayalew et al, , 2009Ferrando et al, 2008;Beccaluva et al, 2009Beccaluva et al, , 2011Frezzotti et al, 2010) have therefore been the focus of extensive study over the previous two decades (Fig. 1a).…”