Petrology, Mineral and Isotope Geochemistry of the External Liguride Peridotites (Northern Apennines, Italy)

Abstract

Mantle peridotites of the External Liguride (EL) units (Northern Apennines)

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

“…This latter resembles the composition of External Liguride lherzolites hosting secondary pyroxenite GV10, which were chemically and isotopically identified as a potential MORB-type mantle source (Rampone et al 1995;Borghini et al 2013). For each pyroxenite-peridotite melt fraction pair, obtained at 1 GPa for different T P using Lambart et al (2016) modeling, we mixed the composition of pyroxenite GV10 and lherzolite MM3 melts using the method proposed by Sorbadere et al (2013) (see details in caption of Fig.…”

“…Although the EL peridotites are considered Page 3 of 24 _####_ exposed subcontinental lithospheric mantle sectors (e.g., Rampone et al 1995), their MORB-like isotopic composition and chemical features suggest that they were formed by lithospheric accretion of ordinary asthenospheric mantle (Rampone et al 1995). Therefore, they represent good proxies of an MORB-type fertile mantle source that is modified by deep melt infiltration and melt-rock reaction processes before it undergoes partial melting and basaltic melt extraction (Borghini et al 2013(Borghini et al , 2016, as envisaged by recent MORB petrogenesis models (e.g., Lambart et al 2012).…”

Re–Pt–Os Isotopic and Highly Siderophile Element Behavior in Oceanic and Continental Mantle Tectonites

“…properly assigned to purely extensional environments (e.g., Piccardo and Guarnieri 2010; 206 Rampone et al 1995Rampone et al , 1996. 207 208…”

Volcanology and geochemical study of the volcanic rocks of the Bafmeng area (Mount Oku, Cameroon Volcanic Line)

“…Therefore, the transition of spinel to plagioclase lherzolite in the mantle xenoliths of Bafmeng is governed by a continuous reaction resulting in a systematic compositional variation in coexisting minerals at decreasing pressure within the plagioclase stability field (Borghini et al, 2010). The development of a plagioclase bearing assemblage indicates that this peridotite have been partially reequilibrated at relatively low pressure, from spinel to plagioclase lherzolite facies condition (Rampone et al, 1995) and it turns out that, this type of peridotite at the initial state was at equilibrium at the spinel facies, but underwent a destabilisation and after re-equilibrium in the plagioclase facies (Tamen et al, 2015). An evidence of mantle exhumation from about 22-9 km.…”