Reinforcing the origin of volcanic rocks from the Massif Central through the isotopic composition of lead and strontium

The Massif Central in France hosts a large volume of Tertiary to Recent continental alkaline volcanism, with evidence of crustal contamination of the differentiated magmas. Detailed investigations on feldspathic basalts and basanite rocks from the Cantal Volcano exposed in the Allanthe basin by lead and strontium isotopes i) reveal the role of the mantle components Depleted Mantle (DM) and Low Velocity Component (LVC, corresponding to the European asthenospheric reservoir) end-members based on (208)pb/(204)pb and (206)p/Pb-204 isotopic ratios, and ii) show contamination by meta-igneous granulites from the lower crust when using (207)pb/(204)pb vs. (206)pb/(204)pb ratios, as only part of the samples plot along the Northern Hemisphere Reference Line (NHRL) mixing line between DM and HIMU (High U/Pb Mantle) end-members. Cross plotting of Pb-Sr isotopes rules out recycled sediment and/or igneous granulite as potential crustal contaminant for the Cantal basalts, but suggests mixing between the low-velocity component (LVC) and EMI (Enriched Mantle I)-pelagic sediments. Replaced in the regional context of the Massif Central, we confirm the existence of several mantle sources and different crustal contaminations in the magmas of the Cantal Volcano. (C) 2015 Elsevier B.V. All rights reserved.