Evidence of Tethyan continental break-up and Alpine collision in the Argentera-Mercantour Massif, Western Alps

Abstract In the Argentera-Mercantour Massif, swarms of high-K calc-alkaline lamprophyres intruded into Carboniferous migmatites and early Permian granites, likely in Permian-Triassic times. The dykes collected multiple magmatic injections, the latest of which of alkaline affinity. Syn-intrusive vesicles and straight chilled margins suggest that the lamprophyres emplaced at a shallow crustal level. Lower greenschist facies mineral assemblages replaced lamprophyre igneous minerals as a result of late-intrusive hydrothermal circulation that occurred soon after the dyke emplacement. The hydrothermal event is constrained at T = 300–350 °C and P