Magma pulses in the Central Variscan Belt: episodic melt generation and emplacement during lithospheric thinning

Magmatism in the central part of the Variscan orogenic belt in Europe has occurred in several distinct episodes. Each episode spanned a few million years and was characterized by a distinct geochemical signature and geodynamic setting: (i) between 340 and 330 Ma (Visean), high-K diorites and granitoids within a zone extending parallel the orogen axis, possibly tracing a palaeosuture; (ii) at 310-307 Ma (Westphalian), calc-alkaline granitoids in the Intra-Alpine domain; (iii) at 304-295 Ma (Stephanian), subalkaline granitoids in Intra-Alpine and Pennine domains; and finally (iv) at 280-270 Ma (Permian) granitoids in Pennine, Austroalpine and South-Alpine domains. The generation and emplacement of granitoid melts in the Variscan crust are suggested to be short-term pulses that are controlled by extensional processes in the lithosphere such as thermal erosion and relaxation of the lithospheric mantle, and decompressional melting