Devonian–Mississippian magmatism related to extensional collapse in Svalbard: implications for radiating dyke swarms

The study presents the first evidence for extensive magmatism in Svalbard in the late Paleozoic at ca. 390–330 Ma. The composition of the magmatic intrusions suggests they are part of a large magmatic province extending thousands of km from Ukraine in the south to the Ural Mountains in the northeast and Svalbard in the northwest. The magmatic rocks intruded along existing tectonic structures formed at ca. 650–550 Ma during the collision of two tectonic plates. This work documents the impact of preexisting structures on subsequent magmatic events, especially in determining preferential pathways for magma in the crust. A similar reasoning can be applied to other contemporaneous groups of intrusions in Russia and to nearby younger intrusions in the Arctic (Yakutsk–Vilyui Large Igneous Province and High Arctic Large Igneous Province), which appear to follow structures related to old plate-collision events. Thus, the apparently radiating pattern displayed by those groups of intrusions is generated by previous episodes of deformation of the crust rather than by uplift and fracturing of the crust around potential mantle plumes, which are focus points of upwelling of magma from the deep Earth interior at the core–mantle boundary.