Abstract

The Mesozoic to present evolution of the central Atlantic realm is interpreted as a two-stage tectonomagmatic scenario involving long-lived asymmetric mantle upwelling phenomena and magmatism within its eastern margin. The first, a pre-drift tholeiitic stage of Triassic-Jurassic age, resulted from the interaction between several elements: (1) a thinned, weakened corridor along the collapsed southern branch of the Variscan belt between eastern North America and western North Africa; (2) a central Atlantic plume located in the triple junction between Africa, North America, and South America; (3) a progressive asymmetric continental breakup between northwest Africa and North America characterized by detachment systems; and (4) a highly thinned European realm pervaded by rift-type basins that we interpret as a large thin-spot-type domain. These conditions would have induced north-northeast–directed large-scale sublithospheric plume channeling from the central Atlantic plume site to the European large thin-spot, leading to widespread early tholeiitic magmatism (Triassic-Jurrassic) within a giant irregular zone of ∼3000 × 4000 km. Plume activity and chaneling continued afterward during a Cretaceous to present second tectonomagmatic stage (passive margin alkaline stage) leading to the onset of alkaline magmatism along a general north-northeast trend in the eastern Atlantic margin (Late Cretaceous) and Europe (Paleocene–Oligocene). As a whole, a north-northeasst–directed propagating magmatic vector can be defined from the Mesozoic to the present.

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