A hot-spot model for early Tertiary volcanism in the N Atlantic

Abstract

Summary The initial stages of rifting of the N Atlantic were accompanied by massive extrusion of volcanic rocks and the accretion to the lower crust of even greater volumes of igneous rock. Emplacement of the bulk of the igneous rocks along the 2000 km long continental rift occurred in as little as 2–3 My. The pattern and timing of magmatic activity can be explained by partial melting of anomalously hot asthenosphere as it welled up to fill the space left by the stretched and thinned continental lithosphere. Asthenosphere temperatures were elevated regionally by 100–150°C over a 2000 km diameter region by the mushroom-shaped head of hot material fed by a mantle plume, which at present is centred beneath Iceland.