1

• Main Authors: J. J. Armitage, T. J. Henstock, T A. Minshull
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Greenland; Sion; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.655.6118; http://eprints.soton.ac.uk/66801/1/jjarmitage-submitted.pdf

Abstract. Rifted margins form from extension and breakup of the con-tinental lithosphere. If this extension is coeval with a region of hotter litho-sphere, then it is generally assumed that a volcanic margin would follow. Here we present the results of numerical simulations of rift margin evolution by extending continental lithosphere above a thermal anomaly. We find that un-less the lithosphere is thinned prior to the arrival of the thermal anomaly or half spreading rates are more than ∼ 50mmyr−1, the lithosphere acts as a lid to the hot material. The thermal anomaly cools significantly by con-duction before having an effect on decompression melt production. If the litho-sphere is thinned by the formation of extensional basins then the thermal anomaly advects into the thinned region and leads to enhanced decompres-sion melting. In the North Atlantic a series of extensional basins off the coast of northwest Europe and Greenland provide the required thinning. This ob-servation suggests that volcanic margins that show slow rates of extension, only occur where there is the combination of a thermal anomaly and pre-