The tilted Iceland Plume and its effect on the North Atlantic evolution and magmatism

• Main Authors: Celli, Nicolas Luca, Lebedev, Sergei, Schaeffer, Andrew J., Gaina, Carmen
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Greenland; Mid-Atlantic Ridge; Iceland; North Atlantic; Northeast Atlantic
• Online Access: https://dair.dias.ie/id/eprint/1129/; https://dair.dias.ie/id/eprint/1129/1/Main_text.pdf

Iceland and the encompassing Northeast Atlantic are characterized by abun- dant volcanism, anomalously high topography and, in many places, anoma- lously thick basaltic crust. This has been attributed to the Iceland Plume, rising from the deep mantle, though its structure and very existence are de- bated. Using seismic waveform tomography with massive datasets, we compute a new, detailed model of the crust and upper mantle beneath Iceland and the surrounding North Atlantic region. The model reveals a large, low-velocity anomaly, indicative of high temperatures, at 400-660 kilometers depth beneath eastern Greenland, where seismic receiver functions also indicate an extensive high-temperature region. The anomaly rises upwards and eastwards toward Ice- land, deflecting around the thick lithosphere of Greenland’s cratons, which we also image in detail. We interpret the major low-velocity anomaly as the Ice- land Plume, ascending from under Greenland and captured by the Mid-Atlantic Ridge. The ascent of the plume beneath the western Northeast Atlantic is con- sistent with its thin lithosphere, documented by our tomography, and abundant seamounts. Our results reconcile previously contrasting views on the structure of the Iceland Plume: while the plume is clearly visible in the transition zone beneath Greenland, it is confined to the upper mantle beneath Iceland.