Investigation of the crust and upper mantle beneath Greenland and the North Atlantic Ocean using PP teleseismic precursor data

Abstract

This project uses teleseismic PP waves whose bounce points (or mid-points) are in the latitude range 50°N to 85°N and longitude range 60°W to 30°E for seismically imaging the crust and the upper mantle in remote areas of the North Atlantic that have sparse station coverage. This project uses more earthquakes than previously possible, recording and processing data from 1990-2015, which enables the imaging of finer detail – related to the higher frequency content. Stacks in the region are traced through areas of highest data density, to obtain the most accurate representations of the subsurface. The stacks reveal unique signatures relating to the passing of the current Iceland hotspot. A strong, bulbous, positive-amplitude arrival is found consistently between 150 and 250km depth near the proposed hotspot track, possibly related to the remnant effect of the hotspot. We also find features that indicate a previously-studied eastward dipping slab predating the major westward subduction relating to the Caledonian orogeny with the collision of Laurentia and Baltica. We also note instances of possible sutures of the North American and Eurasian plates just East of Greenland. Finally, we are able to resolve extensive evidence of the Mid-Atlantic Ridge and the regional Lithosphere-Aesthenosphere Boundary throughout the region.

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Keywords

Geophysics, Geology, Mid-Atlantic Ridge, Seismology, Greenland, Iceland, Faroe Islands, Jan Mayen, Hotspot, PP, Bounce points

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