Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8908733 | Tectonophysics | 2018 | 7 Pages |
Abstract
We investigate the mantle of central-eastern Greenland by using recordings with data from 24 local broad-band seismograph stations. We apply P wave receiver function technique and evaluate the difference in the arrival times of seismic phases that are formed by P to SV mode conversion at the 410-km and 660-km seismic discontinuities. These boundaries mark the top and bottom of the mantle transition zone (MTZ). The difference in the arrival time of the phases from the 410-km and 660-km discontinuities is sensitive to the thickness of the MTZ and relatively insensitive to volumetric velocity anomalies above the 410-km discontinuity. Near the east coast of Greenland in the region of the Skaergaard basalt intrusions we find two regions where the differential time is reduced by more than 2â¯s. The 410-km discontinuity in these regions is depressed by more than 20â¯km. The depression may be explained by a temperature elevation of ~150â¯Â°C. We hypothesize that the basaltic intrusions and the temperature anomalies at a depth of ~400â¯km are, at least partly, effects of the passage of Greenland over the Iceland hotspot at about 55â¯Ma. This explanation is consistent with the concept of tectosphere and implies that the upper mantle to a depth of ~400â¯km translates coherently with the Greenland plate.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Earth-Surface Processes
Authors
Helene Anja Kraft, Lev Vinnik, Hans Thybo,