Enigmatic crustal structure of the Greenland-Iceland Ridge, the Iceland hotspot track
Abstract
The origin of the North Atlantic Igneous Province and its relation to the currently active Iceland hotspot have long been debated in the literature, with decisive observations yet to be reported. One promising approach is high-fidelity crustal seismic structure, the petrological interpretation of which can directly be related to the dynamics of the parental mantle and its chemical composition. This crustal seismology approach is, however, not so straightforward to be applied to continental margin settings because thickened crust at continent-ocean transition zones may not be totally of igneous origin. This ambiguity has been the source of disparate interpretations of the seismic structure of North Atlantic margins; by carving out the part of crustal structure with relatively low velocities, for example, it is possible to raise the average velocity of the 'igneous' crust high enough to fit the prediction of the mantle plume hypothesis. In this regard, the Greenland-Iceland Ridge presents a unique opportunity because, together with the Faeroe-Iceland Ridge, it constitutes the Iceland hotspot track, and as such, the bulk of its crust can be considered to be of igneous origin. In the 1996 Seismic Investigation of the Greenland Margin (SIGMA) conducted jointly by Woods Hole Oceanographic Institution and Danish Lithosphere Centre, active-source wide-angle seismic data were collected along the Greenland-Iceland Ridge, and their preliminary travel time analysis was published in 2001, but without a thorough follow-up analysis. We have recently revisited these important data, using joint refraction and reflection seismic tomography with adaptive importance sampling. This contribution will discuss the crustal structure resolved by this reanalysis along with its uncertainty, as it seems to present a few challenges to the conventional view that this Ridge results from the melting of the putative Iceland mantle plume.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.T11C..07K
- Keywords:
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- 1021 Composition of the oceanic crust;
- GEOCHEMISTRY;
- 8102 Continental contractional orogenic belts and inversion tectonics;
- TECTONOPHYSICS;
- 8104 Continental margins: convergent;
- TECTONOPHYSICS;
- 8105 Continental margins: divergent;
- TECTONOPHYSICS