Abstract
A detailed knowledge of the thickness of the lithosphere in the north
Atlantic is an important parameter for understanding plate tectonics
in that region. We achieve this goal with as yet unprecedented detail
using the seismic technique of S-receiver functions. Clear positive
signals from the crust-mantle boundary and negative signals from
a mantle discontinuity beneath Greenland, Iceland and Jan Mayen are
observed. According to seismological practice, we call the negative
phase the lithosphere-asthenosphere boundary (LAB). The seismic lithosphere
under most of the Iceland and large parts of central Greenland is
about 80 km thick. This depth in Iceland is in disagreement with
estimates of the thickness of the elastic lithosphere (10-20 km)
found from postglacial rebound data. In the region of flood basalts
in eastern Greenland, which overlies the proposed Iceland plume track,
the lithosphere is only 70 km thick, about 10 km less than in Iceland
which is located directly above the proposed plume. At the western
Greenland coast, the lithosphere thickens to 100-120 km, with no
indication of the Iceland plume track identified. Below Jan Mayen
the lithospheric thickness varies between 40 and 60 km.
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