Origin and Evolution of the Iceland Plateau
Abstract
Seafloor spreading within the Iceland region has been complex since the opening of the North Atlantic in late Paleocene-early Eocene. Whereas symmetric magnetic anomalies can be traced parallel to the Reykjanes Ridge and Mohns Ridge back to chrons 23-24, anomalies within the Iceland Plateau, west of the Aegir Ridge and along the Greenland-Iceland-Faeroe Ridge are irregular, indicating plate boundary complexities, most likely associated with branched accretion zones. Our 700 km long refraction/reflection and gravity profile, straddling 66.5°N across the Iceland Insular Shelf, Iceland Plateau and western Norway Basin revealed large variations in crustal structure between the presently active Kolbeinsey Ridge and extinct plate boundaries. The westernmost 300 km of the profile lies across the Iceland shelf, considered to have formed by rifting at the Kolbeinsey Ridge whereas the easternmost 400 km lie across the Iceland Plateau and Norway Basin, a region formed by rifting at the Aegir Ridge and possibly containing slivers of older crust rifted off the east Greenland margin along with the Jan Mayen Ridge. Crustal thickness varies from 4-5 km across the Aegir Ridge to 12-15 km beneath the Iceland Plateau and from 24-28 km beneath the outer Iceland shelf, to 12-13 km near the southern tip of the Kolbeinsey Ridge. Pronounced undulations in lower crustal structure and corresponding gravity highs across the Iceland Plateau are most likely associated with extinct spreading centers indicating that branched crustal accretion zones existed west of the Aegir Ridge prior to the westward ridge jump forming the KR at 26 Ma. Slivers of older crust, rifted off the east Greenland margin may exist between individual rift segments. However, more extensive surveying is required in order to reveal details of crustal evolution within the Iceland Plateau.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.T32B..07B
- Keywords:
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- 7220 Oceanic crust;
- 8105 Continental margins: divergent (1212;
- 8124);
- 8178 Tectonics and magmatism;
- 8416 Mid-oceanic ridge processes (1032;
- 3614)