Seismic Evidence for Late Proterozoic Orogenic Structures Below Kattegat, SW Scandinavia
Abstract
The exposed Grenville-Sveconorwegian crustal provinces of the Baltic Shield in southwestern Sweden and southern Norway are delimited along the Kattegat and Skagerrak coasts. To the southwest the continuation of the late Precambrian basement is masked by Phanerozoic sediments of the Kattegat-Skagerrak platform and the Danish-Norwegian basin. Within the last 25 years hydrocarbon exploration in Kattegat and Skagerrak has generated several marine reflection seismic surveys. We have used this data to correlate the exposed orogenic structures of southwestern Sweden with the seismically observed basement structures in Kattegat and Skagerrak. Borehole data, deep seismic profiles and potential field data are used as well. Interpretation of the reflection seismic lines shows that the reflectivity of the basement is dominated by bundles of dipping reflections down to to 6 s twt. Correlation of the reflection bundles show that they can be divided into two groups; (1) W dipping and (2) SE dipping reflections. The W dipping reflection bundles are interpreted to represent the southwestward continuation of the Sveconorwegian ductile shear zones exposed in SW Sweden. The SE dipping reflections represent older, possibly Gothian, compressional structures that became partially overprinted by the later Sveconorwegian Orogeny. The subcrop of some of the prominent bundles of dipping reflections trends close to faults in the sedimentary cover. This may indicate that some of the interpreted late Proterozoic shear zones were reactivated during the subsequent basin formation and inversion in the Danish area.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2001
- Bibcode:
- 2001AGUFM.T32B0891L
- Keywords:
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- 0905 Continental structures (8109;
- 8110);
- 7205 Continental crust (1242);
- 8100 TECTONOPHYSICS;
- 8105 Continental margins and sedimentary basins;
- 8115 Core processes (1507)