Seismic and Potential Field Evidence for Orogenic Structures in the Danish Area
Abstract
Lower Palaeozoic sediments cover the entire Danish area and vary considerably in depth and thickness. In order to elucidate the structure of the lower Palaeozoic interval and the upper crystalline crust we use an integrated reflection seismic and potential field modelling approach in two key areas: the Kattegat area and the Ringkobing - Fyn High (RFH). Potential field data from the North Sea are analysed for shallow and deep-seated orogenic structures using a variety of transformation and imaging methods. The thin (< 0.5 s twt) sedimentary cover on top of the mainly flat crystalline basement of the Kattegat - Skagerak Platform (KSP) provides good seismic conditions for observing the relationship between internal orogenic crystalline structures and faulting in the top basement level. To the southwest in the Danish basin the lower Palaeozoic sedimentary sequence is deep seated, strongly block faulted and attains a thickness of ~ 1.5 s twt. In large areas the base of the lower Palaeozoic sedimentary interval is situated at a depth of more than 5 s twt and is seismically obscured by thick overlying sediments such as e.g. Zechstein salt. Contrary to the KSP, the RFH is strongly block faulted and probably covered by a thick (> 1.5 s twt) Palaeozoic sequence. Velocity modelling based on wide-angle refraction data, indicates the presence of down faulted Palaeozoic sediments. Deep seismic reflection data indicates internal orogenic crustal structures, probably of pre-Caledonian age, in areas adjacent to RFH.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AGUFM.T51A1116L
- Keywords:
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- 8102 Continental contractional orogenic belts;
- 8105 Continental margins and sedimentary basins;
- 8110 Continental tectonics: general (0905)