| dc.description.abstract | The aim of this study is to achieve a better understanding of the deep basin and crustal configuration of the transition zone between the Møre and Vøring margins. The area selected is based on the distribution of a set of two-ship wide-angle seismic data analyzed here for the first time. The Møre and Vøring margins are part of a broader geological province known as the continental margin off mid-Norway (located between 62 and 69N). This province is described as a passive rifted margin, a seismically inactive continental transition to the deep ocean that has undergone a long period of extension and rifting.
The analysis of the wide-angle seismic data or Expanding Spread Profiles (ESP) provided us, at their location, with velocity-depth information through the crust. This information, supplemented by Ocean Bottom Seismometer (OBS) and sonobuoys data was used in the interpretation and depth conversion of key multichannel seismic lines (MCS). The depth converted MCS lines were then implemented to gravity modelling. The analysis of all these geophysical data resulted in the construction of deep regional crustal transects: the upper crustal part of the geological models were constrained by MCS data, whereas the geometry to the deeper structures (such as top basement and Moho discontinuity) were constrained by ESP, OBS and gravity data.
The deep crustal transects provided valuable information on the topography of and depth to Moho, the amount of crustal thinning and the distribution of the sedimentary units with emphasis on the thickness of the Cretaceous sequence. The study of the structural configuration of the crustal transects (correlation between the Moho uplifts and deep Cretaceous sedimentary basins) suggests, in this area, a rifting model that combines a pure-shear and a simple shear extensional model. Another important observation is the absence of a lower crustal high-velocity body which is widespread on the Vøring margin and visible south of the Jan Mayen Lineament.
The information obtained from the ESPs contributed to a better velocity control in the study area. However, it was crucial to combine ESP with OBS data that reach the upper mantle in order to constrain the deep structures. It would be relevant to acquire more OBS data in the transition zone between the Møre and Vøring margins, especially to the east of the Jan Mayen Lineament, to improve velocity control for the deep basin and crustal configuration. New data would also contribute to delimit the extent of the lower crustal high-velocity body across the transition area. | en_US |