The 3D nature of passive continental margins

Passive margins form after rifting and break-up of a continent. They are called 'passive', but they can still experience active deformation in terms of movements, faulting and volcanism. Such active processes directly impact communities along rifted margins worldwide. In addition, passive margins offer great economic opportunities as many of the world's oil and gas reservoirs occur on continental shelf areas. These reasons point to the necessity of a deep understanding of the processes that shaped passive margins. Passive continental margins may form in orthogonal extension, but because plate motions are rarely exactly orthogonal to plate boundaries, it is common that plate margins experience oblique relative motions during at least part of their evolution. An example of oblique rifting is the early phase of extension between Norway and Greenland (in the Jurassic-Cretaceous), which was characterised by a large component of strike-slip movement. This makes margin development a 3D problem. In this project, we ask the question how the oblique character of many passive margins determined their geometry, faulting style and topographic evolution. We will attempt to answer this question by a unique combination of computer models, laboratory experiments and knowledge from seismic and geological observations. The laboratory experiments will be built of sand and silicone (resembling brittle and ductile crustal materials) in a new modelling laboratory at the University of Bern in Switzerland. The numerical experiments use a new 3D modelling software developed jointly at the Geological Survey of Norway and GNS Science in New Zealand. Our experiments will provide a new view on margin development, which is of direct relevance to margin hazard, hydrocarbon exploration and landscape development studies.

The project is financed by the Norwegian Research Council (project 213399/F20) and the Geological Survey of Norway.

Project participants: