Susanne's ongoing projects
We address the effects of oblique rifting on passive margin geometry using a combination of computer models, laboratory experiments, and knowledge from seismic and geological observations. The numerical experiments use 3D modelling software (SULEC) developed jointly at the Geological Survey of Norway and GNS Science in New Zealand. The laboratory experiments are built of sand and silicone (resembling brittle and ductile crustal materials) in the modelling laboratory at the University of Bern in Switzerland. Our experiments are aimed at providing 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 (NGU).
Participants: Susanne Buiter (NGU), John Naliboff, Guido Schreurs (University of Bern), Susan Ellis (GNS Science), Alvar Braathen (The University Centre in Svalbard), Trond Torsvik (University of Oslo, NGU), Torgeir Andersen (University of Oslo), Per Terje Osmundsen (NGU), Gwenn Peron-Pinvidic (NGU), and Cinthia Labails (Beicip-Franlab).
Scenarios for microcontinent formation
Passive margins result from rifting and continental breakup, and often contain remnants of their rifting history in their complex structural architecture. Seismic studies reveal that magma-poor and magma-rich margins are not just a simple juxtaposition of oceanic and continental crust, but that the transition between the oceanic and continental domains may include various crustal bodies such as microcontinents and continental fragments. Microcontinents present a perplexing formation scenario: seafloor spreading ends in a region that is already warm, and thus weak, and is initiated elsewhere in a region of stronger lithosphere. In this project, we investigate various scenarios for microcontinent formation using dynamic numerical models.
SULEC is a finite element code that solves the incompressible Navier-Stokes equations for slow creeping flows. The code is developed by Susanne Buiter (NGU) and Susan Ellis (GNS Sciences, NZ).
The formation of parallel-dipping normal faults on passive margins
Observations indicate that extension of the continental upper crust is often accommodated by arrays of normal faults. These faults can have alternating dip directions and define a horst and graben structure or they can all dip in the same direction. Arrays of parallel-dipping normal faults are, for example, observed in the extending domains of offshore Norway, the Basin and Range Province, the Galicia margin west of the Iberian Peninsula, and offshore Angola. We investigate factors and mechanisms that favour the formation of an array of parallel-dipping normal faults over a sequence of horst and graben structures. An understanding of the formation and evolution of such fault arrays is of clear importance for improving our understanding of the general framework of the development of the Norwegian margin.