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. In this project, we aim to 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.
We use numerical models, analogue experiments and results from seismic
investigations to investigate controls on fault formation in a
systematic manner. Field and seismic studies provide us with constraints
on the present-day geometry of extensional structures, while modelling
studies may help in understanding the tectonic deformation that created
these geometries. The numerical experiments use
two-dimensional finite element models that can achieve large deformation
with free surface behavior. The analogue experiments are built of (brittle)
sand and (viscous) silicone and their internal deformation is visualized
in an X-ray scanner.