Fault-Propagation Folding in Salt-Influenced Extensional Basins
Dr Christopher A-L Jackson
Dr Oliver B. Duffy
Fault-propagation folding occurs above the lateral and vertical tips of
propagating normal faults and is an important process during the initial
development of normal fault systems. Fault-related folds are particularly welldeveloped in salt-influenced rift basins due to the pronounced mechanical
heterogeneity imparted on the upper crust by salt, which is typically significantly
weaker than the suprajacent rocks and leads to decoupling of sub- (i.e. thickskinned) and supra-salt (i.e. thin-skinned) structures. However, the structural
style and evolution of fault-related folds in salt-influenced rift basins is poorly
understood. In particular, relatively little is known regarding the relationship
between the fault structure and growth rate, and fold geometry and distribution.
Furthermore, the potential kinematic linkages that may occur between fault-fold
systems, through areally-extensive salt layers, has only inferred but never
quantified.
This project will use 2D and 3D seismic reflection data from offshore Norway to
determine the 3D geometry of fault-propagation folds adjacent to large normal
fault systems in a salt-influenced rift basin. Particular emphasis will be placed on
accurately determining how key fold geometric properties, such as amplitude
and width, are related to throw variations along the adjacent normal fault
systems. Furthermore, this project will determine the influence that salt can
have on long-range kinematic interactions between fault systems of varying
sizes.
This PhD would suit a student with an interest in structural geology or tectonics.
The candidate will hold a very strong (very high 2:1 or higher) undergraduate
(BSc or equivalent) and/or masters level degree or equivalent in geology or
geophysics. The PhD student will receive training in 3D seismic interpretation,
wireline log analysis and quantitative structural analysis. These skills will be
useful for a future career in the hydrocarbon industry or in academic or applied
research. For further information on this project please contact Dr Christopher
Jackson (c.jackson@imperial.ac.uk).