The structural evolution of fold and thrust belts and its implications for associated sedimentary basin development

Overview
Compressional settings are some of the most complex and challenging exploration environments. They produce strongly 3D and locally complex structures, many of which are suited to the entrapment of significant hydrocarbon reserves, and they govern the geometry, evolution and sediment supply for associated foreland and piggy-back basins.
In fold and thrust belts, structural development is characterised, and often intensely debated, as being either foreland-, or hinterland-propagating in nature. In some cases, structural domains that show early development as foreland-propagating are characterised by later out-of-sequence, or ‘break-back’, thrusting. The factors that control dominantly foreland versus dominantly hinterland propagating thrust systems are poorly understood. The geometry and thrust-sheet stacking of the evolving thrust belt itself may exert the dominant control, promoting foreland propagation at key points in the belt’s development, and hinterland propagation at other times, perhaps with an oscillatory or cyclic nature throughout the evolution of the thrust belt. The geometry of the evolving thrust sheets and their propagation control accommodation space and sediment supply to the associated basins and thus, in conjunction with sea level, the evolution of the thrust belt exerts a strong control on the sedimentary fill of the basins and ultimately upon their hydrocarbon potential.
This project will investigate foreland versus hinterland propagation in fold and thrust belts to resolve the extent to which the reality for fold-and-thrust belt development is an oscillatory, or pulsatory, switching between foreland-, and hinterland-propagation. It will identify structures in the frontal part of the system which are the earliest disturbances in the previously stable foreland, such as ‘ice-breaker’ loading of the leading edge, that can rotate easy-slip horizons into favourable orientations, and assess the relative balance between low-angle and steep structures that accommodate strain. The project will use detailed 3D seismic datasets from the Apennine foreland to provide structural interpretations and to investigate evolution in relationship to sedimentary fill.
The project will provide a model for the development of fold and thrust belts that a) identifies the style and likely position of early structures related to foreland and hinterland propagating thrusts, and b) characterises the hydrocarbon trapping potential of these features. If oscillatory structural geodynamics in fold and thrust systems are a reality, then the project will provide a basis for interpreting the evolution of accommodation space and sediment supply within thrust-belt related sedimentary basins, and provide an enhanced model for understanding the sedimentary fill, the sequence stratigraphical evolution and the hydrocarbon potential of these basins.

Research context: This project provides a natural extension of two PhD projects recently completed within the research group: 1) Three-dimensional geometry and kinematics within fold and thrust systems and 2) The evolution of the basins and thrust systems of the Cantabrian Arc.

Career routes: Exploration specialisms in compressional settings, seismic interpretation specialism, sequence stratigraphy and structural geological consultancy.