PhD student - Rob Worthington
Funding - PhD Studentship funded by UCD studentship and Fault Analysis Group.
Research Partners
Project description
The basin evolution of offshore West of Ireland, including the Porcupine, Rockall and the Slyne Basins, is dominated by Late Jurassic-Early Cretaceous rifting followed by related thermal subsidence. Whilst the major fault systems in offshore Ireland are of Mesozoic age, there is increasing evidence of fault activity in, so-called, 'post-rift' Cenozoic times. This PhD involves the study of faulting within offshore and Onshore west of Ireland which is believed to be of Cenozoic age.
Research will concentrate on a range of fault-related deformation issues:
(i) The reactivation of basement normal faults during the Cenozoic is known to be selective, but the precise timing, origin and nature of basement fault reactivation has yet to be defined. The project will examine the main controls on both the reactivation geometry and growth of faults and establish the driving mechanism for their extended displacement history.
(ii) The inversion of basement normal faults is generally attributed to Tertiary compression. While its timing is ill-defined, there is evidence of both Paleogene and Neogene reactivation. Inversion of basement normal faults is also selective, but no constraints are available on the localisation and kinematics of inverted basement normal faults and related structures. The project will establish the timing, origin and nature of the inversion of basement structures, and will also consider the extent to which links can be developed between the reactivation of basement faults in compression and in extension.
(iii) A ubiquitous feature of offshore basins is the presence of intra-formational fault systems within Tertiary sequences. Geometrically these systems vary from polygonal through to sub-parallel arrays and there indications that some of these fault systems may be contemporaneous with basement fault reactivation. The geometry and growth of these fault systems will be examined and links between their development and larger-scale basin tectonics will be explored.
Whilst the principal data constraints for the project will be offshore seismic data, there is also some outcrop studies of fault systems in Ireland (in particular around Connemara) which are generally attributed to Tertiary movement. Complementary modelling of certain aspects of faulting may be performed where necessary or possible, including discrete element modelling of the reactivation of basement faults and flexural cantilever modelling of fault-related deformation.