Fault styles in the Porcupine Basin, offshore Ireland: tectonic and sedimentary controls

Abstract

Abstract Analysis of fault style, size and distribution in the Porcupine Basin has demonstrated the existence of a number of fault types. Syn-tectonic growth faults occur on scales ranging from basin-bounding faults to small intrabasinal faults and they range in age from Jurassic through to the end of the Eocene. Tectonic non-growth faults are most pronounced in the post-rift succession. They are generally small and did not significantly influence sedimentation patterns. They frequently occur in clusters and are commonly recorded at mid-Eocene to mid-Miocene horizons. Slump-associated faults occur in association with large-scale sediment failure structures which are most pronounced in the Upper Tertiary succession. Unlike the other fault types, which are extensional in nature and typically planar in shape, these faults can be either extensional or compressional, and frequently have a listric geometry. The interplay of fault types with sedimentation leads to the identification of a number of recognizable seismic facies.