Porcupine Seabight

Porcupine Seabight Basin Stratigraphic range: Paleozoic to Mesozoic
Northeast Atlantic bathymetry, with Porcupine Bank and Porcupine Seabight
Type	Oceanic Basin
Unit of	Atlantic Borderland Basins
Area	60,000 km2
Location
Region	Southwest of Ireland
Type section
Region	Territorial Waters
Country	Ireland

The Porcupine Seabight is a deep-water oceanic basin located on the continental margin in the northeastern portion of the Atlantic Ocean. It can be found in the southwestern offshore portion of Ireland and is part of a series of interconnected basins linked to a failed rift structure associated with the opening of the Northern Atlantic Ocean. The basin extends in a North-South direction and was formed during numerous subsidence and rifting periods between the Late Carboniferous and Late Cretaceous. It is bordered by the

Due to subsidence, water depths range from 3000 m in the south near its mouth to 400 m in the north. The Porcupine Basin lies on the Caledonian metamorphic basement and preserves up to 12 km of sedimentary strata from Late Palaeozoic to Quaternary which includes significant hydrocarbon reservoirs. Sediment was likely sourced from the uplifted Calendonian metamorphic rocks of the Porcupine Median Ridge.

The basin lent its name to Operation Seabight, an Irish drug-bust of November 2008.

The basin was formed during numerous subsidence and rifting periods between the Late Carboniferous and Late Cretaceous. Multiple stages of uplift and subsidence were responsible for sediment input, the formation of accommodation space and the creation of steep basin margins:

Extreme stretching of the lithosphere has been documented in the Porcupine Basin. This stretching is especially found in the southern part of the basin as a result of rotation of the Porcupine Ridge away from the Irish shelf.

There are a number of unconformities found within the basin. Folding, uplift and related erosion during the Jurassic to Cretaceous produced the regional Base Cretaceous Unconformity in the northern section. Accommodation for the Early Cretaceous succession was not only generated by thermal subsidence following the Late Jurassic crustal extension, but also by compressional deformation during the latest Jurassic–earliest Cretaceous.