North Atlantic Igneous Province

North Atlantic Igneous Province
Name	North Atlantic Igneous Province
Type	Large igneous province
Location	North Atlantic Realm
Area	~1,000,000 km² (approx.)
Period	Paleogene
Last eruption	Paleogene

North Atlantic Igneous Province is a major Paleogene large igneous province associated with the opening of the North Atlantic Ocean and with extensive magmatism across parts of western Europe and eastern North America. The province produced flood basalts, intrusive complexes, and volcanic edifices that influenced the geology of Greenland, Iceland, the Faroe Islands, Scotland, and Ireland, and left igneous records in offshore basins and continental margins adjacent to the Atlantic Ocean. Its development is tied to plate reorganization events and mantle processes during the Paleogene epoch of the Paleogene Period.

Overview and Extent

The province encompasses widespread volcanics and intrusions in regions including East Greenland, West Greenland, Icelandic Plateau, the Faroe–Shetland Basin, the Shetland Islands, the Hebrides, Antrim Plateau Basin, and the continental shelf areas off Newfoundland and Labrador. Major elements include the Icelandic flood basalts, the West Greenland flood basalts, the British Tertiary Volcanic Province, and the Hebridean Igneous Complex, extending into offshore provinces examined in the context of North Sea Basin and Labrador Sea rifting. The distribution links to structural elements such as the Mid-Atlantic Ridge, the Greenland–Iceland–Faroe Ridge, and the Porcupine Basin margin.

Geological Setting and Tectonic Evolution

The province formed in the context of the breakup of the northern supercontinent margin following events tied to the fragmentation of Pangaea and the motion of the North American Plate relative to the Eurasian Plate. Tectonic drivers include plume-related uplift attributed to a putative Iceland plume interacting with the lithosphere, and extensional stress related to the opening of the North Atlantic Ocean and the development of the North Atlantic rift system. The timing and mechanics of emplacement relate to plate reorganizations recorded in the Gondwana breakup derivative sequence and to changes in spreading at the Mid-Atlantic Ridge and the Charlie Gibbs fracture zone. Regional structures controlling emplacement include the Wester Gneiss Shear Zone analogues, margin transform faults such as the Makkovik–Pacquet transform, and sedimentary basins like the Faroes Basin.

Magmatism and Rock Types

Magmatism produced tholeiitic flood basalts, transitional basalts, picrites, and evolved intrusive suites including gabbro, dolerite (dike swarms), and granophyre. Central complexes show layered mafic intrusions akin to those in the Rum Igneous Centre and the Tertiary volcanic complexes of Ardnamurchan and Skye. Geochemical signatures record enrichment patterns comparable to plume-rift interactions seen in studies of Hawaii-style plume systems, and isotopic trends link to mantle domains discussed in work on the Deccan Traps and the Columbia River Basalt Group. Petrographic features include olivine-phyric basalts, plagioclase megacrysts, and cumulate textures typical of layered intrusions such as the Sron Garbh gabbro suites.

Chronology and Phases of Activity

Radiometric dating places the main pulse in the earliest Paleogene, particularly during the Paleocene–Eocene boundary interval, with ages clustering around the Paleocene–Eocene Thermal Maximum timeframe and earlier Paleocene events. Key age control comes from 40Ar/39Ar and U–Pb geochronology applied to lavas and intrusive rocks sampled from the Faroe Islands and East Greenland, tying activity to magnetic polarity chrons recorded in the geomagnetic polarity timescale. Multiphase emplacement is documented by successive lava piles, intrusive swarm emplacement synchronous with rift opening episodes recorded in the Basin and Range Province analogues, and by continental breakup markers coincident with seafloor spreading initiation at the Mid-Atlantic Ridge.

Volcanism, Eruptive Features, and Structures

Surface expressions range from extensive plateau basalts and stratified lava flows forming mesas such as those on the Antrim Plateau to volcanic centers including tuyas and subglacial edifices on Iceland and remnants preserved on the Hebrides. Structural features include radial dike swarms, ring complexes, sill complexes, and extensive dyke corridors comparable to the MULL Dyke Swarm and the Vøring Plateau intrusions. Offshore volcanic edifices and hyaloclastite deposits influenced early syn-rift sedimentation in basins like the Hatton Bank and the Newfoundland Basin, while erosional remnants preserved columnar jointing exemplified by landmarks such as the Giant's Causeway.

Economic Geology and Mineralization

The province hosts potential mineral resources including magmatic nickel-copper–platinum-group element (PGE) mineralization associated with layered intrusions similar to deposits studied in the Bushveld Complex context, and base-metal sulfide mineralization within feeder systems and sills. Hydrothermal alteration and associated zones have been evaluated for volcanogenic massive sulfide analogues akin to discoveries in the Midcontinent Rift and for rare-earth element enrichment compared to occurrences in Carbonatite-related provinces. The igneous architecture also influences hydrocarbon prospectivity on continental shelves such as in the Faroe–Shetland Basin and around the Labrador Sea through heat flow anomalies and trap modification.

Environmental and Climatic Impacts

Large-scale volcanism affected greenhouse gas budgets through massive emissions of CO2 and SO2, with temporal coincidence proposed between magmatic pulses and episodes recorded in Paleocene–Eocene Thermal Maximum studies and in isotopic excursions found in the Greenland ice core and marine records from the North Atlantic Deep Sea Drilling Project. Aerosol and greenhouse forcing, coupled with volcanic methane release through contact metamorphism of organic-rich sediments in rift basins like the Faroe–Shetland Basin, have been invoked to explain transient warming and biotic responses documented in the Eocene Thermal Maximum 2 and in marine planktonic turnover observed in regional cores. Paleoenvironmental reconstructions use integrated datasets from institutions such as the British Geological Survey, Geological Survey of Denmark and Greenland, and the United States Geological Survey.

Category:Large igneous provinces Category:Paleogene geology Category:Volcanism of Iceland Category:Geology of Greenland Category:Geology of Scotland