North Atlantic Land Bridge

North Atlantic Land Bridge
Name	North Atlantic Land Bridge
Period	Paleogene–Neogene
Region	North Atlantic Realm
Type	Land connection
Status	Submerged

North Atlantic Land Bridge was a series of intermittently emergent terrestrial corridors that linked paleocontinents across the North Atlantic realm during the Paleogene and early Neogene. It served as a migration route between proximate margins such as Greenland, Iceland, Scotland, Ireland, Norway, Svalbard, East Greenland Shelf, Labrador Sea, Newfoundland and Labrador, Faroe Islands, and the European Plate and North American Plate margins. Paleobotanical, vertebrate, and invertebrate distributions preserved in stratigraphic archives across Greenland and Svalbard reflect episodic connectivity that influenced dispersal patterns in the wake of the Cretaceous–Paleogene extinction event and into the Eocene and Oligocene.

Overview and Geological History

Geological reconstructions combine datasets from institutions such as the United States Geological Survey, British Geological Survey, Geological Survey of Denmark and Greenland, Geological Survey of Canada, and research programs like the Integrated Ocean Drilling Program and International Ocean Discovery Program to resolve rift and drift histories affecting the Atlantic margins. Tectonic events associated with the break-up of Pangea, seafloor spreading at the Mid-Atlantic Ridge, and magmatism related to the North Atlantic Igneous Province contributed to uplift, subsidence, and volcanic archipelagos that intermittently connected continental shelves. Stratigraphic evidence from formations such as the Dorset Formation, Fossil Bluff Formation, and Ellesmere Island Group anchors timing used in plate reconstructions entailing the Iapetus Ocean closure and subsequent opening of the modern Atlantic.

Paleogeography and Formation

Paleogeographic maps derived from collaborators at Paleomap Project, University of Cambridge Department of Earth Sciences, and Columbia University Lamont-Doherty Earth Observatory demonstrate that the land bridge comprised chains of islands, microcontinents, and emergent continental shelf across the North Atlantic Ocean Basin. Paleomagnetic, seismic reflection, and drilling records from the Rockall Trough, Hatton Bank, Porcupine Seabight, and Flemish Cap reveal episodic shallowing linked to thermal subsidence and epeirogenic uplift. Volcanic constructs associated with the Iceland plume and remnants preserved on Jan Mayen and the Faroe–Shetland Channel provided stepping-stones for biotic exchange. Paleogeographic excursions reference events such as the Paleocene–Eocene Thermal Maximum that altered topography and shelf exposure.

Flora and Faunal Migration

The corridor facilitated trans-Atlantic dispersal for temperate and boreal lineages including representatives ancestral to modern taxa recorded in Europe, Asia, and North America. Plant fossils from the Dawn Redwood affinity and genera similar to Metasequoia, Taxodium, Ginkgo relatives, and early Fagales occur in Paleogene floras across Greenland and Scotland indicating floristic continuity with the Appalachian Mountains and Scandinavian Caledonides. Vertebrate interchange included early mammals related to Creodonts, Perissodactyla, Artiodactyla, and insectivores with affinities to faunas described from the Messel Pit, Bighorn Basin, Willwood Formation, and the Fur Formation. Avian dispersal links show affinities to taxa known from Green River Formation and London Clay. Marine and freshwater invertebrate distributions mirrored terrestrial connections, as documented in assemblages from Eocene Baltic amber deposits and Fossiliferous strata on Baffin Island.

Climatic and Sea-Level Influences

Global climatic regimes documented by proxies from Vostok Station, EPICA Dome C, ODP Site 901, and isotopic series (oxygen and carbon) tied to records from the Vostok ice core and Greenland Ice Core Project affected the bridge’s viability. Warm intervals such as the Eocene Climatic Optimum and transient hyperthermals enhanced poleward dispersal by reducing climatic barriers, while cooling trends culminating in the Oligocene and intensified by the Oligocene–Miocene transition contracted ranges. Glacio-eustatic fluctuations associated with Antarctic glaciation and Northern Hemisphere cooling controlled shelf exposure across the Labrador Sea and Norwegian Sea, governed by sea-level records from the Sverdrup Basin and North Sea Basin.

Evidence and Paleontological Record

Fossil evidence derives from collections curated by the Natural History Museum, London, Smithsonian Institution National Museum of Natural History, Royal Ontario Museum, Palaeontological Institute of the University of Copenhagen, and field sites on Spitsbergen (Svalbard), Greenland, Iceland, and eastern Canada. Palynological records, macrofloras, and vertebrate remains from localities such as Hjelm Bay, Moerel Formation, and Arctic Cenozoic outcrops demonstrate shared taxa and phylogenetic links corroborated by molecular clock analyses from laboratories at Harvard University, Max Planck Institute for Evolutionary Anthropology, University of California, Berkeley, and University of Oslo. Biogeographic patterns are further supported by isotopic and sedimentological signatures from cores obtained via IODP and ODP expeditions.

Extinction and Disappearance

The progressive disappearance of the land bridge reflects combined influences of plate tectonics, subsidence following the cessation of rifting, volcanic rearrangement tied to the Iceland plume, and climatic cooling through the late Paleogene into the Neogene that increased sea level and drowned low-lying connections. Regional events such as the Eocene–Oligocene extinction event and Miocene marine transgressions contributed to vicariance and local extirpations. Subsequent isolation fostered endemism in regions like Newfoundland and Labrador and Scotland and altered dispersal routes that later involved the Bering Land Bridge during Neogene and Pleistocene intervals.

Significance for Biogeography and Evolution

The corridor played a central role in shaping Holarctic biogeographic distributions and evolutionary trajectories, influencing clades documented in phylogenies arising from studies at Smithsonian Institution, Kew Gardens, University of Cambridge, and University of Toronto. It explains trans-Atlantic sister-group relationships observed between lineages in Laurasia-derived floras and faunas, underpins hypotheses tested using molecular dating methods from groups studied at Yale University and Stanford University, and frames interpretations of palaeoendemism in Arctic refugia assessed by teams at Universität Zürich and University of Bergen. Understanding the bridge informs conservation paleobiology, paleoceanography, and evolutionary studies at institutions such as Scripps Institution of Oceanography and informs models used by the Intergovernmental Panel on Climate Change for long-term biogeographic responses.

Category:Paleogeography Category:Biogeography Category:Paleontology