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North Atlantic Land Bridge: Northeastern North America, Greenland, Iceland, Arctic Islands, Northwestern Europe

North Atlantic Land Bridge: Northeastern North America, Greenland, Iceland, Arctic Islands, Northwestern Europe

Chapter:
(p.89) Three North Atlantic Land Bridge: Northeastern North America, Greenland, Iceland, Arctic Islands, Northwestern Europe
Source:
Land Bridges
Author(s):
Alan Graham
Publisher:
University of Chicago Press
DOI:10.7208/chicago/9780226544328.003.0004

The North Atlantic Land Bridge was relatively continuous during the late Cretaceous and Paleogene with warm and moist climates allowing for migration of tropical to warm-temperate elements between the New and Old Worlds. It became disrupted after the Early Eocene Climatic Optimum by promulgation of the Mid-Atlantic Ridge into the North Atlantic and by cooling climates. This is in contrast to the Bering Land Bridge which was discontinuous in the Paleogene becoming more continuous in the Neogene when cooling climates facilitated migration of cold-temperate biotas. The two were complementary routes and together account in part for the diversity of the North American flora, along with the N-S orientation of the mountains which allowed migration in response to climate change rather than extensive extinction as in Europe. The Gulf Stream and the Coriolis Effect also influence movement. The concept of geofloras and the Madrean-Tethyan hypothesis are not supported by land bridge history. The Saqqaq, Benothuk, and Vikings (ca. 844 A.D.) were early inhabitants in NE North America adding to the impact of the earliest immigrants via the NW at 15,000 years ago (Asians), ca. 300 years ago (Bering explorers), and again in the NE by the Spanish (1492).

Keywords:   disruption, mid-Atlantic Range, climates, orientation of mountains, Gulf Stream, vegetation, Paleogene, relationships, geofloras, madro-tethyan

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