Читать книгу Biogeography in the Sub-Arctic - Группа авторов - Страница 14

Brian G. J. Upton

School of GeoSciences, University of Edinburgh, UK

The northern landmasses, namely North America, Greenland and Europe/Asia were part of one global super‐continent in the lower Palaeozoic, approximately 420–430 million years (Ma) ago. This super‐continent (Pangaea) resulted from continental collisions. Driven by convective flow deep in the interior of the Earth it is the nature of continents to break apart, re‐join and to come apart again. Such a separation and amalgamation constitutes ‘the Wilson Cycle’, which takes several hundred million years to run its full course. No sooner had Pangaea come into existence than it became subject to tectonic stresses that tended to disrupt it. The North Atlantic Ocean is a late product of the disintegration of Laurasia, a part of Pangaea, which split to form North America, Greenland, Europe and Asia. Continental separation had begun in the south Atlantic region at ca 130 Ma and spread north by 60–50 Ma.