Avalonia

Avalonia Avalonia or is a terrane of Paleozoic , taking its name from the Avalon Peninsula ( Newfoundland ), including the current Poland 's north-west of Germany in the north, the Netherlands , the Belgium , the extreme north of France , the England and Wales , the Irish southern half southeast of Newfoundland , the northern half of the Nova Scotia and eastern New England. A distinction is generally the western Avalonia (current Newfoundland , Nova Scotia and New England ) and East Avalonia (current Irish Southern England and Wales , Belgium , Netherlands , Nord-Pas-de- Calais , Picardy and the Ardennes , northern half of Germany and north-west Poland )

History

At the end of the Proterozoic , the seafloor dives under the supercontinent Gondwana in the phenomenon of subduction , creating the orogeny Cadomian (650-550 Ma). There are original Cadomian rocks buried across southern Britain. What becomes Avalonia separated from Gondwana there are about 490 million years, then joined the continent of Baltica , and finally, with it, colliding with the continent of Laurentia in Silurian and Devonian to form supercontinent Laurussia during the Caledonian Orogeny. After the orogeny Hercynian , who sees the collision of Gondwana against the southern margin of Laurussia, Avalonia is part of the supercontinent Pangaea. In the Cretaceous , when Pangea broke up, Avalonian land are divided into two by the opening of the Atlantic Ocean.

Second hypothesis

However, some geologists believe that only the western part of Avalonia he would have gone out of my 490-ya Gondwana and the eastern part do next after 40 million years, accompanied by the south-west of the Iberian Peninsula , the form of the Avalon terrane-Meguma Southeast Portugal colliding with Laurussia during the Hercynian orogeny.

External Links

• [1] Geology Jamestown (Rhode Island) (en)
• [2] Paleos (fr)
• [3] University of Northern Arizona (en)