1988 Articles

Silurian-Permian palaeocontinental reconstructions and circum-Atlantic tectonics

Kent, Dennis V.; Keppie, J. D.

On the basis of the palaeomagnetic record, supplemented by constraints provided by faunal and tectonic information, reconstructions involving Laurentia, Baltica, Gondwana and numerous continent-like fragments and terranes within the circum-Atlantic Palaeozoic orogenic belts are made for three critical time intervals, late Silurian, early Carboniferous and late Carboniferous-early Permian, all of which bracket important phases of tectonic activity. The late Caledonian-Scandian-Acadian-Ligerian orogenies are due to the predominantly E-W final closure of Iapetus. This phase was followed in mid-Devonian times by a major sinistral megashear along the orogen which eliminated latitudinal separations and resulted in a Pangea-like assembly by the latest Devonian. The final phase involved a rotation of Gondwana with respect to the assembled Euramerican landmass, expressed as late Variscan-Hercynian dextral shear from central Europe to northeastern N America and culminating in the late Carboniferous-Permian Alleghanian orogeny in the Appalachians from New England S and in the Mauritanides.