Title: ASSEMBLY OF PANGEA: COMBINED PALEOMAGNETIC AND PALEOCLIMATIC APPROACH
Abstract: A series of paleogeographic time-slices showing step-by-step convergence of Gondwana, Baltica, Avalonia, Laurentia, and intervening terranes in the Early Ordovician–Early Permian time span has been made utilizing apparent polar wander paths (APWPs), constructed on the basis of paleoclimatic (Gondwana) and paleomagnetic (Baltica, Avalonia, and Laurentia) dataset. A destination assembly for the wandering continents was Pangea, reconstructed in so-called A configuration. A modeling of paleogeographic evolution was made assuming actualistic distribution of paleoclimatic belts, present-day lithospheric plate velocities, and the validity of the geocentric axial dipole magnetic field in the Paleozoic. Ockham's razor has been applied in determination of a longitudinal component of an oceanic width between Gondwana and Laurussia. A drift history of some intervening terranes, incorporated into Caledono–Variscan fold belt of Europe is also shown. The terranes are positioned according to paleomagnetic and geologic information, supplemented by some outcomes of paleontological studies. However, the paleogeography of some Cadomian blocks as those incorporated into the Armorica accreted superterrane, Alpine basement or the Silesian Massif is speculative and have had to be interpolated between better time-and-space constrained positions. Combined with available geological data, reconstructions performed in this study leads to the conclusion that the Rheic Ocean could have been up to 2000–2500 km wide domain during the Early Paleozoic. In turn, the Silurian/Devonian Massif Central-Moldanubian Ocean featured variable geometry, depending upon continuosly changing configuration of the Gondwana-derived terranes. At their waning stages, the Rheic and the Massif Central-Moldanubian Oceans were the second-order domains within a 1500–2000 km wide Theic-ProtoTethys Ocean, separating Laurussia and Gondwana during the Devonian. A sense of the relative movements of the continents confirms the view that the convergence of Gondwana with respect to Laurussia was generally dextrally oblique in the Late Paleozoic. Although paleoclimatic data controlling paleogeographic position of Gondwana represent different types of information than these for Laurentia/Baltica, an inferred story of the Gondwana and Laurussia convergence and Pangea assembly may incorporate a wide spectrum of geological observations.
Publication Year: 2003
Publication Date: 2003-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 33
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