Assembling Pangaea – The Complex Morphology of the Laurussia – Gondwana Collision

The Late Paleozoic convergence and collision between Gondwana and Laurentia resulted in along-strike variations in the Alleghanian–Mauritanide–Variscan orogeny during the assembly of the greater part of Pangaea. A series of ca. 380–290 Ma events segmented the orogen into two principal geodynamic domains with contrasting tectonic evolutions. In the northeast, the European Variscan belt records multiple subduction–collisional tectonic events, including indentation by Laurussian and later Gondwanan promontories and by Gondwana-derived terranes. Late-stage events (330–290 Ma) produced strongly curved deformation belts (oroclines), and late- to postorogenic extension. In contrast, the southern Appalachians formed southwest of the promontory collisions where subduction of Rheic Ocean remnants produced a continuous Andean-style orogenic arc that preceded ca. 290 Ma terminal collision. We explain Pangaea amalgamation using a global model of mantle convection like that of modern Earth.