Variscan orogeny rifted off the north Gondwana margin in early Ordovician. By the end of the Silurian and in Early Devonian times, Baltica and Laurentia drifted towards each other, closing the Iapetus Ocean between them. They collided in the Caledonian orogeny and formed the Caledonide mountains of North America, Greenland, the British Isles and Norway. Seafloor spreading to the south of Avalonia pushed the latter into north Laurentia and thrust up the northern Appalachian Mountains in the acadian phase of the Caledonian orogeny. Contemporaneously the Tornquist Sea between Avalonia and Baltica was entirely closed. Thus Avalonia formed the southern coast of the
Famatinian orogeny part of the orogen as it was subject to metamorphism in the early Paleozoic. To the south in La Pampa Province, outcrops associated with the orogeny are scarce since most of that region has become blanketed by much more recent Quaternary sediments. In Peru's Cordillera Oriental a "Famatinian" orogeny exists which is coeval with the classical Famatinian orogeny found further south. In the time-span from 480 Ma to 435 Ma (Late Cambrian to Silurian) rocks of Cordillera Oriental were deformed and a magmatic arc developed. Towards what is now the east of the Famatinian magmatic arc a Precambrian sedimentary basin