Plate tectonic movements during the Variscan orogeny assembled together four major and two to three lesser tectonostratigraphic terranes. The assemblage of the terranes ought to have involved the closure of at least two ocean basins containing oceanic crust and marine sediments. This is reflected in the ophiolites, MORB-basalts, blueschists and eclogites that occur in-between terranes. Various terranes of the Sudetes are likely extensions of the Armorican terrane while other terranes may be the fringes of the ancient Baltica continent. One possibility for the amalgamation of terranes in the Sudetes is that the Góry Sowie-Kłodzko terrane collided with the Orlica-Śnieżnik terrane causing the closure of a small oceanic basin. This event led to obduction of the Central Sudetic ophiolite in the Devonian period. In the Early Carboniferous the joint Góry Sowie-Kłodzko-Orlica-Śnieżnik terrane collided with the Brunovistulian terrane. This last terrane was part of the Old Red Continent and could correspond either to Baltica or the eastern tip of the narrow Avalonia terrane. Also by the Early Carboniferous the Saxothuringian terrane collided with the Góry Sowie-Kłodzko-Orlica-Śnieżnik terrane closing the Rheic Ocean. Once the main phase of deformation of the orogeny was over basins that had formed in-between metamorphic rock massifs were filled by sedimentary rock in the Devonian and Carboniferous periods. During and after sedimentation large granitic plutons intruded the crust. Viewed in a map today these plutons make up about 15% the Sudetes. Granites are of S-type. The granites and grantic-gneisses of Izera in the west Sudetes are disassociated from orogeny and thought to have formed during rifting along a passive continental margin. The Karkonosze Granite, also in the west Sudetes, have been dated to have formed c. 318 million years ago at the beginning of the Variscan orogeny. The Karkonosze Granite is intruded by somewhat younger lamprophyre dykes. A NW-SE to WNW-ESE oriented strike-slip fault —the Intra-Sudetic fault— runs through the length of the Sudetes. The Intra-Sudetic fault is parallel with the Upper Elbe fault and Middle Oder fault. Other main faults at the sudetes are also NW-SE oriented, dextral and of strike slip type. These include the Tłumaczów-Sienna Fault and the Marginal Sudetic Fault. Volcanism and thermal waters There are remnants of lava flows and volcanic plugs in the Sudetes. The volcanic rocks making up these outcrops are of mafic chemistry and include basanite and represent episodes of volcanism in the Oligocene and Miocene periods. Volcanism affected not only