Plate tectonics help us to explicate the procedure of folding. Harmonizing to the theory of home base tectonics. the earth’s crust is broken up into subdivisions called home bases. These home bases float on the semi-molten mantle. Thermal convection currents in the mantle retarding force these home bases in different waies ensuing in tectonic activity.
Folding occurs when stone beds that were originally horizontal are dead set into a series of wave-like creases. As a consequence of this hit of the earth’s tectonic home bases. the stones are folded and uplifted and fold mountains are created. This procedure is known as orogeny. There have been three major periods of fold mountain edifice. the Caledonian. Armorican and Alpine periods.
The Caledonian period of turn uping took topographic point about 400 million old ages ago when the Eurasiatic home base and the American home base collided. The mediate ocean floor was subducted under both continents and the seafloor deposits were buckled up to organize the sedimentary stones of the Caledonian Fold Mountains.
The Appalachian mountains in North America. the mountains of Norway. Sweden and Scotland. and in Ireland the Dublin-Wicklow mountains and the mountains of the West and North-west were formed as a consequence of this hit.
The Armorican period of folding occurred about 250 million old ages ago when home base tectonics resulted in a hit between the Eurasian and African home bases. Examples of Armorican crease mountains include the Vosges mountains in France and the Black Forest mountains in Germany. These mountains have an East-West tendency as the compaction came from the South. The ridge and valley landscape of Munster is a consequence of Armorican folding. During the Armorican foldings sedimentary stones in Munster were folded to organize ridges of sandstone and vales of limestone. The limestone was easy eroded from the fold anticlines and they are seen today as sandstone mountain ridges such as the Mac Gillycuddy Reeks.
Plate motion is besides responsible for the formation of the Himalayan mountains in Asia. the Alps in Europe. the Andes in South America and the Rocky mountains in North America. These fold mountains were formed as the African home base collided with the Eurasiatic home base. These are the youngest fold mountains. formed 60 million old ages ago. They are known as Alpine crease mountains. The Himalayan mountains are still increasing in size and volcanic and temblor activity in the part shows that these tectonic home bases are still clashing.
