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Origin

The origin of today's mountain topography is debated by geologists. Geologically, the Scandinavian Mountains are an elevated, passive continental margin similar to the mountains and plateaux found on the opposite side of the North Atlantic in Eastern Greenland or in Australia's Great Dividing Range. The Scandinavian Mountains attained its height by tectonic processes different from orogeny, chiefly in the Cenozoic. A two-stage model of uplift has been proposed for the Scandinavian Mountains in South Norway. A first stage in the Mesozoic and a second stage starting from the Oligocene. The uplift of South Norway has elevated the westernmost extension of the sub-Cambrian peneplain which forms part of what is known as the Paleic surface in Norway. In South Norway, the Scandinavian Mountains had their main uplift phase later (Neogene) than in northern Scandinavia which had its main phase of uplift in the Paleogene. For example, the Hardangervidda uplifted from sea level to its present 1200–1100 m in Early Pliocene times.

The various episodes of uplift of the Scandinavian Mountains were similar in orientation and tilted land surfaces to the east while allowing rivers to incise the landscape. Some of the tilted surfaces constitute the Muddus plains landscape of northern Sweden. The progressive tilt contributed to create the parallel drainage pattern of northern Sweden. Uplift is thought to have been accommodated by coast-parallel normal faults and not by fault-less doming. Therefore, the common labelling of the southern Scandinavian Mountains and the northern Scandinavian Mountains as two domes is misleading. There are divided opinions on the relation between the coastal plains of Norway, the strandflat, and the uplift of the mountains.

Unlike orogenic mountains, there is no widely accepted geophysical model to explain elevated passive continental margins such as the Scandinavian Mountains. Various mechanisms of uplift have, however, been proposed over the years. A 2012 study argues that the Scandinavian Mountains and other elevated passive continental margins most likely share the same mechanism of uplift and that this mechanism is related to far-field stresses in Earth's lithosphere. The Scandinavian Mountains can according to this view be likened to a giant anticlinal lithospheric fold. Folding could have been caused by horizontal compression acting on a thin to thick crust transition zone (as are all passive margins).

Alternative lines of research have stressed the role of climate in inducing erosion that induces an isostatic compensation; fluvial and glacial erosion and incision during the Quaternary is thought to have contributed to the uplift of the mountain by forcing an isostatic response. The total amount of uplift produced by this mechanism could be as much as 500 m. Other geoscientists have implied diapirism in the asthenosphere as being the cause of uplift. One hypothesis states that the early uplift of the Scandinavian Mountains could be indebted to changes in the density of the lithosphere and asthenosphere caused by the Iceland plume when Greenland and Scandinavia rifted apart about 53 million years ago.