Norway Geology and Morphology

By | December 17, 2021

The surface of Norway is almost entirely occupied by high lands; there are few low-lying areas and there are no really wide plains; where there are no mountains, the terrain is hilly. To South of the 62 ° Norway the Scandinavian mountains occupy only the western part of the country; at Norway of this latitude it occupies its entire width. The axis of the greater heights runs, in practice, parallel to the coast.

Geologically, Norway belongs to Fennoscandia, a large territory of primitive rocks which were later covered by stratified rocks. Archean crystalline rocks, formed largely of gneiss and granite, form the base: 1. in most of southern Norway; 2. in the northwestern part of the southern mountainous region from Bergen to Namdalen (interrupted on the west coast and at the mouth of the Trondheimfiord by small areas of sandstone); 3. in southern Finnmark. Two species of pre-Cambrian sandstone, in Finnmark and in the central-eastern part (sparagmites), represent probable remains respectively of an ancient glaciation and a period of arid climate. For Norway geography, please check franciscogardening.com.

The demolition work pushed to the base level determined the formation of the pre-Cambric penepiano, which was submerged by the Cambrian-Silurian ocean and covered with layers of sandstone, shale and limestone of varying thickness. Apart from the mountainous areas, these Paleozoic rocks exist only in positions sufficiently protected against denudation, especially as sunken blocks (eg: the Oslo region). During the Siluric and Devonico periods, the Norwegian mountain range was formed by the folding of the Paleozoic layers, accompanied by intrusions, seismic fractures, and the violent gush of eruptive masses that crossed the rocks and produced phenomena of regional metamorphism.

The series of eruptive rocks in the Oslo sinking zone is the result of volcanic action and gigantic displacements in the Hercinian (Permian) era. In Norway, Mesozoic rocks are found only in small deposits on the island of Andoya and contain a few strands of coal, thin and of no economic importance.

Towards the end of the Tertiary, the bare mountain range with its mature surface was uplifted with a movement that peaked along the west coast. This process, together with the formation of fractures, probably explains the intensity that the glaciation reached in this region. It is probable that the mass of the ice acted on a system of valleys that had already been excavated by river erosion before the Quaternary. During this period the whole country was covered by a huge layer of ice.

The topographical aspects of both high and low regions are shaped by glacial erosion; but the importance that fluvial erosion had both before the Quaternary and during the more or less ice-free periods of the interglacial epochs should not be devalued. The entire mountain range is furrowed by valleys similar to gorges, whose cross section tends towards the shape of a U, while the longitudinal section presents frequent differences in height due to thresholds and depressions in the form of steps.

The secondary valleys are usually hanging over the main ones, into which they flow, so that, at the confluence, waterfalls are produced. At the head of the valleys there are often raised cirques, called botner in Norwegian. Not infrequently separate systems of valleys communicate with each other by means of open passages which are very useful as communication routes. A very frequent topographical aspect are the so-called roches moutonnées.

Barely 10% of the country is covered by detrital material, as the largest deposits of Quaternary glaciers are found in the North Sea and on the plains of central Europe, while the Scandinavian peninsula was above all a field of erosion. The deposits above the ancient marine limit can be classified as follows: bottom moraines, which cover the hills and even the plateaus; layers of clay and sand with clay deposits, which occupy the bottom of the valleys, once river beds; sands and breccias deposited in lakes embanked by glacial leftovers in the southern districts of the center; peat bogs in depressions (crushed rocks are rare: they are found particularly in areas with easily decomposable shales).

By far the most important glacial deposits, from an economic point of view, are those below the ancient sea level and with a thickness that reaches 50 m. they were deposited on the front of the glaciers during that period of great accumulation due to the weight of the ice crust. They currently fill the bottom of the valleys or form terraces of sand and clay. These deposits and the ancient beaches, now above sea level, rise in height from the coast towards the interior, indicating a strong accumulation of deposits in the central part of the land mass covered by ice.

The highest ancient sea level was observed at Norway of Oslo at 221 m. on the current level. The oscillations of the terrestrial ice during the melting period are marked by successive series of terminal moraines.

The uplift of the land during the postglacial era was interrupted by several transgressions of the sea: the clearest marine deposit is that of Tapes, Norway of Oslo, located at 70 m. on the current sea level. Examination of sections of the marshes revealed a succession of different phases starting from the ice age; of these phases, some belong to the dry “continental” type, others are of the humid “Atlantic” type (1. boreal; 2. Atlantic; 3. subboreal; 4. sub-Atlantic).

A cross section of Norway results in an oblique profile from W to E: the western slope with respect to the axis of maximum heights is extremely steep, compared to the eastern one. This fact gives the key to understanding important historical as well as geographical features. Southeastern Norway has the largest low-lying and flat regions, between 100 and 500m. high, regions which by their nature are wooded. The limits between these plains and the high regions can be easily distinguished by means of a sharp step marked topographically by the following series of peaks: Lifjell, Gausta, Norefjell, Storrusten, Synesfjell, Prestkampen, Høgtind, in the order of succession from south to north.

North of the Trondheim depression, only the western side belongs to Norway, since in this region the axis of the greatest heights practically coincides with the political border. Immediately to the West of the level Finnmarken plain, located at 200-300 meters above sea level, the Lyngenfjellene mountain range begins, a series of towering peaks, which, with the Jegge-Varre, reaches 1845 m. A SW. the Lofoten range stretches across a series of islands. The aspect of these mountains is famous for the wild and tormented forms, with peaks of more than 1000 m. which rise directly from the sea level. The area covered by glaciers is more considerable: the largest area is the Svartisen, near the Arctic Circle, with an area of ​​489 sq km. It is customary to divide the mountainous region in S. di Trondheim into two parts: Dovre, the northern one, oriented from E. to W., and Langfjellene, (Monti Lunghi), the southern, oriented from Norway to S. However, these are always parts of the same relief. In the region closest to the coast, the mountains take on alpine forms: the Romsdalsfjellene, with the Romsdalshorn (1515 m.); the Sognefjellene, with the Horungene and Skagastøl peaks (2404 m.). Here is located the frozen area of ​​Jostedal which extends for 855 square kilometers. and culminates in Lodalskåpa (2089 m.). At S. del Hardangerfiord there is the other iced field of Folgefomna; to S. of Mount Hallingskarvet (1933 m.) and to E. of Folgefomna is the Hardangervidda, which is the largest high mountain plateau that exists in Europe. The eastern side has this plateau character everywhere (vidde).

The highest peaks in Norway rise on these desolate regions: Snehætta (2286 m.), Rondane (2183 m.) And all the peaks belonging to Jotunheim, among which the highest are Galdhøppigen (2469 m.)) and the Glittertind (2451 m.): the latter with a snow cap currently reaches 2481 m. and is therefore the highest peak in Norway. For more information regarding the geology and morphology of Norway, see. under Scandinavia.

Norway Geology