The most ancient pre-Baikal powerful folded area in the Alps is called the B altic Shield. Throughout the entire period of existence, it steadily rises above sea level. The B altic Shield is subject to erosion. They reveal deep zones in the granite-gneiss belt of the earth's crust.
Shield location
A massive ledge captures part of the northwestern expanses of the East European Platform. It is adjacent to the structures of Caledonia-Scandinavia. They advanced on the crystalline rocks of the folded area.
Karelia, Finland, Sweden, the Kola Peninsula is covered by the B altic Shield. A large ledge runs through the Murmansk and Leningrad regions. Almost the entire Scandinavian Peninsula is occupied by it.
Landforms
The relief of the shield was formed under the influence of glaciations. Many bodies of water here are framed by winding coastlines. They, crashing into the land, form multiple bays and islands. The northern part of the folded uplift is formed from ancient schists and igneous rocks. structurespopping up all over the place. Only in some places they are covered by weak cloaks of Quaternary deposits.
The crystalline B altic Shield has not been covered by sea waters since the Lower Paleozoic era, which is why it was destroyed. Crumpled folds with a complex structure have become excessively hard and brittle. Therefore, when the earth's crust oscillated, cracks appeared in it, which became fracture points. The rocks fell apart, forming massive blocks.
Relief of the Russian platform
Glaciers sliding from the slopes of the Scandinavian mountains destroyed the crystalline foundation, carrying loosened rocks beyond the borders of the Russian platform. Soft structures, accumulating, formed moraine deposits.
The melting glacier for a long time energetically furrowed the B altic Shield. The shape of the relief on the ledge acquired accumulative outlines. Ozes, drumlins, etc. appeared in the folded area.
Relief of the Karelian-Kola block
The Kola Peninsula and Karelia are composed of rocks that are practically not amenable to erosion. They are impervious to water. Although the local rivers are characterized by abundant surface runoff, they have not been able to develop the valleys. Riverbeds are cluttered here with rapids and waterfalls. Water, flooding numerous depressions, formed a lake on a folded uplift.
The relief in this part of the shield is not uniform. A mountain belt stretches along the west of the Kola Peninsula, between the ridges of which large depressions are located. The highest mountain ranges rise above the Khibiny and Lavozero tundras.spades.
The eastern side of the peninsula is occupied by a slightly hilly plateau hanging over the waters of the Crimson Sea. This small hill merges with the lowland that frames the White Sea.
In the region of Karelia, the B altic Shield has characteristic landscapes. The topography of the folded area in this place is denutation-tectonic. The earth's crust is strongly dissected here. Depressions, along which swamps and lakes are scattered, alternate with rocky ridges and hills.
The Maanselkä upland stretches near Finland. Its surface is excessively dissected. On the folded uplift, relief of glacial, accumulative and exarative configurations is everywhere noted. The B altic Shield is dotted with sheep foreheads, large boulders, eskers, valleys and moraine ridges.
Geological structure
The fold uplift is divided into three geosegments: Karelian-Kola, Svecofennian and Sveco-Norwegian. Almost entirely in Russia is the Karelian-Kola region and the southeastern territories of the Svecofenn block.
The geological structure of the Karelian-Kola segment is not the same as that of the White Sea region, which is characterized by extensive developed Proterozoic formations. This is due to three reasons: belonging to different blocks of the geosyncline, historical development, differing in the depth of erosional sections. The Karelian-Kola segment, in contrast to the White Sea block, is more strongly omitted.
The common feature of the tectonic structure of the segments is the north-western strike of the regions. Complexes formed by rocks and folds only occasionally allow themselves to deviate in the meridian or latitudinal direction.
Complexes and folds fan out to the southeast and converge in the northwest. Minerals are genetically interconnected with ancient igneous and metamorphic rocks that formed the B altic Shield. The tectonic structure along the boundaries of the segments is represented by regional deep faults.
The location of the Precambrian intrusive complexes and their metallogeny are under control of the splits. The rocks are grouped into belts extending to the northwest. They are parallel to the places of common occurrence of Precambrian geostructures.
Deposits
The B altic Shield is rich in deposits. Minerals here are distributed along the belts. Particular attention is focused on three of them. Copper-nickel ores are hidden in the Flower Belt of the Kola Peninsula. The structure of the Windy Belt, spread over the Karelian and Arkhangelsk lands, is being actively studied. In the Karelian-Kola segment, a belt with ferruginous quartzites, kyanite schists, and various pegmatites is interesting. The accumulation of rocks is regulated by lithological-stratigraphic and structural-tectonic aspects.
