The Baltic shield is the name of the most ancient pre-Baikal powerful folded region in the Alps. Throughout the entire period of its existence, it steadily rises above sea level. The Baltic shield is prone to erosion. They reveal the 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. The structures of Caledonia-Scandinavia are adjacent to it. They moved on to the crystalline rocks of the folded region.
Karelia, Finland, Sweden, the Kola Peninsula covers the Baltic Shield. A large ledge lies in the Murmansk and Leningrad region. Almost the entire Scandinavian peninsula is occupied with it.
Landforms
Under the influence of glaciation, a shield relief was formed. Many ponds here are framed by winding coasts. Crashing into the land, they form multiple bays and islands. The northern part of the folded uplift is formed from ancient crystalline schists and igneous rocks. Structures everywhere come to the surface. They are only in some places covered by weak quaternary raincoats.
The crystalline Baltic shield has not been covered by sea waters since the Lower Paleozoic era, due to which it was destroyed. Crumpled folds with a complex structure acquired excessive hardness and brittleness. Therefore, when the earth's crust fluctuated, cracks appeared in it, which became places of a break. The rocks fell apart, forming massive blocks.
Relief of the Russian platform
Glaciers crawling from the slopes of the Scandinavian mountains destroyed the crystalline foundation, taking loose rocks beyond the borders of the Russian platform. Soft structures, accumulating, formed moraine deposits.
The melting glacier energetically plowed the Baltic Shield for a long time. The relief shape on the ledge acquired accumulative outlines. In the folded area appeared oz, drumlins and so on.
Relief of the Karelo-Kola block
The Kola Peninsula and Karelia are composed of rocks that are practically not washable. They are impervious to water. Although the local rivers are characterized by abundant surface runoff, they could not develop valleys. The river channels are cluttered here with rapids and waterfalls. Water, pouring numerous hollows, formed on the folded uplift of the lake.
The relief in this part of the shield is heterogeneous. A mountain belt stretches across the west of the Kola Peninsula, between which there are major depressions between the ridges. The highest mountain peaks rise above the Khibiny and Lavozersky tundra.
The eastern side of the peninsula is occupied by a slightly hilly plateau, overhanging the waters of the Bagra Sea. This small hill merges with the lowlands that framed the White Sea.
In the region of Karelia, the Baltic shield possesses characteristic landscapes. The relief shape of the folded area in this place is denutational-tectonic. The crust here is very dissected. The depressions along which swamps and lakes are scattered alternate with rocky ridges and hills.
Near Finland spread the hill of Maanselkä. Its surface is excessively dissected. On the folded uplift, the relief of glacial, accumulative, and exational configurations is everywhere noted. The Baltic shield is dotted with ram foreheads, large boulders, ozas, valleys and moraine ridges.
Geological structure
The folded uplift is divided into three geo-segments: Karelian-Kola, Svekofensky and Sveko-Norwegian. In Russia, the Karelian-Kola region and the southeastern territories of the Svekofennsky block are almost entirely located.
The geological structure of the Karelo-Kola segment is not the same as that of the White Sea region, characterized by extensive developed Proterozoic formations. This is due to three reasons: belonging to different blocks of the geosyncline, historical development, characterized by the depth of erosive sections. The Karelian-Kola segment, in contrast to the White Sea block, is more strongly omitted.
A common feature of the tectonic structure of the segments is the northwestern strike of the regions. The complexes formed by rocks and folds only occasionally allow themselves to deviate in the meridian or latitudinal direction.
Complexes and folds, fan-shaped to the south-east, converge in the north-west. Minerals are genetically related to the ancient igneous and metamorphic rocks that formed the Baltic shield. The tectonic structure along the segment boundaries is represented by regional deep faults.
Under the control of splits is the location of Precambrian intrusive complexes and their metallogeny. The rocks are grouped into belts extending to the northwest. They are parallel to the common sites of Precambrian geostructures.
