Baltic Shield

Baltic shield is called the larger of the two regions of Europe in which the geologically ancient core of the continent is revealed today. It covers most of the region known as Fennoscandia and dips to the southeast at the Eastern European panel from. Its rocks are predominantly crystalline ( gneiss, granite and slate ) and witness the formation of Ur - Europe ( Baltica ) from individual small continents during the Precambrian. The second and much smaller European Shield region is the Podolic shield.

Formation

The earlier, unfolded billion before at least 1 year mountains were eroded since their formation to a relatively flat hull Mountains.

The Baltic Shield covers most of the Scandinavian peninsula (except the Scandinavian Mountains), Finland, Eastern Karelia and the Kola Peninsula. The continental core was firmly welded by multiple Precambrian folds and metamorphoses.

The Baltic shield was at least the entire Phanerozoic through always in a moderate elevation, and therefore a high area. The ballast of kilometers thick ice sheet that covered the plate over the past two million years (Pleistocene ) repeatedly, but caused a slight sinking of the earth's crust into the mantle. Since the re- disappearance of the ice sheet about 10,000 years ago, the plate raises because of the reduced pressure load amplified ( Postglacial land uplift ), which is clearly visible on the coasts of the Baltic Sea. This effect allows for geophysical conclusions on the elasticity of the upper mantle.

Tectonic structure

Due to the predominantly highly metamorphic rocks of the Baltic shield deciphering its geological history was hampered for a long time. Only the use of radiometric dating methods to reconstruct the actual age conditions within the Baltic shield succeeded. Thus, it was found that the Baltic Shield of several rock provinces of different ages is composed representing different orogeny cycles ( Orogenzyklen ).

The measured radiometric age data allowed a subdivision of the Baltic shield from northeast to southwest into the following areas:

  • Saamiden - orogenic embossing mainly from 2.6 to 2.8 Ga ( especially Kola Peninsula, Karelia and the eastern central Finland)
  • Belomoriden - embossed in front of around 2 Ga ( location within the Saamiden in the area of the White Sea )
  • Svekokareliden - embossing before about 1.8 Ga, further division into Kareliden in the north and in the south Svekofenniden ( SW, NW - Finland and Sweden - NO )
  • Svekonorwegiden - embossed in front of around 1 Ga ( SW Sweden and Norway )
Craton Shield (geology) Ukrainian Shield Integrated Authority File
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