The Bavarian Forrest is a mountainous area at the eastern border of Germany, along the borcher to the Czech Republic. This area is geologically called crystalline basement, which impresses the fact that it is the rest of a very old mountain range. In central Europe this kind of crystalline rocks is commonly the basement of younger sedimentary rocks. The rocks are granites or gneiss, which are between 600 and 1,200 Million years old. Here the crstalline rocks are not covered by sedimentary rocks. There are no carbonates, rocks which are subject to solution, so there are absolutely no caves and no karst. Anyway, the geology of this area is very interesting, as it was formed during several very old orogenies, for example the Caledonian Orogeny (500-400Ma) and the Variszian Orogeny (390-270Ma)
An orogeny, the process of mountain formation, is a stress for the involved rocks and result in tectonic modifications of the original rocks. They are folded, lifted and slanted, and vaults were a result of the stress. This vaults were used by ground water to flow deep into the earth, being heated by the earths inner temperature and thus forming huge convection systems. The flowing water dissolved minerals and ores from the rocks, bleached them, and it deposited the minerals in the vaults. High temperature and pressure also transformed the rocks int metamorphic rocks, forming huge amounts of gneiss.
The geology of this landscape influenced the agriculture of this are, and thus also the daily life of the inhabitants. The crstallijne rocks are more or less impermeable and did not react very much with the flora above. But unlike limestone it also did not neutralize the acidity of the soil which was caused by too much water because of the impermeable rocks. The water was damed, there were lakes and many moores. As it is also rather cool with long winters because of the height, the most important agriculture is forestry. The ore vaults were the reason for historic mining activities. Today those depostits are too work intensive to mine, so they are not profitable any more. Some mines were turned into show mines.
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