There are many different processes on Earth, including geological ones. These are the movements of lithospheric plates, mountain building processes, and so on. Our planet has undergone many transformations throughout its existence. Specialists have identified several historical periods of tectogenesis - sets of tectonic processes, one of which is the Caledonian folding.
Definition and timing
The name was given by the European scientist Bertrand in the 19th century and comes from the ancient Latin name for Scotland - Caledonia, since it was there that it was discovered. Caledonian folding is a complex of tectonic phenomena in the Paleozoic (510-410 million years ago).
Characteristic movements of the lithosphere in the period under consideration were: active folding, orogeny and granitization. They caused the formation of typical mountain ranges - the Caledonides.
The very first stages of the Caledonian folding began in the middle of the Cambrian. The central stages covered several geological periods: from the end of the Ordovician to the middle of the Devonian.
General characteristics of periods
In the Cambrian period the climate was sultry;local icing was also observed. Transgression took place almost everywhere. Sedimentary and marine layers predominated. There was a retreat of the seas from certain areas (for example, the Russian platform), the appearance of mountain systems of the Caledonian folding (Sayans, Appalachians, etc.). The fauna was characterized by the emergence of very small skeletal organisms (less than 1 cm).
In the Ordovician period, the climate became warm, tropical; the end of this period of time was marked by glaciation. There has been a significant rise in sea levels in all areas except Gondwana. Among the rocks were common carbonate and marine sediments, volcanic rocks. There was a very significant accumulation of organic matter. The organic world has expanded significantly: the number of varieties of living beings has tripled. By the end of the period, glaciation occurred, which led to the global extinction of many living organisms.
The Silurian time period was characterized by a warm climate, which then became waterless and sultry. At the dawn of this time frame, the melting of glaciers caused significant transgression. The Silurus ended with an extensive retreat of the sea. Clay layered minerals, carbonate marine deposits and rocks of volcanic origin predominated. The early Devonian period was characterized by aridity. The continents were covered with mountain systems of the Caledonian folding, divided by intermountain depressions. In the Lower Devonian, the climate became tropical. The rocks were characterized by massive redsandstones, gypsum, s alts, organogenic carbonate rocks. The Devonian was a period of relative geological stability. The organic world was enriched with new genera and species: the first amphibians, spore plants. Frequent hydrogen sulfide pollution of water bodies caused mass extinction of marine biota.
Regions and mountain systems
Which mountains in the Caledonian folding are studied in school lessons? These are the Andes, the Western Sayan, the Mongolian Altai, the Ural Mountains. Among other things, they include the mountainous territories of Eastern Australia, Greenland, Newfoundland and the Northern Appalachians.
Regions of Caledonian folding in the European region are represented by the Caledonides of Great Britain, some parts of Scandinavia. On the Asian territory, the following Caledonides are distinguished: Kazakh, Chinese, Sayan and Altai. Land areas with mountainous terrain are located in the Chukotka region, in Alaska, in the Andes.
Features
Folded mountain systems are inherent in the incompleteness of education. The most complex structure is characteristic of the Scottish, Scandinavian and Greenlandic Caledonides.
A feature of the vast areas of the earth's crust, recently appeared on the site of the Caledonides, was high activity. At the end of the phase of extinction of parallel movements and smoothing of the planet's surface, these areas were subjected to geological stimulation in the Lower Paleozoic.
The most characteristic features of the Caledonides are inconsistent rock deposits, as well asaccumulation of massive red layers.
Characteristic minerals
The locations of ores of Fe, Ti, Au, Mo are interconnected with the processes taking place in the territories of the Caledonian folding.
Asbestos, talc, magnesite and, in places, chromium, platinum, nickel and native copper are also quite typical. Hydrosilicate deposits of iron ores, hydrothermal deposits of gold, pegmatites and quartz veins with wolframite and molybdenite are known.
The main minerals in the Cambrian period were: oil - Russia (Irkutsk), Sahara, B altic; rock s alt - Siberia, India. Phosphorites were concentrated in Central Asia, China and Vietnam; asbestos - in Tuva; bauxite - in the Eastern Sayan.
Ordovician was rich in oil - USA; oil shale - the B altics; iron ore - Western Sayan, Canada. Copper and cob alt were present in Norway.
