Giant Mountains (German Isergebirge, Polish Góry Izerskie, slang also called Jizerky) are geomorphological total and the northernmost mountain range of the Czech Republic. The mountain range was named after the Jizera River, which springs on the slopes of Smrk, the highest mountain in the Czech part of the mountains. It was formerly regarded as the western tip of the Giant Mountains. Its substantial part is located in Poland, where the highest peak of the whole Jizerské Mountains is the Wysoka Kopa (1126 m).
Around the mountains are the towns of Liberec, Frýdlant, Raspenava, Nové Město pod Smrkem, Świeradów-Zdrój, Szklarska Poręba, Desná, Tanvald and Jablonec nad Nisou. In terms of territorial divisions, the Czech part of the mountain range is located in Liberec, Jablonec nad Nisou and Semily Liberec districts.
Pro Giant Mountains are characteristically aligned surfaces in the top areas forming high-lying plateaus, from which granite peaks are raised and there are shallow depressions containing numerous peat bogs.
Giant Mountains is adjacent to the following geomorphological units (northwards according to the clockwise direction): Frýdlantská pahorkatina, Kotlina Jeleniogórska, Giant Mountains, Krkonoše Mountains, Ještědsko-kozákovský ridge and Žitavská basin. The surrounding units (except the Giant Mountains) are Giant Mountains sharply separated. For example, the northern slope to the Frýdlant Hill, rising above the Smědé valley, has a relative height of 500 m. In the northeast, the High Jizera Ridge above the Kwisy Valley and Malé Kamienné towers similarly. In the south, the mountain range passes smoothly into the Liberec basin, but it is closed by 18 km by a long Black Crest Ridge.
In the Jizera Mountains, there are a total of 28 thousands (peaks with a height above 1000 meters and prominence over 5 meters). Some sources do not mention White Death (1007 m) lying between Holubník and Černá hora, Milíř (1003 m) located south of Jizera and Smrek, the secondary peak of Smrk just beyond the Czech-Polish border. On the contrary, it is sometimes mentioned Świeradowiec, but it is not a separate mountain, but only a retreat of the Łużce.
In the Czech part of the mountains there are 15 thousands of mountains and most of them are finished with distinctive rock formations. They also have relatively deep saddles - 7 has a prominence of at least 100 m. In the Polish part there are 13 thousands, including the highest Wysoke Kopy, however, their appearance is different, the rock formations are much less, the mountains are mostly flat and shallow saddles. Besides Wysoke Kopy, no peak is more prominent than 60 meters.
The following table lists all thousands of altitudes, prominences and isolation. Interestingly, Jizera has a higher prominence than Smrk, the highest mountain in the Czech part of the mountains. On the contrary, Smrk has a higher isolation than Wysok Kopa, the highest mountain of the whole Jizera. Another attraction is the prominence of Černý vrch, which is with height 1026 m to 17. highest, yet it's 4. the most prominent one-thousandth of Jizera.
By the end of the proteozoic by the Assynth wrinkle, a massive mountain formed by tortures and fylity arose in the territory of today's Jizera Mountains. However, during the following 200 millennium, this mountain was almost aligned, and in the Silurian, this area was flooded by the sea. Throughout this period, two plutons, which today form the basis of the mountain range, appeared on the surface. The basilica was consolidated in one block by Kaleon's folding. Today's shape of the relief was formed by two other processes: Hercynian folding and Saxon movements in Tertiary. It was during this period that there were breaks that they were Giant Mountains highlighted. A broken slope has been preserved, for example, at the northern foot of the Špičák, Ořešník, Frýdlantské battlements.
The dominant rocks of today's massif are granite rocks - granite. They came to the surface by exposing two perennial plutons. From these granite bodies there is an older Lusatian pluton, which reaches the mountains in the northwest by the so-called rumba granite. During its solidification, this pluton transformed the heat and pressure of the older rock - slate - into crystalline slate, which forms, for example, a strip of clamps in the northeast of the mountains. In these terminals there was later redness (tin deposits at Nové Město pod Smrkem) and later also springs of mineral springs (Lázně Libverda, Czerniawa Zdrój, Świeradów-Zdrój). The limestones and dolomites forming the Vapenny vrch at Raspenava were converted into marble. The most transformed rocks are the Jizera ortholes forming the Polish High Ridge of Jizera and Smrk Mountain. Above the New Town there is a deposit of another crystalline slate - leptinate. Transformed rocks are also the iron-bordel shale and quartz (White Rock at Příchovice).
The second, Krkonoše-Jizerská pluton is roughly an area from Chrastava to Sněžka. It has been carbonized and its granite forms the majority of Jizerskohorské rock formations. In tertiary hills, mineral springs added, especially basalt. The most massive basalt bodies are Bukovec nad Jizerkou and Buková near Jiřetín. During the quarter, the Jizera Mountains were glaciated only in places, the continental glacier stopped at their northern foothills. Nevertheless, the glacier of the Jizera Mountains influenced it. As a result of frost weathering, there have been departments such as frost chambers and rock walls. Other interesting rock formations in the mountains are rocky bowls, vicaras and rock pitches.
Thanks to their location the Jizera Mountains have a very dense network of watercourses. The ridges of the mountain range lead to a divide between the Baltic Sea and the North Sea. From the west and southwest, the water of the Lužická Nisa flows through the Zittau basin into the Baltic Sea. One of their tributaries is Směda, draining the north of the mountain range. Other important tributaries are Jeřice, Řasnice and Lomnice. On the Polish side, there are significant rivers Bobr, Kamienna and Kwisa. The east and southeast of the area is drained by Jizerou into the Elbe and thus to the North Sea. Its most important tributary is Kamenice.
Water peat bogs are of great importance for the water regime. The peat bog, which is the dominant plant of highlands, can hold large amounts of rainwater in its cells - up to twenty times its own weight. This affects the evaporation and re-humidification of the mountain microclimate. At the same time it also delays the spring runoff.
The only natural water bodies of the Jizera Mountains are peat ponds and pools. By the end of 19. century, only small, purpose-built waterworks were built in the mountains to serve the sawmills and glassworks. After the catastrophic flood of 29. 7. 1897, when there was a record amount of precipitation in the Jizerské hory, decided to protect several other dams in order to protect against such other events. For the newly founded Water Cooperative construction team to regulate river flows and to build dams in the Gorge of Gorge, Professor Otto Intza designed six dams. It was the first valley dam in the Czech Republic, which also raised concerns in its time. Finally, five of these heavy masonry dams were erected, and the construction of the dam on Jeřice was not carried out. The Harcov Reservoir, Bedřichov Dam, Mníšecká Dam, Mlýnická Dam and Jablonecká Dam were completed. Two other dams - this time sprinkled - in the Jizera River basin were completed in 1915. One of them, a dam on White Desna, was tragically broken a year later. The second, Souš Reservoir, today serves as a source of drinking water for Jablonec nad Nisou. The source of water for Liberec and Českolipsko is (once again the dump) the water reservoir Josefův Důl, built in 1976-82 years.
The plans of the Ministry of Agriculture of the Czech Republic include three separate and three pumping systems in the vicinity of Hejnice. However, according to many opinions, there is no reason to build them, as well as floods and extensive changes in protected areas of the mountains.