The entire geological history of the Earth (about 4.5 billion years) is enclosed in a tiny geochronological table compiled by scientists. During this time, the continents split and moved, and the oceans changed their location. Mountains formed on the surface of our planet, then they collapsed, and then new mountain systems arose in their place - even larger and even higher.
In this article, we will talk about one of the earliest epochs of earthly folding - about Baikal. How long did it last? What mountain systems arose at this time? And what are the mountains of Baikal folding - high or low?
The era of Earth folding
The entire history of mountain building on our planet is divided by scientists into arbitrary intervals, periods, and called them folding. They did this primarily for convenience. Of course, there have never been any pauses in the process of forming the earth's surface.
There are six such periods in the history of the planet. The oldest folding is Archean, and the latest is Alpine folding, which continues in our time. Listed below are all the geological foldings of the Earth in chronological order:
- Archean (4.5-1.2 billion years ago).
- Baikal (1.2-0.5 billion years ago).
- Caledonian (500-400 million years ago).
- Hertsinskaya (400-230 Ma ago).
- Mesozoic (160-65 million years ago).
- Alpine (65 million years ago and to this day).
Geomorphological structures that were formed in a particular era of mountain building are called accordingly - Baikalids, Hercynides, Caledonides, etc.
Further we will describe in detail the most famous mountains of the Baikal folding. We’ll tell you where they are located and how they look externally.
Baikal folding: chronological framework and general features of the era
The era of terrestrial tectogenesis, covering the period from 650 to 550 Ma of the geological history of the Earth (Riphean - Cambrian), is commonly called the Baikal folding. It began about 1.2 billion years ago, and ended about 500 million years ago. The geological era was named after Lake Baikal, since it was at this time that the southern part of Siberia was formed. The term was first used by the Russian geologist Nikolai Shatsky in the 30s of the twentieth century.
In the Baikal folding, due to the intensification of the processes of folding, volcanism and granitization in the earth's crust, a number of new geological structures have formed on the body of our planet. As a rule, such formations arose on the outskirts of ancient platforms.
Typical mountains of Baikal folding can be found on the territory of Russia. This, for example, the Khamar-Daban Range in Buryatia or the Timan Ridge in the north of the country. How do they look externally? Will the mountains of Baikal folding be high or low? Let's answer this question.
What do Baikalids look like?
Baikalids formed a very long time ago. Even by geological standards of time. Therefore, it is logical that most of them are now in a dilapidated state. For millions of years, these structures underwent active denudation: they were destroyed by wind, precipitation, and temperature changes. Thus, the mountains of the Baikal folding will be low or medium in height.
Indeed, the absolute heights of Baikalid rarely exceed 2000 meters above sea level. This can be easily verified by comparing the tectonic and physical maps of the Earth. On geological and tectonic maps, the mountains of Baikal folding are usually marked in purple.
True, ancient Baikalids in many places of the globe were partially regenerated (rejuvenated) by later Alpine tectonic movements. So, for example, happened in the mountains of the Caucasus and Turkey.
Significant reserves of non-ferrous metals are most often associated with the geological structures of the Baikal folding. So, within their boundaries are the richest deposits of mercury, tin, zinc, copper and tin.
Mountains of Baikal folding: examples
Geological formations of this age are found in different parts of the world. They are in Russia and Kazakhstan, Iran and Turkey, India, France and Australia. Baikalids are located on the shores of the Red Sea and partially cover the territory of Brazil.
It is important to note that the term "Baikal folding" is common only in the scientific literature of the post-Soviet space. In other countries of the world this era is called differently. So, for example, in Europe, Kadoma and Assinto foldings correspond to it in time, in Australia - Luinskaya, in Brazil - the Brazilian one.
Within Russia, the following geomorphological structures are considered the most famous baikalids:
- East Sayan.
- Hamar-Daban.
- Baikal ridge.
- Yenisei Ridge.
- Timan Ridge.
- Patom Highlands.
Mountains of Baikal folding in Russia. Baikal Range
The name of this ridge is consonant with the name of the mountain building era under consideration. Therefore, we will begin with it the characterization of the main Baikalids of Russia.
The Baikal ridge borders the basin of the lake of the same name from the north-west side. It is located within the Irkutsk region and Buryatia. The total length of the ridge is 300 kilometers.
In the north, the Akitkan ridge visually continues the geological structure. The average altitudes of this Baikalid range from 1800-2100 meters. The highest point of the ridge is the peak of Chersky (2588 m). The mountain is named after the geographer who made a huge contribution to the study of the nature of the Baikal region.
East Sayan
East Sayan is the largest mountain system in southern Siberia, stretching for almost a thousand kilometers. Perhaps the most powerful of the Baikalids of Russia. The highest point of the East Sayan reaches 3491 meters (Mount Munku-Sardyk).
Eastern Sayan is composed mainly of solid crystalline rocks - gneisses, quartzites, marble and amphibolites. In its bowels large deposits of gold, bauxite and graphite were discovered. The most picturesque are the eastern spurs of the mountain system, nicknamed tourists by the Tunka Alps.
The most developed (in the orographic plan) the central part of the East Sayan. It consists of high mountain massifs, which are characterized by vegetation and landscapes of the subalpine type. Kurums are widespread within the Eastern Sayan. This is a huge area of stone placers, consisting of coarse fragments of rocks of various sizes.
Byrranga Mountains
Byrranga is another interesting mountain of Baikal folding. They are located on the northern peninsula of Taimyr. Mountains are a series of separate ridges, hilly plains and plateaus, deeply indented by canyons and trough valleys. The total length of the mountain system is about 1,100 kilometers.
“There is a kingdom of evil spirits, stone, ice, and nothing else,” the Nganasans, representatives of one of the indigenous peoples of Siberia wrote about these places. Russian traveler Alexander Middendorf was the first to map the Byrranga Mountains .
These mountains are very low. Although they look pretty impressive, as they are located right on the ocean. The height of their maximum point is only 1146 meters. The relief of this mountain system is very diverse. Here you can see both steep and gentle slopes, flat and peaked peaks, as well as a huge variety of glacial forms.
Yenisei and Timan ranges
We will end our acquaintance with the Baikalids of Russia by describing two ridges - the Yenisei and Timan. The first of them is located within the Central Siberian plateau and only in some places exceeds a thousand meters in height. The Yenisei Ridge is composed of ancient and very hard rocks - conglomerates, shales, traps and sandstones. The structure is rich in iron ores, bauxite and gold.
Timan Ridge is located in the north of the country. It stretches from the shores of the Barents Sea and adjoins the Ural Mountains. The total length of the ridge is about 950 km. Ridge is weakly expressed in the relief. The most elevated is its central part, where the highest point is located - the Chetlas stone (only 471 m high). Like other structures of the Baikal folding, the Timan ridge is rich in minerals (titanium, bauxite, agate and others).