Lake Baikal - Alexandre SCHOHN

Lake Baikal, its geology and its history

Surrounded by cliffs and forests, Lake Baikal is called the ‘Pearl of Siberia “. Crescent shaped, Lake Baikal is more of 630km long from North to South and only 60km from East to West. The temperature of the water is rarely more than 15 ° C and in winter it is possible to travel by car on the ice who can reach 1 m thick. The center of Lake Baikal is the deepest area (1 642 m) with a very low thickness of the Earth’s crust. An intense blue, its water is so pure that she is drinking.

Lake baikal map — Location of Lake Baikal

Geology

Lake Baikal is a rift to open, which means that it continues to grow in the years to separate the landmasses of Siberia (Siberian craton) in the North-West and the Mongolia mountains Southeast.

The rift is opening by extension of part of the Earth’s crust. During this open, the crust thins and form a ditch collapse. During the extension, normal faults appear forming levels giving the rift a stair shape. The rift may represent the initial training from coast-to-coast Stadium if it is initially located on a continent.

The creation of the Baikal rift comes from the 3 tectonic plates movement: the Indian plate (having helped form the India);. the Eurasian plate between Asia and Europe; the Pacific plate to the West.

First part

The rifting took place in two stages. The first time date to the Precambrian and Paleozoic where we have the presence of a beginning of rifting. During this period, the Siberian craton separates from the Rodinia in 780-750 my. The Rodinia is the supercontinent from 1000 Ma, having consolidated all of the land areas in a continent. During this separation, separation began in the West of the Siberian basin to reach Lake Baikal causing volcanic activity.

Second part

It was during the Oligocene (40-30 my) the rifting took form during the Pliocene the basin of Lake Baikal. Indeed, during the Eocene (40 my) the Indian plate collided and has subducts (pass underneath) under the Eurasian plate. She started to move forward at the speed of 6 cm per year on average leading to the formation of the Himalayas. To the East, the Pacific plate sinks at the speed of 10 cm/year under the Eurasian plate creating a subduction zone. Subject to this double pressure, the Eurasia plate is deformed and form micro-continents which will also be deformed.

training-baikal — Compression of the Indian North plate and the Pacific plate to the East on the Eurasian plate. Causing the rifting of Lake Baikal

Lake Baikal is located on the edge of two geological areas, the Northwest Siberian craton and the belt of the Sayan-Baikal and Mongolia-Okhotsh to the Southeast. These two plates having formerly been disjointed, they are a weak area in the Eurasian plate. Indeed during the Eocene period, the edges of this old stitches began to separate, where now stands the southern part of the Lake.

In the Miocene rift has expanded to the North and the South. The speed gauge picked up strongly during the Paelocene. The Baikal rift has created a deep depression filled by sediments on 4 to 7 km thick. But the speed gauge is relatively high (5 mm per year Yes Yes it’s fast) the deposition of the sediments did not quickly fill the pelvis in training. Lake Baikal, which maximum depth is 1640 meters, then created.

So term Lake Baikal divide Asia into two and become the sixth ocean of the world.

Environment

Lake Baikal is rich in biodiversity. There are more than 1,000 species of plants and more than 2,500 species of animals. His wealth is a consequence of his large quantity in fresh water. Indeed, the Lake is the largest reservoir of fresh water in the world with more than 20% of water fresh not frozen (23 615 km 3). In the Lake one can find more than 60 species of fish, including the Adam. This fish is found only in the Lake Baikalet is one of the main supplies of the Lake. It is also possible to find in the North of the freshwater seals. We might as well talk about the opportunity to meet with bears and snakes along the shores.

The Lake allows to have a continental climate. When the temperatures can drop to-40 ° C in Siberia, the surroundings of Lake Baikal are at a temperature in the vicinity of-16 ° C to-25 ° C. During the winter, the primary means of locomotion is the car on the Lake. Indeed, with its 1 m of thickness in some places, it is possible overland access to many parts of the Lake.

A pipeline is to be set up north of the Lake to extract oil. However access to the pipeline would have devastated a nature reserve and would have been installed on a seismic risk zone. After many actions by Greenpeace and local residents, it was decided to move the factory more away from the Lake to avoid passing on a reserve and a seismic zone.