Overview

Area and population of BNT





Area and population of the Baikal natural territory


Indicator unitTotal
Republic of BuryatiaIrkutsk regionZabaykalsky Krai
1. Area of constituent entities of the Russian Federation thousand square km 1581,03 351,33 798,20 431,50
2. Share of area of constituent entities of the Russian Federation, which is part of the BNT % 24,4 62,7 13,81 12,9
3. Area of BNT thousand square km 386,16 220,44 110,12 55,60
% 100 57,1 28,5 14,4
а) Central ecological zone thousand square km 89,1 57,27 31,83 -
% 100 64,3 35,7 -
b) Buffer ecological zone thousand square km 217,97 162,37 - 55,6
% 100 74,5 - 25,5
c) Ecological zone of atmospheric influence thousand square km 79,09 0,80 78,29 -
% 100 1,0 99,0 -
The population of subjects of the Russian Federation thousand people 4478,1 982,3 2412,8 1083,0
Share of population of subjects of the Russian Federation residing in BNT % 56,5 98,4 58,6 13,8
The population of BNT thousand people 2455,2 956,3 1332,6 166,5
% 100 38,2 55,9 5,9
The number of municipal formations of district-status: a) in the constituent entities of the Russian Federation units 84 21 32 31
b) located in BNT units 37 19 13 5
c) located in the central ecological zone (CEZ) of BNT units 10 6 4 -
 





































Geological properties of the Baikal area

UNESCO’s original reason for listing Lake Baikal as a World Heritage Site in 1996 was the sui generis rift system which has formed the lake and still has serious geological processes underway.

The Baikal Rift Zone (BRZ) is the largest in Russia and second-largest (2) above-water area of this kind on Earth. According to Academic N. A. Florensov, it is characterized by morphologically expressive rift structures, intensive Neogene-Quaternary volcanicity (now extinct), significant geophysical anomalies, high seismic activity and other neotectonic features. The BRZ has a complex pre-rift history and structure, with a highly broken Archean basement, an involved layout of Baikalides, an Early Caledonian fold system abutting on the BRZ from the south, old ultrabasite belts, alkaline intrusions, etc. The linear system of the Baikal rift structures stretch over 2,500 km – from Northwestern Mongolia through the mountains of Eastern Siberia to Southern Yakutia. The system includes watery and dry intermontane areas (trough faults), arranged in a straight or echelon pattern.

The fresh water of the lake, which is rich in oxygen, is a component of this unique geological environment.The water’s condition is significantly determined by it and affects it in return.

1) Source: A. A. Bukharov. Baikal in Numbers - A Reference Guide, Irkutsk, private publisher S. E. Makarov, 2001, p. 72.

2) The world’s largest rift system is the Eastern African rift system, composed of the normal and trough faults of the Red Sea, East Africa and the Gulf of Aden. It includes lakes Tanganyika, Rudolf, Nyasa etc.


Geological age of Lake Baikal:

Prereef (before Baikal) stage (Cretaceous - late Eocene) - 70-35 million years;

Rift stage: – 30-0 million years;

а) Protobaikal (early Baikal) stage (Oligocene - Pliocene) 30-3.5 million years;

б) Neobaikal (Baikal-itself) stage (Pliocene – Holocene) 3.5-0 million years.

Thickness of the Earth crust:

under the Siberian platform– 36-42 km;

under mountain chains of Baikalia (the Baikal region) – 45-55 km.

The smallest thickness till the bottom of crust in the center of Baikal – 34 km.

The capacity of the Cainozoic precipitations in the depression – 3- 8.5 km.

The thinning of crystallized Earth crust under the rift of Baikal – 3-7 km.

Max. elevation of mountain range around Lake Baikal (Barguzinsky depression) – 2840 m.

Max. deepness of Baikal – 1637 m.

Max. capacity of sediments in Baikal depression (according to geophysical data) – 8500 m.

Amplitude of the rift slit (between Max. elevation of mountain range and foundation of Baikal depression) - 12 977 m.

For reference: max. deepness of the ocean (Mariana Trench in the Pacific Ocean) 11 022 m.


The size of vertical shift of prerift solid in fault lines along-shore:

for Southern bay- 8 km, for central bay - 9 km,

for Northern bay – 5-5.5 km.

Horizontal offsets of solids in range of mountains around Baikal – up to 100-150 km.

Speed of tectonic separation of coasts of Baikal – 0.7-2 cm/year.


Seismicity

Number of earth quakes is more than 2000 a year (with infirm up to 8000).

Periodicity of earthquakes: 7 points (magnitude -5) – 1-2 years;

8 points (magnitude -6) - 5-10 years;

9 points (magnitude -7) - 50-100 years;

10 points and more (magnitude more than 7) - 150-200 years.

The main earthquakes:

Tsaganskoye earthquake, 1862 (formation of the Proval embayment) – > 10 points (magnitude > 6.5-7);

Srednebaikalskoye, 1959 (sinking of bottom of Baikal in the midst up to 15-20 m) – 9.5 points (М-6);

Chivyrkuiskoye, 1981 – 9 points (М-5.8);

Kicherskoye, 21.03.1999 – 8 points (М-6);

Kultukskoye, 27.08.2008 – 8 points (М-6.3).

Deepness of epicenter of earthquakes 12- 22 km.

Bottom relief

Abrasion shelf has area from coast of Baikal till deepness of 10-12 m

Slope break (bathyal) - in the deepness of 20-300 m.

Middle bottom slopes for north- west coast – 30-65о.

steepness of eastern Olkhonsky subaqueous slope - less than 45 о.

Radioactive elements in Baikal *

In the water of lake; In silt:

Uranium (U238) – 0.4 mcg/dm3 ((4.95х10-6Bq/g); Uranium (U238) – 12 g/t (150 Bq/kg);

thorium (Th232) – 0.22 mcg/dm3 (0,89х10-6Bq/g); thorium (Th232) – 12 g/t(48 Bq/kg);

potassium (К40) – 940 mcg/dm3 (29.8х10 -6 Bq/g); potassium (К40) – 0.015g/t (476 Bq/kg);

total specific activity– 674 Bq/kg.

Technology-related radio nuclides in silts (1986-1989): specific activity Cs137 – 33-48 Bq/kg (1700 Bq/m2).

Gas hydrates (At first they were found in the bottom sediments 1997 by underwater drilling of international project (“Baikal Bureniye” on the Akademicheski depression)

Deepness of water - 1324 m; Deepness of bottomhole - 300 m.

Top interface of depth of cover of gas hydrates (from bottom of Baikal) – 84-100 m.

Concentration of gas hydrates (approxim.)– 6 mg of gas/1 g of sediment.

Composition in mg/g: NH4 + – 48; Са2++Mg2+ – 18; Na + ,K + – 12; 

HCO3 + – 15.1; F - – 6; Cl - – 17; NO3 - – 2.5; SO42- – 7; water-soluble part in the total mass of solid – less than 31 %

Gas volume in mg/g: methane – 5.9; nitrogen – 44.7; oxygen – 4.5; carbon dioxide – 0.5.

* The figures of radioactivity (Bq/kg) were corrected. In reference book of A.A. Bukharov “Baikal in figures” they are false.