031. Groundwater map
Groundwater map
Groundwater
The map is based on generalizing materials of the Institute of the Earth's Crust, and the Geological Surveys of Buryatia, Chita and Irkutsk using hydrogeological maps of 1:5000000 [Atlas..., 1983] and 1:4500000 scales [National Atlas ..., 1990].
During mapping the method of mapping the main aquifers (hydrogeological formations) was applied. Aquifers are distinguished according to structural and hydrogeological features, the prevailing type of water-ermeability, and reservoir properties of rocks.
In the Baikal basin pore-edge waters, confined to loose unconsolidated sediments of Mesozoic and Cenozoic age, have a wide distribution, as well as crack waters in all lithified metamorphic, igneous and sedimentary rocks of different ages from the Archaean to the end of the Paleozoic - Mesozoic inclusive.
Hydrogeologically, the Baikal basin is a complex system of artesian basins and hydrogeological massifs. Artesian basins occupy intermontane depressions composed of loose rocks of the sedimentary cover and crystalline basement rocks. They are characterized by pore-edge waters of the zone of active water exchange and crack waters, often pressure waters, and foundation waters. Hydrogeological massifs are composed with crystalline rocks of mountain- folded frame and can accommodate crack waters of exogenous fissuring. Thickness of the zone of active water exchange does not exceed 100-150 m.
Most watered are karst carbonate rocks, as well as zones of tectonic dislocations, intersecting the cropping-out foundation or spread along the contacts of sedimentary-metamorphic rocks with igneous and metamorphic rocks. They are often traced by upward unloading both of cold and thermal waters.
References
Atlas of hydrogeological and engineering-geological maps of the USSR. Scale 1:5000000. (1983).
National Atlas of the Mongolian People's Republic, scale 1:4500000. (1990).
