ON THE HYDROGEOLOGY OF THE KUZNETSK BASIN

G. M. Rogov, G. A. Plevako, L. A. Solomko

(Presented by the scientific seminar of the Department of Hydrogeology and Engineering Geology)

Kuzbass is a major industrial center in the east of the country, playing an important role in the economy of the Soviet Union.

The Kuznetsk coal basin, with an area of more than 40 thousand km², is located in a foothill humid landscape zone in the south, a forest-steppe zone in the central part, and a hilly forest-taiga humid region in the north, with average annual precipitation of, respectively, 800 mm, 390 mm, and 450 mm per year.

Groundwater in the Kuznetsk Basin is widely used for the water supply of industrial facilities, and its role in the national economy is rapidly increasing.

The geological and hydrogeological investigations that have been carried out have made it possible to identify certain interesting features in the distribution of groundwater, the conditions of its circulation and formation in different geostructural and landscape zones of the Kuznetsk intermontane artesian basin.

According to the lithologic-facies and geochemical characteristics, the sequence of water-bearing rocks of the basin may be divided into five main aquifer complexes, characterized by specific hydrogeochemical features and representing three structural stages of the basin (G. M. Rogov, 1959).

The first aquifer complex is represented by marine sandy-clayey, effusive-sedimentary, and carbonate Lower and Middle Paleozoic rocks \((\mathrm{Cm}_1—\mathrm{C}_1^{1-3})\) of the basement and margins of the basin. The rocks of the complex are characterized by increased water abundance, especially the carbonate formations in the zone of intensive water exchange. On the Salair Ridge there are springs with discharges of up to 30 l/sec. The operating discharge of wells is 15–20 and more m³/hour.

The second complex is represented by coal-bearing sandy-clayey lagoonal-continental deposits of the Balakhonka Series \((\mathrm{C}_1—\mathrm{P}_1)^{b1}\). The water abundance of the rocks of the complex is low, except for areas located in depressions and river valleys. Well discharges are 1.0–10 m³/hour, and spring discharges up to 1 l/sec. Water inflows into mine workings exceed 200 m³/hour.

The third aquifer complex includes coal-bearing sandy-clayey continental deposits of the Kolchugino Series \((\mathrm{P}_1—\mathrm{P}_2)^{k1}\). The water abundance of the rocks is sharply heterogeneous. The greatest water abundance is characteristic of the sandstone horizons of the Erunakovskaya and Kuznetskaya

formations in river valleys. The yield of wells reaches 50 m³/hour, most often does not exceed 10 m³/hour; the discharge of springs is up to 2–3 l/sec. Water inflows into mine workings amount to 300–400, and in individual cases up to 1500 m³/hour.

The fourth aquifer complex is represented by continental sandy-conglomeratic and clayey formations of Mesozoic, predominantly Jurassic, age. The water abundance of the rocks as a whole is high. The production yields of some wells reach more than 200 m³/hour; there are springs with discharges up to 5 l/sec. Especially high water abundance characterizes the horizons of weathered conglomerates and sandstones in relief depressions and river valleys.

The fifth aquifer complex includes loose sandy-clayey formations of Tertiary and Quaternary age. Among the rocks of this complex, alluvial sand-and-pebble deposits of modern and ancient valleys are characterized by high water abundance. The yield of wells reaches up to 50–70 m³/hour; springs with discharges up to 3–5 l/sec occur.

The rocks of the first aquifer complex constitute the lower structural stage (basement) of the Kuznetsk intermontane artesian basin. The deposits of the second and third complexes make up the middle structural stage; those of the fourth and fifth complexes, the upper structural stage of the basin.

In general, throughout the basin the groundwaters of the indicated complexes are closely hydraulically connected and form a single water-pressure system (A. M. Ovchinnikov, 1961).

The greatest water abundance is characteristic of the upper weathered fractured part of the rocks, up to 100–150 m thick, especially in river valleys and depressions.

The groundwaters of all complexes over the predominant part of the territory are under pressure.

The general direction of groundwater movement is observed from the margins of the basin, from the mountain structures, toward the central part, where they are drained by the Tom, Inya, and their tributaries.

In terms of conditions of formation, groundwaters of infiltration, of modern origin in the zone of intensive water exchange, predominate. An interesting feature is the predominant recharge of groundwaters by atmospheric precipitation in autumn; moreover, in the southern regions the infiltration of precipitation continues in winter as well, owing to the non-freezing of soils beneath the snow cover and its melting from below.

The chemical composition of the groundwaters is complex and is entirely due to the geochemical features of the rocks of the aquifer complexes and to the history of the paleohydrogeological development of the basin (G. M. Rogov, 1959; N. M. Strakhov et al., 1959). The available materials clearly indicate vertical and horizontal zonality of the groundwaters.

The zone of intensive water exchange is characterized by bicarbonate-calcium waters of the leaching type. In areas of excessive moisture they are ultrafresh; over the predominant part of the territory they are fresh, with mineralization of 0.3–0.6 g/l, rarely up to 1 g/l. In individual weakly drained areas, chiefly in the Prisalaír depression, chloride-sulfate-magnesium-calcium and chloride-magnesium waters of the continental salinization type are developed, with mineralization up to 5–8 g/l.

The groundwaters of this zone contain oxygen-nitrogen, sometimes carbon dioxide gases of atmospheric origin. The groundwater environment in the rocks of the first aquifer complex is alkaline (pH 7.0–7.8), and in the others it is acidic (pH 5.0–6.5). The groundwaters of each aquifer-

...complex are characterized by the content of a specific group of heavy and rare metals (G. M. Rogov, 1959).

For the second zone (of retarded water exchange), hydrocarbonate-sodium waters with mineralization up to 3–4 g/l are characteristic; for individual structures composed of rocks of the first aquifer complex, sulfate-hydrocarbonate-sodium waters with mineralization up to 8 g/l are characteristic (Ermakovsky district, Devonian deposits). The groundwaters of this zone are characterized by methane and methane-nitrogen gases, in some cases nitrogen gases (first complex). The groundwaters often contain hydrogen sulfide and carbon dioxide. The conditions of occurrence of the groundwaters are reducing; the medium is sharply alkaline (the pH value increases to 9.0).

The zone of very retarded water exchange is characterized by alkaline, highly mineralized chloride-sodium, more rarely chloride-calcium-sodium waters, with methane, more rarely methane-nitrogen and carbon dioxide gases. At depths of 500–1200 m the mineralization reaches 10 g/l. The groundwaters of this zone contain bromine up to 10 mg/l, iodine up to 0.6 mg/l, and naphthenic acids. The conditions of occurrence of the groundwaters are strongly reducing; the medium is sharply alkaline. The pH value of the groundwaters is greater than 9.0.

Groundwaters in this zone at depths of 1800–2000 m have a temperature of 50–60°C (E. M. Senderzon, 1961).

The groundwaters of the basin are widely used for the water supply of the industrial centers of Kuzbass; however, the groundwater resources make it possible to use them still more extensively. Especially promising for exploitation are the groundwaters of the Jurassic deposits composing the upper structural stage of the basin. Approximate calculations show that, in solving the water-supply problem for the cities of Belovo and Leninsk-Kuznetsk, the possible resources of the central Jurassic basin will be used only by 10–15%. There are sufficiently broad prospects for using the groundwaters of the Cambrian, Devonian, Lower Carboniferous, Jurassic, as well as coal-bearing and Quaternary deposits, with the construction of catchment facilities in river valleys and depressions.

However, for an assessment of the groundwater resources of the basin we at present still do not have sufficient data, nor do we have a detailed hydrogeological map that would reflect the balance and natural resources of the groundwaters of this large and industrially developed basin.

The compilation of such a map is one of the principal problems facing the hydrogeologists of Kuzbass.

The hydrogeological setting of the basin shows that within individual areas there is the possibility of uncovering and bringing to the surface specific types of mineral, and in some cases thermal, groundwaters of therapeutic significance, associated with deep thermometamorphic processes, which will have great practical importance for Kemerovo Oblast, which has no balneological resorts. Thus, in 1956, the Kuzbassuglegeologiya Trust of the West Siberian Geological Administration already discovered carbonated mineral waters of the Borjomi type in the southeastern part of the basin, within the disturbed Tersin anticline, composed of rocks of the second complex. At present the Tersin mineral-water deposit is being explored; the composition and conditions of formation are being studied, and the reserves of mineral waters are being assessed. Research on the study of mineral waters in the Kuznetsk Basin must be considerably expanded, with special attention to be paid to the geochemical features of the aquifer complexes and to the chemical and gas composition of the groundwaters.

Solving the stated problems will make it possible to clarify questions concerning the use of groundwater for the water supply of the industrial centers of Kuzbass, to assess the basin’s prospects for mineral waters, and to make broader use of the composition of groundwater in evaluating individual structures and areas for various mineral resources.

REFERENCES

1. Ovchinnikov A. M. Water-pressure systems of the Earth’s crust. Izvestiya vyssh. uch. zavedenii, No. 8, 1961.

2. Rogov G. M. Some questions of the hydrogeochemistry of groundwater in the Belovo district of Kuzbass. Vestnik ZSGU i NTSU, No. 3, 1959.

3. Strakhov N. M., Zalmanzon E. S., Glagoleva M. A. Essays on the geochemistry of Upper Paleozoic deposits of the humic type. Publishing House of the Academy of Sciences of the USSR, Moscow, 1959.

4. Senderzon E. M. Preliminary data on the geothermy of the Kuznetsk Basin. Materials of the Siberian Thematic Commission on the History of Coal Accumulation, issue 1, Siberian Branch of the Academy of Sciences of the USSR, 1961.