PROCEEDINGS
OF THE TOMSK POLYTECHNIC INSTITUTE
NAMED AFTER S. M. KIROV, HOLDER OF THE ORDER OF THE OCTOBER REVOLUTION
AND THE ORDER OF THE RED BANNER OF LABOR

Volume 260　　　　　　　　　　　　　　　　　　　　　　　　　　　1976

GROUNDWATER OF THE KOLYVAN-TOMSK FOLDED ZONE

P. A. Udodov, A. A. Lukin, P. N. Parshin, N. M. Rasskazov,
A. D. Fateev

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

In this article we shall briefly discuss several regional regularities in the recharge, circulation, and discharge of the groundwater of the Kolyvan-Tomsk folded zone, in the general context of its connection with the surrounding geological structures. These regularities have been identified on the basis of the use of methods for the regional assessment of natural groundwater resources and the water balance (as developed by B. I. Kudelin, 1960), the study of groundwater runoff from one-time measurements of river discharges during the low-water period, and a detailed investigation of the chemical composition, especially the microcomponent composition, of groundwater.

By the Kolyvan-Tomsk folded zone are meant Hercynian structures that approach the daytime surface in the Ob region from Kamen-na-Obi to Tomsk. The geological boundaries of these structures on the east are the Caledonides of the Kuznetsk Alatau and Salair, while on the south, west, and north the Kolyvan-Tomsk Hercynides are submerged beneath the Meso-Cenozoic formations of the West Siberian Lowland. The principal structural elements of the zone (Vdovin, 1956; Matveevskaya, 1956, 1960) are the region of the main Hercynian trough of the Kolyvan-Tomsk geosyncline, the Hercynian geoanticlinal zone (Bugotak, Mitrofanov, and Podlomsk geoanticlines), Hercynian marginal troughs (Tashmin, Kuznetsk, Gorlovsk), and superimposed Meso-Cenozoic erosional-tectonic depressions (Ulanov, Luchanov, Yurgin, Oyashin, Ust-Berd, Iskitim, Doronin, Cherepanov).

One of the main factors in the formation of groundwater of the Kolyvan-Tomsk folded zone is its two-tier geological structure, which determines the most important differences in the conditions of water circulation within the tiers. The lower structural tier is composed of Paleozoic formations from the Lower Devonian to the Lower Permian, represented by the effusive-sedimentary formation \(D_{1-2}\) (geoanticlinal zone), sandy-clayey sediments with interbeds, lenses, and members of limestones and, occasionally, volcanogenic formations \(D_3—C_1\) (region of the main Hercynian trough), carbonate-terrigenous \(C_1\) and coal-bearing \(C_1—P_1\) formations (marginal troughs). The listed formations were strongly dislocated during the Late Hercynian phase of tectogenesis, with the formation of folds linearly elongated in a submeridional direction. The manifestation of phases of tectogenesis, both of the Hercynian and of subsequent cycles, is expressed in magmatic activity (dif-

granite massifs and diabasic dike bodies are developed), as well as in the complex disjunctive tectonics of the structures of the lower level, which are characterized by a block structure. Previous geological investigations have revealed a number of major faults that bound the principal structural elements. Examples of such dislocations are the Priob’e deep fault, the so-called Tomsk overthrust, the faults separating the structures of the Kolyvan–Tomsk folded zone and Salair, and the faults bounding the Bugotak horst-anticlinorium. Along with major faults, a large number of smaller rupture dislocations of submeridional and sublatitudinal trend are observed. The character of dislocations transverse to the strike of the folds has until now remained little studied. As hydrogeochemical investigations have shown, many dislocations mapped earlier manifest themselves in the peculiarities of the chemical composition of groundwater. On the basis of hydrogeochemical criteria, a number of new rupture dislocations have been identified and traced, in particular in the Tomsk area (Udodov, Matusevich, Grigor’ev, 1965). Not all zones of rupture dislocations are characterized by increased water abundance. This is evidently, to a considerable degree, a reflection of their different ages. Moreover, the younger or renewed faults are open to the circulation of waters. Direct hydrogeological indications of the presence of the newest zones of rupture dislocations include locally increased water saturation of rocks, as well as the travertine formation widely developed in the region at sites where waters from fault zones discharge. Apparently, a whole series of rupture dislocations of various trends, known in the Tomsk area, may be assigned to the young ones. They may serve as pathways for replenishment of groundwater resources in Meso-Cenozoic deposits.

Thus, the reservoir properties of the geological formations of the lower structural level are determined only by their fracturing, and under the conditions of circulation here a fissure type of groundwater is developed. Among them it is customary to distinguish fissure waters associated with the destroyed roof of the basement rocks and having regional distribution, and fissure waters of zones of rupture dislocations. In limestones, a fissure-karst type of groundwater is developed. Consequently, the direction of groundwater movement in this structural level is determined by the position of the water-conducting fault zones and by the character of hydrostatic heads. In the distribution of head forces, the basement relief is of great importance. Its general lowering is observed toward the West Siberian Lowland, which determines the direction of regional runoff. However, the presence in the Paleozoic basement of the Kolyvan–Tomsk zone of pronounced local erosional-tectonic depressions complicates runoff. Some of the depressions are closed (the Oyash, Berd depressions); others are open toward the West Siberian Lowland and Kuzbass (the Ulanovskaya, Luchanovskaya, Yurginskaya, Doroninskaya, Cherepanovskaya). These depressions are local zones of deep drainage of fissure waters. The depth of active drainage by erosional-tectonic depressions, determined by the difference in basement elevations, lies within 100–250 m. Along zones of rupture dislocations it may reach considerably greater values.

The weathering crust is of great importance; it has a blanket-like character of distribution, but in some parts it has been eroded. Areas with an eroded crust are most widely developed within orographically elevated geoanticlinal and anticlinal structures and granitoid massifs, as well as in the valleys of the larger rivers. The blanket character of the clayey part of the weathering crust hinders infiltration of atmospheric precipitation and creates heads of groundwater in Paleozoic rocks,

contributes to regional subsurface runoff, hindering discharge into the local hydrographic network. Areas with a removed weathering crust are either recharge areas for groundwater (the watershed spaces of geoanticlinal structures, individual areas in the valleys of the Karakan, Koinikha, Oyash, Ushaika, Kirgizka, and other rivers), or, conversely, areas of discharge of deep waters (the valleys of the Shcherbak, Tugoyakovka, Kungurka, and other rivers).

The upper structural stage is composed of continental sandy-clayey formations of the Cenozoic (Upper Paleogene, Neogene, Quaternary) and, locally, of the Mesozoic (Jurassic and Cretaceous). The total thickness of the loose cover varies on average from 0 to 40 m, increasing within superimposed erosional-tectonic depressions and the slope of the West Siberian Lowland to 200 m and more. In terms of circulation conditions, the groundwater of the upper structural stage belongs to the pore–stratal type. The direction of its movement is determined mainly by the direction of hydrostatic head forces, which, in turn, is determined by orographic factors.

In orographic and hypsometric terms, the Kolyvan–Tomsk folded zone as a whole (in its middle part, together with the adjacent structures of Kuzbass) occupies, among neighboring geological structures, a transitional position from the plains of the West Siberian Lowland to the mountainous regions of the Kuznetsk Alatau and the Salair Ridge. It is an elevated, substantially peneplained plain with average absolute elevations of about 200–250 m. A plain-and-hill relief is typical, as is a general gentle slope of the terrain from the named mountainous regions toward the main drain of the region’s groundwater and surface waters—the Ob River. In detail, however, the orographic plan of the region is rather heterogeneous. Characteristic hypsometric levels and relief types are distinguished within it, which are spatially and, evidently, genetically linked to particular structural elements. As a rule, areas of geoanticlines and large identified anticlines correspond to the higher hypsometric levels and greater dissection of the relief, while areas of young erosional-tectonic depressions correspond, on average, to relatively lower absolute elevations and less dissected relief. Thus, by their orographic features, the first structures act hydrogeologically as recharge areas, and the second as drainage areas for groundwater. At the same time, the recharge areas are characterized by a greater amount of atmospheric precipitation and greater forest cover. This, in combination with the smaller thickness of loose-cover deposits noted for these structures and the weak development of the weathering crust, strengthens their role as recharge areas. The identified recharge and drainage areas are also manifested in the characteristics of the macro- and microcomponent composition, and the gas and isotopic composition of the waters.

The formation of the natural groundwater resources of the Kolyvan–Tomsk folded zone is determined by the noted geological-structural and geomorphological factors, as well as by climatic and landscape conditions. Without dwelling in detail on the latter, we shall only note that determinations of the natural groundwater resources of the active water-exchange zone by the method of hydrograph separation of river runoff (data from long-term observations of river discharges in the region were taken from the reference book Resources of Surface Waters of the USSR..., 1966), and by measurements of low-water river discharges, reveal a definite zonality in the distribution of groundwater runoff depending on landscape-climatic zonality. The magnitude of groundwater runoff decreases with

from north to south. If in the taiga and subtaiga zone, which includes the Tomsk area, the groundwater-runoff modulus (l/sec km²) averages 1–1.5, then in the piedmont drained plain of the forest-steppe zone it is, as a rule, less than one (0.5–1.0), and in the south of the region (forest-steppe south of the Berdi River) it is 0.35–0.7.

Changes in the magnitude of groundwater runoff in the landscape zones are determined by differences in the structural-geological conditions of the areas. As a result, structures identified as recharge areas are also characterized by more intensive groundwater runoff. Thus, in the central part of the region, located within a single landscape zone, the groundwater-runoff modulus varies from 1.75–3.4 within the Bugotak horst anticline (the principal local recharge area) to 0.5 l/sec km² in areas of superimposed erosional-tectonic depressions and on the slope of the West Siberian artesian basin.

For the Paleozoic formations of the region we have distinguished the following aquifer complexes: the sandy-shaly sequence ($D_3$–$C_1$), the effusive-sedimentary sequence ($D_{1-2}$, $D_3$), carbonate rocks, granitoids, and, in addition, waters of zones of fault disturbances. In recharge and discharge areas (geoanticlinal structures and the main Hercynian trough of the Kolyvan-Tomsk geosyncline outside the superimposed erosional-tectonic depressions), the water abundance of the fractured weathering zone of the sandy-shaly and effusive-sedimentary complexes is, on average, characterized by values of the groundwater-runoff modulus equal to the first tenths of l/sec km², and by specific well yields ranging from hundredths to the first tenths of l/sec. In areas of watered fault disturbances within these aquifer complexes, the groundwater-runoff moduli are greater than one, and specific well yields range from 1 to 3 l/sec. At the same time, the water abundance of fault zones in effusive-sedimentary formations is greater than in the flyschoid sequence. Thus, in the area of a watered zone of fault disturbance in the effusive-sedimentary Mitrofanovka member in the basin of the Kungurka River (a left tributary of the Tom River), the groundwater-runoff modulus for an area of 1.5 km² was more than 10 l/sec km². The water abundance of limestones, based on the study of groundwater runoff in the areas of the Vlaskovo and Yashkino quarries, is characterized by a groundwater-runoff modulus of up to 11 l/sec km². Granitoid massifs in the weathering zone are characterized by weak water saturation, since they are drained by the Ob River.

Quantitatively, the groundwater runoff of the Paleozoic complex is controlled, along with landscape-climatic, structural, and geomorphological factors and the reservoir properties of the rocks, also by the hydrodynamic interaction of the watered complexes with one another, with surface runoff, and with the waters of loose deposits overlying the Paleozoic formations. This interaction is expressed, for example, in such frequently observed manifestations of the water regime in the region as a change in the relative share of the surface and groundwater components of runoff depending on changes in plan of the reservoir properties of the rocks.

In areas where river valleys extend beyond the distribution field of poorly permeable sandy-shaly or effusive-sedimentary deposits and cut through members of karstified limestones, an everywhere increase in the groundwater component of runoff is observed. An approximate quantitative estimate of water absorption was made by us only for one such area in the zone of development of the Iskitim limestones in the basin of the Berdi River. According to many years of observations of its runoff at the gauging sections of the village of Stary Iskitim (“Resources...,” 1966), absorption, expressed through the groundwater-runoff modulus, amounts here, on the basis of water-balance calculations, to 5 l/sec km². This figure, vi-

apparently, is also underestimated, since the calculations were made for the entire water-balance area, within which limestones occupy only a small area. Where river valleys leave the limestone field at the boundary with less permeable rocks, there is a rapid increase in river discharge; concentrated outlets of groundwater are observed with a discharge of up to 50 l/sec (a spring in the valley of the Pacha River near the Yashkinskii limestone quarry).

A similar pattern in the regime of surface and groundwater runoff is also characteristic of the case in which the river valley is laid in lithologically homogeneous rocks, but changes its position relative to intensely fractured zones.

The general runoff conditions briefly characterized for the aquifer complexes of the Paleozoic formations of the Kolyvan–Tomsk folded zone make it possible to suppose that, in the formation of the natural groundwater resources of the active water-exchange zone, the main role belongs to local recharge areas.

Consideration of the groundwater of Paleozoic formations shows that the greatest withdrawal of water for domestic and drinking use can be made from the aquifer complex of limestones and from zones of disjunctive disturbances, developed especially in sandstones, effusives, and granites. The quality of the waters, as a rule, meets all GOST requirements. For waters of zones of disjunctive disturbances, iron contents from 1 to 10–16 mg/l are sometimes noted, as well as the presence, above the norm, of such components as mercury, zinc, barium, and others. The latter circumstance makes it necessary to study microcomponents in all hydrogeological investigations in the region for water-supply purposes.

The distribution and formation of the natural groundwater resources of aquifer complexes of the upper structural level in depressions (small artesian basins) and in the area where the Kolyvan–Tomsk Paleozoic structures plunge beneath the deposits of the West Siberian Lowland (the flank of the artesian basin) have so far been studied only poorly, although these waters are of the greatest interest for their practical use as a source of water supply. On the basis of the materials we have obtained, only some approximate figures can be given.

Study of groundwater runoff in the named areas shows that the natural groundwater resources of the upper part of the section of the cover mantle (as a rule, poorly permeable and located within the zone of the active draining influence of river systems) are limited and are characterized by a groundwater-runoff modulus of up to 0.5 l/sec km². But where rivers cut through more permeable aquifer complexes, the groundwater-runoff modulus increases considerably. Thus, in the lower part of the Lebyazh’ya River, where it exposes the water-rich sandy-gravel-pebble Upper Paleogene deposits of the Bolotninskaya suite, the groundwater-runoff modulus is 3 l/sec km². This value of the runoff modulus may be taken for an approximate characterization of the natural groundwater resources of the aquifer horizon of the Bolotninskaya suite. Taking into account its considerable thickness (40–50 m) and broad areal distribution in the Yurga depression (on the order of 3.5 thousand km²), the natural groundwater resources of this horizon alone in the depression are preliminarily estimated by us at a value on the order of 10 m³/sec, that is, sufficient to meet the water needs of a large city. Thus, the groundwaters of the Yurga depression and of the flank of the West Siberian artesian basin north of the depression, in the Ob–Tom interfluve, may be used to supply water to Tomsk, Yurga, and Bolotnoye.

Some idea of the natural resources of groundwater

of Meso-Cenozoic deposits below the local zone of active drainage gives an order of magnitude for the runoff-modulus figures obtained in regional calculations of the water balance for river basins located within superposed erosional-tectonic depressions and in the area where Paleozoic structures plunge toward the West Siberian Lowland. The resources of deeper subsurface groundwater runoff are characterized by the following figures: in the Novosibirsk Ob region—more than 5 (the basins of the Tula and Chik rivers); in the Oyash depression—about 4 (the basin of the Oyash River); in the Yurga depression—on the order of 5 (the basin of the Lebyazhya River); in the Ulanovo depression and on the northeastern slope of the Tom–Yaya interfluve—from 4 to 5.5 l/sec km² (the basins of the Kitat, Latat, and Yaya rivers between the gauging sections of the workers’ settlement of Yaya and Semenovskoye). Part of this runoff is evidently due to the inflow of waters from the aquifer complexes of Paleozoic formations of the Kolyvan–Tomsk folded zone. Recharge of the Meso-Cenozoic aquifer complexes from the Paleozoic structures is confirmed by study of the microcomponent composition of the waters. In the areas of the Ulanovo, Yurga, Oyash, Doronino, and other depressions, a number of hydrogeochemical anomalies have been identified from natural groundwater discharges, reflecting water flows that disperse various mineralization zones.

The approximate data cited indicate substantially higher natural groundwater resources in the Meso-Cenozoic deposits within the young artesian basins and on the slope of the West Siberian artesian basin, as compared with the natural resources of the watered complexes of the bordering Paleozoic structures.

The regional regularities that have been identified in the formation of groundwater served as one of the grounds for selecting the area for exploratory work for the water supply of Tomsk, and are important in resolving questions connected with this work, such as forecasting recharge and groundwater quality during operation of the planned water intake.

REFERENCES

V. V. Vdovin. Geotectonic structures of the Kolyvan–Tomsk arc. Transactions of the Mining-Geological Institute, West Siberian Branch, USSR Academy of Sciences, issue 15, 1956.

B. I. Kudelin. Principles of regional assessment of natural groundwater resources. Moscow University Press, 1960.

A. L. Matveevskaya. On the structure and development of the Kolyvan–Tomsk arc in the area of its junction with the Salair. Transactions of the Mining-Geological Institute, West Siberian Branch, USSR Academy of Sciences, issue 15, 1956.

A. L. Matveevskaya and E. F. Ivanova. Geological structure of the southern part of the West Siberian Lowland in relation to questions of oil-and-gas potential. Moscow–Leningrad, USSR Academy of Sciences Press, 1960.

Resources of Surface Waters of the USSR. Principal Hydrological Characteristics, vol. 15. Altai and Western Siberia, issue 2, Middle Ob. Leningrad, Hydrometeorological Publishing House, 1966.

P. A. Uyudov, V. M. Matusevich, N. V. Grigoryev. Hydrogeochemical prospecting under conditions of semi-closed geological structures of the Tom–Yaya interfluve. Tomsk University Press, 1965.