GEOLOGY OF THE UNCONSOLIDATED DEPOSITS OF THE KEMEROVO AREA OF KUZBASS

F. P. Nifantov

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

After the historic decisions of the Twenty-Second Congress of the CPSU, the Kuznetsk Basin entered a new phase of rapid construction development. Large cities and industrial enterprises are being built at unprecedented rates. In connection with the new scale of construction and the development of the basin’s natural resources, more in-depth and comprehensive geological, hydrogeological, and engineering-geological investigations are required. The Department of Hydrogeology and Engineering Geology of the Tomsk Polytechnic Institute, together with the trust “Kuzbassuglegeologiya,” is conducting hydrogeological and engineering-geological investigations of the industrial districts of Kuzbass. The present work, carried out in accordance with the department’s general plan, briefly illuminates the geological structure of the unconsolidated deposits of the Kemerovo area of Kuzbass. The necessity of these investigations was dictated above all by the needs of expanding construction and by the poor degree of study of the unconsolidated sequence, especially the cover of loess-like rocks, which serve as foundations for structures at many construction sites.

The basis for compiling the work was provided by materials from investigations carried out by the author in the area, literary sources, and materials from the author’s dissertation [6]. The analysis of factual material made it possible to clarify the physical-geographical conditions of the area, to outline the general scheme of the sequence of formation of the unconsolidated strata, and to reveal the principal regularities in the development of the alluvial waters of the area. At the same time, the scheme of formation and the subsidence properties of the loess rocks of the area were clarified.

Physical-Geographical Conditions of the Area

The surface of the Kemerovo area, like that of the entire northern half of Kuzbass, is an elevated, gently rolling plain, dissected near the city of Kemerovo by the broad valley of the Tom River. Along the left bank of the Tom, south of the city of Kemerovo, extends the steppe belt of Kuzbass. In turn, the right-bank part of the area is covered by forest-steppe, which to the north and northeast, beyond the limits of the area, gives way to dark taiga. The relief of the plain is not simple, as it appears upon general acquaintance with the area. Alongside young Upper Quaternary forms—ridges, ravines, and valleys—ancient planation surfaces have been preserved in places, reflecting earlier stages in the development of the country. In the area, south and north of the valley of the Tom River, it has been possible to ...

to establish four ancient planation surfaces. The highest of them is represented by the flat main watersheds of the Kuznetsk Plain. The second is distributed along watersheds of the second order and, finally, the third and fourth, separated by an escarpment, are represented by level platforms scattered along low watersheds descending toward the modern valleys of large rivers. They are sometimes attributed to the high ancient terraces of the Tom River [6].

The entire central part of the region lies within the valley of the Tom River, which near the city of Kemerovo has the form of a basin reaching up to 16 km across. In this section of the valley five terraces are clearly delineated; they create the stepped form of the valley and, because their surfaces are only weakly dissected, are exceptionally convenient for the placement of construction. The principal elements of the terraces are shown in Table 1.

The severe and continental climate of the region is characterized by a cold and prolonged winter and a short, often hot, summer. The region lies in the belt of negative mean annual temperatures. Minimum temperatures in January and February often fall to 50°. Severe winters with snowstorms and frosts have an adverse effect on economic activity and the development of the region. The depth of freezing of soils and grounds in open places sometimes reaches up to 3 meters, but more often does not exceed 2 m. In the region southerly, southwesterly, and southeasterly winds predominate, which should be taken into account in developing the territory of the region.

Of great importance for the development of the region is the Tom River, which flows near the city of Kemerovo from east to west. Kemerovo and many other cities are supplied by its water. However, despite the extensive use of the water of the Tom River for water supply, in recent years, owing to the increased discharge of untreated waters, a deterioration has been noted in the quality of the water of the Tom River and other rivers of Kuzbass. It is necessary to strengthen the sanitary protection of the rivers of Kuzbass and to stop the discharge of untreated waters into the rivers.

Taking into account the entire complex of physical-geographical and geological conditions of the region, as well as the prevailing wind directions, the new city of Kemerovo should be developed along the left bank of the Tom River, east and southeast of the Iskitim River, since this territory is the most favorable from the sanitary and engineering-geological standpoint. This recommendation, first published by us as early as 1935, retains its significance to the present time [5].

Geology of the Unconsolidated Deposits of the Region

Studies carried out in recent years have shown a more complex structure of the region’s unconsolidated stratum than had previously been assumed. In Cretaceous, Tertiary, and Quaternary time, Kuzbass, while remaining a continental land, experienced a whole series of tectonic movements, especially uplifts and subsidences, accompanied now by erosion and now by the accumulation of unconsolidated sediments. As early as 1936, M. A. Usov noted several phases of tectogenesis manifested in Western Siberia. Some of them, including those belonging to the Mesozoic and Cenozoic, affected the Kuznetsk Basin and the Kemerovo region [17, 18].

Along with tectonic movements, exogenous processes within Kuzbass and the region changed repeatedly in connection with changes in the climate of this zone. V. P. Kazarinov established seven heterogeneous horizons of eluvium formed in Western Siberia in Meso-Cenozoic time [1]. Some of them are widespread in Kuzbass and in the region. In particular, the uneven surface of the Paleozoic cemented rocks of the region, created during a number of denudation—

... phases, is overlain not only by Quaternary deposits, but in places by Upper Cretaceous and Tertiary loose rocks of various genesis [6].

The Upper Cretaceous variegated clays, widely distributed beneath the Quaternary sequence of the high watersheds, have been exposed along the watersheds to the south and north of Kemerovo, and also in other districts of Kuzbass. They have also been found near the village of Solomino and studied in detail by A. M. Kuzmin, who noted their Upper Cretaceous age [3]. North of the city of Kemerovo these same Upper Cretaceous clays occur near the village of Berezovaya. These deposits in places reach a thickness of 6–7 m and may serve as raw material for the ceramic and other industries.

After the formation of the Upper Cretaceous and Tertiary rocks, new phases of uplift of the region and the associated denudation of sedimentary rocks took place in the area. Of the Tertiary sediments, only the weathering crust has been preserved locally, occurring here and there beneath the Quaternary sequence of the flat high and low watersheds. These deposits, represented by alluvial white clays and light-gray sands, locally reach a thickness of 3–5 m and are correlated by us with the Tertiary white clays and sands of the Lagerny Garden in the city of Tomsk [6].

In addition to the noted Upper Cretaceous and Tertiary deposits, beneath the Quaternary sequence of the low watersheds there are also redeposited variegated light-yellow, burgundy-red, and locally white clays containing quartz grus. At their base there occur flat boulders of quartzite-like sandstone and pebbles of igneous rocks. The stratigraphic position of these deposits has not been established. Apparently these are Upper Cretaceous and Tertiary clays, displaced, possibly by glaciers, and locally reaching a thickness of up to 8 m.

At the boundary between the Tertiary and Quaternary epochs, a new erosional phase took place, during which the above-listed loose rocks of the area and, in places, the underlying Paleozoic deposits were deeply eroded. On the uneven surface thus formed there remained boulder-pebble deposits, widely distributed over almost all watersheds of Kuzbass beneath Quaternary clays and loams. In the Kemerovo area these deposits are distributed on the watersheds south of the Tom River at relative elevations of 75–100 m above the Tom River, and sometimes reach a thickness of up to 2.5 m. In places they occur considerably lower, at an elevation of 45–50 m above the present river level, and belong to the deposits of the high terraces of the Tom River. However, these deposits differ substantially from the gravels of the river terraces in that their composition includes a large number of angular boulders and pebbles and clayey material consisting of dark-brown or yellow clay. These deposits are also encountered on the high watersheds south of the city of Novokuznetsk, along the eastern face of Tyrgan, along the edge of the high left slope of the valley of the Chesnokovka River near the village of Chusovitina, and at other points. Apparently these same deposits, distributed beneath the loamy-clayey sequence of the watersheds of a number of districts of Kuzbass, were noted by E. M. Senderzon [14], S. F. Trofimov [16], and V. V. Ponomarev [10]. Still earlier, mantle boulder-pebble deposits in the foothill regions of Altai, Gornaya Shoria, and Salair had been established by A. M. Kuzmin [2], K. G. Tyumentsev [15], E. V. Shumilova [20], M. D. Usov [18], and other investigators. Analogous boulder-pebble deposits occur along the Tomsk–Asino line; on the basis of flora remains found in sandy interbeds, A. A. Rogozin dates them as Lower Quaternary [12].

Thus, an exceptionally wide distribution of Lower Quaternary boulder-pebble deposits is observed in Kuzbass and, probably, throughout the entire foothill belt of the West Siberian Lowland, not only on watersheds, but also in ancient valleys and depressions. Po-

Apparently these are glacial, fluvioglacial, and in places alluvial formations, as yet poorly studied; but quite probably they will soon attract far greater attention, since locally, like the ancient alluvial placers of the Urals, they may contain industrial reserves of certain valuable minerals, and in deep pre-Quaternary depressions and valleys they may also contain artesian waters. Where these deposits lie at shallow depth, they may prove to be good ballast for road surfacing and railway construction.

Following the formation of the boulder-pebble horizon, there probably came an epoch of warm and humid climate, during which dark-brown clays formed in Kuzbass. In the Kemerovo area the dark-brown clays have been preserved as separate covers on flat divides and gentle slopes, locally reaching a thickness of 5–6 m. The same clays, distributed beneath Upper and Middle Quaternary loams, have been exposed by mine workings in the Leninsk and other districts of Kuzbass [19]. In lithological composition and stratigraphic position these clays correspond well to the dark-brown Lower Quaternary clays widespread in Gornaya Shoriya and the foothill belt of Altai [8, 9].

On the eroded surface of the brown clays or of other, more ancient rocks in the Kemerovo area, gray silty-clayey and loess-like loams are widely distributed. The former usually occur in water-saturated zones, the latter on dry, well-drained sites. Such, in its main features, is the structure of the unconsolidated deposits of the area’s divides.

An entirely different section of Quaternary rocks is observed in modern river valleys, where Paleozoic rocks are covered by young Middle and Upper Quaternary sediments, sometimes reaching a thickness of up to 55 m. In the valley of the Tom River, which is widely developed in the area, four accumulative and two erosional terraces have been established, characterized in Table 1.

As is evident from the table, especially complex sections occur in the terraces whose channel and valley deposits are unconformably overlain by Upper Quaternary loess-like loams. The fifth terrace, in composition of deposits and in the height of its base above the river, corresponds well to the fifth camp terrace of the city of Tomsk, the deposits of which are dated to the Jurassic [13, 18].

Less complex sections are observed in terraces III¹, III, and II, apparently belonging to a single erosional-accumulative cycle (Table 1). Evidently the formation of the scarps of terraces III and II coincided with an epoch of dry climate, during which mantle loess-like loams formed, covering—except for the first terrace—the deposits of all the more ancient terraces, slopes, and divides. Only the subsequent humid epoch caused a rejuvenation of the rivers. During it, floodplain terraces were formed, lacking a cover of loess-like loams.

Thus, the factual material and the correlations noted make it possible to establish four erosional-accumulative cycles that reflected the principal stages in the development of the valley of the Tom River. During them, the V, IV, III¹, and I accumulative terraces formed. In addition, in Late Quaternary time, after the completion of accumulation of the valley deposits of terrace III¹, a new downcutting occurred and erosional terraces (III and II) were formed. At the same time the region experienced a dry epoch, during which mantle loess-like loams accumulated. Subsequent humidification of the climate revived the river network and biogenic processes; floodplain terraces and modern soils formed.

Terraces of the Tom River in the Kemerovo Area
Table 1

Alluvial waters of the area

The loose deposits of the Tom River include two aquifer horizons: perched groundwater and the alluvial waters of the sands and gravels of the terraces. Perched groundwater occurs in the form of lenses in the cover loams and sandy loams, chiefly beneath negative landforms of the terraces, flat watersheds, and gentle slopes. It has an extremely unstable regime, reaches its greatest abundance in spring and during prolonged rains, and disappears in dry periods of the year. Because of their unstable regime, these aquifers cannot be recommended as reliable sources of water supply. Nevertheless, perched groundwater very often requires detailed study, since it has a major influence on changes in the stability of soils at construction sites.

Alluvial waters are widely distributed in the gravels and sands of the accumulative terraces of the Tom River. In the terraces of the small rivers flowing into the Tom, they are not distinguished by great water abundance, but in places they serve as sources of water supply for collective and state farms. The degree of water abundance of the alluvial deposits of the Tom River valley varies depending on the geomorphological features of the terraces, the facies variability of the aquifer rocks, and the conditions of recharge and drainage. The greatest static and dynamic reserves are concentrated in the sands and gravels of the low I–III terraces, whereas the gravels of the high V and IV terraces are water-bearing only in individual areas remote from deep ravines, river channels, and mining workings. Within all the low terraces that have a common gravel horizon, a confined aquifer is widely developed, occupying large areas in the district [6]. Recharge of the alluvial waters is provided mainly by atmospheric precipitation, to a lesser extent by groundwater from the underlying Paleozoic rocks, and in the first terrace also by the Tom River during rises in its level. Accordingly, the regime of the alluvial waters changes rather sharply with the seasons of the year. In chemical composition the alluvial waters belong to the bicarbonate type; outside pollution zones they are of good quality and, much more extensively than at present, can be used for water supply. Investigations have established the areas of greatest water abundance for the development of new catchment structures.

On the other hand, analysis of the geomorphology and water-bearing character of the Tom River terraces makes it possible to recommend a scheme for opening up the coal deposit that extends beneath the water-bearing gravels of the left-bank terraces. According to this scheme, coal mining should begin not beneath the III and II terraces, as was planned earlier, but beneath the IV, less water-bearing terrace. As drainage zones develop, it will be possible to proceed to coal extraction beneath the third terraces.

This scheme for the sequence of opening coal deposits occurring beneath the valleys of large rivers was recommended by us in 1951 for all districts of Kuzbass having analogous hydrogeological conditions of the terraces [6].

Geology and subsidence of loess-like rocks

Loess-like deposits are widely distributed in the area and have now been studied in sufficient detail [4, 6, 11].

These rocks cover almost all low watersheds, dry slopes, and, with the exception of the first, all river terraces. They reach an average thickness of 6–12 m, and on the IV terrace the total thickness of two horizons of loess-like loams, separated by a layer of buried soil,

in places it proved to be up to 26 m. In zones of permanent water saturation (beneath swamps, depressions, the thalwegs of hollows, beneath northern slopes overgrown with shrubs, and also beneath taiga), the loess-like loams have been altered by subsequent processes of hypergenesis and have changed into ordinary brown or gray carbonate-free loams. Below, the loams are often separated from the underlying rocks by an erosional contact. In places, especially along river terraces, lenses of sandy loam and fine sand with gravel, reaching a thickness of up to 2.25 m, occur within them.

It has been established that during the present climatic epoch, beneath the chernozems of the Kuznetsk steppe and especially beneath the taiga, the cover loess-like loams are degrading almost everywhere; in this process, first of all, their structure changes and, more slowly, the composition of the loams. As a result, in the subsoil horizon the loess-like loams, to a depth of up to 2–3 m, have lost their primary properties and have been transformed into brown carbonate-free heavy loams or even clays. In zones of excess moisture (beneath microdepressions, swamps, and below the groundwater level), processes take place that cause gleying and saturation of the soils with organic substances. Here the loess-like loams have acquired silty properties and a gray color, sometimes preserving their macroporous structure. The noted process of degradation excludes the possibility of the formation of loess-like rocks under the conditions of the humid steppe and forest-steppe of Kuzbass.

With regard to the processes of formation of the loess-like rocks of the area and of Kuzbass as a whole, the following must be emphasized.

1. The formation of the loess-like loams of Kuzbass should not be reduced to a single aeolian process or to a single soil-forming process, since the physical-geographical conditions of the dry steppe changed over time; as a result, heterogeneity is observed in the composition and structure of these rocks, as well as the presence within their thickness of lenses of sand, sandy loam, and horizons of buried soils.

2. The loess-like loams of Kuzbass, which form a continuous cover on watersheds, slopes, and in river valleys, were formed from continental unconsolidated rocks of various genesis during postglacial dry epochs.

3. The principal features of these loams (saturation with calcium carbonate, columnar jointing, macroporosity) formed under conditions of dry steppe; moreover, the process of loess formation proceeded simultaneously with, or following, the deposition of the unconsolidated rock. Under the conditions of the present, more humid climatic epoch, the loams of Kuzbass have entered a new phase of degradation, proceeding unevenly in time and space. Typical loess-like loams possessing the property of subsidence have been preserved only in the upper horizon in dry, well-drained areas, where degradation processes are absent or are manifested extremely weakly. These loams are characterized by a distinctly expressed silty composition, the presence of up to 10–12% calcium carbonate, high macroporosity, and low natural moisture content. The latter varies depending on the seasons of the year; therefore some properties of the loess-like loams do not remain constant. With changes in moisture content, the subsidence of the loams changes especially intensively. At a degree of moisture above 0.7–0.8 they completely lose the property of subsidence [6]. It has been established that the loess-like loams of the lower horizons, owing to increased clayiness and moisture content, are almost entirely non-subsiding. Subsidence in the cover loess-like loams, moreover, occurs only when they are soaked under load. Settlement during soaking without additional load, as occurs in the loess-like rocks of the southern regions of the USSR, is not observed. Hence the magnitude of settlement of structures erected on loams subsiding under load ...

in loams, will evidently prove to be proportional to the applied additional load and to the thickness of the compressible wetted stratum, and not to the total thickness of the collapsible loam, as is stated in the existing technical standards for all loess-like soils without exception. Therefore, in the course of investigations and in the design of structures, the method for determining the magnitude of settlement of structures designed on loess rocks of Kuzbass that are collapsible under load, developed by us as early as 1951 [6, 7], should be more widely applied. The use of this method for determining the magnitude of settlement of structures designed on loams collapsible under load ensures a reduction in the volume of anti-settlement measures and, consequently, in the cost of construction work.

Conclusion

Thus, as a result of the analysis of the research materials and the correlations carried out, the sequence of formation of unconsolidated deposits has been established for the first time for the Kemerovo area; the alluvial waters of the area have been characterized; the principal physical properties of loess-like deposits have been investigated; and a method is recommended for determining settlement of structures that makes it possible to reduce the volume of construction anti-settlement measures. The author believes that this work will be useful for solving questions concerning the geology and hydrogeology of unconsolidated deposits, as well as construction conditions on the loess rocks of Kuzbass.

REFERENCES

1. Kazarinov V. P. Meso-Cenozoic formations of the weathering crust of Western Siberia. Report at the Third Usov Conference, 1948.

2. Kuzmin A. M. Materials for subdividing the glacial period in the Kuznetsk-Altai region. Izv. Zap. Sib. Otdeleniya Geolkoma, VIII-2, 1929.

3. Kuzmin A. M. Materials on the geology and geochemistry of the area of the Solominskoe deposit of Upper Devonian limestones (northern part of Kuzbass). Trudy Tomskogo Gosuniversiteta, vol. 124, 1953.

4. Kuchin M. I. Loess-like rocks of the Ob region and the Kuznetsk Basin. Sbornik nauchnykh trudov TISI, Tomsk, 1960.

5. Nifantov F. P. Engineering-geological characterization of sites of the socialist city of Kemerovo. Vestnik ZSGU, issue 2, 1935.

6. Nifantov F. P. Geology of unconsolidated deposits and physical properties of cover loess-like rocks of the Kemerovo area of Kuzbass. Candidate dissertation, 1951.

7. Nifantov F. P. Determination of settlement of structures on loess-like loams of Kuzbass. Izvestiya TPI, vol. 90, 1958.

8. Petrov B. F. Ancient weathering crust and post-Tertiary deposits of the western part of the Kuznetsk Alatau. Tr. Pochvennogo in-ta, vol. XIX, issue 2, 1939.

9. Petrov B. F. On the loess of Altai. Byull. Komissii po izucheniyu chetvertichnogo perioda, No. 11, 1948.

10. Ponomarev V. V. Hydrogeology of the Jurassic of Central Kuzbass. Kuzbassuglegeologiya, 1949.

11. Rudchenko E. G. Colloidal-dispersed minerals of loess-like loams of the Kemerovo area in connection with the conditions of their formation. In: Problems of construction on loess-like soils, Voronezh, 1961.

12. Rogozin L. A. Geological sketch of the area of archaeological excavations on the bank of the Tom River at the mouth of the Basandaika River. Trudy Tomskogo Gosuniversiteta, vol. 98, 1947.

13. Radugin K. V. Materials on the geology of unconsolidated deposits of the Tomsk–Taiga area. Materialy po geologii Zap. Sib. kraya, No. 9, 1934.

14. Senderzon E. M. The Vorob′evo coal deposit of the Osinovskii coal-bearing area of Kuzbass. Kuzbassuglegeologiya, 1946.

15. Tyumentsev K. G. Geological sketch of the basin of the Kondoma River in the southwestern part of the Kuznetsk Alatau. Izv. Zap. Sib. Geol. upravleniya, issue 2, 1931.

16. Trofimov S. F. Hydrogeological sketch of the Leninsk area of Kuzbass. Sov. geologiya, No. 11, 1938.

17. Usov M. A. Phases and cycles of tectogenesis of the West Siberian region. Publication of the West Siberian Geological Trust, Tomsk, 1936.

1. Usov, M. A. Principal results of the work of the West Siberian Geological Trust on the study of the Quaternary geology of Western Siberia. Bulletin of the West Siberian Geological Trust, No. 1, 1937.

2. Fomichev, V. D. The Kuznetsk Coal Basin. Institute of Geological Sciences, Academy of Sciences of the USSR, issue 11, 1940.

3. Shumilova, E. V. Terraces of the Tom River in its middle course. Materials on the Geology of the West Siberian Territory, issue 8, 1934.