On the Gold-Bearing Character of the Southwestern Slope of the Kuznetsk Alatau

Yu. G. Shcherbakov

(Presented by Professor Doctor F. N. Shakhov)

Certain Features in the Structure of the Gold-Bearing Placers of the Region

Despite all the diversity of the placers of the region, there are many common features in their structure. The most usual section of a valley placer may be represented as follows.

1. Soil–vegetation layer — 0.2–0.4 m.
2. Gray or brown clay, sometimes with a reddish tint — 0.4–3.5 m.
3. Pebble gravel cemented by clay — 2–4 m.
4. Fine sandy pebble gravel cemented by clay — 1–1.5 m.

The lower layer, and sometimes only its lower part, constitutes the gold-bearing “sands.” In channel placers the soil–vegetation layer and the clay layer are absent, while the layer of pebble gravels that do not contain gold usually has a smaller thickness. Sometimes interbeds or lenses of clay appear in the lower layer. Such a section is typical of placers occurring in valleys with a gradient from 0.005 to 0.015. At smaller gradients, which is rather rare, the thickness of the “sands” increases to 2–3 m, and the thickness of the “peat” to 10 meters and more. In the placer of the B. Sueta River, the average thickness of all the alluvium does not exceed 3.5–5.0 m, but in areas with a gentle thalweg it increases to 15 m. An increase in the thickness of the alluvium is also noted in the upper reaches of streams, where their discharge is so small that the accumulation of loose material proceeds more rapidly than its removal; at the same time, the degree of its rounding sharply decreases.

If a placer originates at the very headwaters of a stream, then there the gold-bearing bed is usually not expressed, and the metal is dispersed throughout the entire mass of loose deposits. This is what characterizes the “hollow” stage of a placer.

In a number of the small rivers observed by us, the alluvial deposits in the middle and lower courses have a thickness on the order of several meters, with a clearly expressed gold-bearing bed. At their heads the thickness increases, reaching 11 m, and the regularity in the distribution of gold disappears. In many placers, gold distribution was observed throughout the entire layer of river deposits. Such a character of metal distribution indicates the very initial stage of placer formation and, accordingly, the proximity of the feeding sources, which may be eroded by them

gold-bearing deluvium or terraces. Sometimes, together with an increase in the thickness of the alluvium in the headwaters of a gold-bearing brook, a rather sharply expressed layer of “sands” is observed; however, where the valley has a considerable gradient, its thickness is usually small.

Such a regularity is characteristic of brooks with high and steep sides. In spring, during the rapid melting of a large mass of snow, they carry an enormous quantity of water, which is capable of reworking all of their alluvium. In this process, the gold is concentrated in the bed at the very bedrock.

Of special interest are the regularities in the structure of placers in areas where the gradient of the thalweg increases. Steep sections are found in all gold-bearing valleys, though, of course, not necessarily within the limits of placers. These sections are “steps” developing by deep erosion and gradually advancing toward the headwaters. Their length is usually from 300 to 1500 m, with an average gradient over this interval from 0.015 to 0.04 in the largest of them, and up to 20° in some small brooks. With a gradient of about 0.04 in rivers with a large discharge, there is a considerable decrease in the thickness of the alluvium, many boulders appear, the thickness of the “sands” decreases, and the continuity of the pay streaks disappears. The placer acquires a complex structure, and the gold is distributed in “bushes.” But the most important point is that, usually, the placer is not impoverished in this process; often, on the contrary, it is enriched owing to the removal of a large mass of stony material. For example, the Aptazin placer, with a valley width of 30 to 250 m, has a thalweg gradient in narrow places of up to 0.03 and a thickness of “sands” of 1 m. The maximum concentration of metal was recorded in the steepest sections of the valley, reaching several tens of grams per 1 m³ of “sands.” Similar enrichment of steep sections was observed in a number of placers of the district. Yu. A. Bilibin, considering the process of erosion of an old placer and formation of a new one, comes to the conclusion that the existing placer is completely eroded within the entire erosional step and that the gold is transported for a distance approximately equal to the length of such a “step.” The discrepancy between the distance over which the placer has been transported and the length of the erosional step, which is measured in hundreds or thousands of meters, he explains solely by the retention of gold in fractures of the bedrock. The structure of the valley floor in our district within steep sections is, in turn, step-like and forms, as it were, a series of ledges or small rapids alternating with sections of relatively gentle bottom. The involvement in motion of the entire thickness of alluvial material, and with it the gold-bearing bed, occurs only within such rather rare and small rapids. From this we conclude that within the interval of an erosional step there is repeated erosion of the gold-bearing bed and an equally repeated redeposition of it. With each such erosion, the transport of gold takes place only over a distance approximately equal to the length of the rapid. New deposition of the metal and formation of a layer of sands occur immediately below the ledge, whereas the main mass of stony material continues to be carried farther. The covering of the newly formed section of the “bed” by peat begins following the advance of the ledge upstream, i.e., when the metal no longer reaches this section. In the bed covered by peat, the gold is no longer displaced and is not “rounded” until the next erosion.

It is very difficult to determine precisely the total length of sections within an erosional step in which the entire layer of metal-bearing alluvium becomes active, i.e., is set in motion. Judging from the length of sections with an alluvium thickness of less than 50–70 cm, i.e., the maximum possible thickness of the mobile layer, then, with the valley incised by 20 m, the length of such sections does not exceed several tens of meters, located

…being closely dependent on the bedrock. Easily eroded rocks, such as chlorite schists, produce steeper and, consequently, shorter steps; for example, granites produce gentler and longer ones. The total length of such “steps” is the most probable value of the displacement of the placer downstream during the deepening of the valley (Fig. 1).

Diagram

of the erosion and transfer of a channel placer into the stage of deep valley erosion

Erosional step, 300–2000 m
Average gradient, 0.02–0.04

Conventional symbols:

• Gold-bearing sands;
• Gold-free alluvium—“peat”;
• Bedrock—“bedrock floor”;
• Sections of erosion of the placer and abandonment of gold. Length of the order of 5–30 m. Gradient—0.06–0.35.

Fig. 1

Within the area under consideration, the lower level of the ancient peneplain is clearly established, occurring in different places at elevations from 450 to 550 m. The formation of the modern river network began with the incision of valleys precisely at this level. Its elevation above the thalweg of the gold-bearing valleys of various placers varies, on average, from 50 to 220 m. If we assume that the deepening of the valleys from the beginning of their incision proceeded in a manner analogous to the modern one—and the complete analogy in the structure of the high and the lowest terraces gives us grounds for this—then, having arrived at the conclusion that alluvial gold is transferred, in the stage of deep valley erosion, over short distances measured in the first tens of meters when the valley is deepened on average by 20 meters, the small length of most placers becomes understandable and readily explicable, as does the somewhat rough but nevertheless proportional relationship between the length of placers and the depth of the valley. About 50 placers in the area studied, whose gold supply occurs only in their headwaters, have a total length of only 250 to 1500 m. In all longer placers, including the richest and most extensive ones, stretching for more than 10 km, additional sources of supply are clearly established, located in the valley sides. Nor is the very position of all long placers along the principal structures, which controlled the distribution of gold-ore deposits, accidental.

In the sides of most valleys containing commercial placers, fragments of terraces of the modern hydrographic network are encountered, more often low ones and more rarely high ones—up to 100 m—also with elevated gold content. In a number of cases the content is profitable for mining. Gold-bearing terraces very often serve as the principal or an additional source of gold for the valley placer. The rather widely held opinion that the sources of terrace gold are always located somewhere beyond the limits of the basin of the given river or stream cannot be considered correct. Such an opinion is to a certain degree applicable to terraces of ancien-

hydrographic network, the direction of which may not have coincided with the present one. But at the present time the remnants of the ancient network, preserved in the form of terraces, can be observed only in the watershed areas of the modern relief. In a number of sectors their remnants have been found. We come to the conclusion that the presence of gold-bearing terraces in modern valleys is not a complicating factor in the search for primary sources of gold, since the limited possibilities for its displacement do not allow modern, and still less terrace, placers to arise at a considerable distance from the ore deposit. This circumstance significantly narrows the areas of prospecting, correspondingly increasing their effectiveness.

Morphological Types of Placer Gold and Their Genetic Significance

1. Unrounded, often “rocky” gold is usually characterized by extremely irregular forms, often in the shape of hooks or wires, with sharp edges and corners, very often in intergrowths with quartz or brown iron ore. On the surface of such gold particles, impressions of pyrite crystals are sometimes observed. Usually such gold has a pale-yellow color, sometimes with a greenish tint. However, already at this stage the first signs of rounding are observed. Of several hundred gold particles examined under a binocular microscope, which to the unaided eye appear completely unrounded, only very few actually prove to be such. The initial signs of rounding are expressed in the rounding of the most protruding corners and in the appearance of a rough surface on such roundings. To this group, according to the degree of rounding, have been assigned both completely unrounded and weakly rounded gold, since they always accompany one another and it is impossible to distinguish separate areas of their distribution (Fig. 2, 1).

2. Rounded gold of isometric forms is distinguished by smoothed edges and the absence of sharp projections. The form is often isometric; rods are encountered more rarely. Sometimes depressions inherited from the primary forms are preserved, in which intergrowths with quartz or rock can occasionally be seen. The surface of the gold in the primary depressions is clean; a light-yellow color of the gold is characteristic, whereas the areas that have undergone rounding have a dull, rough surface and bear traces of impacts and scratches (Fig. 2, 2).

3. Rounded gold of discoid forms, often in the form of elongated plates or leaflets, always bears traces of numerous impacts in the form of pits, furrows, and scratches. In most cases it is completely freed from rock. The edges of the disks are more often thinner than the central parts. All transitions are observed from discoid forms to leaflets, the thickness of which usually varies from 0.05 to 0.25 mm. Such leaflets characterize the highest degree of “rounding” of alluvial gold. In the origin of discoid forms, evidently, abrasion plays an essential role (Fig. 2, 3).

Let us dwell on some features of the distribution in the placers of the district of the distinguished morphological types of gold. Unrounded “rocky” gold was observed in many eluvial-deluvial placers located at the heads of small rivers. Such gold is also encountered in amounts from 60 to 90% in the upper parts of streams, in the basins of which deluvial placers are known, and in many other slope placers. Up to 10–20% of it has been noted in the sands of large valley and terrace placers in sectors where their gold is being replenished by ...

…by gold as a result of the river’s reworking of gold-bearing colluvium. It should be noted that in such sectors there is a sharp increase in the gold content of the placer, often accompanied by an increase in the thickness of the pay layer.

Fig. 2. Morphological types of placer gold. 1. Unrounded, often “rocky” gold. 2. Rounded gold of isometric forms. 3. Rounded gold of discoid forms.

Rounded gold of isometric forms begins to occur, in subordinate amounts, together with unrounded gold already in the upper reaches of trough placers. At the same time, its highly characteristic forms appear here—little balls, rods with rounded ends, and forms resembling rice grains. All such gold particles have a rough surface. Taking into account the extremely insignificant distance over which this gold could have been transported, and its forms, it may be assumed with a high degree of probability that the rounding of these gold particles took place in scours of the bedrock.

during their prolonged rotation. These forms have been noted in areas where terraces are absent; consequently, the possibility of transported rounded gold being carried in through their reworking is excluded. In addition, at the sampling sites, among the predominant mass of entirely unrounded stone material, there is occasionally fairly well-rounded pebble of hard rocks, chiefly quartz and quartzite, also round or ellipsoidal but not flattened, which, as Yu. B. Bilibin has shown, likewise indicates its formation by rotary motion in potholes of the bedrock. Thus we see that already at the very heads of channel placers, in depressions of the bottom, there are conditions for the rounding of gold without significant transport. Therefore, the occurrence, together with unrounded gold, of isometric forms of rounded gold is to the same degree an indicator of the proximity of the primary deposit as is the presence of only unrounded forms.

Isometric forms of gold quantitatively predominate over other morphological types in the lower, and sometimes also the middle, parts of most of the district’s short placers, and are very characteristic of those sections of long placers where they receive additional supply through the river’s erosion of metal-bearing colluvium. For such sections of placers, in addition to an elevated metal content, a great diversity of gold forms is characteristic.

The position of discoid gold in placers is just as definite as the position of gold particles of the preceding two morphological types. Quantitatively, it sharply predominates in valley, channel, and some terrace placers of large valleys. In areas lying the first hundreds of meters away from the sources of supply, this type of gold almost completely displaces all others, and the alluvial placers of large valleys often end with it. Up to 10–30% of discoid gold is present in many short placers. It begins to occur in placers and, in individual cases, reaches 30% of the remaining gold already 200–400 m from the head of the placer of a small stream. It sharply predominates in the sands of small tributaries in that part where they intersect the gold-bearing terraces of the main valley. Such a mode of supplying channel placers with gold through erosion of the high terraces of the main gold-bearing valley does occur within the district under consideration, but it must in no case be overestimated; otherwise this may lead to an erroneous assessment of the prospects for lode gold, as happened in one of the district’s areas.

In the present case, the right gold-bearing tributaries of a large river cut, in their lower and sometimes also middle courses, through its ancient terrace, from which a certain amount of rounded gold is derived. At the very heads of the gold-bearing streams, however, unrounded gold and rare gold particles of isometric forms predominate. This gold could not have come from the ancient terrace, because it shows no traces of reworking or redeposition, and the terrace is situated much lower. Moreover, the composition of the alluvium of these streams corresponds to the composition of the rocks being eroded: limestones, greenstone effusives, etc., whereas the alluvium of the river and its terraces contains a significant amount of gabbro pebbles, fragments of which are nowhere present in the alluvium of the tributaries. Finally, in the alluvium of all the gold-bearing streams there are many fragments of oxidized equivalents of disseminated pyrite ores (gossans), containing, according to several analyses, from traces to 22 g/t of gold, as well as limonite casts and dense brown ironstones, sometimes with relics of sulfides—that is, rocks indicating the erosion of metasomatic ore bodies rich in sulfides and containing gold. The gold content of the ore zone eroded by the streams is also indicated by analyses of brown ironstones collected in 1942.

according to K. V. Potemkin’s data, and showing a gold content of from 1 to 3 g/t. At the heads of some small streams, gold has been found in the deluvium. From these still incomplete data it is evident that the negative assessment of the area was given erroneously, and that it deserves the undertaking of prospecting and exploration work for lode gold.

Thus, analysis of the degree of roundness of gold can help guide the search for primary deposits. It should also be noted that among the gold grains studied, transitional morphological varieties were often encountered, but there is no need to separate them into special groups, since they are usually found most often together with the type to which they are most similar.

Possible Primary Sources of Gold in the Region

Within the area under study, three genetic types of hypogene gold mineralization may be distinguished: skarns, gold-sulfide impregnations, and veins. The characteristics of the types distinguished will be given in connection with the structural and lithological features of the enclosing complexes, since these features largely determine the morphological traits of the deposits and their practical value.

Skarns

The contact type of gold mineralization is rather weakly developed in the region. Poor gold-sulfide mineralization is known in light-colored skarns occurring among marbles, near the contact with Cambrian granodiorites (the basin of the Ploskaya River). The limited distribution of this type within the area, the small size of the deposit, and the low gold contents do not make it possible to place great hopes on it, although in neighboring regions industrial gold deposits in skarns are known.

In magnetite skarns of some contact deposits of Mountain Shoria, the content of gold associated with the quartz-sulfide stage of mineralization reaches 2–4 g/t. Of known interest is the question of the fate of gold during the beneficiation of magnetite ores from deposits: whether the tailings become enriched in gold, and whether it can be extracted from them.

Zones of Gold-Sulfide Impregnations

Analysis of the conditions governing the occurrence of manifestations of disseminated gold-sulfide mineralization in the region reveals that most of them are confined to structurally weakened parts of carbonate sequences developing along contacts—often tectonic contacts—between rocks of sharply different relative competence. Usually these are contacts between carbonate and effusive-sedimentary or intrusive complexes. The brecciation zones arising in limestones during the period of folding control the formation of secondary quartzites, which, in turn, subsequently undergo local crushing. Such, often morphologically complex, zones of crushing of secondary quartzites are the most favorable for the additional penetration of ore-bearing solutions and the development of metasomatic disseminated gold-sulfide mineralization. Everywhere, the studied mineralized areas are accompanied by eluvial-deluvial placers and by alluvial placers fed by them. The regularities identified in the structure of the placers and in the distribution within them of morphological types of gold grains helped to discover sources of gold in the estuarine parts of some rivers, where the analysis of one of three samples taken from

gold–sulfide, gold–scheelite, and gold–barite–fluorite formations.

The most widespread are the quartz veins of the gold–sulfide formation. At the same time, a rather poor content of sulfides in the veins is characteristic. The usual associates of gold in veins of this formation are pyrite, arsenopyrite, pyrrhotite, sphalerite, chalcopyrite, galena, and pale ores. Molybdenite occurs more rarely. In addition to sulfides, iron mica is often present in the veins. In veins occurring among limestones, calcite is often noted, the amount of which sometimes increases to 30–40% relative to quartz. It should be noted that the minerals listed occur in different veins in different proportions; often only some of them are present, but usually all of them occur within one vein field and over a small area (for example, the Zhelsai deposit). Veins of the gold–scheelite formation occur somewhat separately; in these, besides gold and scheelite, ordinary sulfides are also present, though in subordinate amounts (the Tebechek deposit). The barite–fluorite formation of gold mineralization, known in the southern part of the district, stands out especially. Its post-Carboniferous age is established on the right slope of Severny Creek, where Carboniferous sandstones are cut by barite veinlets. A spatial connection is noted between barite–fluorite mineralization and young disjunctive disturbances. The industrial significance of this type of mineralization is not yet clear, but it deserves detailed study.

The quartz veins most pronounced in strike and thickness occur in rupture fractures of massive rocks—diorites and granitoids of the Orton and Tebechek complexes. With thicknesses rarely reaching 1 m, the veins are often traceable along strike for 60–more than 100 m, and in individual cases for more than 300 m (the Tebechek deposit). Veins equally persistent in strike and thickness occur in the Zhelsai ore field, likewise in rupture fractures among pyroxene porphyrites. A type of vein is widespread that is localized in contacts between rocks with sharply different relative competence: diorites and limestones or granites and limestones, limestones or shales and effusives. These veins are comparatively well sustained along strike, but their thicknesses are small—from 10 to 30 cm, more rarely up to 1 m. The origin of the fractures is due to separation along the contact during tectonic deformations. This type of vein is most developed in the Zaslonsky and Orton districts. The gold content in the veins is uneven, but high contents have not been observed at the surface, and these veins have not been explored at depth. It should be noted that there are numerous barren veins composed of milky-white quartz and occurring in similar structures. An abundance of quartz fragments in the alluvium of creeks is most often caused precisely by an abundance of barren veins. Therefore, this feature by itself, when directing prospecting without taking other regularities into account, can only divert attention from real sources of gold. As study of the composition of the alluvium has shown, there is no dependence between the quantity of quartz fragments and gold content, still less with its intensity.

Another, morphologically sharply distinct category of quartz veins occurs in the metamorphic schists of the Tashelga–Kondoma zone of folding, whose tectonic structure (characterized above) has caused, over hundreds of kilometers, the development of veins which, as a rule, are very small in thickness—from 1–2 to 10 cm, more rarely up to 30–40 cm. Vein deposits under the conditions of the folding zone may be of industrial interest only where groups of veins are significantly brought together,

sufficiently rich to ensure extraction of the entire mass of enclosing rock. No such deposits are known in the region.

In conclusion it remains to say that, as a result both of field observations and of analysis of all the available material on vein gold–quartz mineralization in the region, no data have been obtained that would increase the prospects of this type of deposit.

On the Relation of Gold Mineralization to Intrusions

Only within the area under study are at least three epochs of hypogene gold mineralization established. The first is connected with the appearance of Cambrian (Salair) diorites, granodiorites, and, to a lesser extent, granites. To the Salair complex we assign the Porozhinsky, Ortonsky, and Asyrsky massifs, and several smaller ones along the Mrassu River. Their lower age boundary is determined by the fact that, occurring among the Kondoma suite, whose age is, to a certain degree conventionally, considered Lower Cambrian, they metamorphose its deposits. Their upper age boundary is determined by the presence of numerous pebbles of analogous composition with the Porozhinsky granites and Ortonsky diorites and granites in the basal conglomerates of the Tremadocian of the Taszk region. The connection of gold mineralization with the named complex is indicated by the close spatial association with it of gold-ore occurrences in the basins of the Zaslonka and Orton rivers and by the known gold content of the Ordovician conglomerates.

The second epoch is established in connection with the Caledonian complex of granodiorites, diorites, and syenites, on the basis of contact gold mineralization in magnetite skarns of the Telbes, Kaz, and Taz groups of deposits. It is possible that the known gold content of the Devonian conglomerates is connected with the erosion of deposits of this epoch of mineralization.

Within the area studied, we have assigned the Kubes and Mastakol massifs to the Caledonian intrusive complex. The lower age boundary of the Mastakol massif is determined by contact metamorphism of Ordovician deposits. The upper age limit is established on the basis of abundant pebbles of martite discovered by V. G. Rutkevich in conglomerates that underlie a very gently dipping effusive sequence in the neighboring Kaz region, dated as Lower Devonian. The origin of the martite pebbles through erosion of the Taz magnetite ores is beyond doubt. The duration of the period of continental conditions that occurred between the middle Silurian and the Lower Devonian is indicated by the absence in the region of marine deposits of this age. The presence of a weathering crust during this period may be judged from the ancient karst widely developed in the area of the Taz deposits. Through careful study of the karst, I. S. Rutkevich determined its post-ore age.

The third epoch of post-Carboniferous gold–barite–fluorite mineralization may be connected with Variscan granites and granodiorites. To this complex we assign the Saralyksky granite massif and granodiorite stocks.

Such a clearly manifested inheritance of metallogenic features by magmatic complexes succeeding one another in time can most reasonably be explained by following F. N. Shakhov’s theory on the origin of granitoid magmas in places where the corresponding massifs are now found.

Of the three established epochs of gold mineralization, the most important in the region is the first, connected with Cambrian magmatism. In this case, most of the gold-ore occurrences are confined, as noted—

... by A. Ya. Bulynnikov, and, for other districts of the Kuznetsk Alatau, to moderately acidic varieties of granitoids and to diorites. Deposits of the second epoch of ore formation are less widely developed. The boundaries of the area of distribution of Variscan mineralization are somewhat unclear. It should only be noted that it is commonly associated with young disjunctives.

Conclusion

The work carried out makes it possible to draw the following principal conclusions.

1. During the erosion of placers at the stage of deep valley erosion, gold is transported a considerable distance, depending on the bedrock, but, as a rule, not exceeding three to four times the amount of valley deepening.

2. The presence of unrounded gold in placers always indicates the proximity of a primary source, since gold begins to become rounded already in the deluvium.

3. At the very heads of trough placers, in depressions of the bottom, conditions exist for the rounding of gold without transport. Therefore, the joint occurrence, together with unrounded gold, of isometric forms of rounded gold also indicates the proximity of a primary source.

4. All short placers, chiefly trough placers, in which unrounded gold predominates, should by their heads point to the location of primary sources, and analysis of these sectors will always suggest their position in the general structure.

5. Only in those sectors of placers that contain unrounded gold, where the process of its release from the parent rock has not been fully completed, is it possible to find rocks composing the ore body and its leached or oxidized parts.

6. All long placers of the district are complex and have several sources of supply, which adjoin sectors of the placer enriched in unrounded gold and in isometric forms of rounded gold. The total metal content here is considerably elevated.

7. The presence of gold-bearing terraces in a valley does not complicate the search for primary sources, since the limited possibilities for the transport of placer gold do not allow modern, and still less terrace, placers to arise at a considerable distance from the ore deposit.

8. The most promising gold deposits in the district belong to the metasomatic type. In limestones they are usually developed with secondary quartzites in crushing zones along their contacts with the effusive-sedimentary sequence of the Lower Cambrian or along the contact with diorites and granodiorites. In silicate rocks, in zones of folding, they form lens-shaped deposits of disseminated sulfide ores.

LITERATURE

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2. Bulynnikov A. Ya.—Gold-ore formations and gold-bearing provinces of the Altai-Sayan mountain system. Tomsk, Publishing House of Tomsk State University, 1948.

3. Gelmersen G.—On the Urals and Altai. Mining Journal, 1838, II, No. 4.

4. Helmnhacker R.—Beiträge zur Kenntniss der secundären Goldlagerstätten. Berg- und Hüttenmännische Zeitung, 1891, Nos. 7, 9, 20, 26, 30, 40, 41, 46, 52; 1892, No. 2.

5. Kuzmin A. M.—Materials on the stratigraphy and tectonics of the Kuznetsk Alatau, Salair, and the Kuznetsk Basin. Proceedings of the Siberian Branch of the Geological Committee, vol. VIII, issue 2, Tomsk, 1928.

6. Kyuz A. K.—Materials on the geology of gold of the western slope of the Kuznetsk Alatau. Collection “Works on Gold Prospecting,” 1935, issue 1.

1. Makarov, A. F. Geological investigations in the systems of the Kondoma, Mrassu, and Lebed rivers. Tomsk, 1904.

2. Obruchev, V. A. Geological survey of the gold-bearing regions of Siberia. Gold and Platinum, 1910, No. 9, St. Petersburg.

3. Reutovsky, V. S. The gold-bearing region of the Tomsk mining district. Vestn. Zolot., 1896, Nos. 6–12.

4. Shakhov, F. N. On the question of the origin of granite magmas. Mineralogical Collection of the Lviv Geological Society, 1956, No. 10.

5. Shchurovsky, G. Geological journey through the Altai. Moscow, 1846, X.

Corrections and Noticed Misprints

In S. A. Stroitelev’s article “Investigation of the Crystallization of Epsomite and Mirabilite,” for technical reasons curly braces have been replaced by square brackets, for example: [100] instead of {100}, etc.