Lithological and Geochemical Features of Proterozoic Deposits in the Area of the Village of Katyushkina

(Batenevsky Ridge, Kuznetsk Alatau)

A. F. Senakolis

(Presented by Professor A. M. Kuzmin)

The most ancient formations developed in the area of the village of Katyushkina are the deposits of the Goldzhinskaya Suite, first distinguished by V. D. Tomashpolskaya near the village of Goldzha. Among the organic remains in it, problematic forms Saralinskia and Osagia have been encountered. The base of the suite has not been found in the area, since its contact with the Cambrian rocks situated to the south is tectonic. On the basis of the problematic forms and of its occurrence beneath faunistically characterized Cambrian formations, the age of the Goldzhinskaya Suite is determined as Proterozoic. In adjacent territories its analogues are known under the names of the Goludennaya [2] and Bidzhinskaya suites [1].

The composition and structure of the Goldzhinskaya Suite were studied on the left side of the Katyushkina ravine, where it is represented most completely. The exposure of the side is satisfactory; in places the suite is cut by small bodies of granodiorites and gabbro. The section begins at the head of the Katyushkina ravine, which separates the Cambrian formations developed to the south from the deposits being described. The study showed that the suite can be subdivided into two parts. Within the lower carbonate-terrigenous subsuite, 11 members have been distinguished, differing in the composition of the constituent rocks (Fig. 1).

The lower, first, member consists mainly of black biotite clay shales with a homogeneous texture. In places the rocks contain a small admixture of pyrite cubes less than 1 mm in size. Among the clayey rocks in the lower part of the member there is a bed of light-gray calcareous phyllitized graywacke sandstones. In the roof the member is cut by a body of gabbro, which obscures its relationship with the overlying deposits. The incomplete thickness is about 200 m.

The second, sandy-clayey, member is represented by an alternation of graywacke and biclastic sandstones, siltstones, clayey

Fig. 1. Structure of the Goldzhin Formation and the nature of variation in rhythm thicknesses: 1—gravelites, 2—sandstones, 3—clayey shales, 4—sandy limestones, 5—clayey limestones, 6—fine-grained limestones with relicts of a fine-clastic structure, 7—thin-bedded fine-grained limestones, 8—gabbro, 9—granodiorites.

shales, often transformed into biotite-sericite phyllites. The thickness of beds of clay shales and siltstones does not exceed 5 m; the thickness of sandstone beds is usually 10–20 m. In the clay shales numerous traces of erosion and fragments of similar clayey rocks are visible. The incomplete thickness of the member is 160 m.

The third member lies, without a noticeable break, upon the one just described. A characteristic feature of its structure is the alternation of clay shales of thin-bedded texture and shaly limestones, often with nests of pyrite. In the roof it is cut by a body of granodiorites. The gradual transition between the formations of the second and third members allows one to suppose that here we are dealing with a large rhythm, more than 350 m thick, which began with sandstones and siltstones, gradually replaced upward in the section by clayey and carbonate deposits. The thickness of the third member is 170 m.

The overlying fourth member is separated from the third, as already noted, by a 300-meter body of granodiorites, traceable for 2 km to the southwest along the strike of the sequence, owing to which part of the section is concealed. The member is composed mainly of clay shales, more often homogeneous, more rarely thin-bedded; its thickness is more than 500 m.

The fifth member consists entirely of sandy shaly limestones, often displaying parallel and oblique bedding. Its incomplete thickness exceeds 75 m.

Higher up, beyond a gabbro sill, part of the sixth, terrigenous-clayey, member is exposed. Its thickness here is only 24 m. It is composed of graywacke and bioclastic sandstones, siltstones, and clay shales, analogous to those exposed in the second member. Unlike the latter, here clay shales play a substantial role, with a subordinate significance of fine- and coarse-clastic rocks.

The seventh member lies upon the one just described with erosion. At its base fine-pebble conglomerates and gravelites are exposed; higher up they are replaced by graywacke and bioclastic sandstones. The member ends with clay shales and siltstones. Its thickness is about 40 m.

The eighth member begins with a 4-meter bed of clayey limestones. Above, over 60 m of the section, beds of clayey and sandy shaly limestones, 4 to 12 m thick, alternate with thicker beds of clay shales.

The ninth member is represented by clayey shaly limestones, which constitute a marker horizon. Its thickness is about 150 m. The tenth member is composed of black “sooty” fine-grained shaly limestones, 15 m thick. Above lies the 80-meter eleventh member of light-gray, weathered on the surface and black on fracture, fine-grained limestones.

The last five members, beginning with the 7th and ending with the 11th, may be combined into one rhythm about 250 m thick. The rhythmicity is confirmed by the gradual replacement of its three constituent parts: the lower—conglomerate-clayey-sandy (7th member), the middle—clayey-carbonate (8th and 9th members), and the upper—carbonate (10th and 11th members). Within each of these parts a finer rhythmicity is observed. Thus, in the 7th member it is expressed in a decrease in the coarseness of fragments of terrigenous rocks from the base to the roof; in the middle part of the rhythm (8th and 9th members), periodicity is emphasized by an increase in the thickness of limestone beds from 4 to 12 m (from bottom upward) and by the disappearance of clayey rocks in the roof. Of the limestone beds, only the lower one contains an admixture of sandy-clayey material, while the upper contains only clayey material. In the 10th and 11th members even the clayey admixture disappears.

It should be noted that the entire lower subformation has a rhythmic struc-

time, which can be judged by the presence in it of clearly expressed preserved rhythms. In the remaining parts of the section described, rhythmicity is not discernible because of the intrusion of intrusive bodies or the poor exposure of the rocks. The formation of the rhythmics should be connected with oscillatory movements of the area described.

The upper subformation has a substantially limestone composition and consists of 9 members. The twelfth member is represented by clayey, obliquely bedded schistose limestones 4 m thick. The overlying, thirteenth, member is composed of fine-grained limestones with relicts of a fine-clastic structure. Its thickness is 60 m.

The fourteenth member has a peculiar structure. Its lower part is composed of clayey limestones with an admixture of fragments of clayey shales no larger than 2 mm. The upper half consists of non-clayey fine-grained limestones, in which an admixture of the smallest plates of clayey shales is also noted. The transition between these parts is gradual; the thickness is about 15 m. Above lie “sooty,” black both in fresh fracture and on the weathered surface, thin-bedded schistose limestones of the fifteenth member, whose thickness is 90 m.

The two pairs of members described (the 12th and 13th, the 14th and 15th) represent, in our opinion, two rhythms, each of which begins with clayey limestones and ends with non-clayey ones. A distinctive feature of the last two rhythms is their sharply asymmetric structure, expressed in the fact that ingredient “a” [3] is small in comparison with ingredient “c,” while the transitional part of the rhythm “b” is not discernible.

The overlying three members make up a more complete rhythm than the two just described. It begins, as in the case of the 12th and 13th members, with a low-thickness seven-meter member of obliquely bedded clayey limestones, replaced by the 300-meter seventeenth member of fine-grained limestones with relicts of a fine-clastic structure. In the latter there are also beds of fine-grained thin-bedded limestones. The rhythm is crowned by the 160-meter eighteenth member of thin-bedded fine-grained limestones. Thus, the rhythm described (the 16th, 17th, and 18th members) characterizes a transition from clayey calcareous sediments below, through fine-clastic non-clayey carbonate deposits, to thin-bedded fine-grained sediments above.

The nineteenth member is composed of black homogeneous clayey shales and has a thickness of about 200 m. The overlying, 350-meter, twentieth member consists of fine-grained, light-gray, “silvery” on the weathered surface, thin-bedded limestones. In its lower part it has two thin beds of clayey schistose limestones. This last fact indicates a gradual transition between the 19th and 20th members, which make up one rhythm. In concluding the description of the rhythmic structure of the Goldzhin Formation, it should be emphasized that the thickness of the rhythms identified in the section is, in general, constant and ranges from 300 to 500 m. A sharp decrease in thickness is observed only at the boundary between subformations.

To study the distribution of minor elements in the deposits of the Goldzhin Formation, 131 samples of sandstones, clayey shales, clayey, fine-grained, and fine-grained limestones from both subformations were analyzed by the spectral method for manganese, copper, barium, titanium, and strontium. In processing the data obtained, we used the methodological procedure applied by N. M. Strakhov et al. [4, 5]. It consists in tracing the forms of migration of various elements “in a generalized ideal profile from the near-shore zone to the pelagic one...” [5]. Such a profile in our case may be represented by the following series of rocks: sandstones → clayey shales → clayey

Table 1

Average content of minor elements in rocks of the Goldzhinskaya Formation, %

limestones → fine-grained limestones with relicts of a fine-clastic structure → very fine-grained limestones.

Analysis of the distribution graphs of minor elements (Fig. 2) shows that both subformations are characterized by a variegated type of element distribution with groups of ordered elements—a transitional modification of the variegated type according to N. M. Strakhov [5]. The ordered elements include barium and titanium. Below is a characterization of the distribution of minor elements in the rocks of the Goldzhinskaya Formation.

The contents of manganese in the deposits of the lower subformation gradually decrease from 0,080% in sandstones to 0,050% in very fine-grained limestones (Table 1). Its distribution in the rocks of the upper subformation is analogous to that described, differing only in lower amounts in all rock classes (1.5–2 times lower).

The distribution curve of copper for the lower subformation is similar to the manganese distribution curves. Maximum values of 0,0030% in sandstones gradually decrease to 0,0015% in limestones. All varieties of rocks of the upper subformation are characterized, in general, by equally small amounts (0,0010%).

The distribution of barium differs somewhat from that of manganese and copper. In sandstones and in clayey and non-clayey limestones of the lower subformation, it is present in amounts from 0,015 to 0,020%. Maximum amounts are noted in clayey shales, where it is 1.5–2 times greater. In the deposits of the upper subformation, barium is generally 2–3 times lower; moreover, the maximum content here is shifted toward clayey and very fine-grained limestones, where it is 1.5–2 times greater than in clayey shales and fine-grained limestones.

The change in the content of titanium in the rocks of the lower subformation is the same as for barium. Here also the greatest amount falls on

Fig. 2. Distribution curves of elements in the deposits of the Goldzhin Formation: 1—for the lower subformation, 2—for the upper subformation (groups of ordered elements are hatched), 3–7—distribution curves of individual elements (solid line for the lower subformation, dotted line for the upper subformation): 3—manganese, 4—copper, 5—barium, 6—titanium, 7—strontium. I—sandstones, II—clay shales, III—clayey limestones, IV—fine-grained limestones, V—thin-grained limestones

in the clay shales (0.26%), which is 2–3 times greater than in the other varieties. In the deposits of the upper subformation it is present in very small amounts (0.003–0.004%) and only in the thin-grained limestones does it rise to 0.030%.

The character of the distribution curves for strontium differs from all those described above. For the lower subformation, a gradual increase in its content is observed, from 0.015% in the sandstones to 0.030% in the thin-grained sediments; the smallest amount of it is in the clay shales (0.010%). The upper subformation is characterized by a sharp increase in the strontium content in all rocks by 3–10 times.

The data presented make it possible to draw the following conclusions.

1. For the deposits of both parts of the Goldzhin Formation, a variegated type of distribution of elements is characteristic in the sequence sandstones → clay shales → argillaceous limestones → fine-grained limestones with relicts of a fine-clastic structure → fine-grained limestones.

2. A distinctive feature of the rocks of the Goldzhin Formation is the relatively high contents of manganese, copper, barium, and titanium in the rocks of the lower subformation and low contents in the upper one. The amounts of strontium, on the contrary, increase sharply in the deposits of the upper subformation.

3. The forms of migration of the indicated elements changed during sediment accumulation in the lower and upper subformations. Copper in early Goldzhin time was transported mainly in the terrigenous part of the sediments, as is indicated by its maximum content in sandstones. In late Goldzhin time it migrated in the form of solutions and, in part, by being absorbed by clay minerals.

4. Manganese, during the period of accumulation of the deposits of the lower subformation, entered to a greater extent in the crystal lattice of the minerals of the terrigenous part, and to a lesser extent as material sorbed by clay matter. Judging from the character of the distribution curve for it in the rocks of the upper subformation (despite the absence of data on its content in sandstones), it may be assumed that the form of migration remained the same.

5. The maximum content of barium in the clay shales of the lower subformation indicates its association with clay minerals. The shift of the maximum toward the pelagic zone testifies to its introduction, during the period of accumulation of the sediments of the upper subformation, in the form of solutions. The same may be said of the forms of migration of titanium.

6. The migration of strontium in early Goldzhin time differed sharply from that of the elements listed above. The gradual increase in its content from sandstones to limestones makes it possible to consider that it was transported mainly in the form of true solutions. During the deposition of sediments of the upper half of the formation, the form of migration remained the same.

REFERENCES

1. V. A. Borisov, A. Yu. Rozanov. New data on the biostratigraphy of the ancient sequences of the Batenev Ridge. Doklady AN SSSR, vol. 158, no. 2, 1964.

2. G. A. Ivankin, I. I. Koptev, V. E. Nomokonov, S. I. Sobolev, V. A. Shpitstyn. New data on the stratigraphy of the Cambrian and Precambrian of the eastern slope of the Kuznetsk Alatau. Materials on the Geology and Mineral Resources of Western Siberia. Tomsk State University Press, 1964.

3. A. M. Kuzmin. Bed and bedding. Proceedings of the Mining-Geological Institute, West Siberian Branch, USSR Academy of Sciences, vol. 11, Novosibirsk, 1950.

4. N. M. Strakhov, E. S. Zalmanzon, M. A. Glagoleva. Essays on the geochemistry of Upper Paleozoic deposits of the humic type. Proceedings of the Geological Institute, USSR Academy of Sciences, issue 23, 1959.

5. N. M. Strakhov. Fundamentals of the Theory of Lithogenesis. USSR Academy of Sciences Press, vol. 1, 1960.