Manganese Potential of the Middle Cambrian of the Batenevsky Ridge

V. A. Shipitsyn, G. A. Ivankin, I. I. Koptev

(Presented by Professor, Doctor K. V. Radugin)

At the present time, within the territory of the Kuznetsk Alatau and its eastern spurs, a number of deposits and ore occurrences of manganese of sedimentary origin are known. The largest concentrations are confined to the Lower Cambrian—the Usinskoye, Mazulskoye deposits, and others. An elevated manganese content is also noted in sedimentary rocks of the Precambrian [6].

In 1965 we established that in the Middle Cambrian of the Batenevsky Ridge, one of the eastern spurs of the Kuznetsk Alatau, there are ore concentrations of manganese of sedimentary origin. The manganese ore occurrences, whose Middle Cambrian age is reliably determined by trilobite fauna, are situated in the basin of the upper course of the Sukhoi Yerba River, in the area between the Son railway station and the Yuliev mine.

Within the Middle Cambrian in this area, a unit of sandy-carbonate-clayey rocks is distinguished, which we assign to the Nameless Formation [3]. The rocks of the Nameless Formation compose the closure of the Sukhoerbinskaya syncline, which closes at the southwestern margin of Son station [3, Fig. 1]. The formation rests with angular unconformity on carbonate rocks of the Martyukhin Formation (Litvinovskaya sequence) of Precambrian age and on limestones of the Bogyul Formation (Efremkinskaya Formation), containing the Obruchev archaeocyathid assemblage.

In lithological composition, the Nameless Formation is subdivided into four parts (from bottom to top):

1. The first (basal) member is composed of dirty-gray siltstones, sandstones, siliceous-clayey shales, black silicilites, and limestones. The thickness of the member varies from 20 to 300 m.

2. The second member is represented mainly by green graywacke sandstones interbedded with siltstones. From bottom to top, coarse-grained varieties are gradually replaced by fine-grained ones. Thickness 400 m.

1. The third member consists of thinly and flysch-like interbedded sandy-carbonate-argillaceous rocks: calcareous sandstones, siltstones and argillites, marls, and clayey limestones. From the base to the top an increase in the content of carbonate material is observed. Thickness 250–400 m.

2. The fourth member is essentially carbonate in composition. The rocks are represented by gray platy detrital (“pseudoolitic”) limestones; at the base the limestones are clayey. Incomplete thickness about 200 m.

The manganese-bearing member is the basal member, which can be traced almost continuously from the bridge across the Srednyaya Erba River near the game farm, across the northern slope of Mt. Skalistaya to the mouth of the Ust-Peshcherny ravine, and then through the system of the Berezovy ravine to the southwestern outskirts of Son station, where the syncline closes and the beds pass into the northern limb. But in the northern limb this member has not been traced everywhere, since it is cut off by a disjunctive fault. The presence of the manganese-bearing member in the northern limb is confirmed by the determination of elevated Mn contents (more than 1%) in metallometric samples on the divide of the Lukov and Poperechny ravines.

A very distinctive feature of the basal member is its lithological composition, which differs sharply from the composition of the rocks of the Bezymyannaya Formation as a whole. The rocks are represented by interbedded dirty-gray siliceous-argillaceous shales, siltstones, fine-grained sandstones, black silicilites, and platy limestones. In the lower part of the member argillaceous-siliceous rocks predominate; in the upper part, carbonate rocks. This feature is manifested everywhere. In the lower part of the member, isolated flows of diabase porphyrites are noted, which indicates the manifestation of volcanic activity during the period of formation of the manganese-bearing sediments.

The thickness of the member increases in the WSW direction. Thus, on the ENE slope of Mt. Skalistaya, on the right side of the Peshcherny ravine, it is only 20 m. But on the right side of the Ust-Peshcherny ravine its thickness is already 130 m, and on the left side of the same ravine—not less than 200 m. At the southwestern outskirts of Son station, the thickness of only the lower argillaceous-siliceous part is not less than 200 m, and the thickness of the member as a whole is on the order of 300–400 m. In the ENE direction the increase in thickness is insignificant, and at the game farm it reaches 40 m.

Signs of manganese mineralization are noted throughout the entire belt of outcrops of the basal member. But the ore occurrence on the right side of the Ust-Peshcherny ravine [3, Fig. 1] has been studied in the greatest detail, where several ore beds are established. The lower bed is located in the argillaceous-siliceous part of the member, but the overwhelming part of the manganese-bearing rocks is confined to the carbonate part. The total thickness of beds with clear signs of manganese mineralization is 20–22 m. Seven ore beds have been noted, the thicknesses and MnO contents of which are, respectively: 1) 0.5 m (11.07–14.81%); 2) 0.1–0.3 m (11.65–12.24%); 3) 0.4 m (12.05%); 4) about 1.5 m (3.82–7.27%); 5) about 6.0 m (1.40–6.66%); 6) 0.9 m (2.25%); 7) 0.4 m (6.37%).

The thicknesses of the beds and the MnO contents change along strike. There is a tendency toward an increase in thicknesses and contents in the southwest direction, that is, toward an increase in the total thickness of the member. Therefore it is advisable to carry out additional prospecting work near the southwestern outskirts of Son station, where the synclinal structure closes and the thickness of the basal member reaches its maximum value. Analyses of three hand samples from this area show MnO contents from 13.54 to 58.80%. In the northeast direction the beds wedge out, and on the left side of the Peshcherny ravine a single bed 0.20–0.40 m thick with an MnO content of 7.27% has been exposed.

The ores are represented by two types: manganiferous limestones and oxide ores. The limestones of the lower bed have a massive and breccia-like texture and contain rare remains of algae. In the upper—carbonate—part of the member, the manganiferous limestones are represented by thin-bedded platy black or chocolate-brown varieties, often with a fauna of small brachiopods and trilobites: Peronopsis sp., Oryctocephalina aff. reticulata N. Tchern., Prochedinella sp., Pagetidae.

The oxide ores are composed predominantly of pyrolusite and psilomelane, which form pinching-out interbeds and lenses among carbonate–siliceous–clayey and sandy–clayey rocks. The question of the genesis of the oxide ores remains unclear. The available materials at present make it possible to assume their exogenic nature.

In lithological composition and in the presence of volcanogenic rocks, the Bezymyannaya Formation belongs to the group of volcanogenic–siliceous formations (after N. S. Shatsky), to which most known manganese-ore deposits are confined [7]. The paragenesis of rocks (clayey–siliceous shales, sandstones, siltstones, limestones) corresponds to a greater degree to a remote siliceous formation. As an example of the latter, N. S. Shatsky cites a sequence of siliceous–clayey, terrigenous, and carbonate rocks of Lower Carboniferous age on the western slope of the Southern Urals, with which a number of manganese-ore deposits are associated [7].

Of greatest interest for the planning of prospecting work for manganese in the Middle Cambrian on the territory of the Batenevsky Ridge are volcanogenic–carbonate–siliceous and sandy–clayey–siliceous rocks, which are characteristic of manganiferous formations. Such rocks are rather widely distributed in the Batenevsky Ridge. In the area of Sukhie Solontsy they are known under the name of the Tolcheinskaya Formation [1, 5]; in the area of the villages of Verkhnyaya Erba and Sukhaya Erba they are distinguished as the Karasuk Formation [8]. Outcrops of carbonate–siliceous–clayey rocks are also observed southeast of the settlement of Zverosovkhoz, where pyrolusite is noted macroscopically in them, and the MnO content in individual samples reaches 2.0%. Carbonate–siliceous–clayey rocks with Middle Cambrian trilobites are also exposed near the mouth of Podtemnyi Log (the seventh member of the Kureninskaya Series [4]), in which spectral analysis establishes a manganese content of more than 1%.

Rocks of analogous material composition and Middle Cambrian age are also known beyond the Batenevsky Ridge, in particular in the area of the middle course of the Bely Iyus River (Bezymyannaya Formation [2]).

Regardless of the practical significance of the described ore occurrences, their established confinement to the Middle Cambrian and the considerable distribution of deposits of this age within the Kuznetsk Alatau and its spurs broaden the prospects for prospecting for manganese deposits in this region.

In conclusion, the main regularities in the distribution of manganiferousness should be noted, which are established in the area between Son Station and the Yuliney mine and which may be used in further prospecting work.

1. Manganese-ore occurrences are confined to the base of a transgressive (ingressive) series of the Middle Cambrian, beginning with carbonate–siliceous–clayey rocks, which upward in the section are successively replaced by sandstones, siltstones, argillites, marls, and terminate with limestones.

2. The overall manganiferousness (the number of ore beds, their thicknesses, and MnO content) increases with an increase in the thickness of the member of carbonate–clayey–siliceous rocks.

1. The greatest concentrations of manganese should be expected in the centriclinal closure of the synclinal structure, where the thickness of the member reaches its maximum value.

2. The greatest number of ore beds is observed in that part of the section where argillaceous-siliceous rocks are interbedded with limestones.

REFERENCES

1. R. T. Bognibova. New data on the stratigraphy of the Cambrian deposits of the Sukhie Solontsy area (Azyr-Tal Ridge). Transactions of SNIIGGiMS, issue 34, 1965.

2. G. A. Ivankin, I. I. Koptev, V. E. Nomokonov, V. A. Shipitsyn. On the stratigraphy of the ancient strata of the eastern slope of the Kuznetsk Alatau. Materials on the Mineralogy, Petrography, and Mineral Resources of Western Siberia and Krasnoyarsk Territory, issue 3, Tomsk State University Press, 1965.

3. I. I. Koptev, V. E. Nomokonov, A. K. Semashko, V. A. Shipitsyn. On the stratigraphy of the ancient strata of the area of the upper course of the Sukhoy Erba River (Batenevsky Ridge). TPI Publishing House (in press).

4. A. F. Senakolis, I. I. Koptev, V. A. Shipitsyn. New data on the stratigraphy, paleontology, and lithology of the Upper Precambrian and Lower Cambrian deposits of the Batenevsky Ridge. Proceedings of TPI, 151, 1966.

5. V. D. Tomashpolskaya. Stratigraphy and paleontology of the Cambrian of the Batenevsky Ridge and the Azyr-Tal Ridge. Author’s abstract of dissertation, Tomsk, 1964.

6. R. A. Tsykin. Principal results of the study of manganese-bearing capacity in the south of Krasnoyarsk Territory. Materials of the Geological Conference, Krasnoyarsk, 1966.

7. N. S. Shatsky. On manganese formations and the metallogeny of manganese. Proceedings of the USSR Academy of Sciences, Geological Series, No. 4, 1954.

8. V. M. Yaroshevich. Stratigraphy of the Sinian and Cambrian deposits of the Batenevsky Ridge, the Azyr-Tal Ridge, and the basin of the Bely Iyus River. Publishing House of the Siberian Branch of the USSR Academy of Sciences, Novosibirsk, 1962.