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Features of magmatim-related metallogeny of Gorny Altai and Rudny Altai (Russia)
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ScienceDirect Russian Geology and Geophysics 59 (2018) 1010–1021 www.elsevier.com/locate/rgg
Features of magmatim-related metallogeny of Gorny Altai and Rudny Altai (Russia) I.V. Gaskov * V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia Received 12 April 2017; accepted 2 August 2017
Abstract The Rudny Altai and Gorny Altai regions had different geologic histories and differ in metallogenic patterns. The Vendian–Early Cambrian to Permian–Triassic multistage evolution of Gorny Altai included subduction, accretion–collision, and rifting events accompanied by magmatism and related mineralization. Metallogeny evolved in discrete pulses, with especially abundant Late Paleozoic–earliest Mesozoic mineralization. The Devonian–Carboniferous pulse produced diverse mineral deposits (iron, mercury, gold, silver, molybdenum, tungsten, cobalt, polymetallic ores, and rare earths), some of considerable economic value. The territory of Gorny Altai includes several large ore districts that belong to different zones. They are the Beloretsk–Kholzun iron district in the west, the Kayancha–Sinyukha fluorine–gold district in the northeast, the Kurai gold–mercury and Yustyd rare-metal–silver districts in the southeast, and the Kalguty rare-metal–tungsten and Ulandryk U–REE–Cu districts in the south. The largest mineral deposits are Kholzun (Fe, P2O5), Karakul (Co, Bi), Sinyukha (Au), Aktash and Chagan-Uzun (Hg), Ozernoe and Pogranichnoe (Ag), Kalguty (Mo, W), Alakha (Li, Ta), Rudnyi Log (Y,Fe-specularite), and Urzarsai (W-scheelite). Mineralization in Rudny Altai is mainly pyritic: copper–pyrite, pyrite–polymelallic ore, and barite–polymelallic ore. It resides in suprasubduction basalts and rhyolites and in Emsian to Frasnian island-arc volcanics at different stratigraphic levels of Devonian volcanosedimentary sequences in six ore districts. The Kurchum high-grade metamorphic block hosts copper–pyrite and gold–quartz mineralization related to Hercynian volcanism. © 2018, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved. Keywords: metallogeny; mineral deposits; mineralization; magmatism; Gorny Altai; Rudny Altai
Introduction Altai occupies the western part of the Altai-Sayan fold area and comprises of the Southwestern and Gorny Altai blocks of commensurate sizes (Fig. 1). Southwestern Altai, about 100 km wide, extends in the SE direction for 1000 km, continuing into Mongolia and China. Rudny Altai is located in its northwestern part and extends for 500 km over the territory of Russia and Kazakhstan. Rudny Altai borders the Kalba zone along the Irtysh large fault in the west and Gorny Altai along the 600 km NW Northeastern shear zone in the east. Gorny Altai makes up the northeastern part of the Altai territory and is traceable for more than 300 km eastward as far as the West Sayan Range bounded by the Shapashal fault. Geological surveys in the Gorny and Rudny Altai regions show that they differ in history and metallogeny patterns. The
first review of the Gorny Altai metallogeny appeared in the 1960s (Kuznetsov, 1963) and was followed later by numerous works focused on general metallogenic features (e.g., Goverdovskii, 1998; Rikhvanov, 1998). The exceptionally rich metallogeny of Rudny Altai has been more extensively and thoroughly studied for decades from 1950s to the 2010s (Chekalin and D’yachkov, 2013; Gaskov, 2015; Gorzhevskii et al., 1955; Shcherba et al., 1984; etc.). However, the relation of mineralization with specific magmatic events remains controversial because the chronology and history of magmatism are still poorly constrained. In this study we use recent geological and geochronological data to trace the evolution of metallogeny in the Gorny and Rudny Altai regions and its relation to magmatism.
Gorny Altai: geological background * Corresponding author. E-mail address: [email protected] (I.V. Gaskov)
Gorny Altai had a long and complex geological and tectonic history (Berzin and Kungurtsev, 1996; Berzin et al.,
1068-7971/$ - see front matter D 201 8, V.S. So bolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.rgg.201 + 8.07.020
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Fig. 1. Location map of Rudny and Gorny Altai in the framework of the Altai–Sayan fold area, after (Buslov et al., 2013). Abbreviations stand for names of deep faults: Ch, Chara; I, Irtysh; NE, Northeastern.
1994; Buslov, 1992, 1998; Buslov et al., 2013; Dobretsov and Buslov, 2007; Dobretsov et al., 2004, 2005; Kruk, 2015a; Shokalskiy et al., 2000; Vladimirov et al., 2003; Zonenshain et al., 1990). The geological history comprised six major events: (1) Vendian–Early Cambrian formation of oceanic, island-arc and back-arc systems; (2) Middle Cambrian–Early Ordovician accretion of perioceanic and island arc systems to the margin of Siberia; (3) Middle Ordovician–Early Devonian passive continental margin processes; (4) Devonian–Early Carboniferous origin and evolution of the active continental margin; (5) Carboniferous–Early Cambrian continental collision of Siberia and Kazakhstan during the activity of the Tarim plume; (6) Permian–Early Mesozoic within-plate magmatism associated with the Siberian superplume. All these events have produced eventually a collage of terranes that differ in age and origin (Berzin and Kungurtsev, 1996; Buslov, 1998). They are major synclinal or anticlinal fold structures or a combination of local coeval structures comprising several zones with different patterns of geology, magmatism, and metallogeny. According to the terrane model (Nokleberg et al., 2004), they are the zones of Charysh, Kholzun–Chuya, Talitsa, Anui– Chuya, Biya–Katun’, Uimen–Lebed’, and Teletsk, listed from west to east (Fig. 2), which generally agree with the structural zones distinguished by Kuznetsov (1963). The zones are bounded by regional or local faults; the former control magmatism and related mineralization, while the latter are barren. The regional faults are primarily the Northeastern shear zone between the Early Paleozoic Gorny Altai and Late Paleozoic Rudny Altai regions. It is a system of complex branched en-echelon zones of intense shearing, foliation, and mylonitization (Uspenka–Karelensky, Kedrovoe–Butachikha, Lokot’, etc.), 600 km long and 2–20 km wide, which
accommodates Permian–Jurassic granites. The Charysh– Terekta fault separating the Charysh and Kholzun–Chuya zones from the Talitsa and Anui–Chuya zones extends for more than 400 km within Gorny Altai and on into Northwestern Mongolia, and is intruded by igneous rocks of different ages and types. Another large fault of Sarasa–Kurai, which likewise controls magmatism and related mineralization, bounds the Anui–Chuya structure zone in the northeast. It has a very complex structure and is actually a system of regional en-echelon faults: Sarasa, Kadrin, and Kurai. The Chokrak large fault lies between the Biya–Katun’ and Anui–Chuya zones and the Shapshal fault in easternmost Altai separates it from the West Sayan Range. Local faults free from signatures of magmatism and mineralization bound some zones. Fragments that represent early oceanic and island arc settings of Gorny Altai were found within the Biya–Katun’ and Uimen–Lebed’ zones. The Biya–Katun’ zone within the Biya–Katun’ uplift is composed of Neoproterozoic carbonate sediments with quartzite and greenstone-facies volcanics lying under a Lower–Middle Cambrian volcaniclastic sequence with layers of reef archaeocyathan limestones and dolomites; all rocks are heavily deformed. Ordovician and Silurian strata are missing, and Devonian rocks most often lie immediately over Cambrian and Neoproterozoic strata. The plutonic rocks include the oldest small plagiogranite–gabbro–pyroxenite bod−1) and small multiphase ies of the Meshtueryk complex (C pyroxenite, gabbro, and granite intrusions of the Barangol complex (496 ± 5 Ma), which are spatially related with fields of Middle Cambrian volcanics, as well as 384 ± 4 Ma subduction-related gabbro, diorite, and granite of the Kinderli complex (Kruk, 2015a). Mineralization is restricted to small occurrences of hydrothermal-metasomatc magnetite in Cam-
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Fig. 2. Tectonics and metallogeny of Gorny Altai, based on tectonic map by Kuznetsov (1963). 1–7, zones: Charysh–Inya (1), Talitsa (2), Kholzun–Chuya (3), Anui–Chuya (4), Biya–Katun’ (5), Uimen–Lebed’ (6), Teletsk (7); 8, fault zones, abbreviated as NE, Northeastern, ChT, Charysh–Terekta, SK, Sarasa–Kurai, Ch, Chokrak, Sh, Shapshal; 9–18, mineral deposits: 9, iron deposits Beloretsk (1), Inya (2), Kholzun (3), Korgon (4), Kedrovoe (5), and Kharlovo (6); 10, manganese deposit Prozrachnoe (1) and ore occurrences; 11, gold deposits Sinyukha (1), Choya (2), Novofirsovo (3), Murzinka (4) and ore occurrences; 12, Cu–Mo deposit Kulbich (1); 13, polymetallic ore–Co Karakul (1) and Vladimirovka (2); 14, sheelite–polymetallic ore and polymetallic ore deposits Urzarsai (1), Krasnyi Yar (2), Ursul (3), and Novochagyr (4) and ore occurrences; 15, Sb–Ag deposits Ashatin (1), Ozernoe (2), Pogranichnoe (3) and ore occurrences; 16, Mo–W deposits Kalguty (1) and Dzhumala (2); 17, Hg deposit Aktash (1) and Chagan-Uzun (2) and ore occurrences; 18, rare metal–REE deposits Li–Ta Alakha (1), Fe–REE Rudnyi Log (2), Koksa (3), and Kumir (4).
brian volcanics; jaspellite and siderite in carbonates; and titanomagnetite in gabbro and ultramafic intrusions of the Barangol complex. Redeposited eluvium hosts the Selezen manganese ores while Precambrian carbonates in the northeast store gold–carbonate mineralization (Sarasa and Sibiryachikha fields). Small mafic bodies bear disseminated gold (0.2 to 34.5 ppm) and sulfides (Sukhon’koe, Nochnoi Log, Novoe, and Cheremshan occurrences). The Uimen–Lebed’ zone occupies a complexly structured trough of the same name. Its section begins with Neoproterozoic carbonates and Lower–Middle Cambrian volcanic-sedimentary rocks discordantly overlain by Ordovician and Silurian variegated sandstone and shale in the northern part and by Middle–Upper Devonian volcanics and sediments in the south. Plutonic rocks are Middle–Late Cambrian gabbro and granite of the Sarakoksha complex (512.2 ± 6.2 Ma) and the Devonian Yugala (406 ± 4 to 399 ± 2 Ma), Turochak (390 ± 7 Ma), and Kyzyltash (D2) complexes emplaced in an active continental margin setting (Babin et al., 2004; Kruk, 2011, 2015b). Rich scarn gold–sulfide mineralization
(Sinyukha, Maisk, Choya, and Ulmen deposits; Isha and Oyuk occurrences) follows the contacts of the Yugala diorite–granite and carbonate intrusions (Shokalskii et al., 2000; Gaskov et al., 2010). The Yugala diorite–granite complex hosts the Kulbicha porphyry Cu–Mo deposit, the Akkem quartz– molybdenite vein deposit, and the Isha and Maisk–Lebed’ fields with up to 20 and 40 tons of total gold reserves, respectively. Gold contents in several epithermal gold and silver fields are up to 8.4 ppm Au and 436 ppm Ag, with the especially rich Chura occurrence, while the total gold predicted potential of this ore cluster reaches 322 tons (Gusev, 2002). Hydrothermal-metasomatic occurrences of magnetite ores are found at the contact of granititc rocks with the Devonian and Cambrian wallrocks and Ti-magnetite mineralization resides in gabbronorite and gabbro–syenite complexes (Salganak occurrence). Stockwork quartz–sheelite minerals coexist with polymetallic ore–Ag–Pb veins (Urzarsai deposit) in the southeastern part of the zone. The Kholzun–Chuya and Anui–Chuya zones bear signatures of Middle Cambrian–Early Ordovician accretion and
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collision events with deposition of thick flysch. The Kholzun– Chuya zone extends in the SE direction in western Gorny Altai along the Rudny Altai boundary. The section consists of Neoproterozoic schists within the Terekta horst overlain by heavily deformed Lower Cambrian volcanics and sediments lying under Cambrian–Ordovician flysch. In the Kargon and Kalguty superposed basins, Middle Devonian sediments lie immediately upon Precambrian schists. Plutonic rocks mainly belong to the 375 ± 11 Ma Rokhman gabbro–diorite–granite and (362–375) ± 1 Ma Borovlyanka granodiorite–granite complexes (Kruk, 2015b) that formed in an active continental margin setting. Later rifting-related igneous rocks are less abundant: the Tarakhta syenite–monzodiorite–granosyenite (247 ± 3 Ma) and Belokurikha (232 ± 5 Ma) and Chindagat– Kalguty (212–190 Ma) granite–leucogranite complexes. Metallogeny in the Kholzun–Chuya zone is the most diverse and richest over Gorny Altai. Iron resides in the Korgon Formation (D2krg) of basalts, andesites, ryolites, and sediments within the Korgon trough (Kholzun, Korgon, Timofeevka, and other deposits) in the Beloretsk–Kholzun district at the Rudny Altai boundary (Gas’kov et al., 1999; Kassandrov, 2010; Yolkin et al., 1994), the Kholzun V–P–Fe deposit being the largest one (~700 × 106 tons). Iron ores coexist with manganese mineralization of two types: (1) oxide and carbonate ores in volcanicsedimentary rocks (Prozrachnoe deposit) and (2) oxidized ores in weathered Mn-bearing rocks (Bostok and Bostal occurrences). Skarn iron (Beloretsk and Inya deposits) occurs in contacts of the Upper Devonian plutons within the Korgon trough (Kalugin et al., 1981; Kassandrov and Ivanov, 1979; Kassandrov et al., 1998) while W–Mo–Bi–rare metal ores (1.85% WO3 and 0.005–0.088% Mo and Bi) reside in greisen granites of the Belokurikha complex. Disseminated, pocket-, and vein-like Co mineralization is spread in a 400 m thick and more than 2 km long strips along contacts of the gabbro–diorite stockwork intrusion (Vladimirovka deposit, 0.5% Co on average). Other mineralization occurrences within the Korgon trough are rare-metal–REE–U ores, especially the Kumir Sc–Y–U–Th deposit in albitized, sericitized, and tourmalinized contacts of the Kumir stockwork (Belokurikha complex, 240 Ma). Iron–REE–Cu ores (Koksa, Vodopadnoe, and Rudnyi Log deposits, with up to 7.5% Cu, 36% Fe, 0.1% Y, 0.16% Co, 30 ppm Ag, and 0.5 ppm Au) are hosted by Middle Devonian volcanics (rhyolite, dacite, and andesite) in the southeastern Kalguty superposed trough. The Yustyd trough accommodates the Yustyd ore district with magmatic mineralization of various compositions (Sb–Ag, Sn–W, W– Bi–Co, Ni–Co–As, Au–Ag–Hg, and Sb–Hg). Most ores reside in black shales (D2–3) lying over redbed and volcanic-sedimentary rocks (D1–2). There were two main events of magmatism and ore formation (Gusev and Gusev, 2010; Pavlova et al., 2008; Tret’yakova, 2011): Late Devonian–Early Carboniferous and Middle Permian–Early Triassic. The early D3–C1 event produced the Yustyd granites (375.4 ± 5.5 Ma, D3–C1) with REE (351.4 ± 1.4 Ma) and Sn–W (359.0 ± 3.4 Ma) ores and postgranite dolerite dikes (351.8 ± 3.8 Ma) with Cu–W–Bi–Co mineralization (349.8 ± 3.9 Ma, Karakul deposit). The Karakul deposit in the western contact of the
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Barburgazy pluton consists of closely spaced roughly parallel chlorite–tourmaline–quartz metasomatic orebodies, up to 30 m thick, 1500 m long, and more than 300 m along the dip. The mineralogy includes cobaltite and glaucodote often coexisting with sheelite, bismuthite, chalcopyrite, tetrahedrite, arsenopyrite, pyrrhotite, and pyrite. The P2–T1 event began with intrusions of the Terekta dolerite dikes (255 Ma) and the Chuya lamprophyres (250 ± 4.5 Ma) with Ni–Co–As veins (258–250 Ma). The intrusions were followed by emplacement of the Tarakhta granosyenite (238 ± 2.5 Ma) with related Sb–Ag (240 ± 3.5 Ma) and Hg (234.4–231.5 Ma) mineralization. The Askhatin, Ozernoe, and Pogranichnoe Sb–Ag deposits are the richest. The Askhatin deposit is located in the northeastern Ozernoe–Askhatin ore field among the Middle– Upper Devonian Barburgazy and Boguty Formation clastics. The 800 m long and 16 m thick orebodies consist of siderite veins and less abundant breccias and linear stockworks that store massive and disseminated sulfide–sulfosalt mineralization, with a potential of 7100 tons of silver (351 ppm Ag on average), 163,000 tons of copper (0.82%), 92,000 tons of stibnium (0.36%), 13,000 tons of bismuth (0.055%) (Bedarev and Dalilkhan, 1987). Complex ores are associated with Devonian volcanism in the southeastern part of the Kholzun– Chuya zone (Tyutinsky, Korumda, Kyzyl-Chin, Ursul, and Kazinikhinsky deposits) and with Late Paleozoic–Early Mesozoic plutonism, including the Krasnyi Yar Pb–Sn deposit and the Bolshoi Yaloman deposit with a diverse mineralogy (quartz, epidote, calcite, galena, sphalerite, chalcopyrite, pyrite, pyrrhotite, marcasite, molybdenite, and sheelite). The Anui–Chuya zone occupies a basin of the same name and extends in the NW–SE direction parallel to the Kholzun– Chuya zone across the whole Gorny Altai area. Its sedimentary section consists of thick Cambrian and Ordovician flysch at the base and Ordovician and Silurian shales and limestones in the middle, discordantly overlain by Devonian and Lower Carboniferous volcanics and sediments, as well as Carboniferous coal-bearing continental sediments in the southeastern part of the zone. Deformation is restricted to isoclinal folding along faults. Abundant plutonism associated with active margin collisional processes produced gabbro–granite suites of the Topolnoe (397 ± 5 Ma) and Ust’-Belaya (374 ± 3 Ma) complexes, granite–leucogranite intrusions of the Elinovo–Butachikha (377 ± 5 Ma), Shebelik (3065 Ma), and Chindagatui– Kalguty (216–190 Ma) complexes which host diverse related mineralization. Devonian volcanics store polymetallic ores (Shargaita, Il’inka, Shiroky Log deposits) of galena, sphalerite, chalcopyrite, pyrite, and pyrrhotite coexisting with molybdenite, sheelite, quartz, epidote, and calcite. The South-Altai metallogenic belt in the southeast of the zone includes the Kalguty and Alakha ore clusters (Gusev and Gusev, 2014). The Kalguty cluster comprises the Kalguty, Dzhumala, and South Kalguty Mo–W deposits and the Sadokbai, Filial, Torbernit, Upper Akkol, West and North Kalguty ore occurrences hosted by the 216 ± 3 Ma Kalguty granite complex (Annikova et al., 2006). The largest Kalguty Mo–W deposit is located in the eastern part of the complex, with 1.9% WO3, 0.1% Bi, 0.04% Be, and Mo <0.01% in both granites and their
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wallrocks. The Alakha ore district and the Alakha Li–Ta deposit are located in the highland part of the Chuya basin (Kosh-Agach area). Mineralization occurs along the margins of the Alakha spodumen granite–porphyry stockwork and consists of spodumen, tantalite, and pollucite metal-bearing minerals and barren micas and feldspar in greisenized, albitized, and quartzitized rocks. The Li (0.8%) and Ta (0.012%) ores contain also 0.12% Rb, 0.026% Ce, 0.004% Nb, and 0.006% Bi. Epithermal Hg deposits make up the Kurai mercury belt, about 100 km long and 6–8 km wide extending toward the Chuya roadway in the southeast of the zone. The belt comprises more than 100 Hg occurrences and two economic carbonate–cinnabar (Aktash) and listwanite (Chagan-Uzun) deposits. The Aktash sheet-, pocket-, and vein-like orebodies occur among dolomitized, quartzitized, and argillized limestones and shales. The ore mineralogy consists of cinnabar, antimonite, pyrite, tetrahedrite, realgar, calcite, dolomite, and quartz. The Chagan-Uzun deposit forms ore columns and lenses of cinnabar with minor amounts of other sulfides (antimonite, millerite, gersdorffite, pyrite and realgar) in serpentinized porphyry and their tuffs and tuffaceous sandstone. Mercury mineralization is mainly hosted by Mesozoic mafic and ultramafic magmatism in deep faults and by small subalklaine basaltic intrusions. The Charysh and Talitsa zones record a passive continental margin setting. The Charysh zone occupies the Charysh basin in western Gorny Altai, at the boundary with Rudny Altai. The Lower Paleozoic section is the most complete and consists of Cambrian mostly clastic sediments to Upper Silurian shales and limestones overlain discordantly by Middle Devonian weakly deformed volcanic-sedimentary rocks. Plutonic rocks, mostly of Early Mesozoic age, are restricted to the Kur’ya and Novofirsovo troughs and belong to the Mayorka (381 ± 4 Ma) and Borovlyanka (375 ± 1 Ma) granite–leucogranite complexes, the Ust’-Belaya (364–374 ± 3 Ma) gabbro–diorite– tonalite–granodiorite complex, and the Kharlovo (330–334 Ma) monzogabbro and monzodiorite complex; the later rifting-related magmatism is limited to the 248 ± 1 Ma Sinyushka complex (Kruk, 2015a) Magmatism-related metallogeny is sporadic and mainly associated with Devonian volcanism and plutonism. It consists of small Ag–polymetallic ore (Novochagyr) and polymetallic ore (Shiroky Log and Chernaya Rechka) occurrences as quartz–carbonate veins and quartz–feldspar metasomatic rocks with galena and sphalerite (locally with argentite and copper minerals) along contacts of Devonian subvolcanic intrusions and in Ordovician–Silurian carbonate and clastic sediments. Devonian rhyodacite subvolcanic intrusions within the Novofirsovo trough hosts the Novofirsovo epithermal gold–silver field with up to 5 ppm Au, 42.2 ppm Ag, 0.41% Cu, 0.27–5.75% Pb, and 0.33–6.58% Zn; the predicted gold resources amount to 45 tons. A layered gabbro intrusion of the Kharlovo complex in the northwestern zone part, which consists of tens of meters thick metal-bearing (at least 14% Fe and 8 m) or barren gabbro layers, hosts the Kharlovo Ti-magnetite deposit. The 425 to 2650 m long orebodies store more than 3.5 × 109 tons of
metals with average contents of 15.3% FeO, 5.9% TiO2, 0.08% V2O5, and 11% Al2O3. The Talitsa zone is located east of the Charysh zone within the Talitsa anticlinal uplift. The section stripped in the anticline core begins with Neoproterozoic–Lower Cambrian shales and schists, porphyry rocks and their tuffs with microquartzite and marble layers, while the limbs are mainly composed of shales and sandstones with layers of Cambrian– Ordovician silicic rocks, jaspers, and porphyry. Widespread plutonic rocks include Upper Devonian gabbro–granite intrusions of the Mayorka (381 ± 4 Ma), Borovlyanka (375 ± 1 Ma), and Ust’-Belaya (364–374 ± 3 Ma) complexes, like in the nearby Charysh zone, as well as later (232 ± 5 Ma) rifting-related granites and leucogranites of the Belokurikha complex. Magmatism-related mineralization in the zone is restricted to sporadic W–Mo–Bi–rare metal ores in granite greisens of the Belokurikha complex. Opaque minerals (hübnerite, wolframite, sheelite, powellite, tetradymite, pyrite, xenotyme, cerussite, and molybdenite) are found in both greisens and quartz veins (1.85% and 7.8% WO3, respectively, and within 0.005–0.088% Mo and Bi). The Teletsk zone is located within the Teletsk and Kurai terranes at the boundary between Gorny Altai and the West Sayan Range delineated by the Shapshal large fault. It is a transitional zone where the structures change direction from NW (Altai-type) to NE (West Sayan-type). The section consists of Neoproterozoic schists overlain by Lower Cambrian volcanic-sedimentary rocks which, in turn, lie under Cambrian–Ordovician clastic-shale flysch. All rocks are deformed, metamorphosed, and intruded by ultramafic, mafic, and granitic rocks. The zone includes the Ulagan superposed basin and fault-line grabens filled with Devonian sediments. The Kurachak magnetite deposit discovered on the left side of Lake Teletskoe and in the headwaters of the Biya and Lebed’ Rivers stores about 15 × 106 tons of ore. Its age and relation with magmatism remain yet unconstrained.
Gorny Altai: metallogeny As noted above, the Vendian–Early Cambrian to Permian– Triassic history of Gorny Altai included multiple subduction, accretion–collision, and rifting events accompanied by magmatism and related mineralization. Metallogeny was unevenly distributed in space and time. The oldest orebodies formed in the Vendian–Cambrian oceanic setting are restricted to the Biya–Katun’ zone. They are composed of magnetite and jaspellite among Cambrian volcanics and carbonate sediments, as well as Ti-magnetite in the Barangol gabbro (496 ± 5 Ma) and jasperoid-hosted gold mineralization in carbonates. Some limited mineralization (the Kaurchak deposit on the left side of Lake Teletskoe in the Teletsk zone) was associated with Middle Cambrian–Early Ordovician accretion and collision. No considerable mineralization has been revealed in the Ordovician–Silurian passive margin setting. Metallogenic processes were especially intense in the Late Paleozoic (D1–C2) active continental margin setting and
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produced diverse mineralization. It includes small Ag–polymetallic ore and polymetallic ore occurrences (Novochagyr, Shiroky Log, Chernaya Rechka) in the Mayorka intrusives (381 ± 4 Ma) emplaced into clastic-carbonate sediments (Charysh zone, western part of the region); the Kharlovo Ti-magnetite deposit in the Kharlovo layered gabbro (330– 334 Ma) farther southeast; the Murzinka gold deposit in the Ust’-Belaya granodiorites (364 ± 8 Ma); the Novofirsovo Au–Ag deposit in Middle–Late Devonian subvolcanic rhyodacites in the south of the zone. The Beloretsk–Kholzun iron district in the Korgon superposed trough (Kholzun–Chuya zone) comprises iron deposits (Kholzun, Korgon, Timofeevka, etc.) in volcanics and sediments and Mn ore occurrences (Prozrachnoe) in the volcanic-sedimentary Korgon Formation (D2krg). Iron mineralization is found as iron–REE occurrences (Koksa, Vodopadnoe, and Rudnyi Log) in Middle–Late Devonian alkali rhyolite–dacite and andesite and as scarn iron deposits (Beloretsk and Inya) in the margins of Late Devonian plagiogranites of the Tigirek pluton. Mineralization in the southeastern part of the zone consists of polymetallic ores hosted by Devonian volcanics (Ursul, Krasnyi Yar, Tyutinsky, Kyzyl-Chin, etc. deposits) and by Middle Devonian granite intrusions (Urzarsai, Bolshoi Yaloman, and Ilgumen deposits). The Yustyd basin of the Kholzun–Chuya zone accommodates the Yustyd ore district with magmatism-related mineralization of various compositions (Sn–W, Cu–W–Bi–Co, and Sb–Hg). The ores formed in two metallogenic events: (i) the Late Devonian–Carboniferous event of REE (351.4 ± 1.4 Ma) and Sn–W (359.0 ± 3.4 Ma) mineralization in the 375.4 ± 5.5 Ma Yustyd granites and REE- and Sn–W-bearing minerals in greisens (D3–C1) and (ii) the Permian–Triassic event which began with 349.8 ± 3.9 Ma Cu–W–Bi–Co mineralization (Karakul deposit) in postgranite dolerite dikes (351.8 ± 3.8 Ma). Occurrences of hydrothermal-metasomatic magnetite and Ti-magnetite ores (Salganak) are found in Devonian gabbro–granite intrusions (406 ± 4 Ma) in the eastern Uimen– Lebed’ zone; gold mineralization, mainly of the sulfide-skarn type (Choya, Sinyukha, Maisk, and Ulmen deposits) occurs along the contacts of a diorite–granite pluton in the Yugala complex (399 ± 2 Ma) and in carbonates. This mineralization coexists with the Kulbich Cu–Mo porphyry deposit, the Akkem quartz–Mo vein ore occurrence, as well as the Isha and Maisk–Lebed’ ore zones with predicted gold resources of 20 to 40 tons, respectively. Volcanic-hosted polymetallic ore (Shirgaita, Il’inka, Shiroky Log deposits, etc.) occur in the southeastern Uimen–Lebed’ zone. The Permian–Triassic event also produced diverse mineralization hosted by within-plate granites. Mineralization of this age coexists with younger rare-metal mineralization (Ni–Co– As, Ag–Sb, Hg) in the Chuya complex of lamprophyre (250.8 ± 4.5 Ma) and granosyenite (241.5–238 ± 2.5 Ma) dikes in the southeast of the area (Yustyd basin). They are, namely, the Askhatin and Pogranichnoe Sb–Ag deposits and Co occurrences (Tret’yakova, 2011). The Kalguty granitoids (216–218 Ma) host Mo–W, Cu–Mo, and Be ores that form the Kalguty ore cluster with the Kalguty, Dzhumala, South Kalguty deposits, as well as epithermal Hg mineralization
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(Aktash and Chagan-Uzun deposits and more than 100 occurrences making up the Kurai ore belt) associated with mafic and ultramafic magmatism in zones of deep faults. W–Mo–Bi–rare metal mineralization, as well as Co mineralization (Vladimirovka deposit) occurs in the Korgon basin of the Kholzun–Chuya zone hosted by greisen granites of the Belokurikha complex (232 ± 5 Ma). The Kumir Sc–Y–U deposit occurs in the margins of the Kumir stockwork intrusions of subvolcanic rhyolites (240 Ma) in the right side of the Kumir River. The Belokurikha granites also host W–Mo–Bi–rare metal minerals in the Talitsa zone.
Rudny Altai: geological background Rudnyi Altai is one of largest metallogenic belts of Eurasia which comprises about fifty economic and numerous small Cu–Pb–Zn deposits (Figs. 1, 3). The Rudny Altai territory is most often interpreted as a Devonian island arc system formed along the margin of the Irtysh–Zaisan ocean (Berzin and Kungurtsev, 1996; Rotarash et al., 1982; Zonenshain et al., 1990). The region includes the Alei and Sinyushka uplifts and the Bystrukha and Belaya Uba basins with their sections consisting of Early Paleozoic (barren) and Late Paleozoic (ore-bearing) units. Fragments of Early Paleozoic rocks appear in the Alei and Sinyushka uplifts and in the Irtysh and Northeastern shear zones (Shcherba et al., 1984). They are heavily deformed and metamorphosed (greenstone-facies) quartz–sericite, sericite–chlorite and actinolite–chlorite schists and sandstones. Devonian and Carboniferous volcanics and sedimentary rocks lie discordantly over the lower unit. They store various Cu–pyrite, pyrite–polymetallic ore, and barite– polymetallic ore deposits and occurrences associated with basalt–rhyoloite volcanics. Since the Fammenian, volcanism in Rudny Altai was composed of barren mainly sodic andesite–dacite lavas and tuffs located within a narrow strip along the southwestern edge of the region. Their intrusive analogs form an NW chain of dikes and large hypabyssal gabbro, gabbro-dolerite and dolerite bodies at the back of the volcanics, near the Northeastern shear zone. Widespread plutonic rocks (Kuzebnyi, 1975; Vladimirov et al., 1997) span a large age range and belong to three groups according to formation settings: preorogenic (380–390 Ma), synorogenic (Zmeinogorsk complex, 309 Ma) and collisional (Kalba complex, 277–266 Ma) granites. All granites are barren. Thus, the Rudny Altai metallogeny consists mainly of pyritic mineralization hosted by basalt–rhyolite volcanism, in six ore districts (Fig. 3): Zyryanovsk, Leninogorsk, Irtysh (in Kazakhstan), Zmeinogorsk, Zolotushinsky, and Rubtsovsk (in Russia). Zyryanovsk ore district makes the southeastern part of the Rudny Altai metallogenic belt. Its section mainly consists of Devonian–Lower Carboniferous rocks of the Podrevnyukha (D1e1), Revnyukha (D1e2–D2ef1), Maslyanka (D2ef2–D2zv1), Khamir (D2zv2–D3), Turgusun (C1t2–v1), and Larikha (C1v2) Formations. The Revnyukha and Maslyanka Formations,
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Fig. 3. Simplified tectonics and metallogeny of Rudny Altai, based on data of the Rudny Altai geological surveys. 1, Middle and Upper Devonian volcanic-sedimentary rocks; 2, sedimentary fill of the Belaya Uba–Maimyr back-arc basin; 3, high-grade volcanic-sedimentary rocks of the Kurchum block; 4, preorogenic Devonian (D2) diorite, quartz diorite, granodiorite, plagiogranite; 5, Middle–Upper Carboniferous (C2–3) granodiorite, diorite, plagiogranite, and ademelite (Zmeinogorsk complex); 6, Upper Permian–Lower Triassic (P2–T1) biotite and biotite–hornblend porphyry granites (Kalba complex); 7, large faults between fold systems (I, Irtysh; NE, Northeastern shear zone); 8, cross faults; 9, 10, ore districts (9) and deposits (10): pyrite–polymetallic ore and Cu–pyrite (a) and barite–polymetallic ore (b). I, Zyryanovsk ore district: 1, Grekhovsky, 2, Snegirevka, 3, Zyryanovsk, 4, Bogatyrev, 5, Osochikha, 6, Maisk–Zyryanovsk, 7, Putintsevo, 8, Parygino, 9, Maleevka, 10, Zavodskaya, 11, Bukhtarma; II, Leninogorsk district: 12, Ridder-Sokol’nyi, 13, Tishinsky, 14, Shubinka, 15, Starkovka, 16, Strizhkov, 17, Guslyakovsky, 18, Chekmar, 19, Novoleninogorsk, 20, Uspenka, 21, Anisimov Klyuch, 22, Snegirikha; III, Irtysh ore district: 23, Belousovka, 24, Irtysh, 25, Berezovka, 26, Novoberezovka, 27, Nikolaevka, 28, Pokrovka, 29, Shemonaikha, 30, Kamyshin, 31, Artem’evka; IV, Zolotushinsky ore district: 32, Yubileinoe, 33, Kryuchkovo, 34, Zolotukha, 35, Novozolotukha, 36, Orlovka, 37, Gerikhovsky, 53, Lokot’; V, Zmeinogorsk ore district: 38, Vorovsk, 39, Semenovka, 40, Maslyanka, 41, Lazurnyi, 42, Zmeinogorsk, 43, Korbalikha, 44, Srednee, 45, Zarechensk, 46, Strizhkov, 47, Maisk, 48, Tushkanikha; VI, Rubtsovsk ore district: 49, Stepnoe, 50, Talovka, 51, Zakharovka, 52, Rubtsovsk; 54, Korchega Cu–pyrite deposit within the Kurchum block.
which are composed of alternating rhyolite–dacite and basaltic andesite lavas and their tuffs, tuffaceous sandstone, siltstone, and limestone, are ore-bearing and host eight economic deposits and numerous ore occurrences. The two formations are sandwiched between the mostly sedimentary Podrevnyukha Formation (D1e1) and Upper Devonian–Lower Carboniferous limestone and shale (Fig. 4). All economic deposits lie within the Revnyukha uplift. Pyrite–polymetallic ore
mineralization in the uplift forms several 110–130 m thick levels. The lower level in the lower and middle Revnyukha section comprises rather poor vein and disseminated ores (Zyryanovsk and Grekhovsky deposits and several occurrences). The middle level corresponds to the upper Revnyukha and lower Maslyanka Formations with main concordant or combined bodies of continuous or less often vein-disseminated pyrite–polymetallic ores (Zyryanovsk, Grekhovsky, and Maisk
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Fig. 4. Stratigraphy of ore districts in southeastern (Kazakhstan) Rudny Altai. 1, mudstone, siltstone, and silty sandstone; 2, sandstone and tuffaceous outsize sandstone; 3, limestone and limy rocks; 4, basal conglomerate and gravelstone; 5, tuffs and lavas of rhyolite and rhyolite–dacite porphyry; 6, tuffs and lavas of basaltic and basaltic andesite porphyry; 7, subvolcanic rhyolite and rhyolite–dacite porphyry; 8, schists; 9, pyrite–polymetallic ore mineralization; 10, Au–Ag–barite–polymetallic ore mineralization.
deposits). The upper Maslyanka Formation forms the upper level with the Maleevka Cu–pyrite–polymetallic ore deposit. Leninogorsk ore district located 100 km northwest of the Zyryanovsk district extends NW for ~80 km in the central part
of the Sinyusha uplft. The section consists of Eifelian– Givetian volcanic-sedimentary rocks that belong to the Leninogorsk (D1e2), Kryukovsky (D2ef2), Il’inka (D2ef2), Sokol’nyi (D2ef2), Uspenka (D2ef2–D2zv1), and Belaya Uba
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(D2zv–D3f) Formations (Fig. 4). The rocks host nine economic pyrite–polymetallic ore and barite–polymetallic ore deposits and a number of ore occurrences in three lithostratigraphic units. They are: the Ridder-Sokol’nyi, Novoleninogorsk, and Dolinnoe deposits and several occurrences of Au- and Ag-rich barite and polymetallic ores of the Leninogorsk field in the lower unit (Kryukovsky Formation), within a caldera-like depression composed of sands and shales with rhyolite–dacite layers; the Tishinsky pyrite–polymetallic ore deposit at the top of large Tishinsky–Belyi Lug stratovolcano in the middle unit, at the boundary between the Il’inka and Sokol’nyi Formations; and the Guslyakovsky, Chekmar, Strezhan, Shubinka, and Starka pyrite–polymetallic ore and Cu–Zn–pyrite deposits in the upper unit, at the boundary between the Uspenka and Belaya Uba Formations. Barite–polymetallic ore mineralization grades into Cu–pyrite–polymetallic ores up the section. Irtysh ore district is located in the western flank of the Rudny Altai metallogenic belt, within the southwestern slope of the Alei uplift and comprises two 5 km wide ore fields (Nikolaevka and Berezovka–Belousovka) extending for tens of kilometers along the Irtysh shear zone (Fig. 3). The Nikolaevka ore field is composed of Middle–Upper Devonian volcanic-sedimentary rocks that belong to the Losikha (D2ef), Talovka (D2zv), Gerikhovsky (D3f), Nikolaevka (D3f), and Snegirevka (D3f–fm) Formations (Fig. 4). The Losikha, Talovka, and Gerikhovsky Formations host the Kamyshin, Nikolaevka, Pokrovka, and Novoshemonaikha Cu–pyrite and pyrite–polymetallic ore deposits and several ore occurrences associated with subvolcanic rhyolite porphyry. The Berezovka–Belousovka field consists of volcanic-sedimentary rocks of the Orlovka (D2ef), Shipunikha (D2ef–zv), and Irtysh (D2zv–D3f) Formations injected by subvolcanic rhyolite or less often basaltic dikes and sills. Pyrite–polymetallic ore mineralization (Berezovka, Novoberezovka, Irtysh, Belousovka, Prognoznoe, and Kar’yernoe deposits and about 30 occurrences) reside mainly within the Shipunikha and Irtysh Formations. Zmeinogorsk ore district lies in the northeast of the Rudny Altai belt at the boundary with Gorny Altai within the northwestern end of the Bystrukha basin and its junction with the northeastern Alei uplift. The ore-bearing Lower and Upper Devonian sedimentary and volcanic rocks belong to the Melnichnaya (D1e2–D2ef), Sosnovka (D2zv1), Zavodskaya (D2zv), Davydovka (D2zv2), and Kamenka (D3f) Formations (Fig. 5). Basalt–rhyoloite volcanics are interlayered with clastic sands and shales. Note that Emsian–Eifelian and Lower Givetian volcanics are of felsic compositions while alternated mafic and felsic rocks appear later (Givetian–Frasnian) Pyrite–polymetallic ore mineralization is of gold–barite–polymetallic ore and pyrite–polymetallic ore types: Zarechenoe, Zmeinogorsk, Karamysh, and Petrovka deposits in the lower stratigraphic unit (Melnichnaya Formation) and Korbalikha, Srednee, Lazurny, Semenovka, and Maisk deposits in the Givetian–Frasnian unit. The two mineralization types are separated also laterally and form the Zmeinogorsk and Korbalikha ore fields.
Zolotushinsky ore district is located in the northwestern part of Rudny Altai, within the southwestern slope of the Alei uplift. Lower–Upper Devonian volcanic-sedimentary ore-bearing rocks belong to the Melnichnaya (D1e2–D2ef), Sosnovka (D2zv1), Zavodskaya (D2zv), Davydovka (D2zv2), and Kamenka (D3f) Formations (Fig. 5). Pyrite mineralization is found in two lithostratigraphc units. The richer lower unit is composed of tuff-sedimentary rocks of the Zavodskaya Formation (D2zv1sv) which host large economic Cu–Zn–pyrite deposits (Orlovka, Zolotushinsky, Novozolotushinsky, and Lokot’). All deposits occur at the contact between rather clastic sediments of the Zavodskaya Formation and the overlying rhyolite–dacite volcanics of the Davydovka Formation, as well as within the apical parts of subvolcanic porphyry bodies. The upper metalliferous unit with the Yubileinoe and Surgutan deposits lies within the variegated volcanic-sedimentary Kamenka Formation (D3f) of interlayered breccias, sandstone, siltstone, tuff, and rhyolite–dacite lavas. Ores reside in coarse clastic sediments and in aureoles of subvolcanic rhyolite–dacite porphyry. Rubtsovsk ore district is located in the northwestern end of the Rudny Altai belt, within the Rubtsovsk volcanic depression on the northeastern slope of the Alei uplift. Like the neighbor Zmeinogorsk and Zolotushinsky ore districts, the Rubtsovsk district is composed of Devonian volcanic-sedimentary rocks that belong to the Melnichnaya (D1e2–D2ef), Sosnovka (D2zv1), Zavodskaya (D2zv), Davydovka (D2zv2), and Kamenka (D3f) Formations (Fig. 5). The district accommodates four pyrite–polymetallic ore economic deposits (Talovka, Stepnoe, Rubtsovsk, Zakharovka) and several ore occurrences at two stratigraphic levels, in two separate ore fields. The Talaya and Stepnoe deposits (Talovka ore field) reside in the lower stratigraphic unit and lie among rather sedimentary rocks of the Zavodskaya Formation (D2zv). The Rubtsovsk and Zakharovka ore fields occur in the upper part of the section among tuff-sedimentary rocks of the Lower Kamenka Subformation. High-grade mafic volcanics (amphibolites) of the Kurchum block in southern Rudny Altai host Cu–pyrite mineralization (Fig. 3) in the Karchiga deposit and several ore occurrences of Spassky, South Anticinal, Shandybulak, etc. (Lobanov and Gaskov, 2012). The Cu–pyrite deposits and occurrences differ markedly from those hosted by island arc basalt–rhyolite volcanics. The ore-bearing amphibolites were derived from tholeiitic basalts and have N-MORB major-element signatures. Mineralization is mostly copper which is five times more abundant than zinc and makes up concordant sheets, bands, or less often lenses. The Kurchum block also hosts gold–quartz (Avrora–Polevaev group) and gold–listwanite (Maralikha) deposits. Gold mineralization is more abundant within pyrite– polymetallic ore deposits in all ore districts of Rudny Altai, especially as gold–barite–polymetallic ore deposits in the Zmeinogorsk and Leninogorsk districts.
Fig. 5. Stratigraphy of ore districts in northwestern (Russian) Rudny Altai. 1, Lower Paleozoic shale and sandstone; 2, mudstone, siltstone, and silty sandstone; 3, sandstone and outsize tuffaceous sandstone; 4, limestone and limy rocks; 5, mixed breccias; 6, basal conglomerate and gravelstone; 7, tuffs and lavas of rhyolite and rhyolite–dacite porphyries; 8, tuffs and lavas of basaltic and basaltic andesite porphyry; 9, subvolcanic rhyolite and rhyolite–dacite porphyry; 10, pyrite–polymetallic ore mineralization; 11, Au–Ag–barite–polymetallic ore mineralization.
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Rudny Altai: metallogeny The most widespread mineralization in Rudny Altai occurs within the Emsian–Frasnian volcanic-sedimentary rocks and is associated with basalt–rhyolite volcanism. Volcanism and related mineralization formed during subduction events within the Devonian island arc system. Mineralization is controlled by volcanic-tectonic structures at intersections of transversal faults and longitudinal structures between blocks. The mosaic structure of the metallogenic belt results from oblique subduction, with widespread strike-slip faulting (Buslov et al., 2003). Volcanism of calc-alkaline, mostly rhyolitic compositions, evolved in discrete pulses, from felsic to mafic rocks, synchronously with clastic-volcanic deposition in a shallow shelf. The history of volcanism included the Late Emsian– Early Eifelian, Late Eifelian–Early Givetian, and Late Givetian–Frasnian events which migrated from southeast to northwest of the region. The stratigraphic levels of most abundant mineralization move in the NW direction laterally and from the Emsian–Eifelian to Givetian–Frasnian stratigraphically (Avdonin, 1987; Filatov, 1986). Pyrite–polymetallic ore mineralization in all ore districts and at different stratigraphic levels occurs as stratified sheet- or lens-like orebodies among tuffs and sediments, which are folded together with the host rocks. The ores are pocket- or vein-like, disseminated, massive or rarely layered, with collomorphic and globular textures of very fine or fine aggregated particles. The orebodies are accompanied by asymmetric hydrothermalmetasomatic quartz–sericite and sericite–quartz–chlorite aureoles, more abundant in the subore zone. All mineral deposits in Rudny Altai are hosted by volcanics and have pyritic, Cu–pyritic, pyrite–polymetallic ore, and barite–polymetallic ore compositions. The high-grade Kurchum metamorphic block in the south of the region is dominated by mafic volcanism with Cu–pyrite (Korchega deposit) and gold mineralization.
Conclusions The Rudny and Gorny Altai regions have had different geological histories and differ in metallogenic patterns. The Vendian–Early Cambrian to Permian–Triassic evolution of Gorny Altai included subduction, accretion–collision, and rifting events accompanied by magmatism and related mineralization. The history of metallogeny consisted of discrete pulses, with especially abundant Late Paleozoic and Early Mesozoic mineralization. The Late Paleozoic pulse produced diverse mineral deposits (iron, mercury, gold, silver, molybdenum, tungsten, cobalt, polymetallic ores, and rare earths), some of considerable economic value. The territory of Gorny Altai includes several large ore districts that belong to different zones. They are the Beloretsk–Kholzun iron district in the west, the Kayancha–Sinyukha fluorine–gold district in the northeast, the Kurai gold–mercury and Yustyd rare-metal–silver districts in the southeast, and the Kalguty rare-metal–tungsten and Ulandryk uranium–REE–copper districts in the south.
The largest mineral deposits are Kholzun (Fe, P2O5), Karakul (Co, Bi), Sinyukha (Au), Aktash (Hg), Chagan-Uzun (Hg), Ozernoe and Pogranichnoe (Ag), Kalguty (Mo, W), Alakha (Li, Ta), Rudnyi Log (Y,Fe-specularite), and Urzarsai (W– scheelite). Mineralization in Rudny Altai is mainly pyritic: copper– pyrite, pyrite–polymelallic ore, and barite–polymelallic ore. It resides in Devonian suprasubduction basaltic–rhyolitic volcanics and in Emsian to Frasnian island-arc rocks at different stratigraphic levels, in six ore districts. Pyrite–polymetallic ore mineralization in all ore districts and at different stratigraphic levels forms stratified sheet- or lens-like orebodies among tuffs and sediments, which are folded together with the host rocks. The Kurchum high-grade metamorphic block in the southern Rudny Altai bears copper–pyrite and gold–quartz mineralization related to Late Paleozoic volcanism. The study was carried out as part of the government assignment, Project 0330-2016-0001.
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Kuzebnyi, V.S., 1975. Igneous Rocks in the Southwestern Altai and Their Metallogeny [in Russian]. Nauka, Alma-Ata. Kuznetsov, V.A., 1963. Tectonic regional division and main features of magmatism-related metallogeny of Gorny Altai, in: Problems of Geology and Metallogeny of Gorny Altai. Izd. SO AN SSSR, Novosibirsk, pp. 6–68. Kuznetsov, V.A., 1976. Genetic groups, ore formations, and mineraltypes of mercury deposits, in: Mercury Metallogeny [in Russian]. Nedra, Moscow, pp. 7–12. Lobanov, K.V., Gas’kov, I.V., 2012. The Karchiga copper massive sulfide deposit in the high-grade metamorphosed rocks of the Kurchum block: geologic structure, formation, and metamorphism (Rudny Altai). Russian Geology and Geophysics (Geologiya i Geofizika) 53 (1), 77–91 (101–119). Nokleberg, W.J., Badarch, G, Berzin, N.A., Diggles, M.F., Hwang, D.H.,, Khanchuk, A.I., Miller, R.J., Naumova, V.V., Obolenskiy, A.A., Ogasawara M., Parfenov, L.M., Prokopiev, A.V., Rodionov, S.M., Yan, H., 2004. Northeast Asia Geodynamics, Mineral Deposit Location, and Metallogenic Belt Maps, Stratigraphic Columns, Descriptions of Map Units, and Descriptions of Metallogenic Belts. USGS Open-File Report 2004-1252. Pavlova, G.G., Borisenko, A.S., Goverdovskiy, V.A., Travin, A.V., Zhukova, I.A., Tret’yakova, I.G., 2008. Permian–Triassic magmatism and Ag–Sb mineralization in southeastern Altai and northwestern Mongolia. Russian Geology and Geophysics (Geologiya i Geofizika) 49 (7), 545–557 (720–733). Rikhvanov, L.P., 1998. Appraisal of the mineral potential of the Altai Republic, in: Mineral Resources of the Altai Republic: State and Development Prospects. Proc. Regional Conf. [in Russian]. GAGU, Univer-Print, Gorno-Altaisk, pp. 8–12. Rotarash, I.A., Samygin, S.G., Gredyushko, E.A., Kelman, G.A., Milev, V.V., Perfiliev, A.S., 1982. The Devonian active continental margin in Southwestern Altai. Geotektonika, No. 1, 44–59. Shcherba, G.N., D’yachkov, B.A., Nakhtigal, G.P., 1984. Metallogeny of Rudny Altai and Kalba [in Russian]. Nauka, Alma-Ata. Shokalskii, S.P., Babin, G.A., Vladimirov, A.G., Borisov, S.M., 2000. Correlation of Magmatic and Metamorphic Complexes in the Western Altai–Sayan Fold Area [in Russian]. Izd. SO RAN, Filial Geo, Novosibirsk. Tret’yakova, I.G., 2011. The History of Hydrothermal Cobalt Mineralization in the Altai–Sayan fold Area and its Relation to Magmatism [in Russian]. Author’s Abstract. Candidate Thesis, IGM, Novosibirsk. Vladimirov, A.G., Ponomareva, A.P., Shokalskii, S.P., Khalilov, V.A., Kostitsyn, Yu.A., Ponomarchuk, V.A., Rudnev, S.N., Vystavnoi, S.A., Kruk, N.N., Titov, A.V., 1997. Late Paleozoic–Early Mesozoic granitoid magmatism in Altai. Geologiya i Geofizika (Russian Geology and Geophysics) 38 (4), 715–729 (755–770). Vladimirov, A.G., Kruk, N.N., Rudnev, S.N., Khromykh, S.V., 2003. Geodynamics and granitoid magmatism of collisional orogens. Geologiya i Geofizika (Russian Geology and Geophysics) 44 (12), 1321–1338 (1275–1292). Yolkin, E.A., Sennikov, N.V., Buslov, M.M., Yazikov, A.Yu., Gratsianova, R.T., Bakharev, N.K., 1994. Paleogeographic reconstruction of the Western Altai–Sayan area in the Ordovician, Silurian, and Devonian and their geodynamic interpretation. Geologiya i Geofizika (Russian Geology and Geophysics) 35 (7–8), 118–144 (100–124). Zonenshain, L.P., Kuzmin, M.I., Natapov, L.M., 1990. Geology of the USSR: A Plate Tectonic Synthesis. Geodyn. Ser. 21, Page, B.M. (Ed.). AGU, Washington, D.C.
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ScienceDirect Russian Geology and Geophysics 59 (2018) 1010–1021 www.elsevier.com/locate/rgg
Features of magmatim-related metallogeny of Gorny Altai and Rudny Altai (Russia) I.V. Gaskov * V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia Received 12 April 2017; accepted 2 August 2017
Abstract The Rudny Altai and Gorny Altai regions had different geologic histories and differ in metallogenic patterns. The Vendian–Early Cambrian to Permian–Triassic multistage evolution of Gorny Altai included subduction, accretion–collision, and rifting events accompanied by magmatism and related mineralization. Metallogeny evolved in discrete pulses, with especially abundant Late Paleozoic–earliest Mesozoic mineralization. The Devonian–Carboniferous pulse produced diverse mineral deposits (iron, mercury, gold, silver, molybdenum, tungsten, cobalt, polymetallic ores, and rare earths), some of considerable economic value. The territory of Gorny Altai includes several large ore districts that belong to different zones. They are the Beloretsk–Kholzun iron district in the west, the Kayancha–Sinyukha fluorine–gold district in the northeast, the Kurai gold–mercury and Yustyd rare-metal–silver districts in the southeast, and the Kalguty rare-metal–tungsten and Ulandryk U–REE–Cu districts in the south. The largest mineral deposits are Kholzun (Fe, P2O5), Karakul (Co, Bi), Sinyukha (Au), Aktash and Chagan-Uzun (Hg), Ozernoe and Pogranichnoe (Ag), Kalguty (Mo, W), Alakha (Li, Ta), Rudnyi Log (Y,Fe-specularite), and Urzarsai (W-scheelite). Mineralization in Rudny Altai is mainly pyritic: copper–pyrite, pyrite–polymelallic ore, and barite–polymelallic ore. It resides in suprasubduction basalts and rhyolites and in Emsian to Frasnian island-arc volcanics at different stratigraphic levels of Devonian volcanosedimentary sequences in six ore districts. The Kurchum high-grade metamorphic block hosts copper–pyrite and gold–quartz mineralization related to Hercynian volcanism. © 2018, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved. Keywords: metallogeny; mineral deposits; mineralization; magmatism; Gorny Altai; Rudny Altai
Introduction Altai occupies the western part of the Altai-Sayan fold area and comprises of the Southwestern and Gorny Altai blocks of commensurate sizes (Fig. 1). Southwestern Altai, about 100 km wide, extends in the SE direction for 1000 km, continuing into Mongolia and China. Rudny Altai is located in its northwestern part and extends for 500 km over the territory of Russia and Kazakhstan. Rudny Altai borders the Kalba zone along the Irtysh large fault in the west and Gorny Altai along the 600 km NW Northeastern shear zone in the east. Gorny Altai makes up the northeastern part of the Altai territory and is traceable for more than 300 km eastward as far as the West Sayan Range bounded by the Shapashal fault. Geological surveys in the Gorny and Rudny Altai regions show that they differ in history and metallogeny patterns. The
first review of the Gorny Altai metallogeny appeared in the 1960s (Kuznetsov, 1963) and was followed later by numerous works focused on general metallogenic features (e.g., Goverdovskii, 1998; Rikhvanov, 1998). The exceptionally rich metallogeny of Rudny Altai has been more extensively and thoroughly studied for decades from 1950s to the 2010s (Chekalin and D’yachkov, 2013; Gaskov, 2015; Gorzhevskii et al., 1955; Shcherba et al., 1984; etc.). However, the relation of mineralization with specific magmatic events remains controversial because the chronology and history of magmatism are still poorly constrained. In this study we use recent geological and geochronological data to trace the evolution of metallogeny in the Gorny and Rudny Altai regions and its relation to magmatism.
Gorny Altai: geological background * Corresponding author. E-mail address: [email protected] (I.V. Gaskov)
Gorny Altai had a long and complex geological and tectonic history (Berzin and Kungurtsev, 1996; Berzin et al.,
1068-7971/$ - see front matter D 201 8, V.S. So bolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.rgg.201 + 8.07.020
I.V. Gaskov / Russian Geology and Geophysics 59 (2018) 1010–1021
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Fig. 1. Location map of Rudny and Gorny Altai in the framework of the Altai–Sayan fold area, after (Buslov et al., 2013). Abbreviations stand for names of deep faults: Ch, Chara; I, Irtysh; NE, Northeastern.
1994; Buslov, 1992, 1998; Buslov et al., 2013; Dobretsov and Buslov, 2007; Dobretsov et al., 2004, 2005; Kruk, 2015a; Shokalskiy et al., 2000; Vladimirov et al., 2003; Zonenshain et al., 1990). The geological history comprised six major events: (1) Vendian–Early Cambrian formation of oceanic, island-arc and back-arc systems; (2) Middle Cambrian–Early Ordovician accretion of perioceanic and island arc systems to the margin of Siberia; (3) Middle Ordovician–Early Devonian passive continental margin processes; (4) Devonian–Early Carboniferous origin and evolution of the active continental margin; (5) Carboniferous–Early Cambrian continental collision of Siberia and Kazakhstan during the activity of the Tarim plume; (6) Permian–Early Mesozoic within-plate magmatism associated with the Siberian superplume. All these events have produced eventually a collage of terranes that differ in age and origin (Berzin and Kungurtsev, 1996; Buslov, 1998). They are major synclinal or anticlinal fold structures or a combination of local coeval structures comprising several zones with different patterns of geology, magmatism, and metallogeny. According to the terrane model (Nokleberg et al., 2004), they are the zones of Charysh, Kholzun–Chuya, Talitsa, Anui– Chuya, Biya–Katun’, Uimen–Lebed’, and Teletsk, listed from west to east (Fig. 2), which generally agree with the structural zones distinguished by Kuznetsov (1963). The zones are bounded by regional or local faults; the former control magmatism and related mineralization, while the latter are barren. The regional faults are primarily the Northeastern shear zone between the Early Paleozoic Gorny Altai and Late Paleozoic Rudny Altai regions. It is a system of complex branched en-echelon zones of intense shearing, foliation, and mylonitization (Uspenka–Karelensky, Kedrovoe–Butachikha, Lokot’, etc.), 600 km long and 2–20 km wide, which
accommodates Permian–Jurassic granites. The Charysh– Terekta fault separating the Charysh and Kholzun–Chuya zones from the Talitsa and Anui–Chuya zones extends for more than 400 km within Gorny Altai and on into Northwestern Mongolia, and is intruded by igneous rocks of different ages and types. Another large fault of Sarasa–Kurai, which likewise controls magmatism and related mineralization, bounds the Anui–Chuya structure zone in the northeast. It has a very complex structure and is actually a system of regional en-echelon faults: Sarasa, Kadrin, and Kurai. The Chokrak large fault lies between the Biya–Katun’ and Anui–Chuya zones and the Shapshal fault in easternmost Altai separates it from the West Sayan Range. Local faults free from signatures of magmatism and mineralization bound some zones. Fragments that represent early oceanic and island arc settings of Gorny Altai were found within the Biya–Katun’ and Uimen–Lebed’ zones. The Biya–Katun’ zone within the Biya–Katun’ uplift is composed of Neoproterozoic carbonate sediments with quartzite and greenstone-facies volcanics lying under a Lower–Middle Cambrian volcaniclastic sequence with layers of reef archaeocyathan limestones and dolomites; all rocks are heavily deformed. Ordovician and Silurian strata are missing, and Devonian rocks most often lie immediately over Cambrian and Neoproterozoic strata. The plutonic rocks include the oldest small plagiogranite–gabbro–pyroxenite bod−1) and small multiphase ies of the Meshtueryk complex (C pyroxenite, gabbro, and granite intrusions of the Barangol complex (496 ± 5 Ma), which are spatially related with fields of Middle Cambrian volcanics, as well as 384 ± 4 Ma subduction-related gabbro, diorite, and granite of the Kinderli complex (Kruk, 2015a). Mineralization is restricted to small occurrences of hydrothermal-metasomatc magnetite in Cam-
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Fig. 2. Tectonics and metallogeny of Gorny Altai, based on tectonic map by Kuznetsov (1963). 1–7, zones: Charysh–Inya (1), Talitsa (2), Kholzun–Chuya (3), Anui–Chuya (4), Biya–Katun’ (5), Uimen–Lebed’ (6), Teletsk (7); 8, fault zones, abbreviated as NE, Northeastern, ChT, Charysh–Terekta, SK, Sarasa–Kurai, Ch, Chokrak, Sh, Shapshal; 9–18, mineral deposits: 9, iron deposits Beloretsk (1), Inya (2), Kholzun (3), Korgon (4), Kedrovoe (5), and Kharlovo (6); 10, manganese deposit Prozrachnoe (1) and ore occurrences; 11, gold deposits Sinyukha (1), Choya (2), Novofirsovo (3), Murzinka (4) and ore occurrences; 12, Cu–Mo deposit Kulbich (1); 13, polymetallic ore–Co Karakul (1) and Vladimirovka (2); 14, sheelite–polymetallic ore and polymetallic ore deposits Urzarsai (1), Krasnyi Yar (2), Ursul (3), and Novochagyr (4) and ore occurrences; 15, Sb–Ag deposits Ashatin (1), Ozernoe (2), Pogranichnoe (3) and ore occurrences; 16, Mo–W deposits Kalguty (1) and Dzhumala (2); 17, Hg deposit Aktash (1) and Chagan-Uzun (2) and ore occurrences; 18, rare metal–REE deposits Li–Ta Alakha (1), Fe–REE Rudnyi Log (2), Koksa (3), and Kumir (4).
brian volcanics; jaspellite and siderite in carbonates; and titanomagnetite in gabbro and ultramafic intrusions of the Barangol complex. Redeposited eluvium hosts the Selezen manganese ores while Precambrian carbonates in the northeast store gold–carbonate mineralization (Sarasa and Sibiryachikha fields). Small mafic bodies bear disseminated gold (0.2 to 34.5 ppm) and sulfides (Sukhon’koe, Nochnoi Log, Novoe, and Cheremshan occurrences). The Uimen–Lebed’ zone occupies a complexly structured trough of the same name. Its section begins with Neoproterozoic carbonates and Lower–Middle Cambrian volcanic-sedimentary rocks discordantly overlain by Ordovician and Silurian variegated sandstone and shale in the northern part and by Middle–Upper Devonian volcanics and sediments in the south. Plutonic rocks are Middle–Late Cambrian gabbro and granite of the Sarakoksha complex (512.2 ± 6.2 Ma) and the Devonian Yugala (406 ± 4 to 399 ± 2 Ma), Turochak (390 ± 7 Ma), and Kyzyltash (D2) complexes emplaced in an active continental margin setting (Babin et al., 2004; Kruk, 2011, 2015b). Rich scarn gold–sulfide mineralization
(Sinyukha, Maisk, Choya, and Ulmen deposits; Isha and Oyuk occurrences) follows the contacts of the Yugala diorite–granite and carbonate intrusions (Shokalskii et al., 2000; Gaskov et al., 2010). The Yugala diorite–granite complex hosts the Kulbicha porphyry Cu–Mo deposit, the Akkem quartz– molybdenite vein deposit, and the Isha and Maisk–Lebed’ fields with up to 20 and 40 tons of total gold reserves, respectively. Gold contents in several epithermal gold and silver fields are up to 8.4 ppm Au and 436 ppm Ag, with the especially rich Chura occurrence, while the total gold predicted potential of this ore cluster reaches 322 tons (Gusev, 2002). Hydrothermal-metasomatic occurrences of magnetite ores are found at the contact of granititc rocks with the Devonian and Cambrian wallrocks and Ti-magnetite mineralization resides in gabbronorite and gabbro–syenite complexes (Salganak occurrence). Stockwork quartz–sheelite minerals coexist with polymetallic ore–Ag–Pb veins (Urzarsai deposit) in the southeastern part of the zone. The Kholzun–Chuya and Anui–Chuya zones bear signatures of Middle Cambrian–Early Ordovician accretion and
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collision events with deposition of thick flysch. The Kholzun– Chuya zone extends in the SE direction in western Gorny Altai along the Rudny Altai boundary. The section consists of Neoproterozoic schists within the Terekta horst overlain by heavily deformed Lower Cambrian volcanics and sediments lying under Cambrian–Ordovician flysch. In the Kargon and Kalguty superposed basins, Middle Devonian sediments lie immediately upon Precambrian schists. Plutonic rocks mainly belong to the 375 ± 11 Ma Rokhman gabbro–diorite–granite and (362–375) ± 1 Ma Borovlyanka granodiorite–granite complexes (Kruk, 2015b) that formed in an active continental margin setting. Later rifting-related igneous rocks are less abundant: the Tarakhta syenite–monzodiorite–granosyenite (247 ± 3 Ma) and Belokurikha (232 ± 5 Ma) and Chindagat– Kalguty (212–190 Ma) granite–leucogranite complexes. Metallogeny in the Kholzun–Chuya zone is the most diverse and richest over Gorny Altai. Iron resides in the Korgon Formation (D2krg) of basalts, andesites, ryolites, and sediments within the Korgon trough (Kholzun, Korgon, Timofeevka, and other deposits) in the Beloretsk–Kholzun district at the Rudny Altai boundary (Gas’kov et al., 1999; Kassandrov, 2010; Yolkin et al., 1994), the Kholzun V–P–Fe deposit being the largest one (~700 × 106 tons). Iron ores coexist with manganese mineralization of two types: (1) oxide and carbonate ores in volcanicsedimentary rocks (Prozrachnoe deposit) and (2) oxidized ores in weathered Mn-bearing rocks (Bostok and Bostal occurrences). Skarn iron (Beloretsk and Inya deposits) occurs in contacts of the Upper Devonian plutons within the Korgon trough (Kalugin et al., 1981; Kassandrov and Ivanov, 1979; Kassandrov et al., 1998) while W–Mo–Bi–rare metal ores (1.85% WO3 and 0.005–0.088% Mo and Bi) reside in greisen granites of the Belokurikha complex. Disseminated, pocket-, and vein-like Co mineralization is spread in a 400 m thick and more than 2 km long strips along contacts of the gabbro–diorite stockwork intrusion (Vladimirovka deposit, 0.5% Co on average). Other mineralization occurrences within the Korgon trough are rare-metal–REE–U ores, especially the Kumir Sc–Y–U–Th deposit in albitized, sericitized, and tourmalinized contacts of the Kumir stockwork (Belokurikha complex, 240 Ma). Iron–REE–Cu ores (Koksa, Vodopadnoe, and Rudnyi Log deposits, with up to 7.5% Cu, 36% Fe, 0.1% Y, 0.16% Co, 30 ppm Ag, and 0.5 ppm Au) are hosted by Middle Devonian volcanics (rhyolite, dacite, and andesite) in the southeastern Kalguty superposed trough. The Yustyd trough accommodates the Yustyd ore district with magmatic mineralization of various compositions (Sb–Ag, Sn–W, W– Bi–Co, Ni–Co–As, Au–Ag–Hg, and Sb–Hg). Most ores reside in black shales (D2–3) lying over redbed and volcanic-sedimentary rocks (D1–2). There were two main events of magmatism and ore formation (Gusev and Gusev, 2010; Pavlova et al., 2008; Tret’yakova, 2011): Late Devonian–Early Carboniferous and Middle Permian–Early Triassic. The early D3–C1 event produced the Yustyd granites (375.4 ± 5.5 Ma, D3–C1) with REE (351.4 ± 1.4 Ma) and Sn–W (359.0 ± 3.4 Ma) ores and postgranite dolerite dikes (351.8 ± 3.8 Ma) with Cu–W–Bi–Co mineralization (349.8 ± 3.9 Ma, Karakul deposit). The Karakul deposit in the western contact of the
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Barburgazy pluton consists of closely spaced roughly parallel chlorite–tourmaline–quartz metasomatic orebodies, up to 30 m thick, 1500 m long, and more than 300 m along the dip. The mineralogy includes cobaltite and glaucodote often coexisting with sheelite, bismuthite, chalcopyrite, tetrahedrite, arsenopyrite, pyrrhotite, and pyrite. The P2–T1 event began with intrusions of the Terekta dolerite dikes (255 Ma) and the Chuya lamprophyres (250 ± 4.5 Ma) with Ni–Co–As veins (258–250 Ma). The intrusions were followed by emplacement of the Tarakhta granosyenite (238 ± 2.5 Ma) with related Sb–Ag (240 ± 3.5 Ma) and Hg (234.4–231.5 Ma) mineralization. The Askhatin, Ozernoe, and Pogranichnoe Sb–Ag deposits are the richest. The Askhatin deposit is located in the northeastern Ozernoe–Askhatin ore field among the Middle– Upper Devonian Barburgazy and Boguty Formation clastics. The 800 m long and 16 m thick orebodies consist of siderite veins and less abundant breccias and linear stockworks that store massive and disseminated sulfide–sulfosalt mineralization, with a potential of 7100 tons of silver (351 ppm Ag on average), 163,000 tons of copper (0.82%), 92,000 tons of stibnium (0.36%), 13,000 tons of bismuth (0.055%) (Bedarev and Dalilkhan, 1987). Complex ores are associated with Devonian volcanism in the southeastern part of the Kholzun– Chuya zone (Tyutinsky, Korumda, Kyzyl-Chin, Ursul, and Kazinikhinsky deposits) and with Late Paleozoic–Early Mesozoic plutonism, including the Krasnyi Yar Pb–Sn deposit and the Bolshoi Yaloman deposit with a diverse mineralogy (quartz, epidote, calcite, galena, sphalerite, chalcopyrite, pyrite, pyrrhotite, marcasite, molybdenite, and sheelite). The Anui–Chuya zone occupies a basin of the same name and extends in the NW–SE direction parallel to the Kholzun– Chuya zone across the whole Gorny Altai area. Its sedimentary section consists of thick Cambrian and Ordovician flysch at the base and Ordovician and Silurian shales and limestones in the middle, discordantly overlain by Devonian and Lower Carboniferous volcanics and sediments, as well as Carboniferous coal-bearing continental sediments in the southeastern part of the zone. Deformation is restricted to isoclinal folding along faults. Abundant plutonism associated with active margin collisional processes produced gabbro–granite suites of the Topolnoe (397 ± 5 Ma) and Ust’-Belaya (374 ± 3 Ma) complexes, granite–leucogranite intrusions of the Elinovo–Butachikha (377 ± 5 Ma), Shebelik (3065 Ma), and Chindagatui– Kalguty (216–190 Ma) complexes which host diverse related mineralization. Devonian volcanics store polymetallic ores (Shargaita, Il’inka, Shiroky Log deposits) of galena, sphalerite, chalcopyrite, pyrite, and pyrrhotite coexisting with molybdenite, sheelite, quartz, epidote, and calcite. The South-Altai metallogenic belt in the southeast of the zone includes the Kalguty and Alakha ore clusters (Gusev and Gusev, 2014). The Kalguty cluster comprises the Kalguty, Dzhumala, and South Kalguty Mo–W deposits and the Sadokbai, Filial, Torbernit, Upper Akkol, West and North Kalguty ore occurrences hosted by the 216 ± 3 Ma Kalguty granite complex (Annikova et al., 2006). The largest Kalguty Mo–W deposit is located in the eastern part of the complex, with 1.9% WO3, 0.1% Bi, 0.04% Be, and Mo <0.01% in both granites and their
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wallrocks. The Alakha ore district and the Alakha Li–Ta deposit are located in the highland part of the Chuya basin (Kosh-Agach area). Mineralization occurs along the margins of the Alakha spodumen granite–porphyry stockwork and consists of spodumen, tantalite, and pollucite metal-bearing minerals and barren micas and feldspar in greisenized, albitized, and quartzitized rocks. The Li (0.8%) and Ta (0.012%) ores contain also 0.12% Rb, 0.026% Ce, 0.004% Nb, and 0.006% Bi. Epithermal Hg deposits make up the Kurai mercury belt, about 100 km long and 6–8 km wide extending toward the Chuya roadway in the southeast of the zone. The belt comprises more than 100 Hg occurrences and two economic carbonate–cinnabar (Aktash) and listwanite (Chagan-Uzun) deposits. The Aktash sheet-, pocket-, and vein-like orebodies occur among dolomitized, quartzitized, and argillized limestones and shales. The ore mineralogy consists of cinnabar, antimonite, pyrite, tetrahedrite, realgar, calcite, dolomite, and quartz. The Chagan-Uzun deposit forms ore columns and lenses of cinnabar with minor amounts of other sulfides (antimonite, millerite, gersdorffite, pyrite and realgar) in serpentinized porphyry and their tuffs and tuffaceous sandstone. Mercury mineralization is mainly hosted by Mesozoic mafic and ultramafic magmatism in deep faults and by small subalklaine basaltic intrusions. The Charysh and Talitsa zones record a passive continental margin setting. The Charysh zone occupies the Charysh basin in western Gorny Altai, at the boundary with Rudny Altai. The Lower Paleozoic section is the most complete and consists of Cambrian mostly clastic sediments to Upper Silurian shales and limestones overlain discordantly by Middle Devonian weakly deformed volcanic-sedimentary rocks. Plutonic rocks, mostly of Early Mesozoic age, are restricted to the Kur’ya and Novofirsovo troughs and belong to the Mayorka (381 ± 4 Ma) and Borovlyanka (375 ± 1 Ma) granite–leucogranite complexes, the Ust’-Belaya (364–374 ± 3 Ma) gabbro–diorite– tonalite–granodiorite complex, and the Kharlovo (330–334 Ma) monzogabbro and monzodiorite complex; the later rifting-related magmatism is limited to the 248 ± 1 Ma Sinyushka complex (Kruk, 2015a) Magmatism-related metallogeny is sporadic and mainly associated with Devonian volcanism and plutonism. It consists of small Ag–polymetallic ore (Novochagyr) and polymetallic ore (Shiroky Log and Chernaya Rechka) occurrences as quartz–carbonate veins and quartz–feldspar metasomatic rocks with galena and sphalerite (locally with argentite and copper minerals) along contacts of Devonian subvolcanic intrusions and in Ordovician–Silurian carbonate and clastic sediments. Devonian rhyodacite subvolcanic intrusions within the Novofirsovo trough hosts the Novofirsovo epithermal gold–silver field with up to 5 ppm Au, 42.2 ppm Ag, 0.41% Cu, 0.27–5.75% Pb, and 0.33–6.58% Zn; the predicted gold resources amount to 45 tons. A layered gabbro intrusion of the Kharlovo complex in the northwestern zone part, which consists of tens of meters thick metal-bearing (at least 14% Fe and 8 m) or barren gabbro layers, hosts the Kharlovo Ti-magnetite deposit. The 425 to 2650 m long orebodies store more than 3.5 × 109 tons of
metals with average contents of 15.3% FeO, 5.9% TiO2, 0.08% V2O5, and 11% Al2O3. The Talitsa zone is located east of the Charysh zone within the Talitsa anticlinal uplift. The section stripped in the anticline core begins with Neoproterozoic–Lower Cambrian shales and schists, porphyry rocks and their tuffs with microquartzite and marble layers, while the limbs are mainly composed of shales and sandstones with layers of Cambrian– Ordovician silicic rocks, jaspers, and porphyry. Widespread plutonic rocks include Upper Devonian gabbro–granite intrusions of the Mayorka (381 ± 4 Ma), Borovlyanka (375 ± 1 Ma), and Ust’-Belaya (364–374 ± 3 Ma) complexes, like in the nearby Charysh zone, as well as later (232 ± 5 Ma) rifting-related granites and leucogranites of the Belokurikha complex. Magmatism-related mineralization in the zone is restricted to sporadic W–Mo–Bi–rare metal ores in granite greisens of the Belokurikha complex. Opaque minerals (hübnerite, wolframite, sheelite, powellite, tetradymite, pyrite, xenotyme, cerussite, and molybdenite) are found in both greisens and quartz veins (1.85% and 7.8% WO3, respectively, and within 0.005–0.088% Mo and Bi). The Teletsk zone is located within the Teletsk and Kurai terranes at the boundary between Gorny Altai and the West Sayan Range delineated by the Shapshal large fault. It is a transitional zone where the structures change direction from NW (Altai-type) to NE (West Sayan-type). The section consists of Neoproterozoic schists overlain by Lower Cambrian volcanic-sedimentary rocks which, in turn, lie under Cambrian–Ordovician clastic-shale flysch. All rocks are deformed, metamorphosed, and intruded by ultramafic, mafic, and granitic rocks. The zone includes the Ulagan superposed basin and fault-line grabens filled with Devonian sediments. The Kurachak magnetite deposit discovered on the left side of Lake Teletskoe and in the headwaters of the Biya and Lebed’ Rivers stores about 15 × 106 tons of ore. Its age and relation with magmatism remain yet unconstrained.
Gorny Altai: metallogeny As noted above, the Vendian–Early Cambrian to Permian– Triassic history of Gorny Altai included multiple subduction, accretion–collision, and rifting events accompanied by magmatism and related mineralization. Metallogeny was unevenly distributed in space and time. The oldest orebodies formed in the Vendian–Cambrian oceanic setting are restricted to the Biya–Katun’ zone. They are composed of magnetite and jaspellite among Cambrian volcanics and carbonate sediments, as well as Ti-magnetite in the Barangol gabbro (496 ± 5 Ma) and jasperoid-hosted gold mineralization in carbonates. Some limited mineralization (the Kaurchak deposit on the left side of Lake Teletskoe in the Teletsk zone) was associated with Middle Cambrian–Early Ordovician accretion and collision. No considerable mineralization has been revealed in the Ordovician–Silurian passive margin setting. Metallogenic processes were especially intense in the Late Paleozoic (D1–C2) active continental margin setting and
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produced diverse mineralization. It includes small Ag–polymetallic ore and polymetallic ore occurrences (Novochagyr, Shiroky Log, Chernaya Rechka) in the Mayorka intrusives (381 ± 4 Ma) emplaced into clastic-carbonate sediments (Charysh zone, western part of the region); the Kharlovo Ti-magnetite deposit in the Kharlovo layered gabbro (330– 334 Ma) farther southeast; the Murzinka gold deposit in the Ust’-Belaya granodiorites (364 ± 8 Ma); the Novofirsovo Au–Ag deposit in Middle–Late Devonian subvolcanic rhyodacites in the south of the zone. The Beloretsk–Kholzun iron district in the Korgon superposed trough (Kholzun–Chuya zone) comprises iron deposits (Kholzun, Korgon, Timofeevka, etc.) in volcanics and sediments and Mn ore occurrences (Prozrachnoe) in the volcanic-sedimentary Korgon Formation (D2krg). Iron mineralization is found as iron–REE occurrences (Koksa, Vodopadnoe, and Rudnyi Log) in Middle–Late Devonian alkali rhyolite–dacite and andesite and as scarn iron deposits (Beloretsk and Inya) in the margins of Late Devonian plagiogranites of the Tigirek pluton. Mineralization in the southeastern part of the zone consists of polymetallic ores hosted by Devonian volcanics (Ursul, Krasnyi Yar, Tyutinsky, Kyzyl-Chin, etc. deposits) and by Middle Devonian granite intrusions (Urzarsai, Bolshoi Yaloman, and Ilgumen deposits). The Yustyd basin of the Kholzun–Chuya zone accommodates the Yustyd ore district with magmatism-related mineralization of various compositions (Sn–W, Cu–W–Bi–Co, and Sb–Hg). The ores formed in two metallogenic events: (i) the Late Devonian–Carboniferous event of REE (351.4 ± 1.4 Ma) and Sn–W (359.0 ± 3.4 Ma) mineralization in the 375.4 ± 5.5 Ma Yustyd granites and REE- and Sn–W-bearing minerals in greisens (D3–C1) and (ii) the Permian–Triassic event which began with 349.8 ± 3.9 Ma Cu–W–Bi–Co mineralization (Karakul deposit) in postgranite dolerite dikes (351.8 ± 3.8 Ma). Occurrences of hydrothermal-metasomatic magnetite and Ti-magnetite ores (Salganak) are found in Devonian gabbro–granite intrusions (406 ± 4 Ma) in the eastern Uimen– Lebed’ zone; gold mineralization, mainly of the sulfide-skarn type (Choya, Sinyukha, Maisk, and Ulmen deposits) occurs along the contacts of a diorite–granite pluton in the Yugala complex (399 ± 2 Ma) and in carbonates. This mineralization coexists with the Kulbich Cu–Mo porphyry deposit, the Akkem quartz–Mo vein ore occurrence, as well as the Isha and Maisk–Lebed’ ore zones with predicted gold resources of 20 to 40 tons, respectively. Volcanic-hosted polymetallic ore (Shirgaita, Il’inka, Shiroky Log deposits, etc.) occur in the southeastern Uimen–Lebed’ zone. The Permian–Triassic event also produced diverse mineralization hosted by within-plate granites. Mineralization of this age coexists with younger rare-metal mineralization (Ni–Co– As, Ag–Sb, Hg) in the Chuya complex of lamprophyre (250.8 ± 4.5 Ma) and granosyenite (241.5–238 ± 2.5 Ma) dikes in the southeast of the area (Yustyd basin). They are, namely, the Askhatin and Pogranichnoe Sb–Ag deposits and Co occurrences (Tret’yakova, 2011). The Kalguty granitoids (216–218 Ma) host Mo–W, Cu–Mo, and Be ores that form the Kalguty ore cluster with the Kalguty, Dzhumala, South Kalguty deposits, as well as epithermal Hg mineralization
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(Aktash and Chagan-Uzun deposits and more than 100 occurrences making up the Kurai ore belt) associated with mafic and ultramafic magmatism in zones of deep faults. W–Mo–Bi–rare metal mineralization, as well as Co mineralization (Vladimirovka deposit) occurs in the Korgon basin of the Kholzun–Chuya zone hosted by greisen granites of the Belokurikha complex (232 ± 5 Ma). The Kumir Sc–Y–U deposit occurs in the margins of the Kumir stockwork intrusions of subvolcanic rhyolites (240 Ma) in the right side of the Kumir River. The Belokurikha granites also host W–Mo–Bi–rare metal minerals in the Talitsa zone.
Rudny Altai: geological background Rudnyi Altai is one of largest metallogenic belts of Eurasia which comprises about fifty economic and numerous small Cu–Pb–Zn deposits (Figs. 1, 3). The Rudny Altai territory is most often interpreted as a Devonian island arc system formed along the margin of the Irtysh–Zaisan ocean (Berzin and Kungurtsev, 1996; Rotarash et al., 1982; Zonenshain et al., 1990). The region includes the Alei and Sinyushka uplifts and the Bystrukha and Belaya Uba basins with their sections consisting of Early Paleozoic (barren) and Late Paleozoic (ore-bearing) units. Fragments of Early Paleozoic rocks appear in the Alei and Sinyushka uplifts and in the Irtysh and Northeastern shear zones (Shcherba et al., 1984). They are heavily deformed and metamorphosed (greenstone-facies) quartz–sericite, sericite–chlorite and actinolite–chlorite schists and sandstones. Devonian and Carboniferous volcanics and sedimentary rocks lie discordantly over the lower unit. They store various Cu–pyrite, pyrite–polymetallic ore, and barite– polymetallic ore deposits and occurrences associated with basalt–rhyoloite volcanics. Since the Fammenian, volcanism in Rudny Altai was composed of barren mainly sodic andesite–dacite lavas and tuffs located within a narrow strip along the southwestern edge of the region. Their intrusive analogs form an NW chain of dikes and large hypabyssal gabbro, gabbro-dolerite and dolerite bodies at the back of the volcanics, near the Northeastern shear zone. Widespread plutonic rocks (Kuzebnyi, 1975; Vladimirov et al., 1997) span a large age range and belong to three groups according to formation settings: preorogenic (380–390 Ma), synorogenic (Zmeinogorsk complex, 309 Ma) and collisional (Kalba complex, 277–266 Ma) granites. All granites are barren. Thus, the Rudny Altai metallogeny consists mainly of pyritic mineralization hosted by basalt–rhyolite volcanism, in six ore districts (Fig. 3): Zyryanovsk, Leninogorsk, Irtysh (in Kazakhstan), Zmeinogorsk, Zolotushinsky, and Rubtsovsk (in Russia). Zyryanovsk ore district makes the southeastern part of the Rudny Altai metallogenic belt. Its section mainly consists of Devonian–Lower Carboniferous rocks of the Podrevnyukha (D1e1), Revnyukha (D1e2–D2ef1), Maslyanka (D2ef2–D2zv1), Khamir (D2zv2–D3), Turgusun (C1t2–v1), and Larikha (C1v2) Formations. The Revnyukha and Maslyanka Formations,
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Fig. 3. Simplified tectonics and metallogeny of Rudny Altai, based on data of the Rudny Altai geological surveys. 1, Middle and Upper Devonian volcanic-sedimentary rocks; 2, sedimentary fill of the Belaya Uba–Maimyr back-arc basin; 3, high-grade volcanic-sedimentary rocks of the Kurchum block; 4, preorogenic Devonian (D2) diorite, quartz diorite, granodiorite, plagiogranite; 5, Middle–Upper Carboniferous (C2–3) granodiorite, diorite, plagiogranite, and ademelite (Zmeinogorsk complex); 6, Upper Permian–Lower Triassic (P2–T1) biotite and biotite–hornblend porphyry granites (Kalba complex); 7, large faults between fold systems (I, Irtysh; NE, Northeastern shear zone); 8, cross faults; 9, 10, ore districts (9) and deposits (10): pyrite–polymetallic ore and Cu–pyrite (a) and barite–polymetallic ore (b). I, Zyryanovsk ore district: 1, Grekhovsky, 2, Snegirevka, 3, Zyryanovsk, 4, Bogatyrev, 5, Osochikha, 6, Maisk–Zyryanovsk, 7, Putintsevo, 8, Parygino, 9, Maleevka, 10, Zavodskaya, 11, Bukhtarma; II, Leninogorsk district: 12, Ridder-Sokol’nyi, 13, Tishinsky, 14, Shubinka, 15, Starkovka, 16, Strizhkov, 17, Guslyakovsky, 18, Chekmar, 19, Novoleninogorsk, 20, Uspenka, 21, Anisimov Klyuch, 22, Snegirikha; III, Irtysh ore district: 23, Belousovka, 24, Irtysh, 25, Berezovka, 26, Novoberezovka, 27, Nikolaevka, 28, Pokrovka, 29, Shemonaikha, 30, Kamyshin, 31, Artem’evka; IV, Zolotushinsky ore district: 32, Yubileinoe, 33, Kryuchkovo, 34, Zolotukha, 35, Novozolotukha, 36, Orlovka, 37, Gerikhovsky, 53, Lokot’; V, Zmeinogorsk ore district: 38, Vorovsk, 39, Semenovka, 40, Maslyanka, 41, Lazurnyi, 42, Zmeinogorsk, 43, Korbalikha, 44, Srednee, 45, Zarechensk, 46, Strizhkov, 47, Maisk, 48, Tushkanikha; VI, Rubtsovsk ore district: 49, Stepnoe, 50, Talovka, 51, Zakharovka, 52, Rubtsovsk; 54, Korchega Cu–pyrite deposit within the Kurchum block.
which are composed of alternating rhyolite–dacite and basaltic andesite lavas and their tuffs, tuffaceous sandstone, siltstone, and limestone, are ore-bearing and host eight economic deposits and numerous ore occurrences. The two formations are sandwiched between the mostly sedimentary Podrevnyukha Formation (D1e1) and Upper Devonian–Lower Carboniferous limestone and shale (Fig. 4). All economic deposits lie within the Revnyukha uplift. Pyrite–polymetallic ore
mineralization in the uplift forms several 110–130 m thick levels. The lower level in the lower and middle Revnyukha section comprises rather poor vein and disseminated ores (Zyryanovsk and Grekhovsky deposits and several occurrences). The middle level corresponds to the upper Revnyukha and lower Maslyanka Formations with main concordant or combined bodies of continuous or less often vein-disseminated pyrite–polymetallic ores (Zyryanovsk, Grekhovsky, and Maisk
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Fig. 4. Stratigraphy of ore districts in southeastern (Kazakhstan) Rudny Altai. 1, mudstone, siltstone, and silty sandstone; 2, sandstone and tuffaceous outsize sandstone; 3, limestone and limy rocks; 4, basal conglomerate and gravelstone; 5, tuffs and lavas of rhyolite and rhyolite–dacite porphyry; 6, tuffs and lavas of basaltic and basaltic andesite porphyry; 7, subvolcanic rhyolite and rhyolite–dacite porphyry; 8, schists; 9, pyrite–polymetallic ore mineralization; 10, Au–Ag–barite–polymetallic ore mineralization.
deposits). The upper Maslyanka Formation forms the upper level with the Maleevka Cu–pyrite–polymetallic ore deposit. Leninogorsk ore district located 100 km northwest of the Zyryanovsk district extends NW for ~80 km in the central part
of the Sinyusha uplft. The section consists of Eifelian– Givetian volcanic-sedimentary rocks that belong to the Leninogorsk (D1e2), Kryukovsky (D2ef2), Il’inka (D2ef2), Sokol’nyi (D2ef2), Uspenka (D2ef2–D2zv1), and Belaya Uba
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(D2zv–D3f) Formations (Fig. 4). The rocks host nine economic pyrite–polymetallic ore and barite–polymetallic ore deposits and a number of ore occurrences in three lithostratigraphic units. They are: the Ridder-Sokol’nyi, Novoleninogorsk, and Dolinnoe deposits and several occurrences of Au- and Ag-rich barite and polymetallic ores of the Leninogorsk field in the lower unit (Kryukovsky Formation), within a caldera-like depression composed of sands and shales with rhyolite–dacite layers; the Tishinsky pyrite–polymetallic ore deposit at the top of large Tishinsky–Belyi Lug stratovolcano in the middle unit, at the boundary between the Il’inka and Sokol’nyi Formations; and the Guslyakovsky, Chekmar, Strezhan, Shubinka, and Starka pyrite–polymetallic ore and Cu–Zn–pyrite deposits in the upper unit, at the boundary between the Uspenka and Belaya Uba Formations. Barite–polymetallic ore mineralization grades into Cu–pyrite–polymetallic ores up the section. Irtysh ore district is located in the western flank of the Rudny Altai metallogenic belt, within the southwestern slope of the Alei uplift and comprises two 5 km wide ore fields (Nikolaevka and Berezovka–Belousovka) extending for tens of kilometers along the Irtysh shear zone (Fig. 3). The Nikolaevka ore field is composed of Middle–Upper Devonian volcanic-sedimentary rocks that belong to the Losikha (D2ef), Talovka (D2zv), Gerikhovsky (D3f), Nikolaevka (D3f), and Snegirevka (D3f–fm) Formations (Fig. 4). The Losikha, Talovka, and Gerikhovsky Formations host the Kamyshin, Nikolaevka, Pokrovka, and Novoshemonaikha Cu–pyrite and pyrite–polymetallic ore deposits and several ore occurrences associated with subvolcanic rhyolite porphyry. The Berezovka–Belousovka field consists of volcanic-sedimentary rocks of the Orlovka (D2ef), Shipunikha (D2ef–zv), and Irtysh (D2zv–D3f) Formations injected by subvolcanic rhyolite or less often basaltic dikes and sills. Pyrite–polymetallic ore mineralization (Berezovka, Novoberezovka, Irtysh, Belousovka, Prognoznoe, and Kar’yernoe deposits and about 30 occurrences) reside mainly within the Shipunikha and Irtysh Formations. Zmeinogorsk ore district lies in the northeast of the Rudny Altai belt at the boundary with Gorny Altai within the northwestern end of the Bystrukha basin and its junction with the northeastern Alei uplift. The ore-bearing Lower and Upper Devonian sedimentary and volcanic rocks belong to the Melnichnaya (D1e2–D2ef), Sosnovka (D2zv1), Zavodskaya (D2zv), Davydovka (D2zv2), and Kamenka (D3f) Formations (Fig. 5). Basalt–rhyoloite volcanics are interlayered with clastic sands and shales. Note that Emsian–Eifelian and Lower Givetian volcanics are of felsic compositions while alternated mafic and felsic rocks appear later (Givetian–Frasnian) Pyrite–polymetallic ore mineralization is of gold–barite–polymetallic ore and pyrite–polymetallic ore types: Zarechenoe, Zmeinogorsk, Karamysh, and Petrovka deposits in the lower stratigraphic unit (Melnichnaya Formation) and Korbalikha, Srednee, Lazurny, Semenovka, and Maisk deposits in the Givetian–Frasnian unit. The two mineralization types are separated also laterally and form the Zmeinogorsk and Korbalikha ore fields.
Zolotushinsky ore district is located in the northwestern part of Rudny Altai, within the southwestern slope of the Alei uplift. Lower–Upper Devonian volcanic-sedimentary ore-bearing rocks belong to the Melnichnaya (D1e2–D2ef), Sosnovka (D2zv1), Zavodskaya (D2zv), Davydovka (D2zv2), and Kamenka (D3f) Formations (Fig. 5). Pyrite mineralization is found in two lithostratigraphc units. The richer lower unit is composed of tuff-sedimentary rocks of the Zavodskaya Formation (D2zv1sv) which host large economic Cu–Zn–pyrite deposits (Orlovka, Zolotushinsky, Novozolotushinsky, and Lokot’). All deposits occur at the contact between rather clastic sediments of the Zavodskaya Formation and the overlying rhyolite–dacite volcanics of the Davydovka Formation, as well as within the apical parts of subvolcanic porphyry bodies. The upper metalliferous unit with the Yubileinoe and Surgutan deposits lies within the variegated volcanic-sedimentary Kamenka Formation (D3f) of interlayered breccias, sandstone, siltstone, tuff, and rhyolite–dacite lavas. Ores reside in coarse clastic sediments and in aureoles of subvolcanic rhyolite–dacite porphyry. Rubtsovsk ore district is located in the northwestern end of the Rudny Altai belt, within the Rubtsovsk volcanic depression on the northeastern slope of the Alei uplift. Like the neighbor Zmeinogorsk and Zolotushinsky ore districts, the Rubtsovsk district is composed of Devonian volcanic-sedimentary rocks that belong to the Melnichnaya (D1e2–D2ef), Sosnovka (D2zv1), Zavodskaya (D2zv), Davydovka (D2zv2), and Kamenka (D3f) Formations (Fig. 5). The district accommodates four pyrite–polymetallic ore economic deposits (Talovka, Stepnoe, Rubtsovsk, Zakharovka) and several ore occurrences at two stratigraphic levels, in two separate ore fields. The Talaya and Stepnoe deposits (Talovka ore field) reside in the lower stratigraphic unit and lie among rather sedimentary rocks of the Zavodskaya Formation (D2zv). The Rubtsovsk and Zakharovka ore fields occur in the upper part of the section among tuff-sedimentary rocks of the Lower Kamenka Subformation. High-grade mafic volcanics (amphibolites) of the Kurchum block in southern Rudny Altai host Cu–pyrite mineralization (Fig. 3) in the Karchiga deposit and several ore occurrences of Spassky, South Anticinal, Shandybulak, etc. (Lobanov and Gaskov, 2012). The Cu–pyrite deposits and occurrences differ markedly from those hosted by island arc basalt–rhyolite volcanics. The ore-bearing amphibolites were derived from tholeiitic basalts and have N-MORB major-element signatures. Mineralization is mostly copper which is five times more abundant than zinc and makes up concordant sheets, bands, or less often lenses. The Kurchum block also hosts gold–quartz (Avrora–Polevaev group) and gold–listwanite (Maralikha) deposits. Gold mineralization is more abundant within pyrite– polymetallic ore deposits in all ore districts of Rudny Altai, especially as gold–barite–polymetallic ore deposits in the Zmeinogorsk and Leninogorsk districts.
Fig. 5. Stratigraphy of ore districts in northwestern (Russian) Rudny Altai. 1, Lower Paleozoic shale and sandstone; 2, mudstone, siltstone, and silty sandstone; 3, sandstone and outsize tuffaceous sandstone; 4, limestone and limy rocks; 5, mixed breccias; 6, basal conglomerate and gravelstone; 7, tuffs and lavas of rhyolite and rhyolite–dacite porphyries; 8, tuffs and lavas of basaltic and basaltic andesite porphyry; 9, subvolcanic rhyolite and rhyolite–dacite porphyry; 10, pyrite–polymetallic ore mineralization; 11, Au–Ag–barite–polymetallic ore mineralization.
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Rudny Altai: metallogeny The most widespread mineralization in Rudny Altai occurs within the Emsian–Frasnian volcanic-sedimentary rocks and is associated with basalt–rhyolite volcanism. Volcanism and related mineralization formed during subduction events within the Devonian island arc system. Mineralization is controlled by volcanic-tectonic structures at intersections of transversal faults and longitudinal structures between blocks. The mosaic structure of the metallogenic belt results from oblique subduction, with widespread strike-slip faulting (Buslov et al., 2003). Volcanism of calc-alkaline, mostly rhyolitic compositions, evolved in discrete pulses, from felsic to mafic rocks, synchronously with clastic-volcanic deposition in a shallow shelf. The history of volcanism included the Late Emsian– Early Eifelian, Late Eifelian–Early Givetian, and Late Givetian–Frasnian events which migrated from southeast to northwest of the region. The stratigraphic levels of most abundant mineralization move in the NW direction laterally and from the Emsian–Eifelian to Givetian–Frasnian stratigraphically (Avdonin, 1987; Filatov, 1986). Pyrite–polymetallic ore mineralization in all ore districts and at different stratigraphic levels occurs as stratified sheet- or lens-like orebodies among tuffs and sediments, which are folded together with the host rocks. The ores are pocket- or vein-like, disseminated, massive or rarely layered, with collomorphic and globular textures of very fine or fine aggregated particles. The orebodies are accompanied by asymmetric hydrothermalmetasomatic quartz–sericite and sericite–quartz–chlorite aureoles, more abundant in the subore zone. All mineral deposits in Rudny Altai are hosted by volcanics and have pyritic, Cu–pyritic, pyrite–polymetallic ore, and barite–polymetallic ore compositions. The high-grade Kurchum metamorphic block in the south of the region is dominated by mafic volcanism with Cu–pyrite (Korchega deposit) and gold mineralization.
Conclusions The Rudny and Gorny Altai regions have had different geological histories and differ in metallogenic patterns. The Vendian–Early Cambrian to Permian–Triassic evolution of Gorny Altai included subduction, accretion–collision, and rifting events accompanied by magmatism and related mineralization. The history of metallogeny consisted of discrete pulses, with especially abundant Late Paleozoic and Early Mesozoic mineralization. The Late Paleozoic pulse produced diverse mineral deposits (iron, mercury, gold, silver, molybdenum, tungsten, cobalt, polymetallic ores, and rare earths), some of considerable economic value. The territory of Gorny Altai includes several large ore districts that belong to different zones. They are the Beloretsk–Kholzun iron district in the west, the Kayancha–Sinyukha fluorine–gold district in the northeast, the Kurai gold–mercury and Yustyd rare-metal–silver districts in the southeast, and the Kalguty rare-metal–tungsten and Ulandryk uranium–REE–copper districts in the south.
The largest mineral deposits are Kholzun (Fe, P2O5), Karakul (Co, Bi), Sinyukha (Au), Aktash (Hg), Chagan-Uzun (Hg), Ozernoe and Pogranichnoe (Ag), Kalguty (Mo, W), Alakha (Li, Ta), Rudnyi Log (Y,Fe-specularite), and Urzarsai (W– scheelite). Mineralization in Rudny Altai is mainly pyritic: copper– pyrite, pyrite–polymelallic ore, and barite–polymelallic ore. It resides in Devonian suprasubduction basaltic–rhyolitic volcanics and in Emsian to Frasnian island-arc rocks at different stratigraphic levels, in six ore districts. Pyrite–polymetallic ore mineralization in all ore districts and at different stratigraphic levels forms stratified sheet- or lens-like orebodies among tuffs and sediments, which are folded together with the host rocks. The Kurchum high-grade metamorphic block in the southern Rudny Altai bears copper–pyrite and gold–quartz mineralization related to Late Paleozoic volcanism. The study was carried out as part of the government assignment, Project 0330-2016-0001.
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