#1Origin and alteration of platinum group minerals in chromite deposits of the Ulan-Sar'dag ophiolite Olga Kiseleva¹, Evgeniya Airiyants¹, Dmitriy Belyanin¹,2, Sergey Zhmodik¹,2 1 Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, Russian Federation 0 300 км F Russia 2-Novosibirsk State University, Novosibirsk, Russian Federation Republic of Buryatia N Ulan-Sar'dag massive Northern branch Irkutsk Region Ulan-Sar'dag Republic Irkutsk of Tuva Baikal lake Ulan-Ude Trans-Baikal Territory Southern branch Mongolla The geographical position of the Ulan-Saridag massif China + The Ulan-Sar'dag ophiolite massive is tectonic sheet. It is part of ophiolite complexes of Eastern Sayan and fold-thrust region of Central- Asian Fold Belt. The massive is part of the Dunzhugur Island Arc of Paleosian Ocean in Riphean-Vend Age. The ophiolite complex consists of the northern and southern branches, which may have been formed in different geodynamic settings. The Ulan-Sar'dag ophiolite is located ab. between these structural branches. We received some interesting new data chemical composition of chrom-spinelides and platinum mineralization for this massive. Alluvium and glacial deposit Carbonaceous with volcanics formation (O-S) Volcano-sidemintary-carbonaceous (O-S) a) tholeiite-basalt-carbonaceous b) tuff-shale-carbonaceous c) conglomerates Dolomite-limestone phosphate-bearing formation Carbonaceous formation (O-S) Dolomite formation (D-C) 888888888 10 km HAHHA + + + + + Plagio-gneiss-granite Gargan block (Tuva-Mongolian microcontinent) (Ar) Graywacke-sandstone-shale (V-Pr) ++ Sandstone-shale- carbonaceous-flishoid formation a) b) Limestone-dolomite (Pr-V) x Х Olistostrome-carbonaceous- terrigenous formation Ophiolite formation: a b C L a) ultrabasite; b) melange; c) gabbro Gneiss-migmatite formation Granite formation a) syenite-granosyenite b) diorite-plagiogranite a) b) k a) granites k b) basites Faults Geological schematic map of the south-eastern part of the Eastern Sayan#2ultrabasites serpentinites conus removal Ilchir suite Photos Ulan-Sar'dag ophiolite massive. - ultrabasites Siliceous thickness Irkut suite gneisses Ophiolite massive Ulan-Sar'dag consist of mantle section (serpentinites, dunites, peridotites garzburgites, pyroxenites, gabbro). Volcanic-sedimentory formation are presented Ilchir suit. The rocks of ophiolitic complexes are deformed in condition of greensheet to amfibolites facies. A trench 200 meters long opens the volcanites of the Ilchir suit and their contact with the ultrabasites. Those was volcanogenic thickness with interbedding volcanites and sulfidized black shale. Rocks of the normal and subalkaline series represent in volcanic association: picrobasalts, basalts, andesibasalt, boninites, andesites, trachyandesites, trachytes, dacites. dunite-harzburgite serpentinites zone of talc rocks Ilchir suite Scheme of the geological structure of the Ulan-Sar'dag ophiolite massive. T + + 2 KM quaternary deposits limestones granodiorites of the Xx L Sumunur complex diorites of the Sumunur complex gneiss granites of the Gargan block ultrabasic rocks of the Ilchir complex serpentinites pyroxene dunite greenstone effusives[ of the Ilchir suite granite intrusions of the Kholbinsky complex faults sampling points#3Features of volcanic rocks The distribution of rare-earth elements, HFSE (high field strength elements) and LILE (lithophilic elements) in volcanic rocks are typical of MORB, boninites, island-arc volcanics and OIB basalts. Discrimination diagramm of Th-Hf/3-Ta E-MORB • Picrobasalt Boninite •Andesibasalt CAB (calc-alkiline basalt) • Andesites OIB (alkiline oceanic within-plate basalts) •Trachyandesite Discrimination diagrams of Nb/Y and Zr/Ti for volcanic rocks and apogabbros of the Ulan-Sar'dag massive Zr/Ti 10 0,1 0,01 Th Volcanic Are& Island Are Tholeiites Hf/3 Picrobasaltes, basaltes 11 13 12 * 14 Andesite-basaltes, andesites 10 ☐ 7 A Dacites, rhyolites N-MORB A E-MORB Alkali Basalt • 9 Trachyandesites, alkali basaltes 15 16 Metaperidotites, metagabbro ° 1 0 5 4 ° 6 A 3 ㅁ 2 Discrimination diagramm of Th√-NbN alkali-rhyolite phonolite 100.00 trachyte dacite+rhyolite ▲ 12 trachy- andesite * 14 andesite+basaltic andesite 8 ☐ Δ 10 ☐ foidite alkali basalts basalts 16 12272×TONOU a 9 11 13 10.00 VOLCANIC ARC ARRAY BABB 20 ThN A 15 1,00 Fincreasing subduction components PM IAT&Bonimite 1E-3 0,01 0,1 Nb/Y 1 10 0,10 no subduction components CAB MORB-normalized diagrams distribution of HFSE in vulcanites and peridotites of Ulan-Sar'dag massif 100 10 1 Peridotites, gabbro 100 10 1 Gabbro, metagabbro 0,1 0,1 0 8 Th Nb Ta La Ce Nd Zr Sm Ti Gd Tb Dy Y Er Yb 2 3 <―4 Th Nb Ta La Ce Nd Zr Sm Ti Gd Tb Dy Y Er Yb 56 17 100 10 0,1 Ta 1000 N-MORB E-MORE -MORB AB 0,01 L 0,01 0,10 MORB OIB ARRAY →SSZ-E → AFC OIB-CE FC 1000 100 Increasing partial melting degree 10 0.1 1,00 10,00 100,00 NbN 1 100 10 0,1 1000 100 0.1 10 100 Boninite 10 7 N-MORB 1000 Andesites, dacites 9 8 N-MORB 10 100 Picrobasaltes, basalts Cs Rb Ba U Th Ta Nb La Ce Sr Pr Nd Zr Hf Sm Eu Gd Ti Tb Dy Ho Y Er Tm Yb 11 14 12 N-MORB E-MORB Basalt, trahyandesites Cs Rb Ba U Th Ta Nb La Ce Sr Pr Nd Zr Hf Sm Eu Gd Ti Tb Dy Ho Y ОІВ 16 17 15 13 10 1000 100 10 100 10 Boninite La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu N-MORB 17 Andesites, dacites 1 8 La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu UCC 10. Picrobasaltes, basalts La Ce Pr Nd Sm Eu Gd ть Dy Ho Er Tm Yb Lu 11 14 12 13 E-MORB Basalt, trahyandesites Er Tm Yb 1 La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu N-MORB OIB 17 16#4Features of chromitites Chromitites are located within the mantle section (dunites, garzburgites, serpentenites). Massive chromitites consist of aggregate euhedral to subhedral crystal shape of chromite grains, only separated one from the other by a thin film of chlorite and serpentine or olivine and minor serpentine. 5 CM Shlieren, lensoidal pods Shlieren, lensoidal pods Structural and textural features and stages of deformation are: 1) lenticular (from one to three centimeters in thikness); 2) irregular ore bodies (lenses some centimeters thick, pods, schlieren); some lenses, pods, schlieren pods is grouped forming vein type. 3) schlieren type during the tectonic processes is transformed to structure of tectonic flow, deformation structure up to forming the structure of "snowball" type – massive chromitites; Al 12 Cr IV 16 VII XX VII 3+ Fe 12 2 ☐ 3 Ore Chr-spineles consist of chrompicotite, alumochromite, chromite, ferrochromite and Chr- magnetite and magnetite. Chr-spineles have composition (wt.%): Al2O3 10÷22 и 36÷39, Сг₂О3 46÷53 и 28÷35; MgO 12÷15 и 19÷20 wt.%. Studied chromitites show chemical characteristics typical of podiform chromite deposits Diagram compositions of Chr-spineles of the Ulag-Sar'dag massive Vein type Vein type, deformed pods 7 CM Structure of "snowball" Deformed structure Table of Chr-spinel parameters Al# I group 24-60 Cr# 36-74 II group 14-23 74-81 III group 13-27 68 - 81 Mg# 45-74 32 - 48 28-35#5a Features of chromitites 10 6 в Chromite in the mantle peridotites of the massif. a) thin-banded, b) massive veins, c) schlieren. 100 Fe/Fe (Crsp) II 10 Cr# (Crsp) 1.0 Chromites Ulan-Sardag massive Grl Grll Grill Literature data from different ★ geodynamic setting 0,8 * 4 * 5 * 6 * 7 8 * 9 10 A 11 A 12 * 13 A 14 A 15 0.6 * 0.4 0.2 Boninites Alaskan type 10 TiO2 ms% (Crsp) LIP *** OIB IAT Bon 0.1 ARC * * MORB Features of MPG mineralization in chromitites ☆ a C Os-Ir Os Lr Ru-Ir-Os b Chr 10 μm Cct Mlr RuAsS Lr (Ru,Os)S 10 μm d Lr Er Mg# (Crsp) 0.0 0.01 Al,O, ms% (Crsp). 1,0 0.8 0,6 0.4 0.2 0.0 0,1 0 5 10 15 20 25 30 35 40 45 50 MORB ES; Al# (21-60), Cr# (36-74), Mg# (59-84) Boninite ES; Al# (14-23), Cr# (74-81), Mg# (46-63) Literature data 10 20 Al2O3 ms% (Crsp) 30 40 50 Discriminatory diagrams showing the Al2O3 - Fe²+/ Fe³+, TiO2 - Al2O3 ratios and Cr-Mg# in the chromites of their chromites according to literature data and data Ulan-Sar'dag massive. Chemical parameters of chrom-spinelides and parental melt Alyskyn type ES; Al#13-20), Cr# (67-81), Mg# (42-50) composition in equilibrium with podiform chromitites are located in three fields: MORB, suprasubduction zones, boninites, Alaskan type. MORB from Mid oceanic ridge basalt; Cr#<0,7 Back-arc basalt; Cr#<0,7 Oceanic-island basalt; Cr<0,7 Island arc, high K and calc-alcalain basalt; Cr#>0,7 Iisland arc boninite and tholeite basalt; Cr>0,7 Large igneous province: Flood Basalt; Cr#>0,7 Spinel in abissal peridotites Chromite in ophiolitic mantle high Al# Chromite in ophiolitic mantle high Cr# Chromitite in subcontinental mantle Chromitite in continental layered intrusion Chromitite in Alaskan-type complexes 20 μm 10 μm Minerals of the platinum group in chromites (BSE): a) grain of iridosmin in chrom- spinelide; b) concretion of millerite and zonal grain of laurite (in the center of the phase with erlichmanite minal and inclusions of osmium; c) concretion of laurite and laurit-erlichmanite with multiple inclusions (Os-Ir-Ru); d) interpenetrating concretion of laurite and erlichmanite with nanosized inclusions Os. Distribution and PGE mineralization are typical for podiform chromitites of world ophiolite complexes. Platinum group mineralization consist of Os-Ir solid solution, two generation of sulfides PGE (magmatic Lr-Er and hydrothermal newly-formed Lr). Native osmium, ruthenium, RhNiAs are in close assotiation with chlorite, serpentine, sulfides of nikel. Metamorphism from green shale to amphibolite facies leads to a change in magmatic platinum group minerals, dissolution, remobilization PGE. The rise in temperature leads to the enlargement and agglomeration of nanoparticles of PGE from nano- to micro-level.#6Ore chr-spinels from the podiform chromite on the discriminatory diagrams are divided into three groups and localized in the fields MORB-type (I group), supra-subduction zone (boninites) peridotites (I, II groups), Alaskan type (III group) (a-c). Graphic plots of calculated Al2O3 composition of melts in equilibrium with Ulan-Sar'dag chromitites, compared with spinel melt relationship for MORB (a) and Arc lavas and chromitites Alaskan type (b). 100 Fe/Fe (Crsp) Chromites Ulan-Sardag massive ■Grl Grill Grill Literature data from different geodynamic setting Cr# (Crsp) b 1.0 ☆ Boninites ☆ 4 ★ 5 * 6 0.8 II * 7 ✰ 8 * 9 10 10 11 A 12 * 13 A 14 A 15 0,6 ⭑ 0,4 MORB 0,2 Alaskan type 10 TiO2 ms% (Crsp) LIP *** OIB A MORB ** Bon 0,1 ARC IAT ALO3 ms% (Crsp) Mg# (Crsp) Al2O3 ms% (Crsp) 0,0 0,1 T 0.01 0 5 10 15 20 25 30 35 40 45 50 1.0 0.8 0,6 0,4 0.2 0.0 10 20 30 40 50 dTiO, (ms%) melt e Al2O3 ms% (melt) f ALO, (ms%) melt 14 1,4- 1.2. y=4,873(lnx)-0,948 R²=0,998 20 MORB ES; Al# (21-60), Cr# (36-74), Mg# (59-84) g (TiO2)melt Boninite ES; Al# (14-23), Cr# (74-81), Mg# (46-63) Alyskyn type ES; Al#13-20), Cr# (67-81), Mg# (42-50) Literature data MORB from Mid oceanic ridge basalt; Cr#<0,7 Back-arc basalt; Cr#<0,7 Oceanic-island basalt; Cr<0,7 Island arc, high K and calc-alcalain basalt; Cr#>0,7 lisland arc boninite and tholeite basalt; Cr>0,7 Large igneous province: Flood Basalt; Cr#>0,7 Spinel in abissal peridotites Chromite in ophiolitic mantle high Al# Chromite in ophiolitic mantle high Cr# Chromitite in subcontinental mantle Chromitite in continental layered intrusion Chromitite in Alaskan-type complexes 2- 12 1,0- 0,8- y-0,48(lnx)+0,42 10 R²=0.987 0,6- 0,4- 0.2 0,0- TiO2 (ms%)sp T T T T T 0,0 0.2 0.4 0.6 0,8 1.0 1.2 1.4 1,6 y=3,354(lnx)+2,522 R²=0,994 6 10 y-6,426(Inx)-5,513 15 R²=0,998 1.5- Troodos boninites MORB Thetford boninites 0,5 ALO (ms%) sp Boninites Al2O3 ms% (sp) 10 20 15 20 25 30 35 40 45 50 8 (Al2O3)melt ☆ 16 18 20 The chr-spinels composition of podiform chromitites, in terms of their FeO, MgO, Al2O3, TiO2 contents, is considered to function of the parental melt composition. We estimated the Al2O3, TiO2 contents and FeO/MgO of the parental melt composition in equilibrium with the podiform chromite (table above). The chr-spineles of group I correspond to trend (Al2O3) sp - (Al2O3) melt for MORB setting (d). The chr-spineles of group II and III correspond to trend Island arc boninites (8) Alaskan type chromitites (15) (e). The calculated abundance TiO2 in melt is very low and do not reach (arrive) the field of MORB type. Despite the low TiO2 content, the trend of (TiO2)s - (TiO2)melt corresponds to this trend for MORB spinel's. It is remarkable that the ratios of (TiO2) sp/(TiO2)melt are similar to this ratio in chr-spinels from abyssal peridotites (f). Based on calculated of abundance TiO2 and Al2O3 in melt chr-spineles of massive Ulan-Sar´dag lie in Boninitic field (g). sp#7PGE distribution and mineralization Total PGE concentration in 9 chromitites samples ranges from 242 to 992 ppb and is about 2.5 to 5.5 times higher than in serpentinized peridotites. The all chromitites have enrichment Pd (78-903 ppb). It is unusual for chromitites. There is no obvious correlation between PGE abundance and chromite composition. All samples has positive correlation among the pairs Os-Ir (R₂-0.79), Ir-Ru (R2=0.71), Os-Ru (R2=0.64). Palladium has no correlation with another elements. Chondrite-normalised PGE patterns of Ulan-Sar'dag chromitites display average (Os+Ir+Ru)/(Rh+Pt+Pd) ratios typical of Cr-rich chromitites formed in the mantle section of supra-subduction zone ophiolites In most cases, PGE patterns are characterized by a consistent positive anomaly in Ru, and a negative anomaly in Pt. Graphs of the distribution of PGE in chromitites of Ulan-Sar'dag ophiolite Rocks/C1 10 0.1 0,01 1 Os Ir Ru Rh Pt Pd -YC-2a-12 YC-7-13 BCK-17-17 YC-6-12 BC-294-16 BCK-20-17 YC-3-13 BC-307-16 Literature data: I - Ahmed Hassan Ahmed, Hesham M. Harbi, Abdelmonem M. Habtoor (2012). Compositional variations and tectonic settings of podiform chromitites and associated ultramafic rocks of the Neoproterozoic ophiolite at Wadi Al Hwanet, northwestern Saudi Arabia. Journal of Asian Earth Sciences 56,118–134. II - Prichard H. M., Lord R. A., Neary C. R. (1996). A model to explain the occurrence of platinum and palladium - rich ophiolite complexes. Journal of the Geological Society, 153, 323-328. (Chromitittes from Oman ophiolite, northen Semail) III - Tsoupas G., Economou-Eliopoulos M. (2008). High PGE contents and extremaly abundant PGE-minerals hosted in chromitites from Veria ophiolite complex, northern Greece. Ore Geology Reviews 33, 3-19. IV-Gurskaya L.I., Smelova L.V., Kolbancev L.R., Lyahnickiy U.S., Shahova S.N. (2004) Platinum mineralization in chromite- bearing ultrabasic-basic massives of chromitites from Ray-Iz massive Polyar-Ural. Publishing office St-Pet. mapfactories FSBI. 306 p (in Russian). V - Agafonov L.V., Lhamsuran G, Kuguget K.S., Oydup Ch.K. (2005). Platinum-bearing of ultramafic-mafic complexes of Mongolia and Tuva. Ulaan-Batar, 224. For all publications: 1 - the chromitites are enriched in Os-Ir-Ru, 2 - chromitites enriched in Pt-Pd Graphs of the distribution of PGE in massif chromitites (literatura data) Rocks/C1 100 10 1 C 0,1 0,01 0,001 0,0001 0,00001 0,000001 Os -I-11-2 Ir Ru Rh Pt Pd -II-1―III-1 III-2 IV-1--IV-2 V--VI#8PGE mineralization are represented by Os-Ir-(Ru) solid solutions, native Os, Ru, laurite-erlichmanite (Ru,Os)S2, laurite (RuS2), irarsite (IrAsS), zakarinit (RhNiAs). Diagram of composition Os-Ir-Ru alloys . • . • . • Sulfides of PGE are the predominant phases in the chromitites of the Ulan-Sar'dag ophiolite. They occur as idiomorphic inclusions in chrom-spineles. Solid solutions of Os-Ir-(Ru) were found as idiomorphic inclusions in spinel, and in xenomorphic grains in intergrowths with laurite. Solid-solution laurite-erlichmanite and Os-Ir correspond to early high-temperature magmatic stage. The phases (Os, Ir, Ru) of varying composition are common as numerous micro- and nano-size inclusions in laurite-erlichmanite. Native Os (Os> 80 wt.%) and Ru (Ru=93 wt.%) occur in polyphase aggregates, together with chalcocite, laurite, laurite-erlichmanite, heazlewoodite, zakarinite, Os-Ir-Ru solid solutions. Laurite and laurite-erlichmanite RuS2-(Ru,Os)S2 are represented most widely. There are two groups: 1) laurite- erlichmanite (Ru,Os)S2; 2) laurite RuS2 - phase of variable composition (Ru,Os)S2 occurring in multi- component aggregates of heterogeneous composition and containing a large number of rounded and rectangular micro-inclusions of native Os, (Os-Ir), and Ru. Laurite has homogeneous microstructure and composition consistent with the stoichiometric composition. It forms individual grains in chlorite and serpentine. It is known that (Os-Ir) and solid solutions of laurit-erlichmanite are forming before or nearly simultaneously with the segregation of chrome - spinel in the upper mantle at T=1200°C and P= 5-10 kbar. Sulfo-arsenides and arsenides of Ru, Ir, Rh, Ni are formed from the residual fluid phase at post-magmatic stage, together with heazlewoodite. It is possible that in chromitites from Ulan-Sar'dag ophiolite there are two generations of sulphides: The first generation - magmatic solid solutions of laurite-erlichmanite. The second stage- the newly formed laurite, with primary laurite-erlichmanite or intergrowths with chalcosine, and millerite confined to zones of chloritization. Os Ru individual grains inclusion in RuS2 * inclusion in Crsp A poliphase agregates Diagram of composition PGE sulfides (Ru+Rh)S, ■individual grains ▲ poliphase agregates The predominance of Os, Ru sulphides over the solid solutions of Os-Ir-Ru indicates a higher sulfur fugacity in the mantle source of Ulan-Sar'dag ophiolite OSS LAURITE ERLICHMANITE Ir (Ir+Pt+Pd)S₂#9Os Os RuS2 I-MAGMATIC STAGE (Os,Ru)S2 Os-Ir-Ru Os-Ir 10 μkm 10 um Desulfurization processes (Ru,Os)S2 RuS2 Os (Ir, Ru, Rh)AsS 20 μkm 10 μkm (Ru,Os)Sz Processes of integration and aglomeration (Ru,Os)S2 Os Ru-Ir-Os 20 μm Cct Os 10 μm II-POSTMAGMATIC STAGE substitution of laurite-erlichmanite by irarsite Chr (Ir, Ru,Rh)AsS Os 10 μm (Ru,Os)S2 (Ir, Ru, Rh)ASS (Ru,Os)S2 20 ukm 60 ukm III - METAMORPHIC STAGE Remobilization, enlargement of nanorparticle to microlevel, recrystallization (under increasing temperature) (Ru,Os)Sz OSS2 RuS2 10 μm Os Mlr RuAsS RuS (Ru,Os)S 10 μm 20 μkm RuS Ru-Ir-Os Hzl RhNiAs Ru (Ir, Ru,Rh)AsS 20 ukm 10 μm#10CONCLUSION 1. The geochemical features of the volcanic and ultramafic rocks are consistent with Supra-Subduction Zone 2. Chr-spinels rarely alteratied and can be used a reliable petrogenetic indicator. The primary chemistry of chr-spinels provides important information about the composition of the parental melt, magmatic processes (partial melting). Chr-spinels formed by participation of magmas of different composition and then changed in suprusubduction setting. Chr-spinels are localized into three fields: MORB, High-Al chromites from MORB-like tholeiitic magmas (in a back-arc setting), during melt/mantle interaction with a subsequent change to a subduction setting. High-Cr spineles are thought to form from boninitic magmas in an island arc environment (subduction setting) 3. Chr-spinels are localized in the fields MORB-type (the first group), Supra-subduction zone (Boninites) peridotites (the second and part of the first group), Alaskan type (the third group). The chromites falling into the field of the Uralo-Alaskan type could be formed during the partial melting of the fluid metasomatized mantle, with the interaction of andesitoid melts with the rocks of the overlying mantle wedge. 4. Chondrite-normalised PGE patterns of Ulan-Sar'dag chromitites display average (Os+Ir+Ru)/(Rh+Pt+Pd) ratios typical of Cr-rich chromitites formed in the mantle section of supra subduction zone ophiolites. The processes leading to extreme fractionation of PGE can be connected fluid-saturated supra-subduction. It is known that (Os-Ir) and solid solutions of laurite-erlichmanite are forming before or nearly simultaneously with the segregation of chrome - spinel in the upper mantle at T=1200°C and P= 5-10 kbar. We suppose there are two generation of sulphides in chromitites from Ulan-Sar'dag massive 1- PGM generation – magmatic solid solutions of laurite-erlichmanite. - 2 generation the newly formed laurite, with primary laurite-erlichmanite or intergrowths with chalcosine, and millerite is found in zones of chloritization. It has assotiation with serpentine, chlorite, irarsite, and BSE sulfides (Ni). The predominance of Os, Ru sulphides over the solid solutions of Os-Ir-Ru indicates a higher sulfur fugacity in the mantle source of Ulan-Sar'dag massive, than other ultrabasic massive of Dunzhugur ophiolites. Sulfo-arsenides and arsenides of Ru, Ir, Rh, Ni are formed from the residual fluid phase at post-magmatic Gargan microcontinent subduction subduction sediment oceanic crust subduction island arc Siberian continent eclogites and blue schists island arc accretion prism a Siberian continent: sedimentary cover (a), foundation (b) Microcontinents slab window Oceanic crust of the Paleo-Asiatic a lb ocean (a), its overlapping sediments (b) Ophiolites of back-arc spreading Siberian continent island arc back-arc basin HFSE+LILE+LREE spreading Pplum Island-arc formations of primitive island arcs Island-arc formations of mature island arcs Intrusive formations of mature island arcs Terrigenous-tufogenic rocks The paleoreconstruction of the formation of the Sayano-Baikal-Muya accretionary-collisional belt Olistostromes turbidites Amphibolites, Eclogites Alkaline volcanics Faults#11Thank you for attention