Бас редактор ЖҰРЫНОВ Мұрат Жұрынұлы, химия ғылымдарының докторы, профессор, ҚР ҰҒА академигі, Қазақстан Республикасы Ұлттық Ғылым академиясының президенті, АҚ «Д

Бас редактор ЖҰРЫНОВ Мұрат Жұрынұлы, химия ғылымдарының докторы, профессор, ҚР ҰҒА академигі, Қазақстан Республикасы Ұлттық Ғылым академиясының президенті, АҚ «Д

Accessory zircon extracted from serpentinized dunite and harzburgite of the Tekturmas Zone of Central Kazakhstan, which is one of the largest ophiolite zones in the western part of the Central Asian Belt, has been studied for the first time. A U–Th–Pb (SIMS) geochronological study of this zircon was carried out and the age of its crystallization was estimated at 467 ± 3 Ma, which corresponds to the boundary between the Dapingian and Darriwilian stages of the Middle Ordovician. The presence of accessory Middle Ordovician zircon in dunite and harzburgite is most likely a reflection of the last stage of ultramafic depletion associated with melting of mafic rocks that form the upper parts of the ophiolite section in the northern part of the Tekturmas Zone.

Microinclusions of Re-, Mo-, Cu-, Pb-, and Bi-bearing sulfides are found for the first time in Cu sulfide ores of the Maike occurrence, northern Ulytau. The microinclusions are characterized by various morphologies and chemical compositions. According to microprobe data, eight sulfides contain up to 49.46 wt % Re, as well as Fe, Cu, Mo, Pb, and Bi. The formulas of sulfides are (Re,Mo,Cu ± Fe,Os,Pt)2S3, (Re,Mo)S2, ReS3, Re2S7, (Pb,Re,Zn)S2, (Pb,Re,Fe)S2, (Pb,Re,Fe)2S3, and (Re,Fe)(Pb,Bi)S3. For the first time, we identified a previously unknown Pb–Re–Zn–S phase, a Rh and Sb assemblage in a Re–Fe–Pb–Bi–S mineral phase, and ReS3 and Re2S7 sulfides.

Significant outcome of the studies is a discovery of accessory siegenite, platinum telluride-moncheite, silver telluride-hessite, lead telluride-altaite, lead selenide, solid solutions of metals of the iridium group (Ir, Os, Ru), REEs (Dy, Er, Y, Ce), reported for the first time from picrites of the Karaturgay complex, where they occur in association with previously known sulfides. Zigenite and millerite are found in picrite diabases in association with pentlandite, pyrite, and galena. These minerals have not been previously recorded from rocks of the Karaturgay complex. Numerous mineral microinclusions identified in present study show unusual mineral associations not previously documented in the region, including cobaltite-gersdorffite minerals with Pt, Ir, Rh, Ru, Os; ullmannite, silver telluride-hessite, lead telluride-altaite, sperrylite, testibiopalladite, native silver, acanthite, melonite, vavrinite, REE-bearing phosphates and fluorophosphates and rhenium minerals. From the sequence of formation of mineral phases and the analysis of the isothermal sections of the condensed Fe-Ni-S system it can be concluded that formation of the Karaturgay type sulfide copper-nickel mineralization apparently took place in several temperature regimes. Schematic model of the sequence of formation of PGE, rare minerals and sulfide of copper-sulfide ores from the Mayke ore occurrence with a discussion of the stages of mineral formation is presented.

The paper is dedicated to major aspects of petrology and metallogeny of mafic and ultramafic rocks of Northern Ulytau Range. The Karatugay Complex is introduced for hypabyssal diabase-picrites of the Western Ulytau Belt. They are considered as products of spinel peridotite melting, which makes them different from the Lower-Paleozoic upper-subduction ophiolite complexes of Central Kazakhstan, the products of garnet lherzolite melting. The rock-forming and accessory mineral contents for picrites and picritic diabases are given. A presence of apopicritic olivine, which is the outmost member of the picrite-diabase sequence, and a presence of pure larnite does not exclude their origin as a result of high-calc larnite melts differentiation, while composition of these melts could approach that of kimberlites. Obtained geochemical signatures suggest that the Karaturgai Complex was derived from Ti and Cr depleted mantle melts, which were enriched with (Cu-Ni)+(Zn-Pb)+PGE, REE (Y, La, Yb) and also lithophylic elements (Zn, Sr, Ba). Intrusion of the hypabyssal Karaturgai Complex occurred during the ongoing collision of the suspect terranes presently incorporated into the tectonic collage of the Ulytau Megaterrane, probably, at the time of the assemblage of the Rodinia Supercontinent.

The analysis of data on the stratigraphy of Lower Paleozoic sedimentary and sedimentary-volcanogenic sequences in central Kazakhstan made it possible to specify their ages, structural relationships, and correlation with coeval sections of neighboring areas. It is shown that olistostromes widespread in the Agyrek-Arsalan accretionary wedge of the central Kazakhstan Paleozoides are of Katian age. Three stratigraphic units are defined in continuous siliceous sections: Paracordylodus gracilis Beds, Periodon flabellum Beds, and Paroistodus horridus Beds. It is established that Lower Cambrian carbonate-basaltic, Middle-Upper Cambrian carbonate, Upper Cambrian-Lower Ordovician carbonate-terrigenous, and Lower-Middle Ordovician volcanogenic, tuffaceous-siliceous, and siliceous sequences associated with serpentinite melange belong to different lithotectonic zones of Early Paleozoic basins.