News Registration Abstract submission Deadlines Excursions Accommodation Organizing committee
First circular Second circular Abstracts Seminar History Program Travel Contact us
Первый циркуляр
Второй циркуляр
Оформление тезисов
Важные даты
Обратная связь

Тезисы международной конференции

Рудный потенциал щелочного, кимберлитового

 и карбонатитового магматизма

Abstracts of International conference

Ore potential of alkaline, kimberlite

and carbonatite magmatism

Rare-metal granites and rare-earth syenites in the context of anorthosite-rapakivigranite formation of Ukrainian Shield

Sheremet Ye.M.*, Krivdik S.G.**, Sedova Ye.V.***

 *Ukrainian State Research and Design Institute of Mining Geology, Rock Mechanics and Mine Surveying, NAS of Ukraine (UkrNIMI, NAS of Ukraine), Donetsk, Ukraine; **Institute of Geochemistry, Mineralogy and Ore Formation, NAS of Ukraine, Kiev, Ukraine, ***Donetsk National Technical University, Donetsk, Ukraine.

EvgSheremet@yandex. ru


In Ukrainian Shield anorthosite-rapakivigranite formation (1.85‑1.7 milliard years) is represented in three megablocks: in Priazovie – gabbro-syenite south Kalchik complex; in Ingul-Ingulets ‑ Korsun-Novomirgorod anorthosite-rapakivigranite pluton; in Volyn megablock – Korosten anorthosite-rapakivigranite pluton.

Rare-metal granites of lithium-fluorine type in the context of the above formations of anorthosite-rapakivigranite formation are known respectively as kamennomogilskie (Priazovie), russkopolyanskie (Ingul-Ingulets megablock); leznikovskie and perzhanskie (North-West megablock).

By their petrochemical composition granites of all massifs of the kamennomogilsky complex is no different from similar petrographic differences of south Kalchik complex and rapakivi granites and are identical to rare-metal leukogranites of Ukrainian Shield (US): russkopolyanskie, leznikovskie and perzhanskie granites.

Comparison of chemical composition of biotites of granites of south Kalchik complex and rapakivi granites and rare-metal granites of US by the level metal-alkalinity environment (Marakushev-Tararin diagram) (Markushev, Tararin, 1965) shows that completely overlaid in the fields of groups II and III of metal-alkalinity environment of the diagram are biotite compositions of moderately leucocratic granites with content of SiO2 in the range of 71.0‑72.5 % of Korsun-Novomirgorod, Korosten massifs and massifs of south Kalchik complex. Biotites of ultra-acid granites of the kamennomogilsky complex, of leznikovskie and perzhanskie with content of SiO2 in rocks in the range of 73.2‑76.9 % fall compactly into group I of metal-alkalinity environment. There is gradual transition of granite biotite compositions from a moderate group of metal-alkalinity environment to ultra-acid group.

For kamennomogilskie rare-metal granites of the Priazovie the following trend of crystallization differentiation of parent melt is determined: granosyenites → amphibolic granites → amphibole-biotite granites → biotite granites and leukogranites → biotite-muscovite and muscovite leukogranites with topaz and fluorite (+pegmatites). In the process of differentiation the melts were enriched in F, Ta, Nb, Li, Ве, Rb, Sn, W и Mo, the content of which increased in residual melts by a factor of 2‑5 in comparison with less differentiated, and depleted in Ba, Sr, Y, and REE. Maximum content of Y and REE has been registered in amphibolic differences (enriched in calcium). By the level of content of light lanthanides La and Ce granite massifs differ rather strongly reflecting different in depth conditions of development of intrusions and consequently different levels of their erosional truncation. For distribution of REE in kamennomogilskie granites especially specific are: sharp deficiency of Eu typical to all rare-metal granites (Eu/Eu* in the range of 0.02‑0.27) and high content of REE: from 500 to 1700 g per ton (Shcherbakov, 2005).

Comparison of ranges for distribution of REE in kamennomogilskie granites and in perzhanskie and leznikovskie rare-metal granites of the Korosten complex speaks for similar small-depth and hypabyssal conditions for formation of these rare-metal granites with rather intense feldspar fractionation, which specifies low content of barium and strontium and negative europium anomalies in ranges of REE.

In massifs of kamennomogilsky complex widely manifested are processes of alkali-type metasomatism (biotitezation, microclinezation, albitization) and processes of acid metasomatism – partial and more rarely complete granite greysening. Formation of ore bodies with yttrium‑rare-earth mineralization is closely connected with zones of alkali-type metasomatism, whereas for greisenized rocks rare-metal mineralization is typical.

Syenite Azov intrusion and rare-earth deposit of the same name of south Kalchik complex of the Priazovie (Azov Sea Region) are typical indications of the multistage formation of sub-alkaline- alkali-type metasomatism.

According to Melnikov V. S., Voznyak D. K. et al. (2000) syenites of the Azov deposit are products of crystallization of residual melt formed as a result of fraction crystallization of basic melt of subcrustal origin. Hypersolvus composition of alkali feldspars, extremely ferruginous composition of femic minerals containing H2O, F and CO2 and negative europium anomaly (Shcherbakov, 2005) in distribution of REE are indications of high level of melt differentiation. The Azov deposit is the upper part of thick fractional column where accumulation of fluorophilous rare elements and enrichment in fluid components took place. High temperature of the melt enriched in fluid components contributed to high amount of concentration of rare elements. Magma pocket contained residual melt enriched in rare elements (Zr, RRE) and volatile components (water, halides, carbonic oxides). Formation of zirconium and zirconium-lanthanide ores at the Azov deposit took place in the process crystallization differentiation of syenite melt in magma pockets by a mechanism of stratified intrusions.

Syenite intrusion of Yastrebetsky stock (and zirconium deposit of the same name) is located in Sushchano-Perzhanskaya tectonic zone of Volyn megablock of US and is classified as derivatives of Korosten anorthosite-rapakivigranite pluton. Yastrebetsky syenite massif with its rich zirconium ores is almost similar in every way to the Azov deposit. Britholite, orthite, and bastnasite, which are typical minerals of rare-earth and zirconium‑rare-earth ores of the Azov deposit, both by their gross chemical composition and ranges of the content of rare earths and yttrium were found identical or close at those two deposits. There is a number of differences caused by both different level of differentiation of parent melts, and may be by different directions of their fractioning.

Syenites of Velyka Vyska massif are one of those of the final differentiates of anorthosite-rapakivigranite Korsun-Novomirgorod pluton. High iron content of these syenites and minerals in them as well as considerable concentration of such incompatible elements as Zr, TR, Y, Nb and low concentration of Sr and Ba speak for residual nature of the melts from which these rocks were formed. By their petrological and geochemical features Velikoviskovsk syenites occupy intermediate position between fayalite-hedenbergite syenites of South-Kalchik massif and similarly-named rocks of the Azov deposit.

Syenites occur in many anorthosite-rapakivigranite plutons, however, within the Ukrainian Shield syenite trend in the evolution of these plutons is most pronounced. For example, south Kalchik massif in Priazovie is essentially syenite analog of such plutons. The weight of evidence suggests that this trend might have been worked in abyssal conditions at reduced fugacity of oxygen and thus it could manifest itself in more eroded plutons. Korsun-Novomirgorod pluton and South Kalchik massif, as realized by us, differ by higher erosional truncation (Krivdik., Tkachuk, 1990).

All characteristics of the main elements and rare-earth components of rare-metal granites and rapakivi granites of US indicate distinctively enough that they belong to A-type granitoids. Belonging to A-type granitoids is the determinative circumstance both with relation to their geochemistry and metallogenic specialty and with relation to melt evolution and formation paragenesis.

To our opinion genesis of formations of US of anorthosite-rapakivigranite formation under consideration is attributable to their formation in rift zones attached to the up-going plumes of convective currents. The rising mass of the substance in the form of soft diaper, which by its composition corresponds to alkali-type pyrolite, while raising has been differentiating and enriching in low-melting alkali and other lithophylic elements and volatiles in its upper part and has been depleting of them in its low part.

At the bottom of lithosphere, which is responsible for conditions of melting of alkali and alkali-basic magmas (Zonnenshain et al., 1976), in the upper part of diaper a shell saturated with alkali where pockets of molten rock occurred has been forming. While raising additional differentiation of alkali magmas could take place. Heat currents and flows of lithophylic elements and volatiles from diaper came into continental lithosphere that resulted in occurrence of local sources of melting with formation of eutectic granite magmas. Simultaneous rise to the surface of alkali melts from diaper and acid crust melts resulted in the occurrence of bimodal series, which are anorthosite-rapakivigranite formations.

Rare-earth specialty of syenite magmas and rare-element specialty of acid eutectic magmas are the result of differentiation of magma of integrated geotectonic process in which differentiates of alkali basaltoid magmas possessed rare-earth specialty and eutectic melts aroused as residual magmas with accumulation of rare lithophylic elements.




Krivdik S. G., Tkachuk V. I. Petrology of Ukrainian Shield alkaline rocks. Kiev: Naukova Dumka, 1990. 408 p. (in Russian).

Maraqkushev A. A., Tararin I. A. On mineralogic kriteria of granitoid alkalinity // Proceedings of the Academy of Sciences of the USSR. Series: Geology. 1965. No. 3. P. 20-37. (in Russian).

Melnikov V. S., Voznyak D. K., Grechanovskaya Ye. Ye. et al. The Azov zirconium‑rare-earth deposit: mineralogical peculiarities // Mineralogichesky zhurnal (Mineralogical Magazine). 2000. Vol. 22, No. 1. P. 42-61 (in Russian).

Shcherbakov I. B. Petrology of Ukrainian Shield. –Lvov: ZUKC, 2005. 366 p. (in Russian).

Zonnenshain L. P., Kuzmin M. I., Moralev V. M. Global tectonics, magmatism and metallogeny. Moscow: Nedra, 1976. 231 p. (in Russian).