Download article

Mineralogical and geochemical aspects of rare-earth elements behavior during metamorphism (on the example of the Upper Precambrian structural-material complexes of the Bashkir megaanticlinorium, South Urals)

S.G. Kovalev, A.V. Maslov, S.S. Kovalev

Original article



open access

Under a Creative Commons license

Abstract. The article provides new data on geochemistry and mineralogy of rare-earth elements (REE) in rocks of structural-material complexes of the Bashkir megaanticlinorium, which underwent metamorphic transformations of various nature: contact metamorphism (Suran section); syn- and postgenetic contact-dislocation metamorphism (Shatak complex) and hydrothermal metamorphism (Uluelga-Kudashmanovo zone). It has been established that when a magmatic melt is exposed to sediments, the latter are enriched with REEs with the formation of rare earth minerals (monazite, allanite, xenotime et al.). The study of the chemical composition of monazites and allanites showed that all variations of oxides in the composition of the former are due to isomorphous Ce-Ca-Th substitutions in the structure of minerals, but redistribution of these elements was an independent process characteristic of each structural-material complex. The study of allanites made it possible to establish the presence of isomorphism according to the Ca↔Ce, La, Nd principle, as well as the sharp difference between the characterized minerals in the amount of MgO, Fe* and MnO from analogues from other regions, which indicates the presence of a regional component in the chemical compositions of minerals altogether, geotectonic settings of mineralization formation. The temperature regimes of mineral-forming processes with metamorphic transformations of rocks calculated from chlorite and muscovite compositions (344-450°C – Suran section, 402-470°C – Shatak complex, 390-490°C – Uluelga-Kudashmanovo zone) indicate the possibility of stable coexistence of the association monazite-allanite. It was established that when a magmatic melt on the sedimentary substrate of the frame, the lanthanides enrich the exocontact rocks with the formation of newly formed REE-mineral associations. At the same time, the processes of formation of rare-earth mineralization are largely determined by the physicochemical parameters and thermobaric conditions of the accompanying and subsequent metamorphism.

South Ural, Bashkir megaanticlinorium, structural-material complexes, Upper Precambrian, rare-earth elements, contact metamorphism, monazite, allanite


  • Bingen B., Demaiffe D., Hertogen J. (1996). Redistribution of rare earth elements, thorium, and uranium over accessory minerals in the course of amphibolite to granulite facies metamorphism: the role of apatite and monazite in orthogneisses from southwestern Norway. Geochim. Cosmochim. Acta, 60(8), pp. 1341-1354.
  • Chopin C. (1981). Talc-phengite: a widespread assemblage in high-grade pelitic blueschists of the Western Alps. J. Petrol., 22(4). рр. 628-650.
  • Dobretsov N.L., Lavrentiev Yu.G., Ponomareva L.G., Pospelova L.N. (1974). Statistical studies of white micas of the glaucophans schist strata. Coll. papers: Statistical methods in geology, 236, pp. 113-133. (In Russ.)
  • Drits V.A., Kossovskaya A.G. (1991). Clay minerals: mica, chlorite. Moscow: Nauka, 176 p. (In Russ.)
  • Ernst R.E. (2014). Large igneous provinces. London: Elsevier, 653 p.
  • Finger F., Krenn E. (2006). Three metamorphic monazite generations in a high_pressure rocks from Bohemian Massif and the potentially important role of apatite in stimulating polyphase monazite growth along a PT loop. Lithos, 95, pp. 103-115.
  • Gibson D.H., Carr S.D., Brown R.L., Hamilton M.A. (2004). Correlations between chemical and age domains in monazite, and metamorphic reactions involving major pelitic phases: an integration of ID-TIMS and SHRIMP geochronology with Y-Th-U X-ray mapping. Chem. Geol., 211, pp. 237-260.
  • Janots E., Engi M., Rubatto D., Berger A., Gregory C., Rahn M. (2009). Metamorphic rates in collisional orogeny from in situ allanite and monazite dating. Geology, 37(1), pp. 11-14.
  • Janots E., Negro F., Brunet F., Coffee B., Engi M., Bouybaoene M.L. (2006). Evolution of REE mineralogy in HP-LT metapelites of the Septide complex, Rif, Morocco: monazite stability and geochronology. Lithos, 87, pp. 214-234.
  • Kohn M.J., Malloy M.A. (2004). Formation of monazite via prograde metamorphic reactions among common silicates: Implications for age determinations. Geochim. Cosmochim. Acta, 68(1), pp. 101-113.
  • Kovalev S.G., Vysotskiy I.V. (2006). A new type of noble metal mineralization in terrigenous rocks of the Shatak graben, western slope of the southern Urals. Lithology and Mineral Resources, 41(4), рp. 371-377. (In Russ.)
  • Kovalev S.G., Michurin S.V., Vysotsky I.V., Kovalev S.S. (2013). Geology, mineralogy and metallogenic specialization of carbon-containing strata of the Uluelginsko-Kudashman zone (western slope of the South Urals). Lithosphere (Russia), 3, pp. 67-88. (In Russ.)
  • Kovalev S.G., Kovalev S.S., Vysotsky S.I. (2017). Th – REE mineralization in Precambrian rocks of the Bashkir meganticlinorium: species diversity and genesis. Zapiski RMO = Proceedings of the Russian Mineralogical Society, 5, pp. 59-79. (In Russ.)
  • Kovalev S.S., Kovalev S.G. (2017). The first find of calcioankilite in terrigenous rocks of the Bashkir meganticlinorium. Geologiya. Izvestiia Otdeleniya nauk o Zemle i prirodnykh resursov Akademii nauk Respubliki Bashkortostan, 23, pp. 45-50. (In Russ.)
  • Kovalev S.S., Kovalev S.G., Timofeeva E.A. (2017). New data on the geology, geochemistry and mineralogy of the Suran and Inturatov sections (Bashkir meganticlinorium). Geologicheskiy sbornik, 13, pp. 101-118. (In Russ.)
  • Kovalchuk N.S. (2015). Rare-earth mineralization in metamorphic schists of the Puyvinskaya suite (RF2), Subpolar Ural. Vestnik of the Institute of Geology of the Komi Science Centre UB RAS, 10, pp. 38-44. (In Russ.)
  • Kranidiotis P., MacLean W.H. (1987). Systematic of Chlorite Alteration at the Phelps Dodge Massive Sulfide Deposit, Matagami, Quebec. Economic Geology, 82, pp. 1808-1911.
  • Krogh E.J., Raheim A. (1978). Temperature and pressure dependence of Fe-Mg partitioning between garnet and phengite, with particular reference eclogits. Contrib. Mineral Petrol., 66(1), pp. 75-80.
  • Lanzirotti A., Hanson G.N. (1996). Geochronology and geochemistry of multiple generations of monazite from the Wepawaug Schist, Connecticut, USA: implications for monazite stability in metamorphic rocks. Contrib. Mineral. Petrol., 125, pp. 332-340.
  • Larionov N.N., Bergazov I.R. (2006). State geological map of the Russian Federation. Scale 1: 200 000. Sheet N-40-ХХП (explanatory note). Ufa, 185 p. (In Russ.)
  • Maslov A.V., Kovalev S.G. (2014). Noble metal specialization of terrigenous rocks of the lower and middle Riphean of the Bashkir anticlinorium (Southern Urals). Geology and mineral resources of Siberia, 3(2), pp. 11-14. (In Russ.)
  • Maslov A.V., Nozhkin A.D., Podkovyrov V.N., Letnikova E.F., Turkina O.M., Grazhdankin D.V., Dmitrieva N.V., Isherskaya M.V., Krupenin M.T., Ronkin Yu.L., Gareev E.Z., Vescheva S.V., Lepikhina O.P. (2008). Geochemistry of fine-grained terrigenous rocks of the Upper Precambrian of Northern Eurasia. Yekaterinburg: UB of RAS, 274 p. (In Russ.)
  • Massonne H.J., Schreyer By.W. (1989). Stability field of the high-pressure assemblage talc+phengite and two new phengite barometers. Europ J. Mineral., 1, pp. 391-410.
  • McFarlane C.R.M., Connelly J.N., Carlson W.D. (2005). Monazite and xenotime petrogenesis in the contact aureole of the Makhavinekh Lake Pluton, northern Labrador. Contrib. Mineral. Petrol., 148, pp. 524-541.
  • Parnachev V.P., Rotar A.F., Rotar Z.M. (1986). Middle Riphean volcanic-sedimentary association of the Bashkir meganticlinorium (Southern Urals). Sverdlovsk: UC AN USSR, 105 p. (In Russ.)
  • Puchkov V.N. (2000). Paleogeodynamics of the Southern and Middle Urals. Ufa: Dauria, 146 c. (In Russ.)
  • Puchkov V.N. (2013). Plumes in the geological history of the Urals. Bull. MOIP, Otd. geol., 88(4), pp. 64-73. (In Russ.)
  • Puchkov V.N., Kovalev S.G. (2013). Plume events in the Urals and their relationship with subglobal epochs of riftogenesis. Coll. papers: Continental rifting, associated processes. Irkutsk: IZK SB RANS, pp. 34-38. (In Russ.)
  • Savko K.A., Korish E.Kh., Pilyugin S.M., Polyakova T.N. (2010). Phase equilibria of rare-earth minerals during metamorphism of carbonaceous schists of the Tim-Yastrebovskaya structure, Voronezh crystalline massif. Petrology, 18 (4), pp. 402-433. (In Russ.)
  • Smith H.A., Barero B. (1990). Monazite U-Pb dating of staurolite grade metamorphism in pelitic schists. Contrib. Mineral. Petrol., 105, pp. 602-615.
  • Taylor S.R., McLennan S.M., (1985). The continental crust; its composition and evolution. Cambrige: Blackwell, 312 p.
  • Tomkins H.S., Pattison D.R.M. (2007). Accessory phase petrogenesis in relation to major phase assemblages in pelites from the Nelson contact aureole, southern British Columbia. J. Metam. Geol., 25, pp. 401-421.
  • Wing B.A., Ferry J.M, Harrison T.M. (2003). Prograde destruction and formation of monazite and allanite during contact and regional metamorphism of pelites: petrology and geochronology. Contrib. Mineral. Petrol., 145, pp. 228-250.

Sergey G. Kovalev
Ufa Federal Research Centre of the Russian Academy of Sciences
16/2, Karl Marx st., Ufa, 450077, Russian Federation

Andrey V. Maslov
Zavaritsky Institute of Geology and Geochemistry of the Ural Branch of the Russian Academy of Sciences
15, Vonsovsky st., Yekaterinburg, 620016, Russian Federation

Sergey S. Kovalev
Ufa Federal Research Centre of the Russian Academy of Sciences
16/2, Karl Marx st., Ufa, 450077, Russian Federation


For citation:

Kovalev S.G., Maslov A.V., Kovalev S.S. (2020). Mineralogical and geochemical aspects of rare-earth elements behavior during metamorphism (on the example of the Upper Precambrian structural-material complexes of the Bashkir megaanticlinorium, South Urals). Georesursy = Georesources, 22(2), pp. 56-66. DOI: