English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Authors distinguish two groups of productive metamorphogenic-metasomatic rocks enriched with high-alumina minerals: stratified horizons in the stratum of plagiogneisses of early Archean and Proterozoic ages widely spread in Karelia and the Kola peninsula (Keyv formation) – aluminous (kyanite) formation of shields of the ancient platforms (metamorphic, Keyv type); unstratified metasomatic rocks that form the internal and external suture zones of the gneiss blocks, polyfacial metamorphic complexes of the andalusite-sillimanite and kyanite-sillimanite thermodynamic types, formed along the uneven-aged, typically pelitic rocks, widely manifested in the Urals – aluminous formation of folded belts (hydrothermal-metasomatic, Ural type). Comparison of the distribution of rare-earth elements in the rocks enclosing kyanite deposits of Keyv suite and Ural deposits revealed that they have the same type of directivity, but in the rocks of the Kola peninsula, the amount of rare-earth elements is higher. The reason is, apparently, a larger process of metamorphism and alkaline magmatism in the Kola peninsula in the Precambrian. A detailed study of kyanite deposits allowed to determine polygenic and polychronic properties of kyanite ores, as well as to identify three natural morphogenetic ore types: metamorphic, metamorphogenic-metasomatic and metasomatic. Comparison of the rare-earth elements shows that the metamorphogenic kyanites contain the greatest amount of rare-earth elements, and the lowest contents are characteristic for the metasomatic kyanites from quartz veins selvages and kyanite porphyroblasts of recrystallization zones. Deposit reserves of the metamorphogenic-metasomatic kyanites are low. In order to increase their economic importance the authors advise to implement the industrial development of kyanite deposits containing rare and rare-earth elements at levels that allow under certain dressing technologies to carry out their complementary profitable extraction.

Rare and rare-earth elements in kyanite ores of Kola peninsula and the Urals