Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: an online database of alkaline rock and carbonatite occurrences

Orto-Yrigakhskoe, Tundrovoye And Nomotookhskoe

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Occurrence number: 
136-02-001
Country: 
Russia
Region: 
Anabar
Location: 
Longitude: 113.1, Latitude: 71.97
Carbonatite: 
Yes

In 1964-5 numerous carbonatitic dykes and eruptive pipes were discovered on the eastern slope of the Anabar shield in three distinct areas. They are emplaced in Proterozoic and Cambrian sedimentary rocks. A great number of kimberlite pipes are also developed in the area. The carbonatite pipes have diameters between 75 and 275 m and comprise tuffaceous rocks with a breccia texture of xenoliths in a fine-grained cement. The xenoliths are angular and consist of sedimentary limestones, dolomotized limestones, sandstones and granite gneisses. The cement, which forms about 80% of the rock, consists of dolomite, apatite, magnetite, phlogopite and fine-grained calcite with accessory pyrochlore, baddeleyite, zircon, columbite, fersmite, pyrite, chalcopyrite, sphalerite, alkali amphibole and aegirine. Lapin et al. (1976) give chemical compositions of magnetite, including trace elements, and show that they are chemically similar to magnetite in typical plutonic carbonatites. There are nine dykes of carbonatite varying from 0.1 to 1 m in thickness. They comprise massive textured rocks of calcite, phlogopite, apatite and subordinate serpentine, magnetite, perovskite and rutile.

Age: 
Geological evidence indicates an upper Triassic age (Marshintsev, 1974).
References: 

*LAPIN, A.V., GARANIN, V.K., MARSHINTSEV, V.K. and KUDRYAVTSEVA, G.P. 1976. Composition and internal structure of magnetite from explosion carbonatite breccia of the northeastern margin of the Siberian Platform. Doklady Earth Science Sections, American Geological Institute, 228: 129-32.
MARSHINTSEV, V.K. 1974. Carbonatitic formations of the eastern slope of the Anabar Arc Yakut Branch of the Academy of Sciences, Yakutsk, 199 pp.
*MARSHINTSEV, V.K. and BALAKSHIN, G.G. 1969. Nature of carbonatite at the east flank of the Anabar Arch. Doklady Earth Science Sections, American Geological Institute, 188: 70-3.

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