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Main Minerals of Abnormally High-Grade ores of the Tomtor Deposit (Arctic Siberia) Full article

Общее Language: Английский, Genre: Full article,
Status: Published, Source type: Translated
Journal Russian Geology and Geophysics
ISSN: 1068-7971
Output data Year: 2015, Volume: 56, Number: 6, Pages: 844-873 Pages count : 30 DOI: 10.1016/j.rgg.2015.05.003
Tags Carbonatites, Halloysite, Minerals of the crandallite group, Monazite, Pyrochlore, REE deposit
Authors Lazareva E.V. 1 , Zhmodik S.M. 1,2 , Dobretsov N.L. 2,3 , Tolstov A. 1 , Shcherbov B.L. 1 , Karmanov N.S. 1 , Gerasimov E.Yu. 4 , Bryanskaya A.V. 5
Affiliations
1 V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
2 Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia
3 A.A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
4 G.K. Boreskov Institute of Catalysis, pr. Akademika Lavrent’eva 5, Novosibirsk, 630090, Russia
5 Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Lavrent’eva 10, Novosibirsk, 630090, Russia

Funding (5)

1 Президиум СО РАН 40
2 Президиум СО РАН 94
3 Russian Foundation for Basic Research 13-05-12056 (01201369163)
4 Russian Foundation for Basic Research 14-05-00668 (01201451216)
5 The Ministry of Education and Science of the Russian Federation

Abstract: The Tomtor massif of Paleozoic ultramafic alkaline rocks and carbonatites is located in the northern part of the Sakha Republic (Yakutia). The massif (its total area is ~ 250 km2) is ~ 20 km in diameter, with a rounded shape and a concentrically zoned structure. The core of the massif consists of carbonatites surrounded by a discontinuous ring of ultramafic rocks and foidolites. The outer part is composed of alkali and nepheline syenites. All rocks are weathered and covered with eluvium, which is the thickest after carbonatites enriched in phosphates and REE. The weathering profile consists of four layers, from the top: kaolinite-crandallite, siderite, goethite, and francolite. The highest-grade ores are observed in the bedded deposit which fills depressions in “sagging” eluvium. The ores are laminated and cryptogranular, with high Nb, Y, Sc, and REE contents (on average, 4.5% Nb2O5, 7-10% REE2O3, 0.75% Y2O3, and 0.06% Sc2O3). The highest-grade ores are natural Nb and REE concentrates. The total REE content in some layers is > 10%. The morphologic features of the highest-grade phosphate ores from the northern part of the Burannyi site were studied. The ore-forming minerals belong to the pyrochlore group, crandallite group (goyazite), and monazite-Ce. The pyrochlore group minerals occur mainly as crystals that were completely replaced by barium-strontium pyrochlore and/or plumbopyrochlore but retained the original faces; also, they occur as numerous conchoidal fragments. The grains of the pyrochlore group minerals sometimes have a zonal structure, with an unaltered pyrochlore core and a reaction rim. Goyazite occurs predominantly as colloform grains. According to SEM and TEM data, monazite occurs in the ores as ~ 50 nm particles, which cover the outer part of halloysite tubes (800–3000 nm long and 300 nm in diameter) as a dense layer and make up peculiar biomorphic aggregates. The mineralogical data, the occurrence of biomorphic aggregates, and the close association of organic remains with ore minerals suggest that the high-grade ores of the Tomtor deposit, including the Burannyi site, resulted from a hydrothermal-sedimentary process with a presumably important role of bioaccumulation of REE phosphates.
Cite: Lazareva E.V. , Zhmodik S.M. , Dobretsov N.L. , Tolstov A. , Shcherbov B.L. , Karmanov N.S. , Gerasimov E.Y. , Bryanskaya A.V.
Main Minerals of Abnormally High-Grade ores of the Tomtor Deposit (Arctic Siberia)
Russian Geology and Geophysics. 2015. V.56. N6. P.844-873. DOI: 10.1016/j.rgg.2015.05.003 publication_identifier_short.wos_identifier_type publication_identifier_short.scopus_identifier_type publication_identifier_short.rinz_identifier_type
ArticleLinkType.TRANSLATED_TO_ORIGINAL: Лазарева Е. , Жмодик С.М. , Добрецов Н.Л. , Толстов А. , Щербов Б. , Карманов Н. , Герасимов Е.Ю. , Брянская А.В.
Главные рудообразующие минералы аномально богатых руд месторождения Томтор (Арктическая Сибирь)
Геология и геофизика. 2015. Т.56. №6. С.1080-1115. DOI: 10.15372/GiG20150603 publication_identifier_short.rsci_identifier_type publication_identifier_short.rinz_identifier_type
Dates:
Submitted: Sep 30, 2014
Accepted: Jan 29, 2015
Published print: Jun 1, 2015
Published online: Jun 6, 2015
Identifiers:
publication_identifier.wos_identifier_type WOS:000355922000003
publication_identifier.scopus_identifier_type 2-s2.0-84930579852
publication_identifier.rinz_identifier_type 24043719
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