Issue 1(45), 2017

DOI 10.21440/2307-2091-2017-1-23-26

Structural and chemical features of potash feldspars from pegmatites of the Lipovskoe vein field (Middle Urals) pdf

A. V. Zakharov, O. L. Galakhova

The authors studied structural and chemical properties of the potassium feldspars from different types of granitic pegmatites of Lipovskiy vein field, located 70 km northeast of Ekaterinburg city, in vicinity of the Lipovskoe village. These pegmatites gained worldwide fame at the beginning of the last century because of the active extraction of pink tourmalines (rubellites). For the study authors selected potassium feldspars from two types of granitic pegmatites – conventional and contaminated (desensitized granite veins were untested, as potassium feldspars are absent in them). According to the powder roentgenometry, orthoclase and intermediate microcline were only in normal granitic pegmatites, and intermediate and maximum microcline – in lithium-bearing contaminated veins. Microprobe analysis of the potassium feldspars also showed variability in their chemical composition from the structural ordering of minerals. Microclines and orthoclases from the ordinary pegmatites are enriched by sodium and depleted by cesium and rubidium, and potassium feldspars from the lithium-bearing veins, on the contrary, are depleted by
sodium and enriched by rare alkaline elements. Authors established that at increase of the contents of Rb and Cs there is an increase of the degree of triclinity of the potassium feldspars, i.e. in substantially pure (maximum) microcline forms in the contaminated pegmatites of Lipovskiy vein field. An interesting fact is the drastic decrease in the number of perthite intergrowths of albite in a matrix of potassium feldspar from the contaminated pegmatites compared to conventional granite veins.
In many samples of microcline from the contaminated pegmatites, perthite intergrowths are visually absent and, apparently, make up microperthite intergrowths.

Keywords: potassium feldspar; granitic pegmatites; Lipovskoe vein field; Middle Urals.

 

REFERENCES

1. Emlin E. F., Vakhrusheva N. V., Kaynov V. I. 2002, Samotsvetnaya polosa Urala: Rezhevskoy gosudarstvennyy prirodno-mineralogicheskiy zakaznik. Putevoditel’ [Ural semiprecious band: Rezhevskoy State Nature and Mineralogical Reserve. Guide], Yekaterinburg-Rezh, 156 p.
2. Pekov I. V., Memetova L. R. 2008, Mineraly granitnykh pegmatitov Lipovki, Sredniy Ural [Minerals of Lipovka granitic pegmatites, Middle Urals]. Mineralogicheskiy al’manakh [Mineralogical Almanac], no.13, pp. 7–44.
3. Zakharov A. V., Erokhin Yu. V. 2013, Kadastr mineral’nykh vidov Lipovskogo rudnogo polya [Cadastre of mineral species of Lipovka ore field]. Vestnik Ural’skogo otdeleniya RMO [Bulletin of the Ural Branch of Russian Mineralogical Society], no. 10, pp. 38–46.
4. Maleev V. P., Kudryashov A. M., Sychugov A. E., Biryukov V. V. 1960, Otchet o rezul’tatakh geologorazvedochnykh rabot na Lipovskom mestorozhdenii silikatnykh nikelevykh rud [Report on the results of exploration work on the Lipovka deposit of silicate nickel ores]. Artemovskiy, vol. 1–9.
5. Frank-Kamenetskiy V. A. 1983, Rentgenografiya osnovnykh tipov porodoobrazuyushchikh mineralov [Roentgenography of the main types of rockforming minerals], Leningrad, 359 p.
6. Afonina G. G. 1995, Opredelenie trenda Al/Si uporyadocheniya i kolichestva Al v tetraedricheskikh pozitsiyakh kalievykh polevykh shpatov po rentgenogrammam poroshka [Trend Detection of Al / Si ordering and the amount of Al in the tetrahedral positions of potassium feldspars for radiographs of powder]. Zapiski VMO [Zapiski RMO], vol. 124, no. 3, pp. 65–79.
7. Afonina G. G., Makagon V. M., Shmakin B. M. 1978, Bariy- i rubidiysoderzhashchie kalievye polevye shpaty [Barium and rubidium potassium feldspars], Novosibirsk, 110 p.
8. Kamentsev I. E., Smetannikova O. P. 1983, Rentgenografiya osnovnykh tipov porodoobrazuyushchikh mineralov [Radiography of the main types of rockforming minerals], Leningrad, pp. 245–255.
9. 2003, Mineraly. Karkasnye silikaty [Minerals. The framework silicates], Moscow, vol. 1, 583 p.
10. Senderov E. E. 1990, Protsessy uporyadocheniya karkasnykh alyumosilikatov [Processes ordering framed aluminosilicates], Moscow, 208 p.
11. Zagorskiy V. E. 2012, Mineralogiya miarol v pegmatitakh Malkhanskogo mestorozhdeniya turmalina v Zabaykal’e: polevye shpaty zhily Sosedka [Mineralogy of miarols in pegmatites of Malkhan tourmaline deposit in Transbaikalia: feldspars of Sosedka vein]. Geologiya i geofizika [Russian Geology and Geophysics], vol. 53, no. 6, pp. 683–697.
12. Peretyazhko I. S. 2010, Protsessy obrazovaniya miarolovykh granitnykh pegmatitov. Avtoreferat na soiskanie uchenoy stepeni doktora geol.-min. nauk [Processes of formation of miarolitic granitic pegmatites. Abstract for the degree of Doctor of geologo-mineralogical sciences], Irkutsk, 38 p.
13. Gordienko V. V., Kamentsev I. E. 1975, Vliyanie krupnykh kationov Rb i Cs na protsess uporyadocheniya kalinatrovykh polevykh shpatov [The impact of large cations of Rb and Cs in the process of ordering K–Na feldspars]. Mineralogiya i geokhimiya [Mineralogy and geochemistry], vol. 5, pp. 41–56.

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