Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-23T22:52:01.276Z Has data issue: false hasContentIssue false

Compositional Variation of pyroxene and mica from the Little Murun ultrapotassic complex, Aldan Shield, Russia

Published online by Cambridge University Press:  05 July 2018

Roger H. Mitchell
Affiliation:
Department of Geology, Lakehead University, Thunder Bay, Ontario, Canada P7B 5El
Nikolai V. Vladykin
Affiliation:
Vinogradov Institute of Geochemistry, Russian Academy of Science, P.O. Box 4019, Irkutsk-33, Russia 664033

Abstract

Pyroxene and mica found in plutonic rocks of the Little Murun ultrapotassic pluton exhibit trends of compositional evolution that permit evaluation of the differentiation sequence of the complex. Pyroxene evolves from diopside in kalsilite and phlogopite pyroxenites through aegirine-diopside in shonkinite to aegirine in late stage charoitite and evolved hypabyssal rocks. The compositional trend is unusual in that the hedenbergite content of the pyroxenes never exceeds 15 mol.% and is thus unlike pyroxene compositional trends found in sodic alkaline complexes. Mica is Al- and Ti-poor and ranges in composition from Fe-rich phlogopite through biotite towards tetraferriannite. Compositional trends of mica found in ‘lamproite-like’ hypabyssal rocks are identical to those observed in the micaceous plutonic rocks; hence the former are considered to be representatives of the lamprophyric facies of the magmas which formed the plutonic series.

Type
Mineralogy
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Alekseyev, Y.A. (1983) Geology of new types of carbonatites and associated rocks. Dokl. Akad. Nauk SSSR, 272, 134–7.Google Scholar
Bilibina, T.V., Daskova, A.D., Donakov, V.I. Titov, V.K., and Shchukin, S.N.(1967) Petrologiya shche- lochnogo vulkanogenno-intruzivnogo kompleksa Aldanskogo shchita (Petrology of the Alkaline Volcanic Intrusive Complexes of the Aldan Shield). Nedra Press, Leningrad.Google Scholar
Biryukov, V.M. and Berdnikov, N.V. (1993) The paragenetic relation between charoite mineralization and alkali metasomatism. Jnternat. Geol Rev., 35, 585602.CrossRefGoogle Scholar
Droop, G.R. (1987) A general equation for estimating Fe3+ concentrations in ferromagnesian silicates and oxides from microprobe analyses using stoichiometric criteria. Afag., 51, 431–5.Google Scholar
Ivanyuk, G.Y. and Evdokimov, M.D. (1991) Pirokseny charoitogo mestorozhdeniya Sirenevyy Kamen i nekotorye zakonomernosti ikh obrazovaniya (Pyroxenes from the charoitic ore deposit Sirenevii Kamen and some observations on their genesis) Zap. Vses. Mineral. Obshch., 120, 6274.(Russian).Google Scholar
Kogarko, L.N., Kononova, V.A., Orlova, M.P. and Woolley, A.R. (1995) Alkaline Rocks and Carbonatites of the World Part 2: Former USSR. Chapman & Hall, London.Google Scholar
Konyev, A.A., Vorobyev, Y.I. and Bulakh, A.G. (1993). Charoit - der Schmuckstein aus Sibirien und sine seltenen Begleitminerale, Lapis, 13—20.Google Scholar
Kostyuk, V.P., Panina, L.I., Zhidkov, A.Y., Orlova, M.P. and Bazarova, T.Y. (1990) Kalievii shcheloch- noi magmatizm Baikalo-Stanovoi riftogennoi sistemy(Potassic Alkaline Magmatism of the Baikal- Stanovoy Rifting System) Nauka Press, Novosibirsk (Russian).Google Scholar
Makhotkin, I.L. (1991) Lamproity Aldanskoi provintzii (Lamproites of the Aldan province) In: Lamproity (Lamproites)(Bogatikov, O.A., Ryabchikov, I.D. and Kononova, V.A., Eds.) Nauka Press, Moscow, pp. 46113.Google Scholar
Mitchell, R.H. (1980) Pyroxenes of the Fen alkaline complex, Norway. Amer. Mineral., 65, 4554.Google Scholar
Mitchell, R.H. (1994) The lamprophyre facies. Mineral Petrol., 51, 137–46.CrossRefGoogle Scholar
Mitchell, R.H. and Bergman, S.C. (1991) Petrology of Lamproites. Plenum Press, New York.CrossRefGoogle Scholar
Mitchell, R.H. and Platt, R.G. (1982) Mineralogy and petrology of nepheline syenites from the Coldwell alkaline complex, Ontario, Canada. J. Petrol., 23, 186214.CrossRefGoogle Scholar
Orlova, M.P. (1988) Recent finding on the geology of the Malo Murun alkaline pluton. Intemat. GeoL Review, 30, 945–53.CrossRefGoogle Scholar
Orlova, M.P., Borisov, A.B. and Shadenkov, Y.M. (1992) Alkaline magmatism of the Murun areal (sic)(Aldan Shield). Sov. Geol Geophys., 33, 4555.Google Scholar
Panina, L.I., Motorina, I.V., Sharygin, V.V. and Vladykin, N.V. (1989) Biotitic pyroxenites and melilite-monticellite-olivine rocks of the Malo Murun alkaline massif of Yakutia. Geol Geophys., 30, 40–8.Google Scholar
Panina, L.L., Sharygin, V.V. and Motorina, L.V. (1990) Mica pyroxenites as products of early stages of evolution of potassium alkali magma (on the example of the Malomurun alkali massif, Aldan shield). Geol Geophys., 31, 6874.Google Scholar
Prokofiev, V.Y. and Vorobyev, Y.I. (1992) P-T formation conditions for Sr-Ba carbonatites, charoite rocks and torgolites in the Murun alkali intrusion, east Siberia. Intemat. Geol. Rev., 83—92.Google Scholar
Proshenkin, I.E. and Sharygin, V.V. (1990) Features of the composition of pyroxenes of the Sakun massif. Geol. Geophys., 31, 51–6.Google Scholar
Shadenkov, Y.M., Orlova, M.P. and Brisov, A.B. (1990) Pyroxenite and shonkinites of the Malo Murun pluton: intrusive analogs of lamproite. Internal. Geol. Rev., 32, 61–9.CrossRefGoogle Scholar
Smyslov, S.A. (1986) Kalsilite-bearing rocks of the Malomurun massif. Geol. Geophys., 27, 30–4.Google Scholar
Tyler, R.C. and King, B.C., (1967) The pyroxenes of the alkaline igneous complexes of eastern Uganda. Mineral. Mag., 36, 522.Google Scholar
Vladykin, N.V. (1985) First find of lamproites in the USSR. Dokl Akad. Nauk SSSR, 280, 718–22.Google Scholar
Vladykin, N.V. (1990) On the genesis of charoite rocks. Proc. 15th. General Meeting Intemat. Mineral. Assoc. Beijing. Abstracts, 2, 689–90.Google Scholar
Zhidkov, A.Y. and Smyslov, S.A. (1985) Some distinctive features of synnyrites and the typochem- istry of the minerals forming them. Geol. Geophys., 26, 31–9.Google Scholar