Hostname: page-component-77f85d65b8-8wtlm Total loading time: 0 Render date: 2026-04-20T10:21:53.680Z Has data issue: false hasContentIssue false
  • English
  • Français

Magmatic, hydrothermal and subsolidus evolution of the agpaitic nepheline syenites of the Sushina Hill Complex, India: implications for the metamorphism of peralkaline syenites

Published online by Cambridge University Press:  02 January 2018

A. Chakrabarty ,
R. H. Mitchell ,
M. Ren ,
P. K. Saha ,
S. Pal ,
K. L. Pruseth  and
A. K. Sen
A. Chakrabarty*
Affiliation:
Department of Geology, Durgapur Government College, Durgapur 713214, West Bengal, India
R. H. Mitchell
Affiliation:
Department of Geology, Lakehead University, Thunder Bay, Ontario, Canada P7B 5E1
M. Ren
Affiliation:
Department of Geoscience, University of Nevada, Las Vegas, Nevada, USA
P. K. Saha
Affiliation:
Department of Geology, Durgapur Government College, Durgapur 713214, West Bengal, India
S. Pal
Affiliation:
Department of Geology, Durgapur Government College, Durgapur 713214, West Bengal, India
K. L. Pruseth
Affiliation:
Department of Geology and Geophysics, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
A. K. Sen
Affiliation:
Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
*
*E-mail: aniket_chakrabarty@rediffmail.com
Get access Rights & Permissions [Opens in a new window]

Abstract

The Proterozoic Sushina Hill Complex is the only agpaitic complex, reported from India and is characterized by a eudialyte-rinkite-bearing nepheline syenite. The complex is considered a ‘metamorphosed agpaitic complex'. This study describes the mineral assemblages formed during successive stages of evolution from magmatic to hydrothermal stages and low-temperature subsolidus re-equilibration assemblage. The primary-late magmatic assemblage is characterized by albite, orthoclase, unaltered nepheline, zoned diopside-hedenbergite, rinkite, late magmatic eudialyte and magnesio-arfvedsonite formed at ∼700°C with maximum a SiO2 of 0.60. In contrast, a deuteric assemblage (400-348°C) is represented by aegirine-jadeite-rich clinopyroxene, post-magmatic eudialyte, sodalite, analcime and the decomposition assemblages formed after eudialyte with decreasing a SiO2 (0.52-0.48). A further low-temperature subsolidus assemblage (≤250°C) represented by late-forming natrolite could be either related to regressive stages of metamorphism or a continuum of the subsolidus processes. Considering the P/T range of the greenschist - lower-amphibolite facies of metamorphism it is evident that the incorporation of a jadeite component within pyroxene is related to a subsolidus process between ∼400°C and 348°C in a silica deficient environment. We emphasize that the deuteric fluid itself acted as an agent of metamorphism and the decomposition assemblage formed after eudialyte is retained even after metamorphism due to the convergence of subsolidus and metamorphic domains. The formation of jadeite-rich aegirine is not considered to result from metamorphism. Overall it is near-impossible to discern any bona fide metamorphic textures or mineral assemblages in these syenites which appear to preserve a relict mineralogy regardless of their occurrence in country rocks which have experienced greenschist - amphibolite facies metamorphism. The Sushina complex is very similar in this respect to the Norra Kärr complex (Sweden).

Keywords

metamorphosed agpaitic rocksSushina Hilleudialyteclinopyroxenesubsolidus alteration

Information

Type
Research Article
Information
Mineralogical Magazine , Volume 80 , Issue 7 , December 2016 , pp. 1161 - 1193
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2016

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.)

Article purchase

Temporarily unavailable

References

Adams, L.H. (1953) A note on the stability of jadeite. American Journal of Science, 251, 299–308.CrossRefGoogle Scholar
Adamson, O.J. (1944) The petrology of the Norra Kärr district. Geologiska Føreningen Stockholm Førhandlingar, 66, 113–255.CrossRefGoogle Scholar
Aiuppa, A. (2009) Degassing of halogens from basaltic volcanism: insights from volcanic gas observations. Chemical Geology, 263, 99–109.CrossRefGoogle Scholar
Aksenov, S.M., Rastsveteva, R.K., Mitchell, R.H. and Chakrabarty, A. (2014) Crystal Structure of Manganese-Rich variety of Eudialyte from Sushina Hill, India and Manganese Ordering in Eudialyte-group Minerals. Crystallography Reports, 59, 146—154.CrossRefGoogle Scholar
Andersen, T. (1990) Melt-mineral-fluid interaction in peralkaline silicic intrusion in the Oslo rift, Southeast Norway. IV: fluid inclusions in the Sande nordmarkite. Norges Geologiske Undersøkelse Bulletin, 417, 41–54.Google Scholar
Andersen, T., Erambert, M., Larsen, A.O. and Selbekk, R.S. (2010) Petrology of nepheline syenite pegmatites in the Oslo Rift, Norway: zirconium silicate mineral assemblages as indicators of alkalinity and volatile fugacity in mildly agpaitic magma. Journal of Petrology, 51, 2303–2325.CrossRefGoogle Scholar
Armstrong, J.T. (1991) Quantitative elemental analysis of individual microparticles with electron beam instruments. Pp. 261-315 in: Electron Probe Quantificatio.(K.F.J. Heinrich and D.E. Newbury, editors). Plenum Press, New York & London.Google Scholar
Basu, S.K (1993) Alkaline-Carbonatite Complex in Precambrian of South Purulia Shear Zone, Eastern India: its characteristics and mineral potentialities. Indian Minerals, 47, 179–194.Google Scholar
Bell, P.M. and Kalb, K. (1969) Stability ofOmphacite in the Absence of Excess Silica. Carnegie Institut. Washington, Annual Report, Directory Geophysics Laboratory 1967-1968, 97–98 Google Scholar
Chakrabarty, A. (2009) Petrogenesis of carbonatite and associated alkaline rocks, Purulia W.B., India.PhD Thesis, Department of Earth Sciences, Indian Institute of Technology Roorkee, India.Google Scholar
Chakrabarty, A. and Sen, A.K. (2010) Enigmatic association of the carbonatite and alkali-pyroxenite along the Northern Shear Zone: a saga of primary magmatic carbonatites. Journal of Geological Society of India, 74, 403–13.CrossRefGoogle Scholar
Chakrabarty, A. and Sen, A.K. (2013) Geochronological constraints and tectonic implications of the alkaline rocks of South Purulia Shear Zone, W.B., India. Pp. 86–88. in: 18th Convention of Indian Geological Congress & International Symposium “Minerals and Mining in India-The way forward, inclusive of cooperative mineral-based industries in SAARC countries” (extendedAbstract). Google Scholar
Chakrabarty, A., Sen, A.K. and Ghosh, T.K.(2009) Amphibole - A key indicator mineral for petrogenesis of carbonatite from Purulia, West Bengal, India. Mineralogy and Petrology, 95, 105—112.CrossRefGoogle Scholar
Chakrabarty, A., Pruseth, K.L. and Sen, A.K. (2011) First report of eudialyte occurrence from the Sushina hill region, Purulia district, West Bengal. Journal of Geological Society of India, 77,12–16.CrossRefGoogle Scholar
Chakrabarty, A., Pruseth, K.L. and Sen, A.K. (2012) Composition and petrogenetic significance of the eudialyte group of minerals from Sushina, Purulia, West Bengal. Journal of Geological Society of India, 79, 449-159.CrossRefGoogle Scholar
Chakrabarty, A., Mitchell, R.H., Ren, M., Sen, A.K. and Pruseth, K.L. (2013) Rinkite, cerianite-(Ce), and hingganite-(Ce) in syenite gneisses from the Sushina Hill Complex, India: occurrence, compositional data petrogenetic significance. Mineralogical Magazine, 77,3137–3153.CrossRefGoogle Scholar
Chatterjee, N. and Ghose, N.C. (2011) Extensive Early Neoproterozoic high-grade metamorphism in North Chotanagpur Gneissic Complex of the Central Indian Tectonic Zone. Gondwana Research, 20, 362—379.CrossRefGoogle Scholar
Chatterjee, N., Crowley, J.L. and Ghose, N.C. (2008) Geochronology of the 1.55 Ga Bengal anorthosite and Grenvillian metamorphism in the Chotanagpur gneissic complex, eastern India. Precambrian Research, 161, 303–316.CrossRefGoogle Scholar
Chatterjee, N., Banerjee, M., Bhattacharya, A. and Maji, A.K. (2010) Monazite chronology, metamorphism— anatexis and tectonic relevance of the mid-Neoproterozoic Eastern Indian Tectonic Zone. Precambrian Research, 179, 99–120.CrossRefGoogle Scholar
Coleman, R.G. (1961) Jadeite deposits of the Clear Creek area, New Idria District, San Benito County, California. Journal of Petrology, 2, 209–247.CrossRefGoogle Scholar
Curtis, L.W. and Gittins, 1 (1979) Aluminous and titaniferous clinopyroxenes from regionall. metamorphosed agpaitic rocks in central Labrador. Journal of Petrology, 20, 165–186.CrossRefGoogle Scholar
Deer, W.A., Howie, R.A. and Zussman, J. (1992) An Introduction to Rock-forming Minerals. Longman Scientific and Technical, England, pp. 31—46.Google Scholar
Droop, G.T.R. (1987) A general equation for estimation of Fe + concentrations in ferromagnesian silicates and oxides from microprobe analyses using stoichiometric criteria. Mineralogical Magazine, 51, 431–435.CrossRefGoogle Scholar
Duke, N.A. and Edgar, A.D. (1977) Petrology of the Blue Mountain and Bigwood felsic alkaline complexes of the Grenville province of Ontario. Canadian Journal of Earth Sciences, 14, 515–538.CrossRefGoogle Scholar
Dutrow, B.L., Travis, B.J., Gable, C.W.and Henry, D.J. (2001) Coupled heat and silica transport associated with dyke intrusion into sedimentary rock: effects on isotherm location and permeability evolution. Geochimica et Cosmochimica Acta, 65, 3749–3767.CrossRefGoogle Scholar
Fall, A., Bodnar, R.J., Szabó, C. and Pál-Molnár, E. (2007) Fluid evolution in the nepheline syenites of the Ditrau Alkaline Massif, Transylvania, Romania. Lithos, 95, 331–345.CrossRefGoogle Scholar
Floor, P. (1974) Alkaline gneisses. Pp. 124-142 in: The Alkaline Rock. (H. Sørensen, editor). John & Wiley, New York.Google Scholar
Giehl, C., Marks, M. and Novak, M. (2013) Phase relations and liquid line of descent of an iron-rich peralkaline phonolitic melt: an experimental study. Contributions to Mineralogy and Petrology, 165, 283–304.CrossRefGoogle Scholar
Giehl, C., Marks, M.A.W.and Novak, M. (2014) An experimental study on the influence of fluorine and chlorine on phase relations in peralkaline phonolitic melts. Contributions to Mineralogy and Petrology, 167, 1–21.CrossRefGoogle Scholar
Goswami, B. and Basu, S.K. (2013) Metamorphism of Proterozoic agpaitic nepheline syenite gneiss from North Singhbhum Mobile Belt, eastern India. Mineralogy and Petrology, 107, 517–538.CrossRefGoogle Scholar
Hamilton, D.L. (1961) Nephelines as crystallization temperature indicators. Journal of Geology, 69, 321–329.CrossRefGoogle Scholar
Hansteen, T.H. and Burke, E.A.J. (1990) Melt-mineral-fluid interaction in peralkaline silicic intrusions in the Oslo Rift, Southeast Norway; II, High-temperature fluid inclusions in the Eikeren-Skrim complex. Norges Geologiske Undersøkelse Bulletin, 417, 15–32.Google Scholar
Harris, C. and Rickard, R.S. (1987) Rare-earth-rich eudialyte and dalyite from a peralkaline granite dyke at Strumsvola, Dronning Maud Land, Antarctica. The Canadian Mineralogist, 25, 755—762.Google Scholar
Henderson, C.M.B., Hamilton, D.L. and Waters, J.P. (2014) Phase equilibrium in NaAlSiO4 - KAlSiO4 - SiO2 -H2O at 100 MPa pressure: equilibrium leucite composition and the enigma of primary analcime iblairmortites revisited. Mineralogical Magazine, 78, 171–201.CrossRefGoogle Scholar
Hlabse, T.H. and Kleppa, O.J. (1968) The thermochemistry of jadeite. American Mineralogist, 53, 1281–1292.Google Scholar
Holland, T.J.B. and Powell, R. (1998) An internally consistent thermodynamic data set for phases of petrologic interest. Journal ofMetamorphic Geology, 16, 309–343.CrossRefGoogle Scholar
Holm, R.F. (1971) Some garnets, pyroxenes and amphi-boles from nepheline gneisses in Ghana. American Mineralogist, 56, 2111–2122.Google Scholar
Iwasaki, M. (1960) Clinopyroxenes intermediate between jadeite and aegirine from Suberidani, Tokusima Prefecture. Journal Geological Society of Japan, 66, 334–340.CrossRefGoogle Scholar
Karup-Møller, S. (1969) Xonotlite-, pectolite- and natrolite-bearing fracture veins in volcanic rocks from Nuussuaq, West Greenland. Gronlnads Geologiske Undersøgelse, 80, 4—20.Google Scholar
Khomyakov, A. (1995) Mineralogy of Hyperagpaitic Alkaline Rocks. Clarendon Press, Oxford, UK, 222 pp.Google Scholar
Koark, H.J. (1960) Zum gefügeverhalten des nephelins in zwei vorkommen alkaliner kristaliner schiefer. Bulletin of the Geological Institution of the University of Upsala, 39, 1–31.Google Scholar
Koark, H.J. (1968) Zu hülle, inhalt, gefüge und alter des alkaligesteinsvorkommen von Norra Kärr im südlichen mittelschweden. Geologiska Föreningen i Stockholm Förhandlingar, 91, 159–184.CrossRefGoogle Scholar
Kogarko, L.N., Lazutkina, L.N. and Romanchev, B.P. (1982) The origin of eudyalite mineralization. Translations from Geokhimiya, 10, 1415—1432.Google Scholar
Kontak, D.J. and Corey, M. (1988) Metasomatic origin of spessartine-rich garnet in the South Mountain Batholith, Nova Scotia. The Canadian Mineralogist, 26,315–334.Google Scholar
Kornprobst, J., Cantagrel, J.-M., Fabries, J., Lasserre, M., Rollet, M. and Soba, D. (1976) Existence, au Cameroun, d'un magmatisme alcalin panafricain ou plus ancien, la syénite néphélinique à mboziite de Nkonglong — comparison avec les roches alcalines connues dans la meme region. Bulletin de la Société Géologique de France, 18, 1295—1305.Google Scholar
Le Maitre, R.W. (2002) Igneous Rocks: A Classification and Glossary of Terms. Cambridge UP, UK.CrossRefGoogle Scholar
Lumbers, S.B. (1976) Omphacite-bearing nepheline syenite in an anorthosite complex, Grenville, Province of Ontario. Geological Association of Canada/Mineralogical Association of Canada Joint Annual Meeting, Program with Abstracts, 1, 73.Google Scholar
Mahato, A.C., Ren, M., Chakrabarty, A., Sen, A.K., Rajesh, H.M. and Shindo, K. (2013) Reconstruction of magmatic to deuteric stages of eudialyte-bearing Sushina syenite gneiss West Bengal, India. Journal of Indian Geological Congress, 5, 77—93.Google Scholar
Maji, A.K., Goon, S., Bhattacharya, A., Mishra, B., Mahato, S. and Bernhardt, H.J. (2008) Proterozoic polyphase metamorphism in the Chhotanagpur Gneissic Complex (India), and implication for transcontinental Gondwanaland correlation. Precambrian Research, 162, 385–402.CrossRefGoogle Scholar
Markl, G. and Baumgartner, L. (2002) pH changes in peralkaline late-magmatic fluids. Contributions to Mineralogy and Petrology, 144, 331—346.CrossRefGoogle Scholar
Markl, G., Marks, M., Schwinn, G. and Sommer, S. (2001) Phase equilibrium constraints of intensive crystallization parameters of the Ilímaussaq Complex, South Greenland. Journal of Petrology, 42,2231–2258.CrossRefGoogle Scholar
Markl, G., Marks, M.A.W.and Frost, B.R. (2010) On the controls of oxygen fugacity in the generation and crystallization of peralkaline melts. Journal of Petrology, 51, 1831–1847.CrossRefGoogle Scholar
Marks, M.A.W., Schilling, J., Coulson, I.M., Wenzel, T. and Markl, G. (2008) The alkaline-peralkaline Tamazeght complex, High Atlas Mountains, Morocco: mineral chemistry and petrological con-straints for derivation from a compositionally heterogeneous mantle source. Journal of Petrology, 49, 1097–1131.CrossRefGoogle Scholar
Marks, M.A.W., Hettmann, K., Schilling, J., Frost, B.R. and Markl, G. (2011)The mineralogical diversity of alkaline igneous rocks: critical factors for the transition from miaskitic to agpaitic phase assemblages. Journal of Petrology, 52, 439–455.CrossRefGoogle Scholar
Mitchell, R.H. (1996) Classification of undersaturated and related alkaline rocks. Pp. 1—22 in: Undersaturated Alkaline Rocks: Mineralogy, Petrogenesis, and Economic Potentia. (R.H. Mitchell, editor). Short Couse, 24, Mineralogical Association of Canada.Google Scholar
Mitchell, R.H. and Chakrabarty, A. (2011) Peralkaline Nepheline Gneiss from Purulia, West Bengal, India: Paragenesis of a New Eudialyte Group Mineral PERALKCARB 2011. University of Tübingen, Germany (extended abstract), 100—102.Google Scholar
Mitchell, R.H. and Chakrabarty, A. (2012) Paragenesis and decomposition assemblage of a Mn-rich eudialyte from the Sushina peralkaline nepheline syenite gneiss, Paschim Bnaga, India. Lithos, 152, 218–226.CrossRefGoogle Scholar
Mitchell, R.H. and Liferovich, R.P. (2006) Subsolidus deuteric/hydrothermal alteration of eudialyte in lujav-rite from the Pilansberg alkaline complex, South Africa. Lithos, 91, 352–372.CrossRefGoogle Scholar
Mogessie, A., Ettinger, K., Leake, B.E. and Tessardi, R. (2001) AMPH-IMA97: a hypercard program to determine the name of an amphibole from electron microprobe and wet chemical analyses. Computers & Geosciences, 27, 1169–1178.CrossRefGoogle Scholar
Nachit, H., Ibhi, A., Abia, E.H. and Ohoud, M.B. (2005) Discrimination between primary magmatic biotites reequilibrated biotites and neoformed biotites. Comptes Rendus, 337, 1415–1420.Google Scholar
Olivo, G.R. and Williams-Jones, A.E. (1999) Hydrothermal REE-rich eudialyte from the Pilanesberg complex, South Africa. The Canadian Mineralogist, 37, 653–663.Google Scholar
Perchuk, L.L. and Ryabchikov, I.D. (1968) Mineral equilibria in the system nepheline-alkali feldspar-plagioclase and their petrological significance. Journal of Petrology, 9, 123–167.CrossRefGoogle Scholar
Pfaff, K., Wenzel, T., Schilling, J., Marks, M. and Markl, G. (2010) A fast and easy-to-use approach to cation site assignment for eudialyte-group minerals. Neues Jahrbuch für Mineralogie, Abhandlungen, 187, 69–81.CrossRefGoogle Scholar
Platt, R.G. (1996) Nepheline syenite complexes: an overview. Pp. 63—99 in:Undersaturated Alkaline Rocks: Mineralogy, Petrogenesis, and Economic Potentia.(R.H. Mitchell, editor). Short Couse 24, Mineralogical Association of Canada.Google Scholar
Popp, R.K. and Gilbert, M.C. (1972) Stability of acmite-jadeite pyroxene at low pressure. American Mineralogist, 57, 1210–1231.Google Scholar
Pouchou, J.L. and Pichoir, F. (1991) Quantitative analysis of homogeneous or stratified microvolumes applying the model “PAP”. Pp. 31–75 in: Electron Probe Quantitatio.(K.F.J. Heinrich and D.E. Newbury, editors). Plenum Press, New York.CrossRefGoogle Scholar
Ratschbacher, B.C., Marks, M.A.W., Bons, P.D., Wenzel, T. and Markl, G. (2015)Emplacement and geochem-ical evolution of highly evolved syenites investigated by a combined structural and geochemical field study: the lujavrites of the Ilímaussaq complex, SW Greenland. Lithos, 231, 62–76.CrossRefGoogle Scholar
Reider, M., Cavazzini, G., D'Yakonov, Y.S., Frank-kamenetskii, V.A., Gottardi, G., Guggenheim, S., Koval, P.V., Muller, G., Neiva, A.M.R., Radoslovich, E.W., et al. (1998) Nomenclature of the micas. The Canadian Mineralogist, 36, 905–912.Google Scholar
Rekha, S., Upadhyay, D., Bhattacharya, A., Kooijman, E., Goon, S., Mahato, S. and Pant, N.C. (2011) Lithostructural and chronological constraints for tectonic restoration of Proterozoic accretion in the Eastern Indian Precambrian shield. Precambrian Research, 187,313–333.CrossRefGoogle Scholar
Robertson, E.C., Birch, F. and Macdonald, G.J.F. (1957) Experimental determination of jadeite stability relations to 25,000 bars. American Journal of Science, 255, 115–137.CrossRefGoogle Scholar
Saha, A.K. (1994) CrustalEvolution of Singhbhum-North Orissa, Eastern India.Memoir Geological Society of India, 27, 341.Google Scholar
Salvi, S. and Williams-Jones, A.E. (1995) Zirconosilicate phase relations in the Strange Lake (Lac Brisson) pluton Quebec — Labrador, Canada. American Mineralogist, 80, 1031–1040.CrossRefGoogle Scholar
Sanyal, S. and Sengupta, P. (2012) Metamorphic evolution of the Chotanagpur Granite Gneiss Complex of East Indian Shield: current status. Pp. 117-145 in: Palaeoproterozoic of Indi.(R. Mazumder and D. Saha, editors). Special Publications 365, Geological Society, London.Google Scholar
Schilling, J., Wu, F.-Y., McCammon, C., Wenzel, T., Marks, M.A.W., Pfaff, K., Jacob, D.E. and Markl, G. (2011a) The compositional variability of eudialyte-group minerals. Mineralogical Magazine, 75, 87–115.CrossRefGoogle Scholar
Schilling, J., Marks, M.A.W., Wenzel, T., Vennemann, T., Horvath, L., Tarassoff, P., Jacob, D.E. and Markl, G. (2011b) The magmatic to hydrothermal evolution of the intrusive Mont Saint-Hilaire complex: insights into the late-stage evolution of peralkaline rocks. Journal of Petrology, 52, 2147–2185.CrossRefGoogle Scholar
Schönenberger, J. and Markl, G. (2008) The magmatic and fluid evolution of the Motzfeldt intrusion in South Greenland: insights into the formation of agpaitic and miaskitic rocks. Journal of Petrology, 49, 1549–1577.CrossRefGoogle Scholar
Sheard, E.R., Williams-Jones, A.E., Heiligmann, M., Pederson, C. and Trueman, D.L. (2012) Controls on the concentration of zirconium, niobium, and the rare earth elements in the Thor Lake Rare Metal Deposit, Northwest Territories, Canada. Economic Geology, 107, 81–104.CrossRefGoogle Scholar
Sjöqvist, A.S.L., Cornell, D.H., Andersen, T., Erambert, M., Ek, M. and Leijd, M. (2013) Three compositional varieties of rare-earth element ore: eudialyte-group minerals from the Norra Kärr Alkaline Complex, Southern Sweden. Minerals, 3, 94–120.CrossRefGoogle Scholar
Sørensen, H. (1992) Agpaitic nepheline syenites: a potential of rare elements. Applied Geochemistry, 7,417-27.CrossRefGoogle Scholar
Sørensen, H. (1997) The agpaitic rocks — an overview. Mineralogical Magazine, 61, 485–498.CrossRefGoogle Scholar
Tilley, C.E. (1954) Nepheline-alkali feldspar paragenesis. American Journal of Science, 252, 65–75.CrossRefGoogle Scholar
Tilley, C.E. (1957) Problems of alkali rock genesis. 13th William Smith Lecture,323–360.Google Scholar
Tindle, A.G. and Webb, P.C. (1990) Estimation of lithium contents in trioctahedral micas using microprobe data: application to micas from granitic rocks. European Journal of Mineralogy, 2, 595–610.CrossRefGoogle Scholar
Tischendorf, G., Förster, H.-J., Gottesmann, B. and Rieder, M. (2007) True and brittle micas: composition and solid-solution series. Mineralogical Magazine, 71, 285—320.CrossRefGoogle Scholar
Upadhyay, D. (2012) Alteration of plagioclase to nepheline in the Khariar alkaline complex, SE India: constraints on metasomatic replacement reaction mechanisms. Lithos, 155, 19—29.CrossRefGoogle Scholar
Ussing, N.V. (1912) Geology of the country around Julianehaab, Greenland. Meddelelser om Grønland, 38, 1–376.Google Scholar
von, Eckermann H. (1968) New contributions to theinterpretation of the genesis of the norra kärr alkalineRelatively aluminous alkali pyroxene in nephelin body in southern Sweden. Lithos, 1, 76–88.CrossRefGoogle Scholar
Woolley, A.R., Platt, R.G. and Eby, N.E. (1996) syenites from Malawi: mineralogical response t.Google Scholar
Vuorinen, J.H., Hålenius, U., Whitehouse, M.J., Mansfeld, J. and Skelton, A.D.L. (2005) Compositional variations (major and trace elements) of clinopyroxene and Ti-andradite from pyroxenite,ijolite and nepheline syenite, Alnö Island, Sweden Lithos, 81, 55–77 CrossRefGoogle Scholar
Woolley, A.R., Platt, R.G. and Eby, N.E. (1996) Relatively aluminous alkali pyroxene in nepheline syenites from Malawi: mineralogical response to metamorphism in alkaline rocks. The Canadian Mineralogist, 34, 423-434.Google Scholar
Yoder, H.S. and Weir, C.E. (1951) Change of free energy with pressure of the reaction nepheline + albite = 2 jadeite. American Journal of Science, 249, 683-694.CrossRefGoogle Scholar