Summary
Cummingtonite and hornblende occur together in metamorphosed basic rocks interlayered with lower-amphibolite facies sillimanite-muscovite-bearing schists and gneisses in the upper Lake Como region, South-Alpine basement complex of the Alps. Textural, chemical and spectroscopic studies indicate that they do not represent equilibrium pairs, but that hornblende was overgrown by cummingtonite during a late stage of either temperature increase or, more likely, of isothermal pressure release, by a continuous reaction which also produced the reverse zoning of plagioclase.
Zusammenfassung
Im Gebiet des oberen Como-Sees, im südalpinen Basement-Komplex, kommen Cummingtonit und Hornblende zusammen in metamorphen, basischen Gesteinen mit Zwischenlagen von Sillimanit-Muskovit-führenden Schiefern und Gneisen der unteren Amphibolit-Fazies vor. Untersuchung der Texturen, der chemischen Zusammensetzung und Infrarot-Spektroskopie zeigen, daß diese nicht Gleichgewichts-Paare darstellen, sondern daß Hornblende während eines späten Stadiums, entweder bei zunehmender Temperatur, oder eher während isothermalen Druck-Nachlasses durch eine kontinuierliche Reaktion von Cummingtonit überwachsen wurde, die auch für die reverse Zonierung der Plagioklase verantwortlich ist.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Appleman DE, Evans HT (1973) Job 9214: indexing and least-squares refinement of powder diffraction data. US Dept Commerce Natl Techn Inf Serv Report # PB216188
Barbagelata F, Mottana A (1969) Anfiboliti e cloritoscisti negli Scisti di Edolo (Alpi Orobie orientali). Atti Soc It Sc Nat Museo Civ St Nat Milano 109: 425–456
Bocchio R, Crespi R, Liborio G, Mottana A (1980) Variazioni composizionali delle miche chiare nel metamorfismo progrado degli scisti sudalpini dell'alto Lago di Como. Mem Sci Geol 34: 153–176
Boriani A (1965) L'anfibolite a orneblenda e cummingtonite di Ornavasso (Val d'Ossola). Rend Soc Min It 21: 25–34
Buckley AN, Wilkins RWT (1971) Mössbauer and infrared study of a volcanic amphibole. Am Mineral 56: 90–100
Burns RG, Greaves CJ (1971) Correlation of infrared and Mössbauer site population measurements in actinolites. Am Mineral 56: 2010–2033
Burns RG, Strens RGJ (1966) Infrared study of the hydroxyl bands in clinoamphiboles. Science 153: 890–892
Callegari E (1966) Osservazioni su alcune cummingtoniti del masssiccio dell'Adamello. Mem Acc Patav Sci Lett Arti Cl Sci Mat Nat 78: 273–310
Colby JW (1971) Magic IV, a computer program for quantitative electron microprobe analysis. Bell Tel Labs, Allentown, Pennsylvania
De Capitani L, Liborio G (1990) Cummingtonite nelle plutoniti della Val Biandino (Como). Rend Fis Acc Lincei s. 9, 1: 379–385
El Tahlawi MR (1965) Geologie and Petrographie des nordbstlichen Comoseegebietes (Prov. Como, Italien). Mitt Geol Inst ETH Univ Ziirich NF 27: 199pp
Ferry JM, Spear FS (1978) Experimental calibration of the partitioning of Fe and Mg between biotite and garnet. Contrib Mineral Petrol 66: 113–117
Fumasoli MW (1974) Geologie des Gebietes nördlich and sildlich der Jorio-Tonale-Linie im Westen von Gravedona (Como, Italia). Dissertation, ETH Zurich
Gandini P, Schiavinato G (1959) Ortoanfiboliti di Dazio in Valtellina. Rend Ist Lomb Sc Lett 93: 73–94
Garvey RG (1985) Least squares unit cell refinement with indexing on the personal computer. Workshop Microcomputers in X-ray diffraction, Snowmass, Colorado, August 6, 1985
Graham CM, Powell R (1984) A garnet-hornblende geothermometer: calibration, testing, and application to the Pelona Schist, Southern California. J Metamorph Geol 2: 13–31
Guidotti CV (1984) Micas in metamorphic rocks. In:Bailey SW (ed) Micas. Rev Mineral 13: 357–467Hawthorne FC (1981) Crystal chemistry of the amphiboles. In:Veblen DR (ed) Amphiboles and other hydrous pyriboles—Mineralogy. Rev Mineral 9A: 1–102
Hawthorne FC (1983) The crystal chemistry of the amphiboles. Can Mineral 21: 1–480
Hietanen A (1973) Coexisting cummingtonite and aluminous hornblende from garnet amphibolite, Boehls Butte area, Idaho, USA. Lithos 6: 261–264
Hoinkes G, Mogessie A (1986) Coexisting cummingtonite and calcic amphibole in amphibolites from the Schneeberg Complex, Tyrol, Austria. Mineral Petrol 35: 33–45
Kisch HJ (1969) Magnesiocummingtonite-P2/m: a Ca- and Mn-poor clinoamphibole from New South Wales. Contrib Mineral Petrol 21: 319–331
Kisch HJ, Warnaars FW (1969) Distribution of Mg and Fe in cummingtonite-hornblende and cummingtonite-actinolite pairs from metamorphic assemblages. Contrib Mineral Petrol 24: 245–267
Klein C (1968) Coexisting amphiboles. J Petrol 9: 281–330
Mongkoltip P, Ashworth JR (1986) Amphibolitization of metagabbros in the Scottish Highlands. J Metamorph Geol 4: 261–283
Mottana A (1986) Crystal-chemical evaluation of garnet and omphacite microprobe analyses: its bearing on the classification of eclogites. Lithos 19: 171–186
Mottana A, Nicoletti M, Petrucciani C, Liborio G, De Capitani L, Bocchio R (1985) Pre-alpine and alpine evolution of the South alpine basement of the Orobic Alps. Geol Rundschau 74: 353–366
Mueller RF (1961) Analysis of relations among Mg, Fe and Mn in certain metamorphic minerals. Geochim Cosmochim Acta 25: 267–296
Nasir S (1990) Coexisting cummimgtonite-hornblende pairs in meta-mafic rocks from the central Spessart crystalline complex, NW-Bavaria, F.R.G. Chem Erde 50: 181–188
Powell R (1975) Thermodynamics of coexisting cummingtonibe-hornblende pairs. Contrib Mineral Petrol 51: 29–37
Robinson P, Jaffe HW (1969) Chemographic exploration of amphibole assemblages from central Massachusetts and southwestern New Hampshire.Mineral Soc Am Spec Pap 2: 251–274
Rock NM, Leake BE (1984) The International Mineralogical Association amphibole nomenclature scheme: computerization and its consequences. Mineral Mag 48: 211–227
Ross M, Papike JJ, Shaw KW (1969) Exsolution textures in amphiboles as indicators of subsolidus thermal histories. Mineral Soc Am Spec Pap 2: 275–299
Spear FS (1981) An experimental study of hornblende and compositional variability in amphibolite. Am J Sci 281: 699–734
Spear FS (1982) Phase equilibria of amphibolites from the Post Pond volcanics, Mt. Cube Quadrangle, Vermont. J Petrol 23: 383–426
Spear FS, Robinson P, Schumacher JC (1982) Calcic amphiboles and cummingtonites: chemographic relations. In:Veblen DR, Ribbe PH (eds) Amphiboles: petrology and experimental phase relations. Rev Mineral 9B: 50–61
Stephenson NCN, Hensel HD (1979) Intergrown calcic and Fe-Mg amphiboles from the Wongwibinda metamorphic complex, NSW Australia. Can Mineral 17: 11–23
Stout JH (1972) Phase petrology and mineral chemistry of coexisting amphiboles from Telemark, Norway. J Petrol 13: 99–145
Strens RGJ (1966) Infrared study of cation ordering and clustering in some (Fe, Mg) amphibole solid solutions. Chem Comm 15: 519–520
Strens RGJ (1974) The common chain, ribbon and ring silicates. In:Farmer VC (ed) The infrared spectra of minerals. Mineral Soc Monogr 4: 305–330
Tagiri M (1977) Fe-Mg partition and miscibility gap between coexisting calcic amphiboles from the southern Abukuma plateau, Japan. Contrib Mineral Petrol 62: 271–281
Yamaguchi Y, Shikubasa H, Tomita K (1983) Exsolution of cummingtonite, actinolite and sodic amphibole in hornblende in high-pressure metamorphism. Nature 304: 257–259
Author information
Authors and Affiliations
Additional information
With 5 Figures
Rights and permissions
About this article
Cite this article
Mottana, A., Bocchio, R., Crespi, R. et al. Cummingtonite in the amphibolites of the South-Alpine basement complex (upper Lake Como region, Italy): Its relationships with hornblende. Mineralogy and Petrology 51, 67–84 (1994). https://doi.org/10.1007/BF01164915
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01164915