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Re-equilibration of detrital muscovite and the formation of interleaved phyllosilicate grains in low temperature metamorphism, northern Apennines, Italy

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Abstract

Low temperature metamorphosed clastic rocks of northern Apennines (Verrucano) contain detrital and metamorphic muscovite along with aggregates of interleaved phyllosilicate grains. The extent of celadonite substitution in the metamorphic muscovite progressively increases from Al-rich pyrophyllite-bearing samples to Al-poor K-feldspar-bearing samples and appears to be compatible with the phase relation in the AKF and AKNa diagrams. Some detrital muscovite grains, not equilibrated with the present metamorphic mineral assemblages, seem to be unreacted grains retaining their premetamorphic composition. The chemistry of the re-equilibrated “detrital muscovite” is mainly controlled by the activity of Al2O3 that is implied by mineral assemblages in the host rocks and is independent of the original composition of detrital mica. Four types of phyllosilicate associations in the interleaved phyllosilicate grains were recognized: 1) muscovite- pyrophyllite-sudoite; 2) muscovite-pyrophyllite-chlorite; 3) muscovite-paragonite-chlorite; 4) muscovite-chlorite. A microstructural and petrological model is proposed for the origin of interleaved phyllosilicate grains in the Verrucano rocks. The model supports the idea that the interleaved phyllosilicate grains are the result of the trend towards equilibrium between detrital muscovite, metamorphic mineral assemblages and the fluid phase.

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References

  • Alisheva EI, Kletchikow LN, Leiponov KK (1981) Sudoite from the peri-ore chlorite wall rocks of massive sulphide deposits. Mineral Zh 3:71–75

    Google Scholar 

  • Baldelli C, Franceschelli M, Leoni L, Memmi I (1989) Celadonite and ferrimuscovite substitutions in muscovite from Fe3+-rich low-grade psammitic rocks (northern Apennines, Italy). Lithos 23:201–208

    Google Scholar 

  • Carmignani L, Franceschelli M, Pertusati PC, Memmi I, Ricci CA (1982) An example of compositional control of the celadonitic content of muscovite and incoming of biotite in metapelites (Nurra NW Sardinia). Neues Jahrb Mineral Mh 7:289–311

    Google Scholar 

  • Cassinis G, Elter G, Rau A, Tongiorgi M (1979) Verrucano a tectofacies of the alpine mediterranean southern Europe. Mem Soc Geol Ital 20:135–148

    Google Scholar 

  • Costantini A, Decandia FA, Lazzarotto A, Sandrelli F (1988) L'unita' di Monticiano-Roccastrada fra la Montagnola Senese e il Monte Leoni (Toscana Meridionale). Atti Ticinesi di Scienze Terra 31:382–420

    Google Scholar 

  • Cruickshank RD, Ghent ED (1978) Chloritoid-bearing pelitic rocks of the Horsethief Creek Group, southeastern British Columbia. Contrib Mineral Petrol 65:333–339

    Google Scholar 

  • Eggleston RA, Bailey SW (1967) Structural aspects of dioctahedral chlorite. Am Mineral 52:673–689

    Google Scholar 

  • Franceschelli M, Leoni L, Memmi I, Puxeddu M (1986a) Regional distribution of Al-silicates and metamorphic zonation in the low grade Verrucano metasediments from northern Apennines, Italy. J Metamorph Geol 4:309–321

    Google Scholar 

  • Franceschelli M, Mellini M, Memmi I, Ricci CA (1986b) Fine-scale chlorite-muscovite association in low-grade metapelites from Nurra (NW Sardinia), and the possible mis-identification of metamorphic vermiculite. Contrib Mineral Petrol 93:137–143

    Google Scholar 

  • Franceschelli M, Leoni L, Sartori F (1987) Geochemistry and mineralogy of detritic rocks from Verrucano type sequences of northern Apennines (Monti Pisani and Punta Bianca), Italy. Rend Soc Ital Miner Petrol 42:13–32

    Google Scholar 

  • Franceschelli M, Mellini M, Memmi I, Ricci CA (1989) Sudoite, a rock-forming mineral in Verrucano of the northern Apennines (Italy) and the sudoite-chloritoid pyrophyllite assemblage in prograde metamorphism. Contrib Mineral Petrol 101:274–279

    Google Scholar 

  • Frey M (1987) The reaction-isograd kaolinite+quartz+pyrophyllite+H2O, Helvetic Alps, Switzerland. Schweiz Mineral Petrogr Mitt. 67:1–11

    Google Scholar 

  • Frey M, Saunders J, Schwander H (1988) The mineralogy and metamorphic geology of low grade metasediments, northern Range, Trinidad. J Geol Soc Lond 145:563–575

    Google Scholar 

  • Goffe' B, Chopin C (1986) High-pressure metamorphism in the western Alps: zoneography of metapelites, chronology and consequences. Schweiz Mineral Petrogr Mitt 66:41–52

    Google Scholar 

  • Helgeson HC, Delany JM, Nesbitt HW, Bird DK (1978) Summary and critique of the thermodynamic properties of rock forming minerals. Am J Sci 278A:1–229

    Google Scholar 

  • Hower J, Mowatt TC (1966) The mineralogy of illites and mixed layer illite/montmorillonites. Am Mineral 51:825–854

    Google Scholar 

  • Kretz R (1983) Symbols for rocks forming minerals. Am Mineral 68:277–279

    Google Scholar 

  • Mather JD (1970) The biotite isograd and the lower greenschists facies in the Dalradian rocks of Scotland. J petrol 11:253–275

    Google Scholar 

  • Rao TR (1977) Distribution of elements between coexisting phengite and chlorite from the greenschists facies of the Tennant Creel, central Australia. Lithos 10:103–112

    Google Scholar 

  • Rau A, Tongiorgi M (1974) Geologia dei Monti Pisani a sud-est della Valle del Guappero. Mem Soc Geol Ital 13:227–408

    Google Scholar 

  • Robinson GR Jr, Haas J Jr (1983) Heat capacity, relative enthalphy, and calorimetric entropy of silicate minerals: an empirical method of prediction. Am Mineral 68:541–553

    Google Scholar 

  • Sorby HC (1853) On the origin of slaty cleavage. Edimb New Phil J 55:137–148

    Google Scholar 

  • Tardy Y, Garrels R (1974) A method of estimating the Gibbs energies of formation of layer silicates. Geochim Cosmochim Acta 38:1101–1116

    Google Scholar 

  • Van Der Pluijm BA, Kaars-Sijpesteijn CH (1984) Chlorite-mica aggregates: morphology, orientation, development and bearing on cleavage formation in very low-grade rocks. J Struct Geol 3:279–290

    Google Scholar 

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Franceschelli, M., Memmi, I. & Gianelli, G. Re-equilibration of detrital muscovite and the formation of interleaved phyllosilicate grains in low temperature metamorphism, northern Apennines, Italy. Contr. Mineral. and Petrol. 109, 151–158 (1991). https://doi.org/10.1007/BF00306475

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  • DOI: https://doi.org/10.1007/BF00306475

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