Skip to main content Accessibility help

Petrologic evidence for a rhodochrosite precursor of spessartine in coticules of the Venn-Stavelot Massif, Belgium

  • W. Schreyer (a1), H.-J. Bernhardt (a1) and O. Medenbach (a1)


Minute CaMg-bearing rhodochrosite inclusions were discovered in spessartine crystals of small coticule globules enclosed within redschists that form the country rock of the famous coticule bands of Belgium. This points to a former metamorphic reaction relationship between the two minerals, such as rhodochrosite + pyrophyllite = spessartine + quartz + CO2 + H2O. The coexistence of spessartine with Mg-chlorite in the coticule globule could also indicate more complex reactions such as rhodochrosite + sudoite + quartz = spessartine + Mg-chlorite + CO2 + H2O. Our finding casts some doubt on the suggestion by Kramm (1976) that spessartine formed from Mn-montmorillonite in previously glassy volcanic tufts.



Hide All
Chatterjee, N. D. and Flux, S. (1986) Thermodynamic mixing properties of muscovite-paragonitc crystalline solutions at high temperatures and pressures, and their geological applications. J. Petrol., 27, 67793.
De Dycker, R. (1939) Recherches sur la nature et les causes du mrtamorphisme des terrains manganésiféres du Cambrien suprrieur, dans la pattie Sud-Occidentale du massif de Stavelot. Ann. Soc. Geol. Belg., 62, M1-106.
Fransolet, A.-M. (1972) Donnéess nouvelles sur la carpholite de Meuville. Bull. Soc. fr. Minéral. Cristal-logr., 95, 8497.
Fransolet, A.-M. and Bourguignon, P. (1978) Di/trioctahedral chlorite in quartz veins from the Ardenne, Belgium. Can. Mineral., 16, 36573.
Fransolet, A.-M. and Kramm, U. (1983) Mineralogie und Petrologie Mn-reicher Metapelite des Venn-Stavelot Massivs, Ardennen, und die varistische Metamorphose im nordwestlichen Rheinischen Schild. Fortschr. Mineral., 61, 3169.
Fransolet, A.-M. and Schreyer, W. (]977) Metamorphose und Magmatismus im Venn-Stavelot-Massiv, Ardennen. Ibid., 55, 75103.
Fransolet, A.-M. Abraham, K., and Sahl, K. (1984) Davreuxite: a reinvestigation. Am. Mineral., 69, 77782.
Halbach, H. and Chatterjee, N. D. (1982) The use of linear parametric programming for determining internally consistent thermodynamic data for minerals. In High-pressure researches in geoscience (W. Schreyer, ed.) E. Schweizerbart'sche Verlagsbuchhandlung Stuttgart, pp. 475-91.
Hsu, L. C. (1968) Selected phase relationships in the system AI-Mn-Fe-Si-O-H: A model for garnet equilibria. J. Petrol., 9, 4083.
Kramm, U. (1976) The coticule rocks (spessartine quartzites) of the Venn-Stavelot Massif, Ardennes, a volcanoclastic metasediment? Contrib. Mineral. Petrol., 56, 13555.
Kramm, U. (1980) Sudoite in low-grade metamorphic man ganese rich assemblages. Neues Jahrb. Mineral., Abh., 138, 113.
Krosse, S. (1983) Rotschiefer und Coticules der Ardennen (Belgien). Unpublished Diploma Thesis, Ruhr-Universitáit Bochum, 101 pp.
Lamens, J. and Geukens, F. (1984) Volcanic activity in the Lower Ordovician of the Stavelot Massif, Belgium. Med. Kon. Acad. Wet. Brussels, 46, 113.
Lamens, J. and Geukens, F. and Viaene, W. (1986) Geological setting and genesis of coticules (spessartine metapelites) in the Lower Ordovician of the Stavelot Massif, Belgium. J. Geol. Soc. London, 143, 2538.
Lessuise, A. (1981) Le Coticule. Ann. Mines Belgique, 1981, fasc. 2, 101-25.
Medenbach, O. (1985) A new microrefractomreter spindle-stage and its application. Fortschr. Mineral., 63, 11133.
Renard, A. (1878) Sur la structure et la composition minéralogique du coticule et sur ses rapports avec le phyllade oligistif6re. M(m. Cour. Acad. roy. Belgique, 41, 142.
Schreyer, W. (1975) New petrologic evidence for Hercynian metamorphism in the Venn-Stavelot Massif, Belgium. Geol. Rundschau, 64, 81930.
Schreyer, W. Fransolet, A.-M., and Abraham, K. (1986) A miscibility gap in the trioctahedral Mn-Mg-Fe chlor-ites: Evidence from the Lienne Valley manganese deposit, Ardennes, Belgium. Contrib., Mineral. Petrol., 94, 33342.
Spry, P. G. (1990) Geochemistry and origin of coticules (spessartine-quartz rocks) associated with metamorphose massive sulfide deposits. In Regional metamorphism of ore deposits and genetic implications (Spry and Bryndzia, eds) VSP Utrecht, p. 49-75.


Petrologic evidence for a rhodochrosite precursor of spessartine in coticules of the Venn-Stavelot Massif, Belgium

  • W. Schreyer (a1), H.-J. Bernhardt (a1) and O. Medenbach (a1)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.