International Journal of Earth Sciences

, Volume 93, Issue 1, pp 107–118 | Cite as

High-temperature rapid pyrometamorphism induced by a charcoal pit burning: The case of Ricetto, central Italy

  • Flavio CapitanioEmail author
  • Francesco Larocca
  • Salvatore Improta
Original Paper


Bulk chemistry and mineralogy of the peculiar rock of Ricetto (Carseolani Mts., Central Apennines, Italy) was studied to resolve its controversial origin: igneous dyke or anthropic product. This hybrid rock consists of a colorless, felsic component made up of glass plus quartz, and a brown, femic component made up of fans and spherulites of diopside, calcic plagioclase, wollastonite, and melilite. Textural relationships indicate very rapid cooling and immiscibility phenomena. The bulk chemistry of the rock is the same as that of the surrounding siliciclastic sandstone. The 14C analysis of a coal fragment from bottom of the body yields the conventional age of 227(±50) years. The Ricetto occurrence is an example of pyrometamorphism of a siliceous limestone induced by a charcoal pit burning. The small size of the heat source at Ricetto caused an intense but short-lived melting of the country rock. Prograde metamorphism caused a temperature increase up to 1,000–1,100 °C when melilite crystallization conditions were reached at appreciable P(CO2) and high f(O2). Melting occurred in a close system represented by the simplified equation: 3Cal+16.5Qtz+Ms+Bt→Mel+Melt+2H2O+3CO2+0.5O2. Diopside+calcic plagioclase+wollastonite formed by melilite breakdown during rapid cooling, through the reaction: 6Mel+6Qtz+0.5O2→3Di+2An+7Wo. Liquid immiscibility caused the separation between the felsic melt component and the femic melilite-bearing component. Immiscibility was characterized by different fractionation of alumina and alkalies between these two phases. Differences in bulk, glass, and mineral chemistry between the Ricetto and other melilite-bearing pyrometamorphic rocks can be attributed mainly to different protoliths.


Ricetto Central Apennines Pyrometamorphism Melilite breakdown Silicate melt immiscibility 



D. Cosentino (Rome) challenged us to clarify the origin of the Ricetto body. M. Follieri (Rome) gave us encouragement and helpful suggestions. Revisions by A. Mottana (Rome) enabled us to improve both the contents and style of the manuscript. This paper also benefited by revisions and criticism of M. Raith (Bonn) and T. Kunzmann (Munich), which are gratefully acknowledged. G.M. Crisci (Cosenza) and C. Aurisicchio (Rome) provided the XRF and EMP analysis facilities, respectively. Assistance of U. Lanzafame (XRF), L. Martarelli (EMPA), P. Cipollari (SEM), and C. Romano (FTIR) is also acknowledged. Courtesy of R. Marcon (IGI) has been invaluable. During the final revision phase of this manuscript, one of the authors, Salvatore Improta, passed away unexpectedly. Still stunned, the other authors can only mourn for the loss of a such careful scientist and amiable person.


  1. Accordi G, Carbone F, Civitelli G, Corda L, De Rita D, Esu D, Funiciello R, Kotsakis T, Mariotti G, Sposato A (1986) Lithofacies map of Latium-Abruzzi and neighbouring areas. CNR Progetto Finalizzato Geodinamica, sottoprogetto 4Google Scholar
  2. Aurisicchio C, Federico M, Gianfagna A (1988) Clinopyroxene chemistry of the high-potassium suite from the Alban Hills, Italy. Mineral Petrol 39:1–19Google Scholar
  3. Barton M, Varekamp JC, Van Bergen MJ (1984): Complex zoning of clinopyroxenes in the lavas of Vulsini, Latium, Italy: evidence for magma mixing. J Volcanol Geotherm Res 14:361–388CrossRefGoogle Scholar
  4. Bastin ES (1905) Note on baked clays and natural slags in eastern Wyoming. J Geol 13:408–412Google Scholar
  5. Bellotti P, Evangelista S, Milli S, Valeri P (1987) Un corpo lavico nelle Marne ad Orbulina di Ricetto. Rend Soc Geol Ital 10:67–70Google Scholar
  6. Bellotti P, Landini B, Valeri P (1984) Associazioni di facies e lineamenti evolutivi generali del “complesso torbiditico altomiocenico laziale-abruzzese”. Bol Soc Geol Ital 103:311–326Google Scholar
  7. Bentor YK (1982) Combustion-metamorphic glasses. J Non-Cryst Solids 67:433–448Google Scholar
  8. Bindeman IN, Bailey JC (1994) A model of reverse differentiation at Dikii Greben’ Volcano, Kamchatka: progressive basic magma vesiculation in a silicic magma chamber. Contrib Mineral Petrol 117:263–278Google Scholar
  9. Bustin RM, Mathews WH (1982) In situ gasification of coal, a natural example: history, petrology, and mechanics of combustion. Can J Earth Sci 19:514–523Google Scholar
  10. Carbonin S, Dal Negro A, Molin GM, Munno R, Rossi G, Lirer L, Piccirillo EM (1984) Crystal chemistry of Ca-rich pyroxenes from undersaturated to oversaturated trachitic rocks, and their relationships with pyroxenes from basalts. Lithos 17:191–202CrossRefGoogle Scholar
  11. Cipollari P, Cosentino D, Guerrera F, Laurenzi MA, Renzulli A, Tramontana M (1998) Biostratigraphical correlation and geochronology of volcaniclastic horizons across the Tortonian/Messinian boundary in the Apennine foreland basin system. An Tectonicae 13:113–132Google Scholar
  12. Clark BH, Peacor DR (1992) Pyrometamorphism and partial melting of shales during combustion metamorphism: mineralogical, textural, and chemical effects. Contrib Mineral Petrol 112:558–568Google Scholar
  13. Compagnoni B, Galluzzo F, Pampaloni ML, Pichezzi RM, Raffi I, Rossi M, Santantonio M (1991a) Dati sulla lito-biostratigrafia delle successioni terrigene nell’area tra i Monti Simbruini e i Monti Carseolani (Appennino Centrale). Studi Geol Camerti, vol spec 1991/2:173–179Google Scholar
  14. Compagnoni B, Galluzzo F, Santantonio M (1991b) Schema tettonico dei rilievi carbonatici compresi nel F˚ 367 “Tagliacozzo” alla scala 1:50.000. Studi Geol Camerti, vol spec 1991/2:43–46Google Scholar
  15. Cosca MA, Essene EJ, Geissman JW, Simmons WB, Coates DA (1989) Pyrometamorphic rocks associated with naturally burned coal beds, Powder River Basin, Wyoming. Am Mineral 74:85–100Google Scholar
  16. Cundari A, Ferguson AK (1991) Petrogenetic relationships between melilite and lamproite in the Roman Comagmatic Region: the lavas of S. Venanzo and Cupaello. Contrib Mineral Petrol 107:343–357Google Scholar
  17. De Wys EC, Foster WR (1958) The system diopside – anorthite - åkermanite. Mineral Mag 31:736–743Google Scholar
  18. Eskola P (1939) Die metamorphen Gesteine. In: Barth TFW, Correns CW, Eskola P (eds) Die Entstehung der Gesteine. Springer, Berlin Heidelberg New York, pp 263–407Google Scholar
  19. Ferry JM, Wing BA, Penniston-Dorland SC, Rumble D (2002) The direction of fluid flow during contact metamorphism of siliceous carbonate rocks: new data from the Monzoni and Predazzo aureoles, northern Italy, and global review. Contrib Mineral Petrol 142:679–699Google Scholar
  20. Fine G, Stolper E (1985) Dissolved carbon dioxide in basaltic glasses: concentrations and speciation. Earth Planet Sci Lett 76:263–278CrossRefGoogle Scholar
  21. Fine G, Stolper E (1986) The speciation of carbon dioxide in sodium aluminosilicate glasses. Contrib Mineral Petrol 91:105–121Google Scholar
  22. Foit FF, Hooper RL, Rosenberg PE (1987) An unusual pyroxene, melilite, and iron oxide mineral assemblage in a coal-fire buchite from Buffalo, Wyoming. Am Mineral 72:137–147Google Scholar
  23. Freestone IC, Powell R (1983) The low-temperature field of liquid immiscibility in the system K2O–Al2O3–FeO–SiO2 with special reference to the join fayalite–leucite–silica. Contrib Mineral Petrol 82:291–299Google Scholar
  24. Fuhrman ML, Lindsley DH (1988) Ternary-feldspar modeling and thermometry. Am Mineral 73:201–215Google Scholar
  25. Gallo F, Giammetti F, Venturelli G, Vernia L (1984) The kamafugitic rocks of San Venanzo and Cuppaello, Central Italy. Neues Jahrb Mineral Mh 5:198–210Google Scholar
  26. Giordano G (1981) Tecnologia del legno. UTET, Torino, pp 995–1014Google Scholar
  27. Heinrich W, Gottschalk M (1994) Fluid flow patterns and infiltration isograds in melilite marbles from the Bufa del Diente contact metamorphic aureole, north-east Mexico. J Metamorph Geol 12:345–359Google Scholar
  28. Hoscheck G (1974) Gehlenite stability in the system CaO–Al2O3–SiO2–H2O–CO2. Contrib Mineral Petrol 47:245–254Google Scholar
  29. Ihinger PD, Hervig RL, McMillan PF (1994) Analytical methods for volatiles in glasses. Rev Mineral 30:67–121Google Scholar
  30. Koch L (1930) Über das System Wollastonit – Anorthit – Pyroxen. Neues Jahrb Mineral Geol Beilage Bd 61:278–318Google Scholar
  31. Lange J, Carmichael ISE (1987) Densities of Na2O–K2O–CaO–MgO–FeO–Fe2O3–Al2O3–TiO2–SiO2 liquids: new measurements and derived partial molar properties. Geochim Cosmochim Acta 53:2195–2204CrossRefGoogle Scholar
  32. Lange J, Carmichael ISE (1990) Thermodynamic properties of silicate liquids with emphasis on density, thermal expansion and compressibility. Rev Mineral 24:25–64Google Scholar
  33. Lupini L (1993) Il distretto ultalcalino umbro-laziale: mineralogia, petrologia, geochimica e relazioni con il contesto tettonico. PhD Thesis, Univ Perugia, 422 ppGoogle Scholar
  34. Naslund HR (1983) The effect of oxygen fugacity on liquid immiscibility in iron-bearing silicate melts. Am J Sci 283:1034–1059Google Scholar
  35. Osborn EF, Schairer JF (1941) The ternary system pseudowollastonite–åkermanite–gehlenite. Am J Sci 239:715–763Google Scholar
  36. Papike JJ, Cameron KL, Baldwin K (1974) Amphiboles and pyroxenes: characterization of other than quadrilateral components and estimates of ferric iron from microprobe data. Geol Soc Am Progr Abstr 6:1053–1054Google Scholar
  37. Pawley AR, Holloway JR, McMillan PF (1992) The effect of oxygen fugacity on the solubility of carbon-oxygen fluids in basaltic melt. Earth Planet Sci Lett 110:213–225CrossRefGoogle Scholar
  38. Philpotts AR (1976) Silicate liquid immiscibility: its probable extent and petrogenetic significance. Am J Sci 276:1147–1177Google Scholar
  39. Philpotts AR (1977) Archean variolites—quenched immiscible liquids: discussion. Can J Earth Sci 14:139–144Google Scholar
  40. Philpotts AR (1982) Composition of immiscible liquids in volcanic rocks. Contrib Mineral Petrol 80:201–218Google Scholar
  41. Roedder E (1951) Low-temperature liquid immiscibility in the system K2O–FeO–Al2O3–SiO2. Am Mineral 36:282–286Google Scholar
  42. Schölze H (1959) Der Einbau der Wassers in Gläsern. Glastech Ber 32:81–88Google Scholar
  43. Stolper E (1982) Water in silicate glasses: an infrared spectroscopic study. Contrib Mineral Petrol 81:1–17Google Scholar
  44. Stoppa F (1988) L’euremite di Colle Fabbri (Spoleto): un litotipo ad affinità carbonatica in Italia. Bol Soc Geol Ital 107:239–248Google Scholar
  45. Traversa G, Bellotti P, Evangelista S, Milli S, Ronca S, Traversa F, Valeri P (1991) Preliminary data on melilititic lavas of the Carseolani Mountains (Rieti). Per Mineral 60:81–82Google Scholar
  46. Treiman AH, Essene EJ (1983) Phase equilibria in the system CaO–SiO2–CO2. Am J Sci 283A:97–120Google Scholar
  47. Velde D, Yoder HS Jr (1977) Melilite and melilite-bearing igneous rocks. Carnegie Inst Wash Annu Rep Dir Geophys Lab 1976–7:478–485Google Scholar
  48. Visser W, Koster van Groos AF (1979) Phase relationship in the system K2O–FeO–Al2O3–SiO2 with special emphasis on low-temperature immiscibility. Am J Sci 274:70–91Google Scholar
  49. Weiblen PW, Morey GB (1980) A summary of the stratigraphy, petrology, and stricture of the Duluth Complex. Am J Sci 280A:88–133Google Scholar
  50. Williams JP, Su Y-S, Strzegowski WR, Butler BL, Hoover HL, Altemose VO (1976) Direct determination of water in glass. Ceram Bull 55:524–527Google Scholar
  51. Yoder HS (1952) The MgO–Al2O3–SiO2–H2O system and the related metamorphic facies. Am J Sci, Bowen vol, pp 569–627Google Scholar
  52. Yoder HS (1973) Melilite stability and paragenesis. Fortschr Mineral 50:140–173Google Scholar
  53. Zharikov VA, Shmulovich KI, Bulatov VK (1977) Experimental studies in the system CaO–MgO–Al2O3–SiO2–CO2–H2O and conditions of high-temperature metamorphism. Tectonophysics 43:142–162CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Flavio Capitanio
    • 1
    Email author
  • Francesco Larocca
    • 2
  • Salvatore Improta
    • 3
  1. 1.Dottorato di Ricerca in Geodinamica, Scienze GeologicheUniversità Roma TreRomeItaly
  2. BotanicaUniversità La SapienzaRomeItaly
  3. FisicaUniversità La SapienzaRomeItaly

Personalised recommendations