Abstract
Mineralogical and chemical compositions of ejected carbonate inclusions of Vesuvian gaseous phase are compared with those of carbonate sediments of the Somma-Vesuvius area. The basement of Vesuvius mainly consists of Mesozoic limestones. Most of these are characterized by extremely low insoluble residues. In this area thick dolomite beds occur in the Triassic system only. A calcareous layer of approximately 100 to 150 meters thickness characterized by high Sr contents (0.19% Sr in the average) is to be found within the Triassic dolostones. Several carbonate ejecta also show high Sr contents (0.1% Sr) but chemical composition of some of these ejecta differs somewhat from that of the Triassic layer high in Sr. Contact with the volcanic volatile phase and melt has produced some alterations in the composition of many ejecta. Magnesian calcites are abundant and periclase, brucite, tremolite, phlogopite and magnesite were found in the ejecta examined. Silicon, manganese, iron, zinc and, to a smaller extent, potassium and copper have been most probably transported from the volcanic gas phase into ejected carbonate inclusions. Owing to metasomatic actions of the volcanic volatile components, rearrangement and alteration of Ca and Mg contents occurred in the carbonate minerals of several ejecta. Under the influence of volcanic pressure and temperature, magnesium content originally in dolomite might be transformed into the calcite structure. \(\frac{{{\text{MgO}}}}{{{\text{CaO + MgO}}}}\) molar ratios of several carbonate ejecta do not correspond with those found in sedimentary limestones and dolostones. It cannot be proved whether the Mg of the mixed calcite-dolomite ejecta has been partially introduced from the volatiles or lost from the carbonate phases.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Carpenter, A. B.: Mineralogy and petrology of the system CaO-MgO-CO2-H2O at Crestmore, Calif. Am. Mineralogist 52, 1341–1363 (1967).
Chave, K. E.: Aspects of the biogeochemistry of magnesium, 1. Calcareous marine organisms. J. Geol. 62, 266–283 (1954).
De Castro, P.: Il Giura-Lias dei Monti Lattari. Boll. soc. nat. Napoli 71, 1–36 (1962).
— Sulla presenza del Giura nei Monti Aurunci. Boll. soc. nat. Napoli 71, 16–21 (1962).
- Personal communication 1963.
De Lorenzo, G.: Geologia dell'Italia Meridionale. Nuova Ed. a cura di G. d'Erasmo. Napoli: EPSA 1937.
Eaton, J. P., and K. J. Murata: How volcanos grow. Science 132, 925–938 (1960).
Flügel, H. W., u. K. H. Wedepohl: Die Verteilung des Strontiums in oberjurassischen Karbonatgesteinen der Nördlichen Kalkalpen. Contr. Mineral. and Petrol. 14, 229–249 (1967).
Fornaseri, M., and L. Grandi: Contenuto in stronzio di serie calcaree Italiane. Giorn. geol. Ann. museo geol. Bologna [2] 31, 171–198 (1963).
Glover, E. D., and R. F. Sippel: Synthesis of magnesium calcites. Geochim. et Cosmochim. Acta 31, 603–613 (1967).
Goldsmith, J. R.: Some aspectes of the geochemistry of carbonates. In: Researches in geochemistry (P. H. Abelson, ed.). New York: John Wiley & Sons 1959.
— and D. L. Graf: Structural and compositional variations in some natural dolomites. J. Geol. 66, 678–693 (1958).
— and H. C. Heard: Lattice constants of the calcium-magnesium carbonates. Am. Mineralogist 46, 453–457 (1961).
— and O. I. Joensuu: The occurrence of magnesian calcites in nature. Geochim. et Cosmochim. Acta 7, 212–230 (1955).
— and H. C. Heard: Subsolidus phase relations in the system CaCO3-MgCO3. J. Geol. 69, 45–74 (1961).
Graf, D. L., and J. R. Goldsmith: Dolomite-magnesian calcite relations at elevated temperatures and CO2 pressures. Geochim. et Cosmochim. Acta 7, 109–128 (1955).
Harker, R. I., and O. F. Tuttle: Limits of solid solution along the binary join CaCO3-MgCO3. Am. J. Sci. 253, 274–282 (1955a).
— The thermal dissociation of calcite, dolomite and magnesite. Am. J. Sci. 253, 209–224 (1955b).
Imbó, G.: Successione e spessori delle formazioni geologiche nel basamento del Somma-Vesuvio. Ann. osservator. vesuviano 5a Ser. 1-13 (1950).
Johannes, W., and P. Metz: Experimentelle Bestimmungen von Gleichgewichtsbeziehungen im System MgO-CO2-H2O. Neues Jahrb. Mineral. Monatsh. 1, 15–26 (1968).
Metz, P., M. Graef, and W. Johannes: Thermodynamische Berechnung von Gleichgewichtsbeziehungen im System MgO-CO2-H2O. Neues Jahrb. Mineral., Monatsh. 1–2 1–15 (1968).
Parascandola, A.: I minerali del Vesuvio nella eruzione del marzo 1944 e quelli formati durante l'attuale periodo di riposo. Boll. soc. geol. ital. 70, 523–526 (1951).
Rittmann, A.: Die geologisch bedingte Evolution und Differentiation des Somma-Vesuv-Magma. Z. Vulk. 15, 8–94 (1933).
Savelli, C.: Röntgenfluoreszenz-Bestimmung von Si und Al mit innerem Standard. Neues Jahrb. Mineral., Monatsh. 4/5, 124–131 (1967a).
— The problem of rock assimilation by Somma-Vesuvius magma. I. Composition of Somma and Vesuvius lavas. Contr. Mineral. and Petrol. 16, 328–353 (1967b).
Scandone, P., and I. Sgrosso: Sulla presunta lacuna liassica nei Monti Picentini (Salerno). Rend. acc. sci. fis. mat. Napoli 29, 3–7 (1962).
Scarsella, F.: Sulla presenza del Lias nell'isola di Capri. Rend. acc. sci. fis. mat. Napoli 28, 4a (1961).
Sinno, R.: Ricerche chimiche sui pirosseni del Somma-Vesuvio. Boll. Soc. Nat. Napoli 61, 77 (1952).
— Analisi chimiche di alcune dolomie della costiera amalfitana. Boll. soc. nat. Napoli 65, 84–87 (1956).
— Sui carbonati basici di magnesio presenti al Vesuvio. Nota II, Boll. soc. nat. Napoli 67, 46–55 (1958).
Steidtmann, E.: Origin of limestone as disclosed by stains and other methods. Bull. Geol. Soc. Am. 28, 431–450 (1917).
Walter, L. S., P. J. Wyllie, and O. F. Tuttle: The system MgO-CO2-H2O at high pressures and temperature. J. Petrol. 3, 49–64 (1962).
Wedepohl, K. H.: Die Röntgen-Fluoreszenz-Spektralanalyse von geochemischen Proben auf Elemente der Ordnungszahlen 25–40. Z. anal. Chem. 180, 246–259 (1961).
— Geochemie. Berlin: W. de Gruyter & Co. 1967.
Winkler, H. G. F.: Die Genese der metamorphen Gesteine, 2. Aufl. Berlin-Heidelberg New York: Springer 1967.
Zambonini, F.: Mineralogia Vesuviana. Torino: Rosenberg & Sellier 1936.
Author information
Authors and Affiliations
Additional information
The writer is particularly indebted to Prof. K. H. Wedepohl for encouraging this investigation, for many suggestions and discussions and for improvement of the manuscript. The writer wishes to thank: Prof. H. v. Platen for generous help in a part of the experimental work and for many suggestions; Drs. De Castro and Scandone of the Geological Institute of Naples for furnishing sediment samples and for helpful discussions on the geology of the Vesuvius area; all the members of the staff of the Mineralogische Anstalten der Universität Göttingen; die Deutsche Forschungsgemeinschaft and the Italian CNR for a grant and for a NATO scholarship respectively.
Rights and permissions
About this article
Cite this article
Savelli, C. The problem of rock assimilation by Somma-Vesuvius magma. Contr. Mineral. and Petrol. 18, 43–64 (1968). https://doi.org/10.1007/BF00371985
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00371985