caa a22 4500 469056916 CHVBK 20180323132846.0 cr unu---uuuuu 170328e19921201xx s 000 0 ita 10.1007/BF03002937 doi (NATIONALLICENCE)springer-10.1007/BF03002937 Indicazioni petrogenetiche dai granati birifrangenti dei proietti sialici nelle vulcaniti alcalino potassiche dei Monti Sabatini (Lazio) [Elektronische Daten] [Valerio Facchinelli, Mario Gaeta] Petrogenetic implications from birefringent garnets in the sialic ejecta in the alkaline-potassic volcanics of Sabatini Mts. (Latium, Italy) A petrogenetic model is proposed to explaine the conditions favouring crystallization of birefringent grandite garnets in the volcanics of Latium. The numerous findings of ejecta, both of metasomatic and of magmatic derivation according to their textural characters, within the Sabatini Mts. pyroclastics, allowed the qualitative study of the subsolidus reaction leading to the formation of grandite garnets in the hypabyssal phonolite dykes. Such a reaction is related to decarbonation of the basament rocks and may evolve, in a closed system, into a pneumatolitic stage characterized by high T and P (CO2, H2O) under which a grandite garnet acquires a crystal symmetry lower than cubic independently upon its chemical composition. Accademia nazionale dei Lincei, 1992 Grossular nationallicence Andradite nationallicence Metasomatism nationallicence Alkali-potassic magmatism nationallicence Latium (Italy) nationallicence Facchinelli Valerio Dipartimento di Scienze della Terra, Università degli Studi di Roma, «La Sapienza» Piazzale A. Moro, 5, 00185, Roma aut Gaeta Mario Dipartimento di Scienze della Terra, Università degli Studi di Roma, «La Sapienza» Piazzale A. Moro, 5, 00185, Roma aut Rendiconti Lincei Springer-Verlag 3/4(1992-12-01), 295-310 1120-6349 3:4<295 1992 3 12210 https://doi.org/10.1007/BF03002937 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF03002937 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Facchinelli Valerio Dipartimento di Scienze della Terra, Università degli Studi di Roma, «La Sapienza» Piazzale A. Moro, 5, 00185, Roma aut NATIONALLICENCE 700 1- Gaeta Mario Dipartimento di Scienze della Terra, Università degli Studi di Roma, «La Sapienza» Piazzale A. Moro, 5, 00185, Roma aut NATIONALLICENCE 773 0- Rendiconti Lincei Springer-Verlag 3/4(1992-12-01), 295-310 1120-6349 3:4<295 1992 3 12210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer