Original paper

Crystal chemistry of Stromboli clinopyroxene: a comparison with analogues from other Aeolian Islands (Italy)

Pasqual, Daria; Molin, Gianmario; Zanazzi, Pier Francesco

European Journal of Mineralogy Volume 7 Number 2 (1995), p. 369 - 378

15 references

published: Mar 29, 1995
manuscript accepted: Jun 28, 1994
manuscript received: Jun 28, 1994

DOI: 10.1127/ejm/7/2/0369

BibTeX file

ArtNo. ESP147050702012, Price: 29.00 €

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Abstract

Abstract Single clinopyroxene crystals from four different volcanic suites on Stromboli (Aeolian Islands, Italy) were studied by X-ray diffraction and microprobe analysis in order to obtain information on the relations between clinopyroxene crystal chemistry and the petrology of the host rocks, and to provide comparisons with the nearby islands of Vulcano, Filicudi and Salina. Crystal chemical study reveals the coexistence on Stromboli of rocks with two clinopyroxene compositions with C2/c symmetry, diopside and augite, both of which show wide ranges in structural and chemical parameters. Unit cell and Ml site volumes are relatively large, a feature that is indicative of low crystallization pressure, as already observed in clinopyroxene from Vulcano and Salina. Comparable clinopyroxene from Filicudi are characterized by lower volumes and interpreted as having crystallized in a deeper magma chamber (Malgarotto et al., 1993). The intracrystalline Mg-Fe2+ ordering reaction shows closure temperatures for Stromboli clinopyroxene ranging between 620 and 1100°C This wide range indicates different cooling rates related to eruptive mechanisms

Keywords

clinopyroxenecrystal chemistrycalc-alkaline rocksclosure temperaturecrystallization pressure