caa a22 4500 467890196 CHVBK 20180406152746.0 cr unu---uuuuu 170328e20060101xx s 000 0 eng 10.1007/s00710-005-0105-5 doi (NATIONALLICENCE)springer-10.1007/s00710-005-0105-5 Crystallization conditions in the Upper Pollara magma chamber, Salina Island, Southern Tyrrhenian Sea [Elektronische Daten] [P. Donato, H. Behrens, R. De Rosa, F. Holtz, F. Parat] Summary: Pyroclastites erupted from the Upper Pollara magma chamber (13 ka, Salina Island, Aeolian Archipelago) resulted from mingling and mixing of rhyolitic and andesitic magmas. An experimental study has been conducted on the rhyolitic end-member to constrain the pre-eruptive conditions of the magma. In order to check for the role of mixing on the equilibrium phase assemblage, three different starting compositions, corresponding to three different mixing degrees, have been used. The crystallization experiments were conducted at two different oxygen fugacities and at variable temperature and fluid contents. The results indicate that the natural mineralogical assemblage can only be reproduced from a composition showing a certain degree of mixing. Assuming a pressure of 200 MPa (generally accepted for the Aeolian Islands), the pre-eruptive temperature of the magmas is estimated between 755 and 800 °C and the water content of the melt was higher than 4-4.5 wt.%. The Upper Pollara magma crystallized at relatively high fO2 (ΔlogfO2 = Ni-NiO + 1 log unit), compared to rhyolitic magmas from Lipari and Vulcano. As this difference has not been observed for the most primitive magmas the difference in fO2 could be related to different degassing processes operating in Salina and Lipari - Vulcano magmas. Springer-Verlag/Wien, 2006 Donato P. Dipartimento Scienze della Terra, Università della Calabria, Arcavacata di Rende (CS), Italy aut Behrens H. Institut für Mineralogie, Universität Hannover, Hannover, Germany aut De Rosa R. Dipartimento Scienze della Terra, Università della Calabria, Arcavacata di Rende (CS), Italy aut Holtz F. Institut für Mineralogie, Universität Hannover, Hannover, Germany aut Parat F. Institut für Mineralogie, Universität Hannover, Hannover, Germany aut Mineralogy and Petrology Springer-Verlag 86/1-2(2006-01-01), 89-108 0930-0708 86:1-2<89 2006 86 710 https://doi.org/10.1007/s00710-005-0105-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00710-005-0105-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Donato P. Dipartimento Scienze della Terra, Università della Calabria, Arcavacata di Rende (CS), Italy aut NATIONALLICENCE 700 1- Behrens H. Institut für Mineralogie, Universität Hannover, Hannover, Germany aut NATIONALLICENCE 700 1- De Rosa R. Dipartimento Scienze della Terra, Università della Calabria, Arcavacata di Rende (CS), Italy aut NATIONALLICENCE 700 1- Holtz F. Institut für Mineralogie, Universität Hannover, Hannover, Germany aut NATIONALLICENCE 700 1- Parat F. Institut für Mineralogie, Universität Hannover, Hannover, Germany aut NATIONALLICENCE 773 0- Mineralogy and Petrology Springer-Verlag 86/1-2(2006-01-01), 89-108 0930-0708 86:1-2<89 2006 86 710 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer