caa a22 4500 465791662 CHVBK 20180323112026.0 cr unu---uuuuu 170327e19900901xx s 000 0 eng 10.1007/BF00286828 doi (NATIONALLICENCE)springer-10.1007/BF00286828 Origin of the acidic volcanics of the Tolfa district, Tuscan Province, central Italy: an elemental and Sr-isotopic study [Elektronische Daten] [Charlotte Clausen, Paul Holm] Volcanic rocks from the southern part of the Tuscan Province, the Tolfa district, range in composition from dacites to rhyolites. They have relatively high contents of many incompatible elements and their 87Sr/86Sr ratios vary between 0.7129 and 0.7148 (28 analyses) with one analysis of 0.7112. The four major eruption centres of the district can be distinguished geochemically. It is shown that the variation of major and trace elements within each area can be explained by fractional crystallization without significant crustal assimilation. The geochemical patterns of the incompatible elements of the investigated volcanics have a close similarity to the alkaline undersaturated volcanics from the nearby Roman Province. The geochemical and isotopic similarity between the Tolfa volcanics and those of the Roman Province suggests a common origin for these components of the magmas. It is suggested that, while the origin of the LIL-element enrichment of the Roman Province magmas is a mantle which was metasomatised by fluids or melts derived from upper crustal material of sedimentary origin recycled into the mantle by subduction, the Tolfa volcanics were derived directly from the subducted material by melting. Springer-Verlag, 1990 Clausen Charlotte Institute for Petrology, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen K, Denmark aut Holm Paul Institute for Petrology, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen K, Denmark aut Contributions to Mineralogy and Petrology Springer-Verlag 105/4(1990-09-01), 403-411 0010-7999 105:4<403 1990 105 410 https://doi.org/10.1007/BF00286828 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00286828 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Clausen Charlotte Institute for Petrology, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen K, Denmark aut NATIONALLICENCE 700 1- Holm Paul Institute for Petrology, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen K, Denmark aut NATIONALLICENCE 773 0- Contributions to Mineralogy and Petrology Springer-Verlag 105/4(1990-09-01), 403-411 0010-7999 105:4<403 1990 105 410 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer