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Recent basaltic andesite lavas from Merapi volcano contain abundant, complexly zoned, plagioclase phenocrysts, analysed here for their petrographic textures, major element composition and Sr isotope composition. Anorthite (An) content in individual crystals can vary by as much as 55 mol% (An 40^95 ) across internal resorption surfaces with a negative correlation between high An mol% (470), MgO wt% and FeO wt%. In situ Sr isotope analyses of zoned plagioclase phenocrysts show that the 87 Sr/ 86 Sr ratios of individual zones range from 0Á70568 to 0Á70627.The upper end of this range is notably more radiogenic than the host basaltic andesite whole-rocks (50Á70574). Crystal zones with the highest An content have the highest 87 Sr/ 86 Sr values, requiring a source or melt with elevated radiogenic Sr, rich in Ca and with lower Mg and Fe. Recent Merapi eruptive rocks contain abundant xenoliths, including metamorphosed volcanoclastic sediment and carbonate country rock (calc-silicate skarns) analysed here for petrographic textures, mineralogy, major element composition and Sr isotope composition. The xenoliths contain extremely calcic plagioclase (up to An 100 ) and have whole-rock 87 Sr/ 86 Sr ratios of 0Á70584 to 0Á70786.The presence of these xenoliths and their mineralogy and geochemistry, coupled with the 87 Sr/ 86 Sr ratios observed in different zones of individual phenocrysts, indicate that magma^crust interaction at Merapi is potentially more significant than previously thought, as numerous crystal cores in the phenocrysts appear to be inherited from a metamorphosed sedimentary crustal source. This has potentially significant consequences for geochemical mass-balance calculations, volatile saturation and flux and eruptive behaviour at Merapi and similar island arc volcanic systems elsewhere.

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The most recent, mainly explosive eruptions of Ciomadul, the youngest volcano in the Carpatho-Pannonian Region, have been constrained by detailed field volcanological studies, major element pumice glass geochemistry, luminescence and radiocarbon dating, and a critical evaluation of available geochronological data. These investigations were complemented by the first tephrostratigraphic studies of the lacustrine infill of Ciomadul's twin craters (St. Ana and Mohoş) that received tephra deposition during the last eruptions of the volcano. Our analysis shows that significant explosive activity, collectively called EPPA (Early Phreatomagmatic and Plinian Activity), started at Ciomadul in or around the present- and organic matter from lacustrine sediments recovered from both craters, the last of these phreatomagmatic eruptions-that draped the landscape toward the east and southeast of the volcano-occurred at ~29.6 ka BP, some 2,000 years later than the previously suggested last eruption of Ciomadul.