| Abstract: | Microthermometric investigations of silicate-melt inclusions and electron microprobe analyses were conducted on experimentally homogenized silicate-melt inclusions and on the host clinopyroxenes from 4 scoria samples of different layers from the Mt. Somma-Vesuvius medieval eruption (Formazione di Terzigno, 893 A.D.). The temperature of homogenization, considered the minimum trapping temperature, ranges from 1190 to 1260??5 ??C for all clinopyroxene-hosted silicate melt inclusions. The major and minor-element compositional trends shown by Terzigno scoria and matrix glass chemical analysis are largely compatible with fractional crystallization of clinopyroxene and Fe-Ti oxides. Sulfur contents of the homogenized silicate-melt inclusions in clinopyroxene phenocrysts compared with that in the host scoria show that S has been significantly degassed in the erupted products; whereas, Cl has about the same abundance in the inclusions and in host scoria. Fluorine is low (infrequently up to 800 ppm) in the silicate-melt inclusions compared to 2400 ppm in the bulk scoria. Electron microprobe analyses of silicate-melt inclusions show that they have primitive magma compositions (Mg# = 75-91). The composition of the host clinopyroxene phenocrysts varies from typical plinian-related (Mg#???85) to non-plinian related (Mg#???85). The mixed source of the host clinopyroxenes and primitive nature of the silicate-melt inclusions implies that these phenocrysts, in part, may be residual and/or have a polygenetic origin. The similar variation trends of major and minor-elements between homogenized silicate-melt inclusions from the Terzigno scoria, and silicate-melt inclusions in olivine and diopside phenocrysts from plinian eruptions (Marianelli et al., 1995) suggest that the trapped inclusions represent melts similar to those that supplied the plinian and sub-plinian magma chambers. These geochemical characteristics suggest that the Vesuvius magmatic system retained a vestige of the most recent plinian event. |
| Genre: | Article |
| ProdID: | 70021619 |
| Citation Author: | Lima, A.; Belkin, H. E.; Torok, K. |
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| Citation End Page: | 206 |
| Citation Issue: | 3-4 |
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| Citation Language: | English |
| Citation Larger Work Title: | Mineralogy and Petrology |
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| Citation Number Of Pages: | 22 |
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| Citation Search Results Text: | Understanding Vesuvius magmatic processes: Evidence from primitive silicate-melt inclusions in medieval scoria clinopyroxenes (Terzigno formation); 1999; Article; Journal; Mineralogy and Petrology; Lima, A.; Belkin, H. E.; Torok, K. |
| Citation Start Page: | 185 |
| Citation Volume: | 65 |
| Citation Year: | 1999 |
| Type: | citation/reference |
| Text: | Understanding Vesuvius magmatic processes: Evidence from primitive silicate-melt inclusions in medieval scoria clinopyroxenes (Terzigno formation); 1999; Article; Journal; Mineralogy and Petrology; Lima, A.; Belkin, H. E.; Torok, K. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Fri, 1 Jan 1999 00:00 -0600 |
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