By: Jeremiah Green

5-5-00

This project is an investigation of a rock sample collected from the summit of Mt. Vesuvius in Italy. The volcanic rocks found at Vesuvius are unique due to their high potassium content and relatively low silica content when compared to other basalts. The unique chemistry of the rocks found at Vesuvius allows for some unique minerals like leucite and nepheline, this makes them particularly interesting to study. The rock sample was viewed under the petrographic microscope and analyzed under the scanning electron microscope for x-ray analysis. The sample will be analyzed and quantified by using the weight percent by oxide determined from the x-ray spectra and analysis.

There were two goals of the study, the first was to analyze the phenocrysts in the sample to determine what minerals were present as phenocrysts in the sample. The second goal of the experiment was to analyze the whole rock chemistry and compare it to other data of similar rocks in order to name and characterize the rock type. The analyses done on the rock sample were compared to previously published, accepted values of minerals and rock types in order to assign them names. The results of the study showed that the dominant phenocrysts in the sample were pseudoleucite (not actually leucite) and augite. The whole rock chemistry and the observed textures in thin section proved that the sample was in fact a leucitite. Above is an x-ray spectra showing the elements present in this sample and their relative abundance. This spectra is characteristic of the whole rock chemistry of the sample.