Chemistry of the subglacial eruption in Vatnajökull, Iceland

7th October 1995

One tephra sample has been analysed by microprobe. This sample is probably from the initial phase of the eruption. There is some variation from grain to grain in this sample, therefore the chemical variation in all the eruption products is probably larger. This sample classifies as basaltic andesite and contains microphenocrysts of plagioclase, pyroxene and olivine. The eruption is located between two major central volcanoes: Grimsvötn and Bardarbunga. The composition of the analysed sample is not typical for Grimsvötn eruptions, but is possibly related to the Bardarbunga volcano. In the figure below, the analyses of the sample are shown with purple diamonds.

Ti and Fe vs Mg plot Ti and Fe vs. Mg, an image

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