Volcanic systems in Iceland. The interaction of the Mid-Atlantic Ridge with a mantle hotspot produces a geochemical zonation of magma types. The Tholeiitic Series is located in the rift zone, and is characterized by relatively high Fe and Ti concentrations, and low Al and Ca (e.g., Bárdarbunga-Veiðivötn and Grímsvötn). The Transitional Alkalic Series is located on the flanks of the rift zone, and is characterized by relatively high Fe, Ti and alkali metal concentrations for a given SiO2 concentration, but low Al (e.g., Katla and Hekla). The Alkalic Series is located on the flanks of the rift zone, and is characterized by significantly higher Na and K concentrations as compared to the other two series (e.g., Snæfellsjökull).
Base map modified from Óladóttir, B.A., Sigmarsson, O., Larsen, G., and Devidal, J.L., 2011. Provenance of basaltic tephra from Vatnajökull subglacial volcanoes, Iceland, as determined by major- and trace-element analyses: The Holocene 21(7), 1037-1048.
Photomicrograph images in transmitted light of glass shards from Grímsvötn (left), Bárdarbunga-Veiðivötn (center) and Katla (right) volcanic sources. Date of eruption is based on radiocarbon dating of sphagnum leaf samples from peat cores.
Upper: Tabulated results of EPMA analysis of glass shards. Lower: Geochemical fingerprints of volcanic sources based on major-element compositions. The compositional fields are based on Óladóttir et al. (2011).
Ancient Glass Analysis
Ancient Metallurgy and Metal Production