17:15 〜 18:45
[SVC25-P08] Are magmatic systems at ice-covered arc volcanoes affected by deglaciation?
キーワード：stratovolcanoes, magmagenesis, Pleistocene, glacier
The links between volcanic activity and climate have had a significant bearing on the evolution of Earth and humankind. As we enter a period of projected global warming and glacial retreat, it is important to understand whether deglaciation and depressurization of volcanoes will lead to anomalous rates of eruption, styles of activity, and compositions of magma along continental arcs. Well-characterized case studies of volcano evolution throughout periods of deglaciation are required in order to test if such trends can be utilized to improve volcano forecasting and hazard mitigation.
We present results from an investigation of Ruapehu volcano, New Zealand, which hosted a summit ice cap and flank glaciers during the Last Glacial Maximum (~20 ka). This stratovolcano is an ideal candidate for this work, due to its well-defined eruptive history and glacier reconstructions that are based on 40Ar/39Ar, 14C, and 3He geochronology datasets. We collected and analysed lava and tephra samples from dated units that were emplaced since 50 ka to define magma generation and eruption processes during syn-glacial (~50–15 ka) and post-glacial (~15–0 ka) time periods. Petrological observations, major and trace element contents, and Sr-Nd-Pb isotopic data were used to define magma composition trends over time. We have compared these trends to those published for other stratovolcanoes of the circum-Pacific continental arcs to assess the sensitivity of magma systems to the retreat of ice bodies of different thicknesses.
We present results from an investigation of Ruapehu volcano, New Zealand, which hosted a summit ice cap and flank glaciers during the Last Glacial Maximum (~20 ka). This stratovolcano is an ideal candidate for this work, due to its well-defined eruptive history and glacier reconstructions that are based on 40Ar/39Ar, 14C, and 3He geochronology datasets. We collected and analysed lava and tephra samples from dated units that were emplaced since 50 ka to define magma generation and eruption processes during syn-glacial (~50–15 ka) and post-glacial (~15–0 ka) time periods. Petrological observations, major and trace element contents, and Sr-Nd-Pb isotopic data were used to define magma composition trends over time. We have compared these trends to those published for other stratovolcanoes of the circum-Pacific continental arcs to assess the sensitivity of magma systems to the retreat of ice bodies of different thicknesses.