Mount Ruapehu is the tallest mountain on the Northern island of New Zealand. The massive stratovolcano is an excellent example of how scientists put historic glacial periods and volcanism together. Ice-marginal lava flows are a keystone in Ruapehu's history and are well displayed in the Wahainoa Lava Formation (Figure 4). The characteristic columnar jointing and massively thick lava barriers are evidence of major ice-marginal lava flows. Scientists have determined through geochronology that the volcano erupted about 15-51 thousand years ago and the lava flow came into contact with the surrounding valley floor glaciers and built up the enormous lava formations we see today. Using the eruption age and the ice-marginal lava flow data, scientists can gather when glaciers dominated Ruapehu, how high an elevation the glaciers reached, which was about 1300m above sea level, and can use glaciovolcanism as a proxy reconstruct the paleoclimate of about 41-51 thousand and 15-27 thousand years ago.