Pedro Doll

and 9 more

Dating young lava flows is essential for understanding volcano’s eruption frequency, yet challenging due to methodological limitations of commonly used dating techniques. Ruapehu (Aotearoa New Zealand) has produced many lava flows during the Holocene, but constraints on the timing of these eruptions are scarce. Here, we combine paleomagnetic dating and relative stratigraphy to deliver new eruption ages of 18 lava flows with low-to-high error window ranges between 500 and 2700 years (at the 95% confidence level). Our data indicate that the large lava flow field located on the Whakapapa area (northwest Ruapehu) was emplaced during at least three distinct eruptive episodes between 10.6 and 7.4 ka. Two of these episodes closely followed a large collapse event that affected Ruapehu’s northern edifice, and generated large volumes of lava between 10.6 and 8.8 ka, with the third episode producing less voluminous lava flows between 8.1 and 7.4 ka. Following a smaller collapse of the southeastern sector of the edifice at ca. 5.3 ka, several low-volume lava flows were emplaced during at least two distinct eruptive episodes prior to ca. 1.0 ka, which supplied the Whangaehu valley (east Ruapehu) with lava. The youngest age inferred from our data represents the youngest eruption age provided for a lava flow outside Ruapehu’s summit region. This research provides greater detail to the Holocene effusive chronology at Ruapehu, shedding light on partial cone reconstructions after edifice collapses during the early and late Holocene, and the time relationships between trends observed in its effusive and explosive activity.