Dating of lava flows of the Avacha volcano, Kamchatka, from paleomagnetic data

Abstract

The paleodirection and paleointensity of the geomagnetic field are determined in seven andesibasalt–basalt samples from three lava flows (L1–L3) of the Avacha volcano. The reliability of the Thellier–Coe method for geomagnetic field paleointensity determination is demonstrated on the sample from the modern lava flow TTI-50 (the Tolbachik Fissure Eruption): the difference between the calculated Han and IGRF12 values is within 3% with a quality factor q 13. The age of lava flows L1–L3 is refined using paleomagnetic data. Flows L1, L2 of the Young Cone were formed in 1827 and 300–600 years ago, respectively, and the age of flow L3 on the crest of the somma is determined at 30–32 ka, which agrees with the known age estimate (14C dating) of the avalanche associated with the catastrophic destruction of the Avacha volcano 29 900 ± 900 years ago.