Abstract

The Southern Volcanic Zone of the Andes (similar to 33-46 degrees S) is a very active volcanic zone with several volcanic centers recording recurrent historical activity (e.g. Llaima, Villarrica, Puyehue-Cordon Caulle, Osorno, Calbuco and Hudson). Tephrochronology is a valuable tool to help better understand the eruptive history of volcanic centers, essential for producing volcanic hazard maps. Additionally, tephrochronology can also be very useful to synchronize stratigraphic records of different nature such as paleoclimatological, paleoceanographical and archaeological records on land, lakes, ice and the ocean. Here we present a (crypto) tephrochronological record from two marine sediment cores retrieved in the Chilean continental margin at similar to 41 degrees S and similar to 41.6 degrees S. The records display continuous sedimentation since the late glacial, as robustly constrained by planktonic foraminifera delta O-18 and C-14 dates. During this period, twenty three cryptotephras were identified as glass shard peaks together with two similar to 25-30 cmethick visible tephras (one in each core). The source of the (crypto) tephras was mainly constrained by major and trace element geochemistry of individual glass shards together with their stratigraphic position, since it is not possible to observe physical characteristics, such as color and grain size, when analyzing cryptotephras. From these, one cryptotephra was robustly correlated with the HW7 eruption from the Hudson volcano occurring in the Late Holocene at similar to 1.5 cal ka BP; and the two visible tephra layers were identified as distant correlatives of the Lepue tephra originating from Michinmahuida volcano and occurring in the Deglaciation/Holocene transition at around 11 cal ka BP. Additionally, eight cryptotephra occurring at similar to 3.6, 6.2, 7.0, 8.5, 9.6, 14.2, 15.9 and 18.2 cal ka BP were robustly identified as sourced from Michinmahuida volcano but where otherwise not correlated, providing novel evidence of pre Holocene activity of this volcanic center. (C) 2021 Elsevier Ltd. All rights reserved.