Age and origin of tephras recorded in postglacial lake sediments to the west of the southern Andes, 44°S to 47°S

Tephra deposits preserved in lake sediments to the west of the Andes, between 44°and 47°S in southern Chile, provide a record of local postglacial eruption history. A series of 32 tephra layers in the sediments of eight small lakes in the study area have been investigated by mineral magnetic analysis, electron microprobe analysis and radiocarbon age determinations. Comparisons with geochemical data from other volcanic sources in southern Chile indicate that Hudson volcano is the most likely source vent for at least seven of the tephra layers found in Chonos-Taitao lake sediments. The seven tephra eruptions that have been identified from widespread and identical tephra deposits, date to 14 560, 13 890, 11 060, 7540, 3840, 2740, and 1560 calendar years ago. The frequency of Hudson volcano eruptions in which tephra is dispersed in both a westerly and easterly direction, similar to that recorded in 1991 from Hudson volcano, may be around 1 per 3800 calendar years during the postglacial period.