Volcanic ash layers are important markers for the chronostratigraphy of paleoclimate and paleoenvironmental archives at the southern tip of South America. However, this requires that tephras are well-dated. We report geochemical data from the MA1 stalagmite formed in a non-karst cave near Mt. Burney volcano in southernmost Patagonia (~53°S). High-resolution LA-ICP-MS analyses, SEM imagery, and NanoSIMS enable to identify volcanogenic signals during the last 4.5 kyrs BP from sub-annual trace element variations and tephra particles in distinct laminae. The new 230Th/U-chronology of MA1 provides precise dating of tephra from Mt. Burney (MB) and Aguilera (A) at 4216 +93/−193 yrs BP (MB2), 2291 ± 33 yrs BP (MB3), 853 +41/−60 yrs BP (MB4) and 2978 +91/−104 yrs BP (A1). This unique high-resolution record of MA1 holds potential to date further eruptions from Southern Andean volcanoes for the tephrochronology in this critical region, and potentially also large-volume explosive volcanism off South America.