The age of the last eruption is controversial. In 1994, radiocarbon dating yielded an age of 10,700 ± 800 years Before Present from a pyroclastic flow. Later, paleosoils and other samples from the same flow were used to deduce similar ages of over 36,770, 42,650, over 35,670 and over 35,520 years before present, respectively. Thus this youngest age estimate was discarded. In 2010, further research identified two younger eruptions, one occurring 39,000 years Before Present and the other 27,500 years Before Present. Other data obtained by uranium-thorium dating indicate an age of 32,600 ± 1,000 years ago for the youngest eruption. Both of these eruptions took place at St. Ana and imply a repose period between eruptions of over 10,000 years. Much older dates obtained by potassium-argon dating are not considered reliable. Alternatively, the latest eruption may have occurred at a satellite vent seeing as sedimentation of the St. Ana lake has been ongoing since 26,000 years ago. These two recent eruptions were fed by different magmas, with the younger eruption coming from deeper magma chambers ( versus ) and involving more primitive magma. The youngest eruption was probably very violent; the Roxolany Tephra which may be associated with it has been found as far as Odessa, Ukraine, away from Ciomadul. If the Roxolany Tephra was formed by the youngest eruption of Ciomadul, the youngest eruption would have occurred 29,600 calibrated radiocarbon years ago based on independent dates of the tephra.