Careful mineral and structural analyses have revealed the characteristics of volcanic ash in the nine horizons of an 80.2 m ice core from Collins Ice Cap, King George Island, Antarctica.
Under the assumption of steady state, the Dansgaard-Johnsen flow model was employed to date the core. The volcanic eruptive sequence established for the South Shetland Islands region since AD 1650 shows seven volcanic eruptive cycles during the past 340 years covered by the ice core. It seems that during the period 1875-1925 there was frequent volcanic activity, with perhaps many eruptions at Deception Island. The years 1650-1800 appear to have been a quiet period, followed by a more turbulent century. The past century is basically a tranquil era except for two turbulent epochs at the beginning of the century and in the 1950s-70s.
Many of the volcanic eruptions in the ice-core sequence are found in the previously reported records for this region. The few that are not in the records should be further investigated. The absence of any 1967-70 eruption trace in the core suggests that this period may represent a minimum in volcanic activity.