  Hammer et al. [1997] report the presence of regularly spaced acidity peaks
(H+, F-, Cl-) in the Byrd Station, Antarctica ice core. The event has a
duration of about one century and falls at the beginning of the deglacial
warming. Volcanism appears to be an unlikely cause since the total acid
deposition of this event was about 18 fold greater than the largest known
volcanic eruption, and since volcanic eruptions are not known to recur with
such regularity. We show that the recurrence period of these peaks averages to
11.5 +/- 2.4 years, which approximates the solar cycle period, and suggest that
this feature may have an extraterrestrial origin. We propose that this material
may mark a period of enhanced interstellar dust and gas influx modulated by the
solar cycle. The presence of this material could have made the Sun more active
and have been responsible for initiating the warming that ended the last ice
age.
