A Scottish speleothem record of the H-3 eruption or human impact? A comment on Baker, Smart, Barnes, Edwards and Farrant

Studies of a stalagmite sample from Sutherland, Scotland, have identified a period of enhanced growth that lasted for four years and has been dated to 1135 +/- 130 BC (Baker el al., 1995). This episode is unique within this sample and has not been observed elsewhere. The authors correlate it with the Icelandic volcanic eruption at 1021 + 130/-100 BC that produced the Hekla-3 (H-3) tephra. There is, however, no direct evidence for a causal relationship between volcanic activity in general, or the H-3 eruption in particular, and the growth patterns of the stalagmite. As an alternative to the volcanic explanation of enhanced growth, we suggest that the speleothem could reflect environmental changes associated with woodland decline and the spread of blanket peat.