Evidence of the impacts of mining and forestry in central west Tasmania has been derived from a high-resolution record spanning the last 190 years. The record (which includes data from pollen, trace metals and 210Pb analyses) was obtained from the top 7.5 cm of a 68 cm core extracted from Lake Dora, a sub-alpine tarn in the West Coast Range in central west Tasmania. Lake Dora lies in close proximity (15 to 30 km) and downwind of three major mining centres - Queenstown, Rosebery and Zeehan.
The Lake Dora core was extracted using a modified hammer driven piston corer (Neale and Walker, 1996), which enabled samples to be collected at 0.25 cm intervals. Lead-210 analyses of these samples have provided a high-resolution sedimentation and dating profile, with each sample representing between two and 16 years of history. Anomalies identified in the 210Pb profile suggest periods of increased sediment deposition, which may correlate to local prospecting. A basal age of around 1810 AD was estimated.
Trace metals analyses of the samples indicated substantial elevations in several metals, commencing ca. 1900 and increasing sharply in the 1950s and 60s. These concentrations subsequently decreased in the 1970s and early 1980s. Comparisons of these changes with the historical records of mining and associated activities have demonstrated some correlation.
The pollen record derived from the Lake Dora core also exhibits substantial temporal changes, both in terms of species composition and pollen abundance. These changes can be related to trends in the trace metal and 210Pb profiles as well as regional mining and forestry activities.
This study forms part of a larger ANSTO project researching human activity and climate variability in Australia.