Taking as a starting point the first official Australian colonial currency: Lachlan Macquarie’s holey dollar of 1812, this line of investigation biomaps at a molecular level the silver in these coins, through a linked series of anthropogenic landscapes, from Spanish colonial silver mines, a remote glacier in Peru and a scientific research centre in Copenhagen.
The silver in the coins was mined from Spanish colonial mines in Peru and Mexico. The majority probably came from the largest silver mine in the world, Potosí (Bolivia). As the silver was extracted (it was found as silver- lead- zinc crystal, called galena) lead dust was released.
Lead from mining silver at Potosi has been detected, wind-born, in ice core samples from the Quelccaya ice cap, the largest tropical ice-mass in the world. Lead dust, falling with snow, was compressed across the years and centuries. Ice cores extracted from the glacial ice, compressed frozen water and atmospheric impurities, are a vertical time capsule and map of human activities, able to trace through mineral contamination in layers of ice, the activities of the Spanish colonial empire.