This study investigated the sources of lead (Pb) in a dusty ice core from the Guliya ice cap in northwest Tibet, spanning from approximately 36,000 years Before Present (Stone Age) to 2015. A change in the lead isotope signature to below Stone Age levels started in 1949, indicating the first emergence of anthropogenic lead. Using a Bayesian mixing model, Chinese gasoline was identified as the primary anthropogenic source until 2007, after which emissions from coal and lead-zinc ores increased.

M. Roxana Sierra-Hernández, Franco Marcantonio, Elizabeth M. Griffith, Lonnie G. Thompson