Figure 2: Ice core records of Cu, Pb, Sb, and Ce concentrations together with EFs, and lake levels of the Lake Titicaca for the period 4500 BC–2000 AD.
From: Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago
From: Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago