Figure 5.

Lead concentration in CG ice core, from ultra‐high‐resolution LA‐ICP‐MS, 1330–1360 C.E. (with an average of 279 measurements per year in 1349–1353). The grey histogram represents declining number of active major mining regions as they were progressively hit by the plague and ceased operations; the red histogram represents the number of mining regions resuming metal production, based on written sources. At present, there are no estimates of volume of aggregate metal production, and thus, the histograms reflect only regions that were active, not volume of Pb produced. The values below 1ng/L here are calculated using semiquantitative calibration data. Smoothing (black line) is provided only as a visual aid, while the red plot presents the raw data. As shown in the methods section in the supporting information, the LA‐ICP‐MS technique [Sneed et al., 2015] measures total element concentration; the spikes can thus be related to individual particles and/or storm event concentrations.