1808 mystery eruption

The second largest sulfur-rich eruption of the last two centuries, after Tambora in 1815, and nobody knows which volcano it was. Ice cores in Greenland and Antarctica both carry the sulfate, and the sulfur's isotopes say it reached the stratosphere, which points to one big tropical eruption (Cole-Dai 2009). Ice-core layer counting dates it to about February 1809, give or take four months. Eyewitnesses in Bogota and Lima date the haze to within a week of 4 December 1808 (Guevara-Murua 2014). It released roughly 12 to 19 million tonnes of sulfur (Timmreck 2021) and helped make 1810 to 1819 the coldest decade in centuries.

The complication: the glass in the ice layer comes in two kinds. Antarctic cores have andesitic glass; a Yukon core has dacitic glass (Yalcin 2006). So there may have been two eruptions close together, or one eruption plus a smaller one. Searched records so far point nowhere: Spanish colonial archives are silent, so it was probably not in Latin America.