Press release describing article in Latin American Antiquity on the methods and findings of soil chemistry exploration at Chunchucmil, Yucatan. In essence, high phosphorous readings, available in the field, allowed for the suggestion of a marketplace for selling food, surrounding a footpath in the Late Classic city. This is not the first phosphorous-based attempt to identify past activity areas, but it does sound significant.
At Ciudad Vieja, we combined several lines of evidence (remote sensing, excavation, ceramics, glass) to suggest a commercial food vendor, iron works, and possible market area also near a footpath in the early sixteenth-century town of San Salvador. Perhaps in the future this might be tested against chemical evidence.