ToF-SIMS applied to historical archaeology in the Alps

The actual route Hannibal followed during the invasion of Italia in the Second Punic War is one of the major questions of antiquity, one that historians/archaeologists have long studied. There are six possible passes Hannibal could have used and one of the many bits of evidence in the ancient literature that might help answer this question is the location of fired rock, the result of a conflagration Hannibal is reputed to have employed to reduce the size of boulders in a two-tier blocking rockslide on the lee side (e.g. Italian) some distance down from the high col. The only route with fired rock along the roadway leading to the Po River Valley or the Dora Riparia is below the Col du Clapier, one of the possible northern routes. ToF-SIMS investigation of the 100-mm thick burned crust in hornblende schist interlaced with veins of quartz-feldspathic minerals yields various elements C, Mg, Na, Ca, Si, Ti, P, Al, Fe and their associated fragments. Hydrocarbon fragments are thought to be products of combustion whereas Ca and Na along with Mg–Fe silicates are derived from the country rock. Aeolian components along with clay minerals settled onto rock surfaces following firing. While the SIMS data clearly would not provide an age for the burnt rock, compositional evidence of the conflagration may relate to Hannibal’s actual route.