From microshards to megaliths: geochemical methods to source far-travelled geological materials (Nicholas Pearce - Aberystwyth e Bologna)

Il seminario si terrà in aula U4-03.

From distal deposits of volcanic ash to archaeological artefacts, identification of the source of this well-travelled geological material is important.  

For volcanic ash, characterisation and provenance of the ash is a key component of tephrochronology studies, and is important in stratigraphic studies, where ash layers form important chronostratigraphic markers, deposited synchronously in different geological environments. Dating the ash gives eruption frequency, and thus informs hazard assessments, and in many cases, the ash deposits form more complete distal records of volcanism than the eroded remnants of volcanoes, giving detail of volcanic history. Eruptions from the Toba caldera in Sumatra, and their compositions will be described, and these provide an excellent example of the information that can be obtained by studying the far travelled ash.  

In archaeological studies, provenancing materials often requires to minimally-invasive or non-destructive analyses (sampling is often not permitted) and Stonehenge provides no better example of this. Application of microanalytical and non-destructive analytical approaches will be described which have been used to determine the origins of some of the Stonehenge orthostats, the so called “bluestones”, which originate in south Wales, some 250 km from where they now stand.