Geochemical characterization of Quaternary tephras from the Campanian Province, Italy

The Campanian province has a rich history of human interaction with volcanic eruptions. In a region currently inhabited by 3 million people, it is crucial to have precise and accurate geochemical characterization of volcanic units within the region so as to identify the spatial distribution of past events. Furthermore, tephrochronology is becoming an important tool in the region for correlating past environmental records. Unfortunately, many of the key units have been geochemically analysed using relatively imprecise methods, making correlation problematic. Although robust correlations have been established in the Campanian province using a range of methods, including stratigraphy and geochronology, more distal correlation requires precise geochemical characterisation of individual glass shards. Here we report major oxide data, geochemically characterising 17 key tephra units within the Campanian province using wavelength dispersive spectrometry (WDS). The new data confirm the trachytic nature of most of the eruptions. To effect more precise correlations between units (especially in distal locations), proximal units must be individually analysed for major oxides using WDS on the vitreous phase, and statistically analysed for robust correlations. In cases where similar geochemistry exists, analysis of trace and rare earth elements may be necessary.