Is laboratory preparation worth it? Use of pXRF for field mapping Magna Roman Fort, Northumberland, UK.

A comprehensive field scanning exercise utilising pXRF was undertaken at the Roman Fort of Magna. Magna ‘the fort on the rock’ Roman fort and settlement remains one of the most intriguing Roman military landscapes along Hadrian’s Wall, UK. Magna has a complex and multi-period history, no other single site along the Roman frontier has the combination of so many key elements of Roman occupation concentrated into such a small area, around 42 acres. These include Hadrian’s Wall, milecastle 46, the Vallum, a series of forts and their towns (both pre-Hadrianic and Hadrianic, and post-Roman), cemeteries, industry, temples, and three major Roman highways. Firstly, a series of five bore holes across the Magna site were undertaken in 2021 and analysed using pXRF. Secondary, horizontal mapping of soil field samples were undertaken pre-excavation and during excavation of milecastle 46 during the 2023 field season. Furthermore, direct in-situ analysis using pXRF will be compared to the laboratory<br/>prepared samples, highlighting the importance of samples preparation, showing the critical need for standardising protocols for the use of pXRF in the field.