Digging on the Database
Liz Sagues on how archaeologists are cutting their teeth on the Museum of London Archaeology Service
'All new technology filters down into archaeology', said one practitioner for whom the computer has – Archaeology almost – replaced the trowel. And why not? As an investigative discipline whose purpose often is to establish when, how and where new technologies were introduced, it is only appropriate that archaeology is itself relying on new technology more and more.
The Tony Clark Laboratory, opened by the Museum of London Archaeology Service (MoLAS) earlier this year and a major centre in Britain for archaeo-geophysical services, is a prime example of putting modern science to archaeological use. Its principal area of work, archaeomagnetic dating, is not inherently innovative: what makes the laboratory so valuable is its specific application of that technique in archaeological contexts.
Priorities for the five staff who work with MoLAS project manager Bill McCann include developing more efficient, user-friendly software to handle all the data involved, and refining even further the precise calibration curve extending from the present hack to 1200BC.
Archaeomagnetic dating relies on the fact that iron oxides in such fired clay objects as kilns, hearths, pottery, brick, even burnt soil and some stone record the direction of the earth's magnetic field at the time of heating. Link changes of direction of magnetic field to precise dates, as Tony Clark has done, and archaeologists are ever grateful. Clark, who worked initially with the Ancient Monuments Laboratory and then independently, has donated his equipment (and his name) to MoLAS and is consultant to the laboratory.
Archaeomagnetic dating is more accurate than radiocarbon, says McCann, instancing how it has pushed back by twenty years – a small but significant change – the dating of one type of pottery common in medieval London.