ELECTRON-SPIN-RESONANCE THERMOMETRY APPLIED TO QUARTZITE COBBLES FROMVERGELEGEN SLAVE LODGE, SOMERSET WEST, SOUTH-AFRICA

This paper describes the use of electron spin resonance spectroscopy t o estimate the degree of heating of quartzite cobbles from hearths on the floor of the archaelogical remains of an eighteenth-century Dutch colonial slave lodge. A novel technique based on the comparison of lin e intensities for the E' and O2- centres in quartz distinguished succe ssfully between cobbles which had been heated to estimated temperature s ranging from 300-degrees-C to 450-degrees-C and controls from an adj acent stream bed. This inexpensive and simple technique could be appli ed to a wide range of archaeological problems involving the thermal hi story of objects consisting of or containing quartz.