Problems associated with the use of coal as a source of (super 14) C-free background material.

Abstract

Many (super 14) C dating laboratories have established that coal samples exhibit a finite (super 14) C age, apparently caused by contamination of the specimens before any laboratory preparation is undertaken. In this work, the possibility that the contamination is due to microbial and fungal activity in the coal substrate is considered and some suggestions are made for alternative sources of background test materials for (super 14) C dating laboratories. Initial results indicate that geologically formed graphites contain little (super 14) C and are likely to be good background test materials, especially in (super 14) C AMS laboratories.