Reference

Krywonos, J. W., G. W. A. Newton, V. J. Robinson and J. A. Riley
1982 Neutron Activation Analysis of Some Roman and Islamic Coarse Wares of Western Cyrenaica and Crete. Journal of Archaeological Science 9(1):63-78.

Abstract

Coarse wares from western Cyrenaica and southern Crete are similar in shape and workmanship and are not distinguished petrologically. It has been possible to identify three distinct groups by neutron activation analysis: (1) Keratokambos (Crete); (ii) Benghazi lime-rich ware; (iii) Benghazi shell-rich ware. The element ratios for (ii) and (iii) are 1·52 ± 0·16 (excluding Na) which suggests a dilution of clay from the same source by shell for example in the shell-rich ware.

The element ratio for Na is only 1·01 and the Na concentration increases linearly with time. This could be Na absorption with time from the brackish water for which the region is renowned.