The Environmental Stability of Ancient Ceramics

Abstract

A series of corrosion experiments was carried out using identical samples of a ceramic of known composition, structure and density which were subjected to a variety of simulated soil solutions. The action of the solutions was monitored by measuring their pH as a function of time at 25 °C and 90 °C. Under all conditions the pH stabilized rapidly. Microscopic and electron microscopic studies showed the presence of reaction/alteration products that would account for the observed pH changes. The findings indicate that ancient ceramics that exhibit no physical deterioration will have below their surface a composition corresponding to the composition of the sherd at the time of its burial.

Phosphates in Archaeological Finds: Implications for Environmental Conditions of Burial*

“…Freestone et al (1985), Walter and Besnus (1989) and Freestone (2001) argued that phosphates can precipitate in potsherds from aqueous solutions, forming sub-microscopic crystals and thin films, or adsorb at the surface of primary mineral phases, leading to high bulk phosphorus, a parameter that is commonly assumed to be a marker for contamination. The experimental work of Vitali et al (1984), Franklin and Vitali (1985) and Collomb and Maggetti (1996) supports this mechanism for phosphorus enrichment in potsherds. In soils, phosphate precipitation is related to environmental conditions, particularly to pH and Eh (Nriagu and Dell 1974;Lindsay and Vlek 1977), which are controlled by a complex interaction of changes in the water table, movement of water in the ground (Medrano and Piper 1997;Ann et al 2000;Pierri et al 2000;Scaccia et al 2002), the presence of organic matter and bacterial activity (Fredrickson et al 1998;Brown et al .…”

The Effect of Purification and Firing of Clays on Trace Element Provenance Studies

“…1974, Widemann 1979, Olin and Sayre 1979 and the alterations during burial (Bieber et al 1976, Prag et ul. 1974, Franklin and Vitali 1985. Results on clays before and after purification or firing have been reported by Attas et al (1977), Birgul et al (1979, Fillieres e/ al.…”

Retention of Phosphate in Buried Ceramics: An Electron Microbeam Approach

“…Thus while all the sherds show a certain amount of evidence of wear and perhaps weathering this is not extreme and may be regarded as typical of much excavated pottery. The sherds are considered t o show 'physical integrity' in the sense of Franklin and Vitali (1985).…”