MECHANICAL PERFORMANCE OF QUARTZ-TEMPERED CERAMICS: PART I,STRENGTH AND TOUGHNESS*

The effect of quartz temper on the physical and mechanical properties of clay ceramics and the elucidation of the underlying mechanisms that are responsible for these effects are presented here. Characteristics studied included bulk density, open and closed porosity, density of impervious portion and fracture morphology. Mechanical behaviour was studied by measuring energy dissipation during fracture, Young's modulus, initial fracture toughness and strength in flexure. The significant increase in toughness with quartz volume fraction is explained by the development of a model that accounts for the crack distribution around the grains. The archaeological implications of the work are discussed on the basis of all the parameters that might affect the potter's choices of raw materials.     

NEW EVIDENCE FOR THE NATURE OF THE ATTIC BLACK GLOSS

New evidence is reported here using transmission electron microscopy, scanning electron microscopy, and laser reflectance for the nature of the black glossy decoration layer present on the Attic black or red figure vases of the sixth to fourth century BC. The black layer, of total thickness about 20 μm, consists mainly of poly crystalline magnetite (Fe₃O₄) particles of dimensions from 0.2 μm down to extremely fine sizes embodied in an amorphous vitreous matrix. On the outer surface of the black paint we discovered for the first time a thin clear glassy film of approximate thickness 0.1 μm which is rich in Al and Fe and poor in Si. This film must be responsible for the characteristic sheen of the surface. This is verified with the reflection of laser light mostly in specular direction, a unique property compared with black paints of other areas and other periods.     

Palaeogeography of an 'Ubaid archaeological site, Saudi Arabia

Palaeogeographic analysis and radiocarbon dating indicate that sometime in the second half of the fifth millennium BC a sea-level rise occurred along the coast of the western side of the Arabian (Persian) Gulf. Cultural remains of the'Ubaid archaeological period are intimately associated with the event and the palaeogeographic environment that accompanied it. The sea-level rise appears to have had a catastrophic effect on habitation sites.     

A GROUND RADAR SURVEY OF MEDIEVAL KILN SITES IN SUZU CITY,WESTERN JAPAN*

A ground-penetrating radar study of medieval kiln sites located near Suzu city, on the Noto peninsula, was conducted prior to excavation. Archaeological site plans estimated from time slices of the closely-spaced parallel radar profiles are compared with excavations and a proton magnetometer survey. The results indicate that non-destructive remote sensing with radar can help to determine effectively the presence and general structural features of intact kiln floors.     

Revisiting the lead isotopic compositions of the Shang bronzes at Hanzhong and the new hypothesis of Qinling as the source of highly radiogenic lead

The provenance of the highly radiogenic lead (HRL) contained in Chinese Shang bronzes has attracted great scholarly attention in recent years. A new study of the Hanzhong Shang bronzes has put forward a hypothesis that the HRL metal may come from the adjacent Qinling Mountains. This article reanalyses the lead isotope ratios and alloy compositions of the Hanzhong bronzes. Combining the analytical results, the modern ore data and the slags from Guanzhong area, we propose that there is no direct evidence to identify Qinling as the provenance of HRL metal (especially lead). Whilst over 80% of the Hanzhong bronzes contain HRL, the indigenous artefacts containing both HRL and special alloying elements (As, Sb, Ni) account only for minor portions. This fact cannot verify that HRL originates from Qinling, and even makes it difficult to prove that most of the Hanzhong bronzes use local metal resources. An alternative argument might be that the HRL used in Hanzhong derived from the Shang dynasty. The use of HRL reflects a unified system for allocating metal resources centred on the Shang kingdom, which has great significance for further understanding of the resource circulation patterns among different bronze cultures and locations during the Shang period.