DETECTING FORGERIES AMONG ANCIENT GOLD OBJECTS USING THE U,Th–4He DATING METHOD*

Forgeries of ancient gold objects are prevalent in almost every collection and some public exhibitions in the past have been exposed as containing forgeries to an embarrassing extent. This situation comes from the fact that it is sometimes impossible to unequivocally recognize forgeries based on their patina or manufacturing and decoration characteristics. We demonstrate that for 13 ancient gold objects the time of their last melting process can be estimated using the U,Th–⁴He dating technique. The extremely small quantities of radiogenic ⁴He found, due to the young age and small sample size, require the use of a specially designed ultrasensitive mass spectrometer. We show that the proposed method is a powerful, and the only, quantitative tool in archaeometry for discriminating between fake and genuine ancient gold objects.     

Non-destructive chemical characterization of ceramic sherds from Shipwreck 31CR314 and Brunswick Town, North Carolina

The purpose of this study was to chemically and texturally characterize ceramic oil jar sherds from North Carolina Shipwreck 31CR314 and to explore the utility of environmental scanning electron microscopy/X-ray energy dispersive spectrometry (SEM/EDS) for that purpose. The oil jar sherds, widely dispersed about Shipwreck 31CR314, are morphologically similar to each other, which suggests they could be from a single jar, but with so few joins this could not be concluded with certainty. Therefore, an aim of this study was to investigate whether chemical or textural characterization of the sherds might reveal unique attributes that could distinguish individual jars; results of characterization perhaps could give information on their origin and possibly site formation processes, such as whether environmental forces could have scattered sherds of a single jar during and after sinking of the ship. Previous studies have indicated this shipwreck is likely the remnants of the Queen Anne's Revenge, flagship of the pirate Blackbeard. Sherds from this shipwreck were compared with similar oil jar sherds excavated from a land site, Brunswick Town, North Carolina, to explore the use of composition and texture as hallmarks. The chemical components of the artifacts were determined by SEM/EDS. This method of analysis is valuable for archaeological research because it is rapid and non-destructive to the ceramic artifacts. Both groups of lead-glazed coarse red earthenware sherds were texturally similar except for the glazed sides of all 31CR314 sherds that exhibited small tracks of unique crescent-shaped marks. These marks may be due to manufacturing effects and immersion in seawater, and the marks may serve as hallmarks for individual jars or potentially individual manufacturers. The sherds were generally similar in composition, but the two groups exhibited distinct differences. Brunswick Town sherds consistently contained more phosphate on unglazed sides, an average 1.46 wt.% P₂O₅, and also contained trace elements not detected in the Shipwreck 31CR314 sherds. These distinct differences could be due to different manufacturing origins for Shipwreck 31CR314 and Brunswick Town ceramics but also could reflect their subjection to different environments during use and loss prior to archaeological recovery.     

Visual thinking and neuroscience

After a consideration of visual thinking in science the role of such thinking in neuroscience is discussed. Three instances are examined - cortical column, retina, impulse - and it is argued that visual thinking is employed, though in different ways, in each. It lies at the core of neurobiological thought.     

AN ARCHAEOMAGNETIC STUDY OF POTTERY KILNS FROM BRÜHL-PINGSDORF (GERMANY)*

Four pottery kilns from Brühl-Pingsdorf (Germany) were dated by comparing their characteristic remanent magnetization with a curve of the palaeo-secular variation of the geomagnetic field. Archaeomagnetic results suggest last heating events between AD 775 and 1020. The archaeological evidence generally supports the relative temporal succession and the duration of use, but indicates that the kilns are about 150 years younger on average. Hence, a systematic offset between these independently developed chronologies must be considered. Rock magnetic parameters display radial variations through the kiln walls. These variations are controlled by the maximum temperature the rock was exposed to. These parameters were used to identify specimen which acquired a thermoremanent magnetization.     

Sub‐micron spongiform porosity is the major ultra‐structural alteration occurring in archaeological bone

Total pore volume and pore size distribution are indicators of the degree of post‐mortem modification of bone. Direct measurements of pore size distribution in archaeological bones using mercury intrusion porosimetry (HgIP) and back scattered scanning electron microscopy (BSE‐SEM) reveal a common pattern in the changes seen in degraded bone as compared to modern samples. The estimates of pore size distribution from HgIP and direct measurement from the BSE‐SEM images show remarkable correspondence. The coupling of these two independent approaches has allowed the diagenetic porosity changes in human archaeological bone in the >0.01 µm range to be directly imaged, and their relationship to pre‐existing physiological pores to be explored. The increase in porosity in the archaeological bones is restricted to two discrete pore ranges. The smaller of these two ranges (0.007–0.1 µm) lies in the range of the collagen fibril (0.1 µm diameter) and is presumably formed by the loss of collagen, whereas the larger pore size distribution is evidence of direct microbial alteration of the bone. HgIP has great potential for the characterization of microbial and chemical alteration of bone. Copyright © 2002 John Wiley & Sons, Ltd.     

A technological crossroads: Exploring diversity in the pressure blade technology of Mesolithic Latvia

A long‐standing debate in archaeology concerns the sources of technological diversification among prehistoric hunter‐gatherers. This includes the study of the emergence and spread of pressure blade technology in Northern Europe during the Early Holocene. Until now, there has been little technological study of lithic collections from the East Baltic region, and our knowledge of the development and spread of this technology in the area is inadequate. This article presents for the first time a technological analysis of lithic assemblages from seven Early and Middle Mesolithic sites in the territory of present‐day Latvia, offering new possibilities for discussing pressure blade technology and research objectives connected with it. Furthermore, variation in elements of this technology is explored in relation to raw‐material characteristics through experimental flint knapping. Finally, the factors influencing diversity in craft traditions, as well as large‐scale communication and shifting spheres of interaction within Northern Europe during the Mesolithic, are discussed.     

Book reviews

Franz von Benda‐Bepkmann. Property in social continuity: continuity and change in the maintenance of property relationships through time in Minangkabau, West Sumatra. The Hague: Martinus Nijhoff, 1979. xviii, 455pp. (Verhandelingen van het Koninklijk Instituut voor Taal‐, Land‐ en Volkenkunde, 86.)

Karl J. Pelzer. Planter and peasant: colonial policy and the Agrarian struggle in east Sumatra, 1863–1947. The Hague: Martinus Nijhoff, 1978. xii, 163 pp. (Verhandelingen van het Koninklijk Instituut voor Taal‐, Land‐ en Volkenkunde 84.)

G. W. J. Drewes (ed. and tr.). Hikajat Potjut Muhamat: an Achehnese epic. The Hague: Martinus Nijhoff, 1979. 286 pp. (Bibliotheca Indonesica, 19.)

Willem Meijer. Indonesian forests and land use planning. Report on a fact‐finding tour aimed towards a co‐ordinated development of forest resources in Indonesia. Lexington, Kentucky: Thomas Hunt Morgan School of Biological Sciences, University of Kentucky, 1975. 112 pp. $3.50, inc. postage. (Available from: University of Kentucky Book Store, Lexington, Kentucky 40506, USA).