摘要:

This paper describes the use of electron spin resonance spectroscopy to estimate the degree of heating of quartzite cobbles from hearths on the floor of the archaeological remains of an eighteenth‐century Dutch colonial slave lodge. A novel technique based on the comparison of line intensities for the E’and O‐2centres in quartz distinguished successfully between cobbles which had been heated to estimated temperatures ranging from 300 °C to 450° C and controls from an adjacent stream bed. This inexpensive and simple technique could be applied to a wide range of archaeological problems involving the thermal history of objects consisting of or containing

ISSN:0003-813X    

DOI:10.1111/j.1475-4754.1993.tb01019.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

A non‐destructive analytical method using both instrumental neutron activation and proton‐induced gamma ray emission techniques was developed to study the provenance of obsidian artefacts from Turkey, Syria and I

ISSN:0003-813X    

DOI:10.1111/j.1475-4754.1993.tb01020.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

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 perio

ISSN:0003-813X    

DOI:10.1111/j.1475-4754.1993.tb01021.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The Nahal Mishmar hoard, found in a cave in the Judean Desert in 1961, is a key find for the study of Chalcolithic metallurgy in Israel and the Levant. Recent analyses of Chalcolithic metalwork from sites such as Shiqmim in Israel raised doubts about the validity of published analyses from the hoard. Accordingly a programme of re‐analysis was established using atomic absorption spectrometry and electron probe microanalysis. The new analyses confirmed the doubts and showed that the metallurgy of Nahal Mishmar was the same as that at the other sites. The alloys used for the cast products in the hoard were generally ternary arsenic‐antimony copper alloys with up to 20% alloy content; less common were compositions with arsenic and nickel. The unusual metallography of these alloys is described. Some suggestions are offered as to the mode of manufacture of the all

ISSN:0003-813X    

DOI:10.1111/j.1475-4754.1993.tb01022.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

This study gathered and reported compositional and descriptive analyses of over 200 Italian Renaissance portrait medals in the collection of the National Gallery of Art, Washington A statistical model was developed for allocation of these medals into meaningful assemblages, using the surface alloy composition, and an expanded nomenclature was formulated. Copper, zinc, tin and lead were the primary elements found to combine to form a wide range of alloys, Common impurities were discovered to be significantly lower in the sixteenth‐century medals when compared with those in the fifteenth‐century medals. Renaissance medallists had an extensive knowledge of metallurgy and could produce a variety of alloys without the use of modern technol

ISSN:0003-813X    

DOI:10.1111/j.1475-4754.1993.tb01023.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Jet has been widely used in the past for jewellery but was just one of a range of black lithic materials employed. When worked into small objects these materials can be visually indistinguishable, yet discrimination is important because of the restricted occurrence of jet. X‐ray fluorescence (XRF) is a rapid non‐destructive discriminatory technique, but not all samples are clearly classified, and inhomogeneity may pose problems. A reassessment of the use of XRF is reported. Other techniques considered include electron spin resonance, infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, scanning electron microscopy and X‐radiography. These were tested on geological materials to define an effective methodology for archaeological material. The recommended approach is a combination of XRF and X‐radiography, although preliminary Fourier transform infrared results showed promise. The X‐ray techniques were tested on Romano‐British assemblages from Catterick a

ISSN:0003-813X    

DOI:10.1111/j.1475-4754.1993.tb01024.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

A combination of micro‐analytical techniques, including thin layer chromatography (TLC), gas chromatography (GC), and combined gas chromatography/mass spectrometry (GC/MS), was employed to study the lipid composition of an adhesive used to repair an Ecton ware jar, recovered from Roman sediments of the River Nene at West Cotton (Rounds, Northamptonshire, U.K.). GC of the total lipid extract of the adhesive showed a complex pattern which was difficult to interpret. TLC was used to fractionate the extract. The fractions were then trimethylsilylated and submitted to GC and GC/MS. Betulin, lupeol, lupenone, allobetul‐2‐ene, and several other pentacyclic triterpenoid compounds were shown to be present in the ancient material. The similarities between the lipid compositions of the adhesive and of contemporary birch bark tar and a birch bark total lipid extract led to the conclusion that the adhesive was derived largely from birch bark, thus providing the first firm evidence for the use of birch bark tar in ancient Br

ISSN:0003-813X    

DOI:10.1111/j.1475-4754.1993.tb01025.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

There has been debate about whether standard principal components analysis is appropriate for the multivariate analysis of compositional data (e.g. oxide composition of glass), Loglinear transformation has been recommended by Aitchison as a prerequisite. This paper argues that previous comparisons of methodological merits have tended to circularity of argument by making assumptions about the form of a good multivariate result. To break the circularity of argument the authors have introduced randomized variables into five data sets. A good result must recognize these randomized variables as noise and place them near the centroid of the principal components scattergram of variable loadings. Standard principal components analysis is found to perform better than loglinear transformation in its ability to recognize the randomized variables. It is concluded that loglinear transformation tends to introduce spurious structure into a table of compositional data.This paper is followed by a comment by M. J. Baxter.

ISSN:0003-813X    

DOI:10.1111/j.1475-4754.1993.tb01026.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0003-813X    

DOI:10.1111/j.1475-4754.1993.tb01027.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Fired ceramics containing zircon inclusions have been dated by allowing the zircons to regenerate their own thermoluminescence (TL) signal, hence auto‐regenerative TL dating. The technique is conceptually straightforward. One first measures the TL accrued since the last heating of the material. The zircon grains are then stored for six months and the TL signal regenerated through self‐irradiation is measured. Since the internal dose‐rate for zircon is dominated by the internal component the age of the sample is simply given by the ratio of the natural to auto‐regenerated signal times the laboratory storage period. The technique, however, requires the measurement of a very small auto‐regenerated signal, which introduces a number of experimental and physical complications. The methods for overcoming these problems and successfully dating zircons by auto‐regeneration ar

ISSN:0003-813X    

DOI:10.1111/j.1475-4754.1993.tb01028.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY