Materials, archaeological studies

The nature and the relative amounts of the impurities in many natural and in some synthetic materials, are often characteristic of the geographic area where the materials occur or were made. This is of particular interest in archaeological studies, since determining the nature and the relative amounts of impurities in many materials allows one to determine their provenance (Maniatis 2004 Guerra and Calligaro 2003). 

Janaway, R. C. (1996). The decay of buried remains and their associated materials, in Studies in Crime An Introduction to Forensic Archaeology (J. Hunter, C. Roberts, and A. Martin, Eds.). London Routledge, 58-85. 

The study of F in archaeological materials is mostly focussed on bone materials or flints. Therefore, this paper is mainly dedicated to the study of these materials and their potential for revealing information on the past some applications of F studies in obsidian and teeth are also mentioned. The following examples illustrate the importance of the chemical and isotopic analysis for archaeological studies, in general. Prior to the presentation of F studies in archaeological bone material and flint, it is important to review their main characteristics in order to be able to adequately evaluate the output and limits of investigations. 

This chapter is an overview of the wide variety of archaeological studies conducted by chemists. From the earliest stone artifacts to the artistic manuscripts and textiles of the more recent past, the studies presented in this volume show the wide range of materials that have been studied by chemical techniques. The field keeps expanding as chemists help provide information valuable in the interpretation of archaeological sites and artifacts. Besides helping to detect fraudulent artifacts and artistic objects in museum collections, chemists have studied the physicochemical deterioration processes that destroy the monuments and objects of the past. Thus, the role of chemists is more than just discovery of the past it includes investigation that may help preserve the artifacts for future generations to enjoy and study. 

The development of HEMS technology will probably have its most important initial impact in archaeological studies as a consequence of its ability to provide determinations on samples in the 1-5-mg range. Materials containing relatively small amounts of organic carbon, for which conventional determinations have been heretofore difficult or impractical, can now be routinely employed. Bone and ceramics are examples of sample types that will see increased attention and utilization as the source of determinations by HEMS. 

Two general kinds of microscopes are employed in archaeological studies, optical microscopes and electron microscopes, and described below. More sophisticated electronic microscopes, including the SEM, the scanning tunneling microscope (STM), and the atomic force microscope (AFM) can be used for measurement of the elemental composition of materials under analysis, thus combining visual and chemical capabilities in a single instrument. 

NAA is widely used in many different fields of sciences. Applications include environmental studies to characterize pollutants, semiconductor materials analysis to measure ultra trace-element impurities, archaeological studies of the distribution of the chemical elements and fossil materials, forensic studies as a non-destructive method (suspect chemical agents, see Figure 17.9), pharmaceutical materials analysis to measure ultra-trace element impurities, etc. Unfortunately, facilities for using this method do not exist everywhere. Otherwise, the sample becomes slightly radioactive, requiring the sample to be quarantined until its activity reaches a state similar to which it was before the NAA. 

Since the beginning of modern science, coal petrology has served as a powerful tool for the characterization of coals for both geological and indnstrial applications. As was mentioned earlier, the applications of coal petrology are wide-ranging. However, the applications of this science may sometimes be observed in apparently unrelated fields such as archaeological studies, materials science, and forensic geology. 

Radiation damage over time creates free radicals in materials. In the case of teeth, free radicals in tooth enamel have been measured to date teeth in archaeology studies and to evaluate exposure of people to ionizing radiation after several major nuclear reactor leaks. Radiation dosimetry and analysis of irradiated foods, gamma-irradiated polymers, and other solids such as ceramics, bone, and coal are common applications of ESR. 

Analytical chemistry plays an important role in the study of art and archaeological materials. Such study has a variety of aims. Some of the most important aims when artifacts are investigated concern the study of the technology used to produce them, to reconstruct their distribution from the production areas, and to understand the use to which they were put in the past. The behavior of ancient people is better understood with the interpretation of such information. Long-term storage often tends to obscure chemical information that contributes to the above-mentioned aims. It is thus important to understand at the deepest possible level all the altering processes that intervene in the life cycle of the ancient object. 

Analytical techniques used for the study of materials or objects of artistic or archaeological importance are expected to provide a wealth of information on (1) the chemical composition or nature of the material under study, (2) the state of alteration of the objects caused by the long-term exposure to the environment, and (3) the effects of restoration procedures. All the above information must be typically extracted from samples that are a complex mixture of different chemical compounds. In fact, ancient artifacts were obtained by manipulating natural products that were often a mixture of both organic and inorganic compounds. Tlie altering processes that intervene in the life cycle of the artifacts contribute to further increase their chemical complexity. 

As a rock, gypsum has been found as stone ashlars and statues in the Ancient Mesopotamia [1]. However, one of the most important uses of gypsum was conglomerate material as mortar manufacturing. Archaeological studies reported the use of gypsum mortars from the Egyptian pyramids, 4 ka BP [2]. 

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