Portfolio
Material analyses
The aim of material analyses is to determine the chemical composition and structure of metals, rocks, ores, and ceramics. Besides material identification, they are also used for provenance studies or form an essential part of authenticity tests. Depending on the problem to be investigated and the quality of the samples, different devices and methods are used, among them the X-ray fluorescence analysis, trace element and ultra-trace element analysis (in the ng/g and pg/g ranges) with the aid of mass spectrometry and neutron activation analysis, or X-ray diffraction for structural analysis of crystals. These investigations may require sample preparation (removal of weathered crusts or corrosion, grinding and milling, mineral separation techniques, preparation of polished sections). Some examinations can be carried out minimally invasive by laser ablation or even non-destructively with (portable) X-ray fluorescence analysis.
Isotope analyses
The determination of isotope ratios, especially the combination of various isotope systems, has a broad field of application in archaeology as well as in earth and life sciences. It is considered to be the most important tool for provenance analysis and for the determination of production processes. Besides, it may serve to classify materials in order to find out, for instance, whether two or several objects and parts of objects, respectively, belong together. For this purpose, CEZA has at its disposal a high-resolution multicollector-inductively coupled plasma mass spectrometer (HR-MC-ICP MS) as well as a thermal ionization mass spectrometer for negative ions (NTIMS), which are used for the determination of isotope ratios of lead, strontium, tin, silver, copper, and osmium. Depending on the sample material and investigated problem, isotope compositions of different elements for the same sample can be determined.
Technological investigations
In many cases, the examination of the manufacturing techniques and the state of preservation of culture historical objects is of particular interest, as certain techniques were practiced only in certain chronological and geographic contexts. The aim is to discover signs of manufacture, missing parts, inclusions or coatings. For the investigation, microscopy in transmitted and reflected light as well as digital microcopy are used together with scanning electron microscopy and radiography with X-rays to obtain information on internal structures. Microscope investigations are either performed non-destructively on the surface of an object, or on samples, which are embedded in synthetic resin and polished. Microstructural investigation of metal or ceramic materials (materialography) is used for qualitative and quantitative descriptions of the properties and conditions of materials. The distribution, structure and orientation of specific phases in the materials may yield information on changes induced on production, due to use or due to ageing.
Authenticity tests
One of CEZA’s core expertise are investigations concerning the authenticity of culture historical objects. Forgeries can be identified by physical dating methods or by their chemical and isotope composition, e.g. the presence or absence of certain elements. A typical example is the presence of cadmium in gold, an element that was discovered in the 19th century and was then used for soldering metals. On the other hand, high-purity metals could only be produced with electrolytic refining that was introduced in the late 19th century. For authenticity tests on different metals and corresponding alloys, element or trace element analyses are performed with micro-XRF or laser ablation coupled with ICP-MS-analysis and the Pb-210 test. Luminescence dating can be used for burnt objects, such as ceramics, while radiocarbon dating provides information about the age of formation of organic materials.
Age determination
Direct age determination on materials and objects is a cornerstone of archaeological research with a wide variety of applications also in geo-, bio- and material science. Organic materials in general can be dated using radiocarbon (14C). This well established and widely used dating technique covers age ranges from historic times back to about 49.000 years. The radiocarbon laboratory at CEZA operates a MICADAS type AMS-system, capable of analyzing small samples down to milli- and microgram sizes. Archaeological woods, timbers, wooden art-objects, musical instruments and furniture can be dated by dendrochronology, a highly precise technique of analyzing tree-rings patterns. Determining the age of fired objects (pottery, bricks, etc.) or the deposition of sediments is carried out by luminescence dating. Additionally, dating methods applied in geoscience such as Rhenium-Osmium or Platinum-Osmium are rounding up our age dating portfolio.
Bioarchaeology
Human and animal remains are substantial sources of bioarchaeological research at CEZA. Anthropological investigations of human bones and teeth include the documentation of human remains and successive analyses regarding the age at death, sex, as well as health conditions and decease, activity patterns and taphonomic processes. Analytical investigations focus on the determination of the stable isotope compositions of strontium, oxygen, nitrogen, and carbon in enamel and bone. They address dietary habits as well as different aspects of human and animal mobility. Oxygen isotope compositions can be determined for the oxygen bound to the structural carbonate as well as the oxygen bound to the phosphate component of the hydroxyapatite. Carbon and nitrogen isotope compositions may be combined with 14C dating of the same collagen extract. CEZA offers wet chemistry and ultra-clean laboratory facilities for sample preparation, a high-resolution multicollector-inductively coupled plasma mass spectrometer (HR-MC-ICP MS) for strontium isotope analysis as well as an isotope ratio mass spectrometer for light stable isotope analyses with different pieces of peripheral equipment. All investigations are conducted in close dialog with our partners in archaeological research.
Scientific reports and services
The selection of appropriate sample material and the application of adequate methods are basic requirements for the production of meaningful analytical data. Accordingly, we offer advice and support in planning scientific investigations of archaeological material, reaching from sample selection to the conception of collaborative research projects.
Analytical data do often not speak for themselves, but require further processing, contextualization with the research question and interpretation in the light of earlier investigations and comparative data. Scientific associates at CEZA offer support regarding graphical presentation, scientific interpretations and collaborative compilation of manuscripts for scientific and popular scientific publications.