Article Outline
- Specific features of carbon-14 dating of mummies
- Type of samples to be analyzed
- Why are mummies more difficult to date?
- How is the dating of a mummy carried out?
- Sample preparation and extraction
- Laboratory analysis
- Examples of mummy dating
- Egyptian mummies: dating burial bandages
- Andean mummies: environmental challenges
- Complex cases: contaminated mummies
- Natural mummies: challenges and opportunities
The dating of mummies is an essential analysis that enables archaeologists to accurately reconstruct the history of ancient civilizations. Among the various methods of archaeological dating,carbon-14 analysis is an essential tool for researchers. However, its application to mummies often raises methodological challenges such as sample selection, contamination risks, chronological limits and the corrections needed to avoid them.
In this article, we explore in detail the process of radiocarbon dating: its specific applications to Egyptian and Andean mummies, as well as the scientific solutions available to us that optimize the precision of carbon-14 dating of mummies.
In summary:
- Carbon-14 allows dating organic materials present on mummies (hair, bones, tissues, bandages...).
- Reliability depends primarily on the choice of sample and the elimination of contamination. Nevertheless, AMS analyses and calibration steps make it possible to obtain very precise dates.
- The results must always be interpreted within the archaeological context.
Specific features of carbon-14 dating of mummies
Carbon-14 dating is an essential analytical method for helping archaeologists establish the chronology of mummies. However, archaeologists need to guarantee reliable results, and a number of technical and methodological issues arise. These include sample selection, contamination and isotopic bias.
Type of samples to be analyzed
To date a mummy using carbon-14, researchers must collect organic materials present. The main samples available to them are:
- Mummified biological tissues: skin, hair, tendons, or bones.
- Mummy bandages: often made of linen, an organic material directly usable for analysis.
- Biological residues: dried fluids, pigments applied to the body, or embalming resins. Their use can, however, pose problems for dating, as we will see later.
Mummy hair is a particularly interesting material for carbon-14 dating due to its resistance to degradation. A study has shown that a specific protocol allows for the extraction of keratin from the hair cortex and requires only about twenty milligrams of sample, which minimizes the impact on the mummy's integrity while providing accurate dates. This technique is particularly well-suited for mummies preserved in museums.
Why are mummies more difficult to date?
Although the analyzable samples on a mummy are varied, several factors complicate carbon-14 dating:
- Modern contamination: exposure to recent varnishes, resins, or bitumen can distort the measurement of the ¹⁴C/¹²C ratio.
- Conservation environment: the development of micro-organisms could artificially rejuvenate dating, if they are not strictly eliminated.
- Organic matter aging: poor preservation could prevent enough matter from being collected for precise dating.
A study conducted on the golden mummy of Dunkirk demonstrated that sample selection and chemical pretreatment were crucial to ensure the reliability of the results. The selective extraction process of keratin from hair thus made it possible to eliminate exogenous materials and obtain reliable dating.
How is the dating of a mummy carried out?
The reliability of a dating of a mummy using carbon 14 relies on a rigorous protocol for sampling, preparation, and laboratory analysis. Each step aims to eliminate possible biases and ensure optimal accuracy despite the challenges inherent in ancient materials.
Sample preparation and extraction
Carbon-14 dating requires meticulous sample preparation. This involves several crucial steps:
- Mechanical and chemical cleaning: this refers to chemical pre-treatment techniques (ABA method: acid-base-acid) for removing modern contaminants.
- Selection of the most reliable fractions: mummified hair is preferred as it offers better resistance to environmental alterations.
- Isotopic filtering: the analysis of carbon isotopic ratios makes it possible to detect potential anomalies.
Laboratory analysis
C14 analysis relies on precise laboratory steps to guarantee reliable and scientifically robust results:
- Measurement of the ¹⁴C/¹²C ratio: accelerator mass spectrometry (AMS) allows the analysis of very small samples.
- Isotopic bias control: are adjustments to account for natural isotopic fractionation.
- Calibration of results: is based on the IntCal 20 or SH Cal20 calibration curves, essential for correcting historical fluctuations in carbon 14.
Examples of mummy dating
Egyptian mummies: dating burial bandages
The linen bandages that wrap Egyptian mummies offer excellent reliability for carbon-14 dating. A study carried out on New Kingdom mummies confirmed their belonging to the 18th Dynasty thanks to accelerator mass spectrometry (AMS). This technique indeed allows for the analysis of very small samples, thus minimizing the impact on the mummy's integrity.
The study of funerary textiles, carried out notably at El Deir in Egypt, has opened new perspectives for the dating of mummies. Researchers were thus able to identify different types of textiles, including new linen bandages and fabrics from daily life. This approach, using a reference material, not only allows for the dating of mummies but also provides information on funerary practices and the social status of the deceased.
A remarkable example is that of the mummy of Nesi-Khons, dated between the 4th and 1st centuries BCE. The bandages of this mummy contained not only an Etruscan text on linen but also a papyrus from the Egyptian Book of the Dead, thus offering a unique opportunity to cross-reference textual data and carbon-14 dating.
Andean mummies: environmental challenges
A recent study on mummies discovered in the Argentine Andes used an innovative approach: researchers performed a cross-dating by dating the louse nits found in the mummies' hair. This method allowed them to estimate the age of these mummies between 1300 and 2300 years, while also providing valuable genetic information about the mummified individuals.
Complex cases: contaminated mummies
Some mummies were treated in the 19th century with modern substances. To counteract these contaminations and achieve reliable dating, scientists must thoroughly clean the samples before analysis to obtain usable results. The case of the mummy of Ramesses II perfectly illustrates this contamination problem.
Natural mummies: challenges and opportunities
Natural mummies, bodies formed under specific environmental conditions that ensure their preservation, present unique challenges for dating.
For example, bodies preserved in permafrost or peat may have absorbed ancient carbon, skewing the results of carbon-14 dating. In such cases, scientists combine several methods beyond C14 dating, such as pollen or wood analysis, to obtain reliable dates.
Carbon-14 is currently the reference method for dating mummies. Thanks to rigorous preparation protocols and accelerator mass spectrometry (AMS), it is possible to obtain precise dates on various organic materials while limiting the risks of contamination. Combined with data from excavations, these results provide a better understanding of funerary practices, preservation conditions, and the history of ancient civilizations. The CIRAM laboratory implements these methods to support research projects and archaeological studies on ancient human remains.
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You might be asking yourself these questions about mummies?
Funeral wrappings, made from plant fibers rich in organic carbon, offer a material particularly suited for carbon-14 dating. Researchers can analyze them when establishing their direct link to the mummy being studied. This approach allows for reliable dating while limiting sampling of human tissues.
Carbon-14 allows dating organic materials up to about 50,000 years old. Egyptian, Andean, or natural mummies fall well within this chronological range. Beyond that, the residual amount of carbon-14 becomes too low to provide reliable dating.
Historical information or inscriptions can sometimes be incomplete, inaccurate, or misinterpreted. Carbon-14 dating allows for the verification of these hypotheses, confirmation of a chronological attribution, or highlighting the reuse of funerary materials.
No. Dating only indicates the age of the analyzed material. To understand the causes of death, researchers use other techniques, such as CT scans, X-rays, DNA analysis, or paleopathological studies.
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