“Equipped with his five senses, man explores the universe around him and calls the adventure science”~Edwin Hubble
Stable Isotopes as Archaeological Data
Stable isotopes are the non-radioactive versions of an atom (Malainey, “Stable Isotopes”, 2011). Atoms are the smallest unit of a unique element. Atoms are comprised of protons, neutrons, and electrons in different unique combinations that relate to a specific element (Malainey, “Elements, Atoms, and Molecules”, 2011). The number of protons is strict to each element, but electrons and neutrons can change. This means of the number of protons change, the element changes. It is the neutrons that are of interest to archaeologists, as these can change and become unique isotopes (McMurry and Castellion 1999).
The process of stable isotope analysis involves measuring and comparing the ratios of specific stable isotopes. Depending on the region, the comparison will be made to a preexisting standard ratio (Malainey, “Stable Isotopes”, 2011). Every specific isotope has a specific relation to biological processing, making them useful in diet, dating, and provenance studies. Archaeological research focuses on the stable isotopes of carbon, nitrogen, strontium, lead, hydrogen and oxygen (Malainey, “Stable Isotopes”, 2011).
Nitrogen, for example, has two isotopes (14N and 15N) which may be useful in identifying certain legumes and beans. These plants are referred to as “nitrogen fixators,” because they exhibit a unique process of converting nitrogen into nutritious nitrates (Malainey, “Stable Isotopes”, 2011). The locational and seasonal levels of nitrogen vary, and relate to the distribution of animals and their diet. This can help archaeologists reconstruct the surrounding environment, providing more context for interpretations. Strontium has chemical properties that are similar to calcium, so the ratio can be used to study provenance through geological formations, or through bone and teeth. The amount of strontium present in the bone varies by location. This difference in the amount of strontium is useful to archaeologists for studying migration patterns (Malainey, “Stable Isotopes”, 2011).
Carbon isotopes are useful in researching archaeological food systems. Stable isotopes of C3 and C4 reflect specific types of plants. This can be useful in studying long-term dietary patterns, as well as regional migrations (Malainey, “Stable Isotopes”, 2011). Stable isotopes of carbon reflect a difference in photosynthetic processes. C4 plants are mostly grasses and corn, C3 are trees and shrubs (Malainey, “Isotope Analysis”, 2011).
Stable Isotope Analysis in Archaeological Interpretations
The archaeological record is made of up physical remains, yet the meanings deciphered by researchers take a more intangible form. Rock imagery, for example, has been used by archaeologists as a source of metaphoric data depicting ritual beliefs. These rock glyphs and paintings are examined with cultural context to study the outward expression of past human thoughts and beliefs (Whitley). One barrier to these cognitive interpretations is the problem of the other mind. Realistically, it is impossible to know what is thought at the time an action is performed, but what can be observed are those residual evidence of ritual behavior (Johnson 2010).
Understanding the ritual experience of an ancient individual requires and understanding many contextual influences. Interpretive archaeologies understand humans as products of their environment, culture, biology, agency and self-identity (Johnson 2010). Interpretive archaeologies, or hermeneutics, seek to understand past societies within their own unique contexts (Renfrew and Bahn 2010). Although Stable Isotope analysis is not directly used in phenomenological interpretation, it can be utilized as part of a diverse dataset to understand the human experience of the past.
Previously, phenomenological interpretations have focused on the relationship between visual and cultural data by comparing rock imagery sites with ethnographic information. This focus has resulted in a strong bias toward the meaning of the imagery, rather than the surrounding context. Researcher Sven Ouzman asserts that the visual bias can be mitigated through examining a more synesthetic experience (Ouzman, 2010). Employing a wider range of evidence can provide each speculative interpretation with a quantitative reference.
For example, researchers Pearson and Meskell applied stable isotope analysis in combination with figurine and burial evidence from Catalhoyuk. The researchers used this evidence to understand long-term food consumption as an investment (Pearson and Meskell, 2015). The carbon and nitrogen isotope data showed that there was a distinct difference in diet between youth and adults. This, along with the considerations of more prestigious grave goods in adults persuaded the researchers to interpret beyond the favored mother goddess cult interpretations (Pearson and Meskell 2015). These new interpretations saw the figurines representing not a strictly female form, but a ritual significance to the bodily flesh (Pearson and Meskell 2015).
Interpretive archaeologies reveal specific contextual experiences from the archaeological record. Illuminating the whole story requires a multi-stranded approach to data collection and analysis, and this is improving exponentially as new technologies and scientific insights develop. This is an important considering the wealth of information that has already been collected to the archaeological record. There are great benefits to incorporating new technologies with previously studied data, especially when applied shifting common interpretations and biases of the past.
2010 Archaeological Theory, 2nd Edition. Oxford: Blackwell.
2011 “Elements, Atoms, and Molecules” In A consumer’s guide to archaeological science analytical techniques. New York: Springer.
“Stable Isotopes” In A consumer’s guide to archaeological science analytical techniques. New York: Springer.
“Isotope Analysis” In A consumer’s guide to archaeological science analytical techniques. New York: Springer.
McMurry, John, and Mary E. Castellion.
1999 Fundamentals of General, Organic, and Biological Chemistry. Upper Saddle River, NJ: Prentice Hall.
2001 Seeing is Deceiving: Rock art and the Non-visual. World Archaeology 33(2):237-256.
Renfrew, Colin, and Paul G. Bahn
2012 Archaeology: Theories, Methods and Practice. London: Thames & Hudson.