Archaeological science (archaeometry)

Archaeological science or archaeometry is the use of scientific techniques in studying archaeological finds. It encompasses natural sciences including chemistry and biology as well as imaging (for example, CT scans that can be used to see inside mummies). Archaeometry largely developed from the 1960s forward thanks to scientific and technological advances, but also owes a debt to the radiocarbon revolution, the method of carbon dating objects devised in the late 1940s. The work of archaeologists has evolved over time from studying artifacts and other evidence of the past to trying to learn about the cultures that produced these manufactured and natural items. With carbon dating, genetic analysis, and other advances, archaeology advanced significantly into the twenty-first century.

Background

Early archaeology was largely concerned with finding and studying objects from the past. The first scientific archaeological excavation was conducted in 1784 by Thomas Jefferson. In the nineteenth century, the field saw a major shift with acceptance of the concept of evolution and development of the three-age system. Known as the classificatory-descriptive period of archaeology, this was the move to classify human prehistory into three time periods, the Stone Age, Bronze Age, and Iron Age. The three-age system was developed in 1836 by Christian Jurgensen Thomsen, an archaeologist and the first curator of the National Museum of Denmark. He edited and published a guidebook for the museum in which he classified artifacts in its collection according to whether they were made of stone, bronze, or iron. The Stone Age was characterized by tools and weapons made of natural materials including stone, bone, and wood. Objects made of copper or bronze were classified as Bronze Age artifacts. Objects from the Iron Age were made using iron and steel, a metal that is harder than bronze and copper and made by heating iron with carbon. An archaeologist with the museum confirmed in the field that Stone, Bronze, and Iron Age objects were clearly stratigraphic.

Several discoveries bookended Thomsen’s work and changed scientific beliefs about Earth. Geologist Charles Lyell published Principles of Geology in three volumes from 1830 to 1833. His work showed that all features of Earth were created by the same natural processes over long periods. Charles Darwin, whose work on evolution was influenced by Lyell’s work, published On the Origin of Species in 1859. Inspired by Darwin, Lyell published a new book of geology supporting evolution. Before the work of these scientists, the planet was believed to be about six thousand years old. These scientists proved that Earth was in fact billions of years old, a concept that inspired a period of intense archaeological exploration of ancient peoples. The resulting books were read by the general population and many became best sellers.

The classificatory-descriptive period ended in the early twentieth century. The classificatory-historical period, which began about 1914, looked beyond the artifacts to try to understand the cultures of the people who made and used them. This period ended about 1960 with processual archaeology or new archaeology, which applied the scientific method—forming a theory, building a model, and testing a hypothesis—to find environmental factors that influenced human behavior. This was aided by computing powers and new statistical techniques to analyze the ever-growing body of data.

Overview

Archaeological science encompasses many fields of study, including biomolecular archaeology, bioarchaeology, environmental archaeology, analysis of materials, and dating methods. The work in these areas has in turn been adopted in other fields, such as forensics.

Biomolecular archaeology is the scientific analysis of organic materials. This includes human tissue and skeletal remains as well as foods, perfumes, plants, and textiles. Scientists study DNA and genetics, for example to seek relationships between ancient humans, plants, and animals and compare them to modern living creatures. This study primarily relies on chemistry, evolutionary biology, and proteomics. Proteomics is the study of proteins from materials including foods, bone, teeth, textiles, art, and parchment. For example, a process known as zooarchaeology by mass spectrometry, or ZooMS, was able to use proteins from the pages of medieval pocket Bibles to identify the animal hides used to make the parchment. Researchers seek to understand how populations moved and migrated; what they ate, grew, and herded; and how their climate changed, among other information.

Bioarchaeology is the study of human skeletal remains from archaeological sites, and represents knowledge from other fields, including paleogenetics and paleodemography, or the study of statistics of ancient populations (such as births and affluence levels). This work includes human osteology, or the identification of human bones, which is also used in forensic anthropology in criminal investigations. Dental histology, or the study of teeth on a microscopic level, includes dental development and condition. Teeth are among the best-preserved remains and can provide information about an individual’s age, health, and society. Geometric morphometrics is the study of the shapes, for example the arrangement and symmetry of petals of a flower. This can help researchers find relationships and track evolutionary biology of living organisms.

Environmental archaeology includes the fields of zooarchaeology, paleoethnobotany, and geoarchaeology. Zooarchaeology looks at the relationships between humans and vertebrate and invertebrate creatures. Researchers try to learn, for example, what humans hunted or domesticated and how they used these animals. They also examine invertebrates, which may have been used as food, medicine, or even poison; to make tools or decorative objects; and to make dyes, among other purposes. Paleoethnobotany is the study of how humans used and related to plants and plant-based material, for example what they grew and gathered and how these plants were used. Geoarchaeology seeks to locate archaeological sites, understand how settlements changed over time, analyze soils and sediments, and understand how humans affected the landscape, among other areas of study.

Artifacts such as ceramics, glass, metals, and lithics (objects made of stone) can tell a great deal about a culture. Analysis of these objects explores not only how and when they were made and employed, but also the technology used.

Dating methods have greatly expanded understanding of the past. Radiocarbon dating uses a natural radioactive carbon that is absorbed by all living things. When they die, they stop absorbing carbon-14. Using tree rings and other known references and the half-life of carbon-14, scientists can determine the age of artifacts. Luminescence dating works by examining unstable trapped electrons in crystal structures of minerals such as quartz. This enables scientists to determine when the minerals were last exposed to daylight and estimate their age.

Bibliography

“Archaeological Science.” Department of Archaeology, University of Cambridge, www.arch.cam.ac.uk/about-us/archaeological-science. Accessed 8 Feb. 2022.

Archaeological Science: An Introduction, edited by Michael P. Richards and Kate Britton, Cambridge UP, 2020.

Finestone, Emma. “Zooarchaeology by Mass Spectrometry (ZooMS).” International Application of Archaeological Science, 27 July 2021, iaas.shh.mpg.de/2021/07/27/zooms/. Accessed 9 Feb. 2022.

Jones, Nicola. “Carbon Dating, the Archaeological Workhorse, Is Getting a Major Reboot.” Nature, 19 May 2020, www.nature.com/articles/d41586-020-01499-y. Accessed 8 Feb. 2022.

“Lithic Artifacts and Lithic Analysis.” Women in Archaeology, 28 June 2017, womeninarchaeology.com/2017/06/28/lithic-artifacts-and-lithic-analysis/. Accessed 9 Feb. 2022.

Patalano, Bob. “Plant Macrofossil Analysis in Archaeological Research.” International Application of Archaeological Science, 6 July 2021, iaas.shh.mpg.de/2021/07/06/plant-macrofossil-analysis-in-the-archaeological-research/. Accessed 9 Feb. 2022.

Renfrew, Colin, and Paul Bahn. Archaeology Theories, Methods and Practice, 8th ed., Thames Hudson, 2020.

“Willard Libby and Radiocarbon Dating.” American Chemical Society, 2016, www.acs.org/content/acs/en/education/whatischemistry/landmarks/radiocarbon-dating.html. Accessed 8 Feb. 2022.

Wodhams, Joel. “The Classificatory-Descriptive Period: Explorers and Romance.” Museum of Ontario Archaeology, 24 July 2017, archaeologymuseum.ca/classificatory-descriptive-period-explorers-romance/. Accessed 8 Feb. 2022.