PXRF Analysis Reveals Unique Deterioration in Ancient Pottery

In a recent study published in Spectroscopy Letters, Dr. Mohamed and Dr. Omar used portable X-ray fluorescence (pXRF) analysis to characterize pottery vessels that were unearthed at the famous archaeological site Saqqara. Their study focused on analyzing the deterioration and degradation of pottery vessels that were found at the site (1).

The Step Pyramid of King Djoser at Saqqara | Image Credit: © PB - stock.adobe.com

Saqqara is an ancient Egyptian village that contains the burial grounds of Egyptian royalty. It is most well-known as the necropolis for the tombs of Old Kingdom pharaohs, most notably King Djoser of the Third Dynasty, who was buried in the Step Pyramid that was constructed for him.

The study focused on three pottery vessels that were excavated from Saqqara. The researchers sought to understand the chemical composition of these artifacts, with the goal being to determine what sort of damage had been inflicted on them between when they were first created to the present day (1). The researchers used a range of techniques, most notably pXRF, but they also employed other spectroscopic techniques and methods such as digital microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), polarized microscopy, and AutoCAD (1).

The researchers observed that the artifacts contained black deposits, along with missing fragments, accumulated dirt, cracks, and the peeling of the slip layer. The researchers believe that these deposits could provide insight into the environmental and historical factors that caused the pottery vessels to degrade (1).

Spectroscopic techniques played different roles in the study. For example, pXRF and SEM analysis was done to determine the elemental composition of these artifacts. The two techniques helped uncover that the pottery vessels had varying concentrations of silicon, iron, and calcium (1). The researchers also identified high levels of chloride salts in the vessels.

Meanwhile, XRD analysis played a crucial role in identifying the primary constituents of the pottery. The researchers discovered the presence of albite, anorthite, wollastonite, quartz, calcite, and hematite in the vessels (1). The polarized microscopy examination uncovered plagioclase feldspar, indicating that the raw clay used in these vessels likely originated from the Nile region (1). Evidence suggested that the pottery had been fired at temperatures exceeding 800 °C, adding a significant dimension to our understanding of the ancient pottery-making techniques (1).

By understanding the chemical composition and damage manifestations, researchers and conservators can develop more effective strategies for the protection and restoration of these invaluable artifacts. This study shows how spectroscopic techniques can help us figure out how to preserve our material culture and ensure that the history humans create and the artifacts they leave behind remain accessible for generations to come (1).

Reference

(1) Mohamed, H. M.; Omar, S. Multi-analytical techniques for characterization of ancient Egyptian pottery objects from Cairo University excavations at Saqqara. Spec. Lett. 2023, ASAP. DOI: 10.1080/00387010.2023.2229904