Abstract
Kaleh Kub, an ancient site located in the Sarayan district of eastern Iran’s South Khorasan province has been excavated since 2018, revealing evidence of Beveled Rim Bowls and other diagnostic pottery types attributed to the 4th millennium BCE. Kaleh Kub has a long sequence divided into four different periods, with cultural deposits attributed to the period of early urbanization, notably from the second period of this site, known as the cultural horizon of Susa II. Kaleh Kub is the easternmost site on the Iranian plateau where Beveled Rim Bowls have been found. Given the site’s importance in recognizing the distribution of this pottery type, this paper aims to structurally analyze clay samples and compare them with three sites index sites with similar technology: Chogha Mish, Abu Fandova, and Tall-e Iblis. The analysis found that while the construction technique of the pottery samples followed a similar pattern, their constituent structure was not similar, indicating different origins of construction materials. This suggests local production of Beveled Rim Bowls pottery at the Kaleh Kub site.
Keywords: Kaleh Kub, Tall-e Iblis, Chogha Mish, Abu Fandova, Petrography, XRF.
 
1. Introduction
Beveled Rim Bowls are handmade pottery vessels known for their rough, upturned rims, porous outer surfaces, and smoother inner surfaces shaped by damp hands. These bowls have been found in Mesopotamia, Iran, and parts of Pakistan, with numerous discoveries across various regions of the Iranian plateau. The Kaleh Kub site in eastern Iran is a significant prehistoric location where these bowls have been identified, dating from the 5th to the 2nd millennium BC. Archaeological layers from the 4th millennium BCE at Kaleh Kub contain various pottery types, including Beveled Rim Bowls, indicating potential local production.
The site’s archaeological studies suggest that the importation of these potsherds is unlikely due to its distance from similar cultural sites, such as the Pishva Pottery Mound and Mahtoot Abad. The presence of numerous Beveled Rim Bowls strengthens the hypothesis of local craftsmanship. Stratigraphic evidence shows that these bowls are located beneath Bronze Age cultural deposits, with noticeable chronological gaps between the 5th and 4th millennia and those of the later Bronze Age cultures, as indicated by radiocarbon dating.
Excavations at Kaleh Kub in 2018 revealed findings similar in pottery type and manufacturing methods to those from Mesopotamia and the Susa Plain, despite the geographic distance. This similarity underscores the significance of local production practices in the region. Overall, the evidence from Kaleh Kub highlights the cultural and historical context of Beveled Rim Bowls within the broader framework of ancient pottery in the Iranian plateau.
 
2. Sites Studied 
2-1. Kaleh Kub
The Kaleh Kub Aysk site is situated in the Sarayan District of South Khorasan Province, eastern Iran, at an elevation of 1,360 meters above sea level. The site is notable for the thickness of its cultural deposits, making it one of the few prehistoric sites in the province suitable for archaeological investigation (Fig. 1).
2-2. Chogha Mish
Chogha Mish is a prominent archaeological mound located in Khuzestan Province, flanked by the Dez and Karun rivers. The site features two ridges, with the taller ridge known as Tepe Boland, which rises about 27 meters above the plain. The shorter section, called the Terrace, stands approximately 9 to 10 meters high. Tepe Boland covers an area of 150 by 200 square meters, while the Terrace spans 300 by 400 square meters (Fig. 3).
2-3. Abu Fandova
Abu Fandova is located ca. 12 km south of Susa and consists of two main sections: a circular southern mound at about 80.75 meters elevation and a northern section with two shorter hills reaching approximately 75.30 meters. This site was surveyed by Robert McAdams in 1960-1961, who identified several cultural periods, including Middle Susa, Susa I, Susa II, Susa IV/D, and potentially the Kassite period (Adams, 1962).
2-4. Tall-e Iblis
Tall-e Iblis is located in the Bardsir Plain, about 80 km from Kerman, and covers over one hectare, measuring 120 by 100 meters. Initially described by Sir Aurel Stein in 1937, a photograph from 1932 shows that the site reached over 10 meters in height. In 1964, Joseph Caldwell identified six cultural periods at Tall-e Iblis, categorized based on pottery changes, labeled from 1 to 6 (Caldwell, 1967).
 
3. Laboratory Methods
A James Swift polarizing binocular microscope was employed for the microscopic analysis of the pottery samples. The magnification used in this study was set at 4x. For petrographic analysis, thin sections with a thickness of 30 microns were prepared for 25 pottery samples, which were subsequently examined using the James Swift polarizing microscope. All sections were prepared in the petrography laboratory of the Conservation and Restoration Research Institute.
 
4. Discussion, Petrographic Study
Quartz: Quartz is present in all examined samples and occurs in two forms: phenocrysts and polycrystalline, exhibiting angular margins within the clay matrix of the pottery. The abundance of quartz varies across the samples; in those from Kale Kub, it constitutes approximately 20-30% of the sample volume, while at Tall-e Iblis, it accounts for about 10%. In the two samples from Abu Fandova and Chogha Mish, quartz makes up 2-5% of the sample volume.
Calcite: Calcite is observed in the samples in two forms: micrite (fine crystal) and sparite (coarse crystal). Given the geological structure of the three study areas, calcite is present in primary sources across all locations. The absence of calcite in some samples can be attributed to the high firing temperatures of the pottery. An important aspect of evaluating the firing temperature of pottery is the presence of calcite and carbonate-based minerals in the clay paste, either as temper or as separate inclusions. Calcite serves as a significant thermal indicator; it and other carbonate compounds decompose at temperatures around 800 degrees Celsius. Notably, calcite is absent in Sample 11, suggesting that its firing temperature exceeded 800 degrees Celsius. In contrast, calcite is observed as separate inclusions in the paste of other samples, indicating that their firing temperatures were below 800 degrees Celsius. In samples K-10, T-20, CH-21, and AB-22, the calcite present in the paste is predominantly of the coarse-crystalline or sparite type.
4-2. Chemical Study
X-ray fluorescence (XRF) analysis of pottery samples from the Kale Kub site and others revealed various oxide compounds, including sodium oxide (Na₂O), magnesium oxide (MgO), aluminum oxide (Al₂O₃), silicon oxide (SiO₂), and several others. The analysis included samples from Kale Kub, Tell Iblis, Chogha Mish, and Abu Fandova, as well as soil from Kale Kub, with results expressed in weight percent (wt%) of oxide compounds.
The chemical analysis of Beveled Rim Bowls from Kale Kub showed a high concentration of silicon oxide, ranging from 54.7% to 64.4%. For pottery from Tell Iblis, the silicon oxide content was 58%, while it was 37% for Choghamish and 39.2% for Abu Fandova. The soil from Kale Kub contained 54.2% silicon oxide.
 
5. Discussion of the Results
The studied pottery primarily consists of quartz, identified through petrographic analyses. Quartz exists in two forms: single crystals, which is more common, and polycrystalline. Its varying content ranges from 3% to 10% in Kaleh Kub pottery, about 10% in Tell Iblis, and 2% to 5% in Chogha Mish and Abu Fandova. The angular edges of quartz fragments suggest they were added secondarily, indicating mining and grinding activities. The polycrystalline quartz points to granitic and metamorphic origins, implying the use of locally sourced soils. Some samples also show a coarse-grained texture, with calcite minerals present in both primary and secondary forms.
 
6. Conclusion
In comparative technological studies of ancient ceramics, chemical and mineralogical analyses provide crucial insights into the elemental compositions and minerals used in these artifacts. To trace clay origins, mineralogical comparisons with reference materials are essential. This study reveals that microscopic and chemical analyses, along with macroscopic examinations, show minimal variation in the Beveled Rim Bowls from the Kaleh Kub site in terms of composition and manufacturing techniques. Ancient potters likely employed similar methods and a limited range of raw materials. The potsherds from Tall-e Iblis, Chogha Mish, and Abu Fandova are entirely handmade and exhibit a similar manufacturing pattern, but their raw materials differ from those at Kaleh Kub. Thus, while the same technology and traditions were used, the origins of the potsherds suggest distinct regional affiliations.