"THE BOTTOM LINE": SUBBASE LAYERS IN IRON AGE CONSTRUCTION AT TEL 'ETON (ISRAEL) AND BEYOND

The subbase layer is a critical component in construction, stabilizing the ground before laying the foundation and enhancing structural durability. This study examines the role of subbase layers in Iron Age II (specifically, 10th–8th centuries BCE) structures, with a focus on excavations at Tel ‘Eton, Israel. The objective was to identify the materials used and assess their significance in ancient construction practices. Archaeological evidence indicates the use of crushed chalk as a subbase material beneath the foundations of residential buildings and fortifications. A comparative analysis of other Iron Age sites showed that similar subbase layers, often made of sand or stones, were prevalent throughout the region. Methodologies included chemical analyses using Fourier-transform infrared spectroscopy (FTIR) to identify material components and geomechanical tests, such as the free swell test, to evaluate moisture-induced volume changes and stability. Results confirm that crushed chalk and other materials like sand and stones were intentionally selected to enhance structural stability. Recognizing subbase layers as a primary construction element is crucial for accurate stratigraphic interpretation, improving dating precision, and advancing our understanding of ancient building techniques. The study highlights the broader significance of subbase layers across historical periods, underscoring their critical role in archaeological research and the evolution of construction practices.