Microarchaeology of a grain silo: Insights into stratigraphy, chronology and food storage at Late Bronze Age Ashkelon, Israel

Pits and silos are storage features that often occur at prehistoric archaeological sites. Their shape, size and content may show a large degree of variability, and their function may be related to a number of behaviors that can provide valuable insight into the occupational history of a site. Such structures are usually investigated through the study of their macroscopic content, which may include stone, ceramic and metal artifacts, charred remains, and plant material in the case of good preservation conditions. However, pits and silos are generally characterized by complex life cycles that encompass also the partial or total removal of fill deposits, and the re-use of earlier structures, which hinder a proper interpretation of their function. This requires the application of a microarchaeological approach to the study of the sedimentary matrix of fill deposits, especially when macroscopic remains are absent or not uniquely related to a specific human activity. Here we present the study of a series of pits from the Late Bronze Age levels at Ashkelon, Israel, which were characterized by multiple fills layers. Using a combination of infrared spectrometry, phytolith analysis, and micromorphology of sediments, we show that one of the pits was used as grain silo and maintained through time. Radiocarbon dating of charred wheat seeds recovered from the primary depositional context thus identified caused a fundamental re-evaluation of the stratigraphy of the excavation area and a better understanding of its chronology.