A 10,400-year-old sunken lime kiln from the Early Pre-Pottery Neolithic B at the Nesher-Ramla quarry (el-Khirbe), Israel

The Pre-Pottery Neolithic B (PPNB) is the first period in human cultural evolution that is characterized by the extensive production of lime plaster for architectural, decorative and ritual purposes. The production of large quantities of lime plaster requires the operation of a lime kiln, a structure where limestone cobbles are heated to high temperatures (> 600 °C) to obtain quicklime, which is then mixed with water to form a moldable lime putty. However, little is known about lime kilns and plaster production processes during the PPNB. This may be because the technology used at that time was simple and left few traces that are unique to lime plaster production. These include combustion features rich in lime plaster and heat-altered sediments, which are difficult to identify through only a visual inspection of the archaeological context. Here we report the study of a small sinkhole at the Nesher-Ramla quarry in Israel, which yielded Early PPNB artifacts. Using infrared spectrometry and micromorphology of sediments, we identified in-situ deposits of heat-altered sediments rich in fragments of burnt limestone, lime plaster, and wood ash in the form of charcoal, phytoliths and siliceous aggregates, which are features consistent with the operation of a lime kiln. Charred botanical remains were characterized and used for radiocarbon dating, which determined the age of the site at 10,400 cal BP. We therefore conclude, based on the examination of the microscopic archaeological record, that this sinkhole was used as a lime kiln during the Early PPNB.