OSL

Archaeological terraces are a prominent feature of the agricultural sphere in hilly landscape throughout the Mediterranean, and dating of these simply built features is of utmost importance. Excavations and optically stimulated luminescence (OSL) dating of the soil fill of terraces were previously carried out on Mt. Eitan, the Judean Highlands, Israel. Archaeological surveys showed that Mt. Eitan was almost continuously settled from the Middle Bronze Age until modern times. However, OSL dating showed that all extant terraces were constructed 500–200 years ago, during the Ottoman Period, while older ages (Hellenistic to Mamluk periods) are limited to the base of several terraces. Many samples dated to the Ottoman period contain older quartz grains, indicating partial bleaching at the time of terrace construction; these grains might preserve older episodes of terrace building. To test this, we calculated ages for all measured aliquots and used the finite mixture model on the dataset to identify age components not apparent in the OSL age spectrum. Results show that aliquot ages cluster into only a few periods, of which four distinct components fall within the 14th–19th centuries (Christ era). The Hellenistic–Roman and Early Islamic periods are also represented, even in areas where terraces with such ages were not found, while the Persian Iron and Bronze Age periods are not represented at all. The unbleached grains thus preserve episodes of terrace building no longer represented in the landscape.