Optical Dating of Agricultural Terrace Deposits

Agricultural terraces are common features of cultivated hillsides across the world and have recently attracted increasing attention as archives of land-use practices and as soil carbon depositories. Such terraces originate from various soil translocation processes and throughout usage are subject of frequent reworking. Establishing chronologies for agricultural terraces usage is, thus, notoriously difficult. Here, we report results from optically-stimulated luminescence dating of terrace sediments that (i) originate from a wide range of locations across Europe stretching from the Polar circle to the Mediterranean; (ii) are derived from various host lithologies including igneous rocks, Triassic sedimentary rocks, Neogene marine deposits, and Pleistocene glacial and periglacial sediments; (iii) represent a range of cultivation styles including labour intensive manual techniques as well as mechanised tillage; and, (iv) cover a wide span of time periods from the Early Bronze Age through to modern times. Reliable chronologies of optical ages, consistent internally and in agreement with independent age information, were established on silt-sized quartz extracts from loess derived terrace deposits and on sand-sized quartz grains derived mostly from sedimentary host rocks. OSL signals of quartz extracted from deposits with igneous and turbiditic host rocks are often not of sufficient quality for optical dating purposes.