Punctuated landscape evolution of the Caesarea (Israel) plot-and-berm agroecosystem in coastal sand inferred from port-OSL and OSL chronologies

In order to date and interpret the natural and anthropogenic forces influencing the evolution of the Early Islamic Plot-and-Berm (P&B) agroecosystem in the sandy coastal hinterlands of ancient Caesarea we integrated historical, archaeological, sedimentological, mineralogical, and meteorological findings with 165 Portable OSL (port-OSL) samples and 26 OSL ages from three structures and ten berm and plot sections, along a 650-m transect. A four-phased punctuated landscape evolution underscores the natural and anthropogenic forces shaping the P&B agroecosystem. The first phase was during the Middle Holocene as initial sandsheet incursion followed the significant reduction in the eastern Mediterranean sea-level rise rate. The second phase of incipient coastal modification, by mixing of local sand and teriatry refuse probably for agricultural practices, was OSL-dated to the Early Roman period and supported by synchronous ceramics. Surprisingly, no evidence for Byzantine activity was found. The third phase centered around 900 CE by OSL dating and ceramics, marked rapid construction of the P&B agroecosystem, characterized by emplacement of dark grey sandy refuse-sourced anthrosols in plots and anthrosediments on berms. This phase reflects late Abbasid and Fatimid influence on the region, as agro-technological innovation, such as the P&B agroecosystem waterharvesting techniques, necessitated organized administrative management, probably responding to religious calls for land reclamation. The last phase, the abandonment of the P&B agroecosystem, was gradual with sporadic activity persisting since the late Fatimid and throughout the early Crusader periods. Aeolian and fluvial forces have been modestly infilling some of the plots with colluvium and sand, slightly eroding and deflating the berms. All four phases posess distinct port-OSL signatures and OSL age ranges demonstrating how relative and absolute luminescence datasets of human-affected landscapes can help estimate depositional rates and refine determination of periods of natural processes and anthropogenic activities.