Natural and human controls of the Holocene evolution of the beach, aeolian sand and dunes of Caesarea (Israel)

The study focuses on the Holocene appearance, chronology and drivers of beach sand deposition and inland aeolian sand transport around the Roman-Byzantine ruins of Caesarea, Israel. Beach sand, sand sheets, nebkha, linear and transverse dunes as well as parabolic and transverse interdunes along two transects were sampled in the current study down to their substrate. Sixteen new optically stimulated luminescence ages cluster at ~5.9-3.3 ka, ~1.2-1.1 ka (800-900. AD) and ~190-120. years ago (1825-1895. AD) indicating times of middle and late Holocene sand sheet depositions and historical dune stabilization. The first age cluster indicates that beach sand accumulated when rates of global sea level rise declined around 6-5 ka. Until ~4. ka sand sheets encroached up to 2.5 km inland. Historical and archaeological evidence points to sand mobilization since the first century AD. Sand sheets dating to 1.2-1.1 ka, coevally found throughout the dunefield represent sand stabilization due to vegetation reestablishment attributed to gradual and fluctuating decline in human activity from the middle Early Islamic period until the 10th century. Historical and chronological evidence of the existence of transverse and coppice dunes from the 19th century suggest that dunes only formed in the last few centuries. The study illustrates the initial role of natural processes, in this case decline in global sea level rise and the primary and later role of fluctuating human activity upon coastal sand mobility. The study distinguishes between sand sheets and dunes and portrays them as sensors of environmental changes.