THE CHRONOLOGY AND FORCING FACTORS OF MIDDLE TO LATE HOLOCENE SAND AND DUNE INCURSIONS ALONG THE COAST OF ISRAEL

Israel's coastal plain is characterized by lobe-like fields of predominantly stable transverse and parabolic quartz sand dunes that protrude 3-6 km inland from the current Mediterranean Sea coastline. Previous studies have mainly concentrated on sand dynamics, surface properties and ecology in the Nizzanim-Ashdod dunefield, south of Tel-Aviv. Inland dune mobilization from the sea shore has been attributed to human decimation of sand-stabilizing vegetation. However, less attention has been paid to the internal structure and chronology of these sands and dunes. This study hypothesizes that since the middle Holocene, several sand incursions have originated to form the current coastal sand and dune fields along the coast of Israel. We aim to determine the timing and mode of sand supply and its connection to short-term climatic perturbations and/or anthropogenic activities.

For the Nizzanim-Ashdod dunefield, back-calculations of current dune mobilization rates, reports of thick sands overlaying archaeological relics from different time periods and sporadic dating by different luminescence methods provide preliminary chronological frame for the past 6 ka. Dune morphologies that are in accordance to current wind directions have been suggested to indicate a relatively modern age for the dunes.

The current study involves the preparation of a database of all the relative and absolute dates and ages of the sands and dunes of coastal Israel based on archaeological and different geological proxies, and a field survey and sampling campaign of the Caesarea-Hadera (north of Tel-Aviv) and Nizzanim-Ashdod dunefields. Transects along the dune advancement direction, including beach sand, foredunes, transverse dunes, and interdunes, were sampled down to their aeolianite (kurkar) substrate by drilling and analyzing exposed sections. Additional sampling was conducted at archaeological sites. Analyses focus on the sedimentological properties of the sand and their OSL age.

Preliminary results indicate that within dunes sand properties are generally similar, while interdune sands usually 2-5 m deep, exhibit sedimentological variability and host several palaeosols characterized by different degrees of pedogenic development.