Last-Glacial to Holocene kurkar ridges, hamra soils, and dune fields in the coastal belt of central Israel

Subparallel elongate ridges of fossil eolianites known locally as "kurkar", fossil soils known locally as "hamra", and loose sand dunes represent the Last Glacial Stage and the Holocene in the central coastal plain of Israel. Detailed mapping of the kurkar ridges in outcrops, quarries, and road cuts, as well as along the coastal cliff, led to a revised stratigraphy. The common concepts that the kurkar ridges are diachronous, that they become younger from east to west, and that they are related to shorelines are rejected in the present study. All the kurkar ridges of the central coastal plain were formed during the Last Glacial Stage. The Kefar Vitkin Hamra, which underlies the kurkar units, was formed about 75-65 ka BP from dunes of dry climates that were turned into red hamra under wet conditions. The Ramat Gan and Dor kurkar units were deposited as sand-dune ridges in dry climates, some 65-50 ka BP, and were cemented soon after. The Nahsholim Sands, interbedded between these two units, represent a pause in the dry conditions, when sandy regosol developed. The overlying Netanya Hamra was developed some 50-10 ka BP, during which sand dunes of dry conditions were turned into red hamra under wet conditions. The overlying Tel Aviv kurkar, which formed as sand dunes and was cemented soon after, accumulated some 5.5 ka BP. The overlying Ta'arukha and Hadera sands, which accumulated from 5.5 ka BP to the present, represent three climatic cycles. Each cycle started with sand invasion during dry conditions, continued through sand stabilization, and ended with initial pedogenesis in semidry conditions. There is a positive correlation between these cycles and the cycles of expansion and contraction of human settlements, from Late Chalcolithic to post-Byzantine times. Expansion correlates with a wetter climate, whereas contraction correlates with desertification of dry periods.