Late Pleistocene-Holocene marsh episodes along the Carmel coast, Israel

Late Pleistocene-Holocene sequences in the southern Carmel coastal plain of Israel were obtained from two cores, 12 and 16 m deep, at the western and eastern longitudinal troughs, separated by a north-south "kurkar" sandstone ridge. The core sequences unconformably overlie the kurkar and were analyzed using X-ray radiography, grain size analysis, organic matter and water content. The sequences include (a) Brown sandy clay units, indicating terrestrial conditions of aeolian sand and dust deposition and pedogenesis dated between 20,200-19,650 and 9540-9130 cal. yr BP (western trough) and to 14,000-13,000 and 7680-7510 cal. yr BP (eastern trough). They are related to gradual warming and wetter climate when the coastline was far to the west; (b) overlying dark silty clay sediments, indicating fresh to brackish, shallow-water marsh with organic and fossil-rich, hydromorphic mineral soil, which prevailed at the western trough until 9010-8640 cal. yr BP (900 yr) and dried while the coastline was 1 km to the west. The marsh deposits were exposed for 3600 yr and populated by Pre-Pottery Neolithic and Chalcolithic settlements before they were covered by marine-aeolian sand at 5100 yr. The Kabara marshes at the eastern trough are asynchronous with the western marshes and prevailed from 7680 to 7510 cal. yr BP until the present. The genesis of these marshes may be related to the transition to a drier climate, resulting in an increasing frequency of large floods, as indicated by the high sedimentation rate, as well as to sea-level rise and its effect on groundwater level.