ABSTRACT

Analyses of carbonate content in a partially consolidated eolianite showed a highly significant correlation between the amount of carbonates in the rock and the degree of consolidation. At least 8% CaCO₃ is required for the cementation to proceed. The cementation results from wetting and drying cycles and proceeds from the upper surface of the dune downwards, through the percolation of ram water and the recrystallization of the dissolved CaCO₃.

Lamination in the dune is a result of particle size differentiation during ripple formation; the calcareous skeletal fragments being coarser grained than quartz sand accumulate on the crest of the ripples. The preservation of the laminated dune structure with alternating laminae of smaller and larger amounts of carbonates supports Friedman's (1964) observation that the reprecipitation during cementation takes place adjacent to the place of dissolution.

The environmental analysis of the factors controlling the formation of eolianite suggests that the correlation of the eolianite ridges with definite climatic phases of the Quaternary is not warranted unless supported by independent evidence. All the eolianites and associated sediments and soils of the coastal plain of Israel were formed under seasonally wet and dry climatic conditions that were not much different from those prevailing today. Because of local factors and disturbances, the sedimentary cycles of the coastal plain were not necessarily time equivalent to the major cyclic events of the Quaternary.