ABSTRACT

Surficial sediments from Syria, Trans-Jordan, Iraq and western Iran may be classified into residual deposits, sheet-wash deposits, residual deposits transported by running water and wind, evaporite deposits, playa lake deposits, and eolian deposits. Residual deposits are dominant and stream deposits are absent. Except for the eolian deposits, the sediments have coarse material of granule and pebble size which consists of fresh rock, but debris of sand grain size and smaller usually consists of clay minerals and quartz. Such fine grained residuum has been cemented by calcite into aggregate grains. The aggregates disintegrate in water, or when moved by the wind, which suggests that the present desert surface generally is in a state of stability. The presence of a film of calcite coating all grains and rock fragments suggests that solution of rocks is not at present an active process over large parts of the desert surface. The large quantities of fine-grained material representing the decompositional residues appear to have been developed during a period of greater humidity than the present one.