الملخص

Generally many major and minor karstic phenomenas have been identified and studied by many researchers at Mosul region, with emphasis mainly on sinkholes that developed at highly water-soluble rocks such as limestone, marly limestone and gypsum that dominated the local geological formations here. The caves in the present study which constitute one of the important karstic phenomena in the area were developed and formed in conglomeritic rocks of fluvial deposits of Quaternary age .This type of occurrence is internationally considered to be very rare. The reasons behind that is firstly the presence of certain type of conglomeritic rocks which consist of calcareous matrix cementing various types of conglomerate fragments. This is the main factor that should be present prior to any development and formation of the caves. The second factor is the abundance of high rate of rainfall leading to the enrichment of underground waters. It is suggested, in the present study that wet Pliestocene climate is the most probable time for the initiation and formation of the caves in the fluvial deposits. This has also been suggested for other karstic phenomenas formed in other geological formations of Mosul city and its neighborhood, north of Iraq.