The Dacht-i-Navar group lies mainly within the southern part of a geological depression with dimensions of . The few more northern centres are separated from the main complex by the clay-filled Nawar basin and a surrounding Pleistocene terrace. The infill, which includes volcanic material, is likely thicker than . This basin has an altitude of , but it is surrounded by higher summits. Despite evaporation, a lake persists within the basin. Probably, the depression was once a valley cut into schists which are pre-Devonian and still crop out in some places. This valley drained southwestward towards the Arghandab River that was eventually blocked by volcanic activity. The Ab-i-Khanduli dry valley still connects Dacht-i-Navar to the Arghandab river. Another possibility is that the valley originally drained eastward towards Qarabagh.