Preliminary results of the Sabkhah Hazawza gravity project, Wadi as Sirhan area, Kingdom of Saudi Arabia

One hundred thirty seven new gravity stations at an average station density of one station per 17.5 km2 have been established in a 40 x 60 km area centered on Sabkhah Hazawza in the northwestern part of the Kingdom of Saudi Arabia. A successful tie to existing Arabian American Oil Co. (ARAMCO) gravity data was made and a simple Bouguer gravity anomaly map was compiled during the survey. The map shows a distinct gravity low of about -8 mgal associated with the sabkhah, its minimum displaced to the northeast of the longitudinal axis of the sabkhah. However, the continuation of the gravity anomaly under the basalt field to the northeast suggests that the gravity anomaly is due to an older basin-like structure. If the sabkhah deposits are due to damming of ancient Wadi as Sirhan by basalt flows, then the deposits are probably thin. Preliminary estimates give a maximum thickness of about 270 m for the sedimentary fill causing the gravity anomaly.