Qualitative Interpretation of Gravity Data Collected in Kalak-Bardarash Area-NW of Erbil City, Iraqi Kurdistan Region

A total of 610 gravity stations were taken to cover the area around Kalak and Bardarash Towns northwest of Erbil City. The existed net of roads was followed to collect the data. All necessary corrections were carried out to calculate and display the complete Bouguer anomalies. The Bouguer anomaly map was carefully analyzed. Regional and residual maps were also derived and displayed using different techniques. The visual inspection of the Bouguer anomaly map showed the presence of five major anomalies: two positive and three negative. Among them is the important high south of Bardarash Town which is the main oil field structure in the area. When these anomalies were compared with the surface geology, lineaments on Landsat and Aster images a good and reliable consistency was found with slight shift in the surface anticlinal axis of Bardarash with that obtained from gravity. The analysis of the regional anomaly map shows that all the anomalies revealed by the Bouguer and residual maps are super-imposed on a main regional anomaly almost trending towards northeast. This major anomaly, which is considered to reflect the effect of basement rocks, shows that the basement complex surface is inclined toward the northeast and East. It has a depth ranging between 6 and 9 km. with the presence of many faults some of which are continuing upwards to the surface