Gravity Field of Kuwait and its Relevance to Major Geological Structures (1)

Regional gravity surveys were done in the state of Kuwait during 1986-1988. The new gravity maps show a good correlation with geomorphological features as well as with deeper geological structures. The free-air anomaly map clearly reflects the topography of the Jal Az Zor and Ahmadi ridges, and Wadi Al-Batin. The Bouguer anomaly map is dominated by two prominent gravity highs correlatable with subsurface structural arches. The north-trending gravity high in eastern Kuwait represents the effect of a major structure, the Kuwait arch, along which many important oil fields are located. A smaller northwest-trending high mapped in western Kuwait indicates the presence of a second subsurface arch, which in this paper is named the Dibdibba arch. The two gravity highs are separate by a wedge-shaped gravity low presumably caused by thicker sediments of the Dibdibba basin. Magnetic measurements along selected profiles show the two arches to be associated with 100-200-nT (nannoTesla) anomalies apparently reflecting the positive subsurface relief of the crystalline basement. Along the length of the Kuwait arch, magnetic data also indicate lateral susceptibility variations possibly related to lithological variations within the basement.