Türkiye Jeoloji Bülteni

A New Contribution to the (IPC) Bouguer Map of a Gap Area in Mosul and Duhok Region (Iraq)

Abstract: The purpose of the current study was to complete an important gap within the Bouguer map of Iraqimplemented by the Iraq Petroleum Company (IPC). In addition, the collected data were processed with recentgravity concepts and methods to establish a new regional geological image. A total of 868 gravity points weremeasured and corrected.The Bouguer anomaly map of the study area was initially drawn up with the parameters and equations used toconstruct the IPC map. The newly-produced map shows a very strong correlation with the old IPC results. A newBouguer map of the study area was then constructed using modern parameters and equations. A comparison betweenthe old and new maps illustrates the difference between recent and previous techniques.The isostatic residual map shows the presence of over-compensated areas close to Chia Gara and Mateen and spreadsto the Aqra zone with a negative value of up to -20 mGal. In contrast, there is under-compensation in the southernregions with positive isostatic anomalies of about 80 mGal. In the researched area there are zero compensation linesaround the larger structures (Chia Gara, Mateen, Mangesh, Aqra, Piris, and Perat). In order to draw up the crustalthickness map, the Moho discontinuity depth was determined using topographic and Bouguer anomaly grids of thestudy area. In addition, the upper mantle anomalies were calculated by continuing the isostatic residual anomaly to45 km upward and then removing the past isostatic residual anomaly, that was continued upward to 35 km. Severalqualitative approaches were used to isolate the regional and remaining anomalies to analyze the gravity data, with anoptimal upward continuation level of 14 kilometers generated for the large and small maps.