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 Iraq implemented by the Iraq Petroleum Company (IPC). In addition, the collected data were processed with recent gravity concepts and methods to establish a new regional geological image. A total of 868 gravity points were measured and corrected.

The Bouguer anomaly map of the study area was initially drawn up with the parameters and equations used to construct the IPC map. The newly-produced map shows a very strong correlation with the old IPC results. A new Bouguer map of the study area was then constructed using modern parameters and equations. A comparison between the 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 spreads to the Aqra zone with a negative value of up to -20 mGal. In contrast, there is under-compensation in the southern regions with positive isostatic anomalies of about 80 mGal. In the researched area there are zero compensation lines around the larger structures (Chia Gara, Mateen, Mangesh, Aqra, Piris, and Perat). In order to draw up the crustal thickness map, the Moho discontinuity depth was determined using topographic and Bouguer anomaly grids of the study area. In addition, the upper mantle anomalies were calculated by continuing the isostatic residual anomaly to 45 km upward and then removing the past isostatic residual anomaly, that was continued upward to 35 km. Several qualitative approaches were used to isolate the regional and remaining anomalies to analyze the gravity data, with an optimal upward continuation level of 14 kilometers generated for the large and small maps.

Keywords

• Gravity exploration,Gap area,Northern Iraq,Geosoft program

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