We present the results of reprocessing and interpretation of the aeromagnetic data, originally acquired by Aeroservice Corporation during the early 1970’s, over the Algerian territory. Comprehensive processing procedures of these data are outlined in this contribution to bring them to a modern standard. The interpretation of the resulting aeromagnetic map using modern derivative and inversion techniques has helped to identify and map the deep structures that control the tectonics of Algeria. The interpreted structural map suggests the presence of important mega shear zones that are associated with different tectonic events that have shaped the geology of Algeria.
During the late of 1960’s and the beginning of the 1970’s Aeroservice Corporation conducted an airborne geophysical survey over the whole of Algeria that focused on geological mapping and mineral resources exploration. The first stage of the countrywide survey was carried out in 1969 over the Saharan basins at constant barometric height of 500 m above the mean sea level with 5 km line spacing, with only magnetic field sensor. The second stage, to complete the national coverage was conducted during the period 1971 to 1974. This survey stage was carried out at constant ground clearance of 150 m, and with nominal line spacing of 2 km and tie line spacing of 40 km. Some areas were flown at 0.5 km line spacing while others were at 5 km. The whole country was divided into panels and flight paths were perpendicular to the main geological structures (see Figure 1). Total magnetic field measurements and four gamma spectrometric channels were recorded during this survey stage. Two configurations of the magnetic sensor were adopted (fixed wing and rotary wing). Cesium and fluxgate magnetometers were employed to measure the magnetic field (Aeroservice, 1975). Navigation was performed using a Doppler system and altitude was measured using a radar altimeter. All the data were recorded on magnetic tapes. During the acquisition profile data were also recorded by printing to a paper analog recorder. A cesium magnetic base station was used to monitor the diurnal geomagnetic activity. The results of the survey were preserved on magnetic tapes as well as flight path and contours maps of total magnetic intensity and radiometric total count. Interpretation maps deconvolution modeling results. The main purpose of the current study was the recover of these archived data and by reprocessing them to modern standards to highly improve their quality. The results of this reprocessing have been the construction of a new more reliable and better quality aeromagnetic map of Algeria consistent with modern processing standards. It is interesting to note that the new map and grid are significantly better than that was possible when the survey was first acquired by Aeroservice Corporation. Initial qualitative and quantitative interpretation of the national map has provided important new understanding of the role that major tectonic elements (lineaments/zones) have played in controlling the geology and structural development of the Algerian territory. This has resulted in a new structural map of Algeria.
