Integration of magnetic, gravity, and well data in imaging subsurface geology in the Ksar Hirane region (Laghouat, Algeria)

Gravity and magnetic surveys, comprised of data from 985 gravity stations and 1373 magnetic stations, were recorded in the Ksar Hirane region in Laghouat, Algeria from May–August 2011 to study the poorly understood thickness of the sedimentary rocks and the structure of the basement rocks. The Bouguer anomalies vary from −48 mGal (northwest) to −58 mGal (southeast) and the magnetic intensities from 42,094 nT (northwest) to 42,344 nT (southeast). The constrained two-dimensional (2-D) forward modeling, three-dimensional (3-D) inversion of measured gravity and magnetic datasets helped us highlight the structure of the basement rocks at Ksar Hirane and determine the thickness of the sedimentary cover. Prominent NE-SW-trending geophysical anomalies that affect the study area were revealed by potential field gradient methods and were in agreement with the geological structure trends. The 3-D constrained inversion of magnetic data showed magnetized Precambrian metamorphic basement rock at shallow depths (approximately 3 km) in the southeast region and deeper (>10 km) in the northwestern part of the region, presenting similar results to that of the 2-D forward modeling of gravity and magnetic data. The inverted gravity data explain the structural architecture of the Ksar Hirane area, dissected by NE-SW sub-vertical faults.