Application of high-resolution aeromagnetic data for structural frame work of Zamfara Basement Complex, North Western Nigeria

Abstract

Zamfara state, located in the northwest of Nigeria, is regarded as one of the richest states in terms solid mineral abundance in Nigeria. Unofficial artisanal miners have found over 120 mining sites in the state. However, there is Insufficient knowledge of local and regional geology in the research area. High resolution aeromagnetic data were utilized to determine the depth of magnetic sources and basement tectonics. Clarifying the tectonic distribution of the basement complex and small portion of Sokoto sedimentary sequence within the research area is the aim of this investigation. Furthermore, this elucidation will help to differentiate the region's causative sources, which include contacts, faults, fractures, silk and dykes. Three approaches were compared for estimating the depth to magnetic sources namely: upward continuation, source parameter imaging, and Euler deconvolution. Euler deconvolution was upward continued to a distance of 1 km for (structural indexes 0 and 1, i.e., for contact and dyke) respectively. The map from these structural indexes exhibits similar patterns in terms of magnetic intrusive geological structures. Most magnetic structures and intrusive depth sources diminish at shallower range < 500 m while deeper sources > 1 km and 1.5 km were still present. The source parameter imaging produces the depth to the magnetic source, which ranges from 85.42 nT, which indicates a basement complex, to 1088.21 nT, which indicates a sedimentary basin. In addition to the subsurface geologic conditions, Visual inspection of the total horizontal derivative (THD), and tilt derivative (TD) revealed swift variations in the lithologic features and tectonic inferences as well as the subsurface geologic conditions. Three primary magnetic lithologic zones were identified from the analytical signal map classification: strong (> 0.051 nT/m), intermediate (0.016 to 0.051 nT/m), and low magnetic zones (< 0.016 nT/m). The lineament map, tilt derivative, and horizontal tilt derivative all showed the amplifications of various structural features (faults, fractures, and folds). These demonstrate the structural control of minerals in this research area.