Application of Ground Magnetic Geophysical Method in the Delineation of Subsurface Structures of Dala Hill in Kano Ancient City, Northwest Nigeria

Abstract

Ground Magnetic measurement was carried out with the aim of delineating the subsurface structures on Dala hill, Kano State. Total magnetic intensity data were acquired using the SCINTREX proton precession magnetometer along closely spaced traverses. The acquired total magnetic intensity data were reduced and plotted using Golden Surfer software to produce the 2D and 3D surface maps for visual inspection. Five profiles AB, CD, EF, GH and IJ were selected for forward modelling using Mag2dc software to give detail information about the causative body parameters. The depths of these bodies from the surface fall in the interval 0.0 m to 8.5 m. The high magnetic anomaly field ranges from -21,752 to 47,205 nT which suggested area of iron occurrences. The study categorized the identified major anomalous features into two: the shallower bodies which penetrated down to a maximum depth of 67.3 m were inferred to be disturbed sediments, fire pits and kilns; whereas the rest, the deep-rooted features with greater depth of penetration reaching up to 193.2m, have high susceptibility range of up to 7.3 SI units, were interpreted to be intrusive ferromagnetic bodies. The findings of the study were in close agreement with recent archaeological findings about the hill.

Geoelectrical Characterization of Subsurface Structures in Dala Hill, Kano, Nigeria: A Comparative Study with Ground Magnetic Data

“…Considering Profile 1, which was taken from the northwestern part of the study area, an intrusion can be observed at the top layer and extends into the weathered layer, covering a total depth range of 2-48 m. This intrusion is characterized by a high resistivity of iron ore, and seems to contain possible iron ore as it shows a good correlation with low chargeability inversion. Additionally, the presence of this intrusion aligns with findings from the ground magnetic survey conducted by Shehu et al [8], further supporting the potential for iron ore mineralization in this area.…”

“…Shehu et al [8] conducted a ground magnetic study to delineate the subsurface structures of Dala Hill. Two classes of anomalies were discovered, with the shallow anomalies correlated with the anthropogenic activities of https://doi.org/10.56578/atg030104 ancient settlers and the deep ones associated with internal geologic features.…”

“…Two classes of anomalies were discovered, with the shallow anomalies correlated with the anthropogenic activities of https://doi.org/10.56578/atg030104 ancient settlers and the deep ones associated with internal geologic features. However, all geophysical methods are affected by equivalence and suppression, which is why Shehu et al [8] recommended the execution of other geophysical studies. Among the methods recommended was ground penetrating radar (GPR) as well as other electrical methods.…”

Investigation of Mineral Deposition in Ijeda, Osun State Southwestern Nigeria Using Ground Magnetic Data

“…The magnetic method was also used as a means in ground water investigation in a basement complex terrain with a view to delineate the subsurface structure, estimate the overburden thickness and access groundwater in the locality (Oni et al, 2020). Ground magnetic measurement was as well carried out with the aim of delineating the subsurface structures on Dala hill, Kano State in the studies carried out by (Shehu et al, 2020). A Ground magnetic survey was equally done to investigate the presence of an iron ore deposit at Oke Aro in Iseyin East, Southwest Nigeria (Adebisi, 2018).…”