Structural study of Wamba and Environs, north-central Nigeria using aeromagnetic data and NigeriaSat-X image

• The tilt derivative (TDR) performs well at low latitudes.
• The major structural trend in the Wamba-Nssarawa-Eggon area is NE-SW.
• The structures within the Benue Trough may be related to the Romanche fracture zones and the Chain and Charcot fracture zones.
• The emplacement of the pegmatites in the Wamba-Nssarawa-Eggon area are fracture controlled.
• The sediment thickness ranges from 1 to 3 km.

Wamba 1:100,000 sheet 210 covers Wamba and Nassarawa Eggon area of North-Central Nigeria and consists of basement rocks, biotite granites and Older Granites in most parts of the northern part and by sedimentary rocks of the Cretaceous Middle Benue Trough in the southern part. High resolution aeromagnetic data was interpreted and the results integrated in a GIS environment with data from NigeriaSat-X image to map out the major structural trends within the area.Reduction-to-the-equator (RTE) operation was carried out on the aeromagnetic data after which several data transforms/derivatives such as horizontal derivative, analytical signal, and tilt derivative were calculated to highlight subsurface boundaries and the major structures within the area. Several digital image enhancement techniques such as general contrast stretching and edge enhancement were applied to the NigeraSat-X image in ERDAS IMAGINE 9.2 after which structures from the interpreted magnetic data and the image were mapped out on-screen using ArcMap 10.The results show that the RTE produced a reasonable geological picture of the area. Also the basement configuration consists of several NE–SW and NW–SE structures that range from 1 km to about 17 km in length with the NE–SW structures being the major trend within the area. The lineaments are mainly within the basement and the Older granites and may be related to the Pan-African Orogeny. This study was also able to map out more accurately the contact between the basement and the sediments hence a modified geological map of the area was produced.

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