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Analysis of recent airborne gravity and magnetic data for the interpretation of basement structures underneath the south–western Benue trough using source edge detector filters

Abdullahi Mukaila, Kumar Raj, Idi Bello Yusuf, Singh Upendra Kumar, Abba Adamu Usman

Acta Geophysica

2023

Vol. 71, no. 4

1595--1606

We present the detail basement and trends of geological structures associated with the Mesozoic-Cenozoic volcanism in the south–western region of the Nigerian Benue trough using recent gravity and magnetic anomalies of the region. The analysis aimed at recognizing and mapping the basement structure that controlled the distribution and source host of hydrocarbon and other economic mineral resources in the region. The structural recognition and mapping is done on the basis of the utilization of the Tilt Angle (TA) and Total Horizontal Derivative of the Tilt Angle (THDTA) of gravity and magnetic data. From these techniques, we have been able to identify and mapped out those edges of anomalous sources due to the gravity and magnetic data that are in association with the basement geological structures of the area. Based on the mapped structural trends, it is observed that the basement structures derived from both the gravity and magnetic anomalies correlated well with the zones of volcanic rocks around Gboko and area between Lefin and Oturkpo. The two locations are sitting over gravity and magnetic highs suggesting high density and susceptibility material below the subsurface. The Euler deconvolution method suggested depths between 1 and 5 km from both gravity and magnetic data. Deeper basement of anomalous sources are suggested between 3 and 5 km. The 1 km depth interprets the regions of basement highs or corresponding to intrusive zones.

On the nature of the Teisseyre-Tornquist Zone

Mazur S., Krzywiec P., Malinowski M., Lewandowski M., Aleksandrowski P., Mikołajczak M.

Geology, Geophysics and Environment

2018

Vol. 44, no. 1

17--30

The Teisseyre-Tornquist Zone (TTZ) is the longest European tectonic and geophysical lineament extending from the Baltic Sea in the NW to the Black Sea in the SE. This tectonic feature defines a transition zone between the thick crust of the East European Craton (EEC) and the thinner crust of the Palaeozoic Platform to the SW. The TTZ is evident from the seismic data as a perturbation of the Moho depth as well as from magnetic and gravity anomaly maps and heat flow distribution. For over a century, the TTZ has been considered a fossil plate boundary of the EEC corresponding to the limit of early Palaeozoic palaeocontinent Baltica. The results of quantitative interpretation of gravity and magnetic data, integrated with data from the new reflection seismic profiles crossing the TTZ, indicate the continuation of the Precambrian basement of the EEC and its lower Palaeozoic cover toward the SW underneath the Palaeozoic Platform. Potential field modelling also suggests the occurrence of a crustal keel underneath the TTZ. These results imply the location of a Caledonian tectonic suture, marking the site of the collision between Avalonia and Baltica, not along the TTZ, but farther SW, in NE Germany and SW Poland.