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Episodes 2020; 43(4): 919-933

Published online December 1, 2020

https://doi.org/10.18814/epiiugs/2020/020054

Copyright © International Union of Geological Sciences.

Updated tectonic terrane boundaries of Botswana determined from gravity and aeromagnetic data

by Chikondi Chisenga1,2*, Yan Jianguo1, Islam Fadel3, Mark van der Meijde3, and Estella A. Atekwana4

1 State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing (LIESMARS), Wuhan University, Box 129, Luoyu Road, Wuhan, China
2 Department of Earth Sciences, Ndata School of Climate and Earth Sciences, Malawi University of Science and Technology, P.O. Box 5196, Limbe, Malawi
3 University of Twente, Faculty for Geo-information Science and Earth Observation (ITC), P.O. Box 217, 7500 AE Enschede, The Netherlands
4 Department of Earth Sciences, College of Earth, Ocean, and Environment, University of Delaware, Newark, Delaware, USA

Correspondence to:*E-mail: cchisenga@must.ac.mw

Received: July 20, 2019; Revised: March 26, 2020; Accepted: March 26, 2020

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We used existing high-resolution gravity and aeromagnetic data to map the crustal units underneath Botswana. The thick sedimentary cover in this region has always been a challenge to understand the geological and tectonic configuration of unexposed crustal terranes using traditional geological methods. We utilized a standard physical mapping technique to convert previously obtained gravity and aeromagnetic data into apparent density and magnetic susceptibility maps, respectively, of the crustal tectonic terranes. Then, the derived maps were fused into a single apparent physical map to facilitate its geotectonic interpretation. The results showed that most of the tectonic boundaries were inaccurately mapped due to limited availability of high-resolution geophysical information. Moreover, we found that some terranes were missing from the current tectonic map. We used the apparent physical property map and the basement rocks information from literature to significantly update the tectonic map of Botswana, which shows the spatial extent of the geological units beneath the Kalahari sedimentary cover. The new map gives an insight into the geodynamics of Botswana crust.