Aeromagnetic mapping of basement structures and gold mineralization characterization of Kirk range area, southern Malawi

Document Type : Research Paper


1 Department of Mining Engineering, Malawi University of Business and Applied Sciences

2 Department of Earth Sciences, Stellenbosch University, South Africa


A high-resolution aeromagnetic survey was conducted in the Kirk Range region in southern Malawi with the goal of obtaining comprehensive geological and structural information. This newly collected data was analyzed and interpreted in order to gain a better understanding of the mode of occurrence of gold mineralization and related structural characteristics. To un-derstand the distribution of magnetic sources, many analytic approaches were applied to the aeromagnetic data, including reduction to the pole, Euler deconvolution, Spectrum analysis, Tilt and Vertical Derivatives filtering. Spectral analysis and Euler deconvolution were used to determine the depth of magnetic sources. The study reveals that the studied region is charac-terized by NE-SW and roughly E-W direction structures and that the gold occurrence is re-stricted within these structures, implying that mineralization is structurally controlled. These structures are found at depths of 200-1000 meters, according to Euler solutions produced from this work. Based on the calculated depths the structures controlling mineralization, in the Kirk Range are interpreted to occur at a depth range of 200 to 1000m and the structures trend in the NE-SW and E-W direction. However current gold mining is taking place at a fairly shallow depth of less than 50m and no gold mine has gone deeper than that. The struc-tural pattern and depth extent estimations show that gold mineralization in the Kirk range is expected to continue up to 1000 meters because the majority of the structures controlling mineralization in the region are located within that depth range. It is therefore recommended that future exploration should go deeper to a depth of about 200-1000 meters or more focus-ing on these NE-SW and E-W structures, because it is expected that at that depth range more mineralization should be intercepted.


[1]    Augustin,J and D. Gabour, “Multi-stage and multi-sourced fluid and gold in the formation of orogenic gold deposits in the world-class Mana district of Burkina Faso – Revealed by LA-ICP-MS analysis of pyrites and arsenopyrites,” Ore Geol. Rev., 2019.
[2]    W. S. Ibrahim, K. Watanabe, and K. Yonezu, “Structural and litho-tectonic controls on Neoproterozoic base metal sulfide and gold mineralization in North Hamisana shear zone, South Eastern Desert, Egypt: The integrated field, structural, Landsat 7 ETM+ and ASTER data approach,” Ore Geol. Rev., vol. 79, pp. 62–77, 2016, doi: 10.1016/j.oregeorev.2016.05.012.
[3]    F. Xiao and Z. Wang, “Geological interpretation of Bouguer gravity and aeromagnetic data from the Gobi-desert covered area , Eastern Tianshan , China : Implications for porphyry Cu-Mo polymetallic deposits exploration,” Ore Geol. Rev., vol. 80, pp. 1042–1055, 2017, doi: 10.1016/j.oregeorev.2016.08.034.
[4]    Hassanein H and Soliman, “Aeromagnetic data interpretation of Wadi Hawashiya area for identifying surface and subsurface structures, northeastern desert, Egypt.,” J. KAU Earth Sci 20(1)117–139, 2009.
[5]    S. An et al., “Interpretation of high resolution aeromagnetic data for structures study and exploration of polymetallic deposits in Kalatage area, eastern Tianshan (NW China),” Geosci. J., vol. 24, no. 3, pp. 315–327, 2020, doi: 10.1007/s12303-019-0027-6.
[6]    A. A. Akinlalu et al., “Aeromagnetic mapping of basement structures and mineralisation characterisation of Ilesa Schist Belt, Southwestern Nigeria,” J. African Earth Sci., vol. 138, pp. 383–391, 2018, doi: 10.1016/j.jafrearsci.2017.11.033.
[7]    A. Shaole, K. Zhou, J. Wang, H. Yang, and Z. Zhang, “Integrated analysis of gravity and magnetic fields in the Eastern Tianshan Belt, Xinjiang, Central Asia: Implications for Cu-Au-Fe polymetallic deposits exploration,” J. Appl. Geophys., vol. 159, pp. 319–328, 2018, doi: 10.1016/j.jappgeo.2018.09.002.
[8]    N. Olasunkanmi, O. Bamigboye, O. Saminu, N. Salawu, and T. Bamidele, “Interpretation of high resolution aeromagnetic data of Kaoje and its environ, western part of the Zuru Schist belt, Nigeria: implication for Fe–Mn occurrence,” Heliyon, vol. 6, no. 1, p. e03320, 2020, doi:.1016/j.heliyon. 2020.e03320.
[9]    M. A. Oladunjoye, A. I. Olayinka, M. Alaba, and M. A. Adabanija, “Interpretation of high resolution aeromagnetic data for lineaments study and occurrence of Banded Iron Formation in Ogbomoso area, Southwestern Nigeria,” J. African Earth Sci., vol. 114, pp. 43–53, 2016, doi: 10.1016/j.jafrearsci.2015.10.015.
[10]  J. Wang and X. Meng, “An aeromagnetic investigation of the Dapai deposit in Fujian Province, South China: Structural and mining implications,” Ore Geol. Rev., vol. 112, no. August, p. 103061, 2019, doi: 10.1016/j.oregeorev.2019.103061.
[11]   A. Miftah et al., Combined analysis of helicopter-borne magnetic and stream sediment geochemical data around an ancient Tiouit gold mine (Eastern Anti-Atlas, Morocco): Geological and mining interpretations, vol. 175. Elsevier Ltd, 2021.
[12]  C. J. Chernicoff, J. P. Richards, and E. O. Zappettini, “Crustal lineament control on magmatism and mineralization in northwestern Argentina: geological, geophysical, and remote sensing evidence,” Ore Geol. Rev., vol. 21, pp. 127–155, 2002.
[13]  Bloomfield.K and Garson.M.S, “The Geology of the Kirk Range-Lisungwe Valley Area. Ministry of Natural Resources. Geological Survey Department. Bulletin No.17.,” Gov. Printer, Zomba. Malawi, 1965.
[14]  J. Chisambi and B. von der Heyden, “Primary gold mineralization in the lisungwe valley area, kirk range, southern Malawi,” South African J. Geol., vol. 122, no. 4, pp. 505–518, 2019, doi: 10.25131/sajg.122.0039.
[15]  J. Chisambi, T. Haundi, and G. Tsokonombwe, “Geologic structures associated with gold mineralization in the Kirk Range area in Southern Malawi,” Open Geosci., vol. 13, no. 1, pp. 1345–1357, 2021, doi: 10.1515/geo-2020-0304.
[16]  M.-L. Airo and S. Mertanen, “Magnetic signatures related to orogenic gold mineralization, Central Lapland Greenstone Belt, Finland,” J. Appl. Geophys., vol. 64, no. 1–2, pp. 14–24, Mar. 2008, doi: 10.1016/j.jappgeo.2007.10.003.
[17]  G. S. Carter, “THE GEOLOGY AND MINERAL RESOURCES OF MALA WI.” Government print, Zomba, Malawi, 1973.
[18]  and D. Z. Chipili., E., “‘The Geology of the North Kirk Range. Ministry of Energy and Mining. Geological Survey Department. T1228A.,’” 1997.
[19]  E. Chipili. and Dulanya.Z, “The Geology of the North Kirk Range. Ministry of Energy and Mining. Geological Survey Department. T1228A.,” 1997.
[20] Z. Dulanya, N. Morales-simfors, and Å. Sivertun, “Journal of African Earth Sciences Comparative study of the silica and cation geothermometry of the Malawi hot springs : Potential alternative energy source,” J. African Earth Sci., vol. 57, no. 4, pp. 321–327, 2010, doi: 10.1016/j.jafrearsci.2009.11.001.
[21]  U. Ring, A. Kröner, and T. Toulkeridis, “Palaeoproterozoic granulite-facies meta-morphism and granitoid intrusions in the Ubendian-Usagaran Orogen ofnorthern Malawi, east-central Africa.,” Precambrian Reserch., vol. 85, 27–51., 1997.
[22] R. B. McConnell, Outline of the geology of Ufipa and Ubende. Bulletin of Geological Survey of Tanganyika. 1950.
[23]  S. Dewaele, P. Muchez, R. Burgess, and A. Boyce, “Geological setting and timing of the cassiterite vein type mineralization of the Kalima area ( Maniema , Democratic Republic of Congo ),” J. African Earth Sci., vol. 112, pp. 199–212, 2015, doi: 10.1016/j.jafrearsci.2015.09.006.
[24] J. L. et al Lenoir, “The Palaeoproterozoic Ubendian shear belt in Tanzania: geochronology and structure,” J. African Earth Sci., vol. 19, no. 3, pp. 169–184, 1995.
[25]  E. H. Ackermann, “Ein neuer Faltengürtel in Nordrhodesien und seine tektonische Stellung im Afrikanischen Grundgebirge.,” Geol. Rundschau, vol. 38, 24–39, 1950.
[26]  E. H. Ackermann and A. Forster, “Grundzuge der Stratigraphie und Struktur des Irumide Orogen.,” 21st International Geological Congress, pp. 182–192, 1960.
[27]  P. H. Macey et al., “Mesoproterozoic geology of the Nampula Block, northern Mozambique: Tracing fragments of Mesoproterozoic crust in the heart of Gondwana,” vol. 182, pp. 124–148, 2010, doi: 10.1016/j.precamres.2010.07.005.
[28] B. De Waele, I. C. W. Fitzsimons, F. Tembo, and B. Mapani, “The geochronological framework of the Irumide Belt: A prolonged crustal history along the margin of the Bangweulu Craton Am. J. Sci., no. February, 2009, doi: 10.2475/02.2009.03.
[29] B. De Waele and B. Mapani, “Geology and correlation of the central Irumide belt,” J. African Earth Sci., vol. 35, pp. 385–397, 2002.
[30]  J. Chisambi and B. von der Heyden, “Primary gold mineralization at Manondo – Choma area, Kirk range, Southern Malawi,” South African J. Geol., no. 4, 2019.
[31]  K. I. Kis, “Transfer properties of the reduction of magnetic anomalies to the pole and to the equator,” Soc. Explor. Geophys., vol. 55, no. 9, pp. 1141–1147, 1990.
[32]  X. Li, “Magnetic reduction-to-the-pole at low latitudes: Observations and considerations,” Lead. Edge, vol. 1, 2008.
[33]  A. M. Aziz, W. A. Sauck, E.-A. H. Shendi, M. A. Rashed, and M. Abd El-Maksoud, “Application of Analytic Signal and Euler Deconvolution in Archaeo-Magnetic Prospection for Buried Ruins at the Ancient City of Pelusium, NW Sinai, Egypt: A Case Study,” Surv. Geophys., vol. 34, no. 4, pp. 395–411, Apr. 2013, doi: 10.1007/s10712-013-9229-z.
[34]  Reid, A.B., Allsop, J.M., Granser, H., Millett, A.J. & Somerton, I.W., “Magnetic interpretation i n three dimensions using Euler deconvolution,” Geophysics, vol. v 55, 80-9.
[35]  M. Dobrin and C. H. Savit, “Introduction to Geophysical Prospecting,” 1988. (accessed Aug. 19, 2014).
[36]  A. and F. S. G. Spector, “Statistical Models For Interpreting Aeromagnetic Data,” Geophysics, 1969.
[37]            J. Garcia-Abdeslem, “Inversion of the power spectrum from gravity anomalies of prismatic bodies,” Geophysics, vol. 60, no. 
6, pp. 1698–1703, 1995, doi: 10.1190/1.1443902.
[38]  Nabighian M.N., “The analytic signal of two-dimensional mag- netic bodies with polygonal cross-section: its properties and use for automated anomaly interpretation.,” Geophys. 37, 507±517.
[39]  F. S. Spector, A. and Grant, “Statistical models for interpreting aeromagneflc data.,” Geophys. 35, 293- 302.
[40] B. De Waele, A. Kampunzu, and F. Tembo, “The Mesoproterozoic Irumide belt of Zambia,” J. African Earth Sci., vol. 46, pp. 36–70, 2006, doi: 10.1016/j.jafrearsci.2006.01.018.
[41]  R. Boyd et al., “The Geology and Geochemistry of The East African Orogen In Northeastern Mozambique,” Geol. Soc. South Africa, vol. 113, pp. 87–129, 2010, doi: 10.2113/gssajg.113.1.87.
[42] B. Bingen et al., “Geochronology of the Precambrian crust in the Mozambique belt in NE Mozambique, and implications for Gondwana assembly,” Precambrian Res., vol. 170, pp. 231–255, 2009, doi: 10.1016/j.precamres.2009.01.005.