Research Article Structural control and Sn-Ta-Nb mineralization potential of pegmatitic bodies in Numbi, South Kivu Eastern D.R Congo I.A. Oyediran a,b, ⁎, C. Nzolang a,c , M.P. Mupenge a , S.O. Idakwo b,d a Department of Geology, Pan African University of Life and Earth Science Institute (Including Health and Agriculture), University of Ibadan, Ibadan, Nigeria b Department of Geology, University of Ibadan, Ibadan, Nigeria c Department of Geology, State University of Bukavu, DR, Congo d Department of Earth Sciences, Kogi State University, Anyigba, Kogi State, Nigeria abstract article info Article history: Received 2 January 2020 Received in revised form 24 May 2020 Accepted 25 May 2020 Available online 29 May 2020 The Numbi pegmatites of South Kivu Province (D.R.C) in the Kibaran belt which intruded the Mesoproterozoic Formation (1.6-0.9 Ga) was investigated to elucidate the structural imprints and geochemical characteristics related to the pegmatitic rocks associated with Sn - Nb - Ta mineralization, source(s) of the mineralisation, pro- cesses responsible for its formation and the economic viability of Tin-Niobium-Tantalum mineralisation. The structural features include: the pegmatitic veins with orientation from N150°E to N160°E characterized with di- rection and dip values averages of N84°E/13°SSE for horizontal veins and N138°E/73°WSW for subvertical veins. From the different stresses, the pegmatite and quartz veins occurred during the same tectonic phase. The char- acteristic high SiO 2 , Al 2 O 3 , Fe 2 O 3 and Na 2 O, indicates peraluminous and S-type pegmatite, ferroan and medium to high K, characteristics of a collisional tectonic environment. The pegmatite showed an enrichment of Rb (114.70 – 1000 ppm), Ta (27.50 – 370.90 ppm), Cs (28.90 – 682.80 ppm), Sn (238 – 2451 ppm) and Nb (31.80 – 139.20 ppm) trace element, consistent with indices for mineralisation. The La/Yb vs. La and Sm/Yb vs. La/Sm diagrams established magmatic compositional heterogeneities and/or mixing in the lava suits that formed the pegmatites. Variation plots of Ta vs Ga, Ta vs Cs, Ta vs Cs + Rb and Ta vs K/Cs showed consistent trend of miner- alization using their position relative to the Beus and Gordiyenkos line. These ratios - K/Ba, K/Rb, Ba/Rb, Rb/Sr and geochemical models- Y vs. Nb, (Y+Nb) vs. Rb, Zr vs. Ta/Zr, B (=Fe+Mg+Ti) vs A(=Al-(K+Na+2Ca), R1(=4Si +11(Na+K)-2(Fe+Ti)) vs R2(=6Ca+2Mg+Al) with observed tectonic markers like lineation/foliation, joints and veins suggests a structurally controlled mineralisation. The Numbi pegmatites are of partial melting of lith- ospheric mantle sources, relatively rich in Sn, Ta and Nb of economic value that are structurally controlled. © 2020 Elsevier B.V. All rights reserved. Keywords: Numbi pegmatites Geochemical models Structural features Lithospheric mantle Sn Ta and Nb mineralisation 1. Introduction South Kivu Province with three other provinces namely; Maniema, Katanga and North Kivu belong to the Kibara belt of Democratic Repub- lic of Congo (Fig. 1), worldwide tilts NE-SW in the SW and NW-SE in the NW parts respectively, has been constantly described as Mesoprot- erozoic orogenic belt (1.6-0.9 Ga) (Debruyne et al., 2015; Dewaele et al., 2015). Granitoids from the Kibara belt consist of granites as well as pegmatites and they chronologically tie up to the Mesoproterozoic formations (1600-900Ma) situated in the Maniema, Kivu and Katanga provinces in Democratic Republic of Congo (Tack et al., 2010). This belt forms large province of metallogeny containing abundant granite- related ore deposits, which are rich in minerals like cassiterite (SnO 2 ), spodumene (LiAlSi 2 O 6 ), columbite-tantalite (Nb, Ta) 2 O 5 ), beryl (Be 3 Al 2 Si 6 O 18 ), wolframite ((Fe, Mn) WO 4 ), amblygonite (Li, Na) AlFPO 4 ), monazite (Ce, La, Y, Nd, Th) and Sn-Nb-Ta in pegmatite (Dewaele et al., 2011, 2013; Dill, 2015). The rapid rising cost-effective manufacturing and societal development especially enhancement in technologies of digital age in the 4 th industrialized revolution still re- quire additional metal supply for electronic devices (Sn, Nb, Ta, Li, W, Cu, Co, Cr, REE, In, etc.). These metals are mined from numerous and di- verse rocks amongst which pegmatites, appear to be the chief supplier of these metals (Lehmann et al., 2014). However, this appeal and desirability by international mining corpo- rations for these Kibaran mineral wealth, expected to be a gain for Congolese people, is the basis of racial conflicts and regional hostilities among the Democratic Republic of Congo and its neighboring countries (Rwanda, Burundi and Uganda) with fair blessing support of multina- tional companies. Rising rebel factions operating in the area in order to have the entire control of the mineralized zones have created disarray and insecurity in the province and a loss for the threatened country (Mantz, 2013). Lithos 368–369 (2020) 105601 ⁎ Corresponding author. E-mail address: oyediranibrahim2012@gmail.com (I.A. Oyediran). https://doi.org/10.1016/j.lithos.2020.105601 0024-4937/© 2020 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Lithos journal homepage: www.elsevier.com/locate/lithos