Volume 8, Issue 5, October 2020, Page: 130-143
Reconstructing Deformation History by Using Microstructural and Petrographic Analysis of Sorobo, Konso Area, Southern Ethiopia
Muluken Fanta Bassa, Department of Geology, Arbaminch University, Arbaminch, Ethiopia
Received: Mar. 10, 2020;       Accepted: May 25, 2020;       Published: Sep. 21, 2020
DOI: 10.11648/j.ijema.20200805.12      View  239      Downloads  54
The deformation history of Sorobo, Konso area (southern Ethiopia) within the Mozambique Belt, is described using microstructural and petrographic analysis. The area is characterized by folds and metamorphic fabrics that trend between NNE and NNW and consist of high-grade, amphibolite- to granulite-facies rocks. It is affected by five deformational phases (D1 to D5) and two metamorphic events (M1 & M2). During shortening deformation events (D1 to D3) the development of gneissosity (D1), the formation of tight to isoclinal and recumbent folds (D2) and the superposition of secondary (upright) fold (D3) on earlier recumbent fold resulting in type-3-fold interference pattern are formed respectively. During fourth deformation phase (D4) most of the rock units of the area are affected by shearing or shows east and west vergence. The area is affected by both sinistral and a dextral sense of shearing but dextral shear-sense appears dominant. Brittle type of deformation phase (D5) was developed and resulting in different types of faults varies in orientation. Peak progressive metamorphism of the granulite facies (M1) and retrogression (M2) are also associated with the deformational phase. An equal-area plot and rose diagram shows the orientation of all fabric, which indicates multiphase deformation. Geological structures in the study areas like faults, joints & fissures, shear zones and folds are important depositional sites for different hydrothermal economic mineral deposits.
Microstructure, Deformation, Metamorphism, Progression, Retrogression
To cite this article
Muluken Fanta Bassa, Reconstructing Deformation History by Using Microstructural and Petrographic Analysis of Sorobo, Konso Area, Southern Ethiopia, International Journal of Environmental Monitoring and Analysis. Vol. 8, No. 5, 2020, pp. 130-143. doi: 10.11648/j.ijema.20200805.12
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This article is an open access article distributed under the Creative Commons Attribution License ( which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Asrat, A. and Barbey, P. (2003). Petrology, geochronology and Sr–Nd isotopic geochemistry of the Konso pluton, south-western Ethiopia: implications for transition from convergence to extension in the Mozambique Belt, International Journal of Earth science (GeolRundsch), 92, pp. 873-890.
Asrat, A., Gleizes, G., Barbey, P. and Ayalew, D. (2003). Magma emplacement and mafic-felsic magma hybridization: structural evidence from the Pan-African Negash pluton, Northern Ethiopia. J Struct Geol 25, pp. 1451–1469.
Davidson, A. (1983). The Omo River Project, Reconnaissance geology and geochemistry of parts of Ilubabor, Kefa, Gemu Gofa and Sidamo, Ethiopia, Ethiopian Institute of Geological Surveys, Bulletin 2, Addis Ababa, pp. 18-42.
Ethiopian Institute of Geological Survey (EIGS) (2010). Geological Map of Ethiopia, 2nd ed., Unpublished technical report, EIGS, Addis Ababa, Ethiopia, 129 pp.
Gichile, S. (1992). Granulites in the Precambrian basement of southern Ethiopia: geochemistry, P–T conditions of metamorphism and tectonic setting. J Afr Earth Sci 15 pp. 251–263.
Kazmin, V., Shiferaw, A. and Balcha, T. (1978). The Ethiopian basement: stratigraphy and possible manner of evolution. Geologische Rundschau 67, pp. 531–546.
Kroner, A. and Stern, R. J. (2004). Pan-African orogeny, North African Phanerozoic, Rift valley, V 1, PP. 1-3.
Kusky, T. M., Abdelsalam, M., Stern, R. J. and Tucker, R. D. (eds.) (2003). Evolution of the East African and related orogens, and the assembly of Gondwana. Precambrian Res. 123, pp. 82-85.
McClay K R (1987). The Mapping of Geological Structures. Department of Geology Royal Holloway and Bedford New College University of London.
Samuel, G. (1991). Structure, metamorphism and tectonic setting of a gneissic terrane, the Sagan Afleta area, southern Ethiopia. Msc thesis, Ottawa-Carleton Geoscience center and University of Ottawa, Canada.
Santosh, M., Morimoto, T. and Tsutsumi, Y. (2006). Geochronology of the khondalite belt of Trivandrum Block, southern India: electron probe ages and implications for Gondwana tectonics. Gondwana Research 9, pp. 261–278.
Shackleton (1979, as cited in Asrat and Barbey, 2003) Petrology, geochronology and Sr-Nd isotopic geochemistry of the Konso pluton, south-western Ethiopia: implications for transition from convergence to extension in the Mozambique belt. Int journal of Earth Science (Geol Rundsch), 92, pp. 873-890.
Stern, R. J. (1994). Arc assembly and continental collision in the Neoproterozoic east African Orogen: implications for the consolidation of Gondwanaland. Annu. Rev. Earth Planet. Sci. Lett. 22, pp. 319–351.
Tadesse S., Milesi JP., Deschamps Y (2003). Geology and mineral potential of Ethiopia: a note on geology and mineral map of Ethiopia. Journal of African Earth Sciences. 36 (2003): 273–313.
Vaughan, A. P. M. and Pankhurst, R. J. (2008). Tectonic overview of the West Gondwana margin. Gondwana Research, 13, pp. 150–162.
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