文章基本信息

标题：Reconstructing Deformation History by Using Microstructural and Petrographic Analysis of Sorobo, Konso Area, Southern Ethiopia
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作者：Muluken Fanta Bassa
期刊名称：International Journal of Environmental Monitoring and Analysis
印刷版ISSN：2328-7659
电子版ISSN：2328-7667
出版年度：2020
卷号：8
期号：5
页码：130-143
DOI：10.11648/j.ijema.20200805.12
语种：English
出版社：Science Publishing Group
摘要：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 (M1andM2). 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, jointsandfissures, shear zones and folds are important depositional sites for different hydrothermal economic mineral deposits.
关键词：Microstructure; Deformation; Metamorphism; Progression; Retrogression