Geology, Petrography and Stratigraphy of Volcanic Products Around Worabe, Central Main Ethiopian Rift
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Date
2024-06
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Addis Ababa University
Abstract
In this paper petrographic, Structural, and stratigraphic investigation of volcanic rocks in the central main Ethiopian rift is presented. Normal faults and several rivers (mainly Dijo River) play a significant role in exposing the lithologic units and in controlling the alteration processes observed in the area. This investigation has done with in the central Ethiopian regional state, specifically around Worabe town in Silte zone, about 170 kilometers south of Addis Ababa (capital city of Ethiopia). This investigation aims to detail the area's lithostratigraphy through fieldwork, petrographic analysis, and structural analysis using field observations and satellite imagery. There are five volcanic lithostratigraphic units (Plateau basalt (300m), Welded tuff (250m), Unwelded to poorly welded tuff (270m), Rift floor basalt and associated scoria (80m), Rhyolitic lava dome and Obsidian with felsic pyroclasts (280m)), which are part of quaternary volcanic products and one sedimentary unit (Volcaniclastic sediments(30m)) are presented in the composite stratigraphic section. The pyroclastic fall deposit (Unwelded to poorly welded tuff) is the dominant product with interlayered pyroclastic flow. The rift floor basalt covers smallest area among volcanic unit in this area. The wider area is covered by felsic volcanic products. A total of 19 samples from the four stratigraphic units (plateau basalt, welded tuff, rift floor basalt and rhyolite) are studied by using a petrographic microscope. Petrographic analysis reveals unique mineral compositions and textures, indicative of different volcanic processes and post-depositional alterations. Furthermore, the study highlights structural controls on volcanic activity, alteration processes, and the influence of geological structures on eruption patterns. To have a better understanding of the petrogenetic and magma plumbing systems, further research is required.
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Geology Petrography, Stratigraphy, Volcanic Products Around Worabe, Central Main Ethiopian Rift