Differentiating Structures and Litho-Units of the Tsaliet Group Around Negash Area, Tigray, Northern Ethiopia
| dc.contributor.advisor | Alene, Mulugeta (PhD) | |
| dc.contributor.author | Abebe, Eyob | |
| dc.date.accessioned | 2020-11-16T08:31:24Z | |
| dc.date.accessioned | 2023-11-09T11:26:23Z | |
| dc.date.available | 2020-11-16T08:31:24Z | |
| dc.date.available | 2023-11-09T11:26:23Z | |
| dc.date.issued | 2013-07-07 | |
| dc.description.abstract | The present study investigates the geology across an area of about 28 km2 in the vicinity of Negash village, Tigray, Northern Ethiopia. The investigation has been carried out petrographical and geochemical properties of volcanic rocks in the area. Field and laboratory works have revealed that the study area comprises dominantly low-grade schistosed metavolcanics and pyroclastics belonging to Tsaliet Group exposed in the western limb of Negash syncline. This contribution aimed to study and differentiate the Negash Tsaliet Group and map, and to present the salient micro-structural analysis of this Group. The mapped units are characterized by volcanic origin protoliths. Based on petrographic description, this Tsaliet Group of the area was affected by three prominent metamorphic episodes referred to as M1, M2, and M3. Further, field observation and petrographic description provided detailed information on the relative timing of deformation, which is as follows: (1) an early deformation stage (D1) followed by (2) D2 stage and 3) brittle phase (D3). D1 and D2 are associated with low-grade greenschist facies metamorphism. The timing relationship between metamorphic and deformational events is also deciphered as follows: the regional metamorphism (M1) accompanied an early Pan-African stage (D1) and M3 metamorphism associated with D2 deformation stage. However, M2 is contact metamorphism associated with local pluton. The ductile deformation phases D1 and D2 are associated with low-grade greenschist facies metamorphism. A brittle stage (D3) is responsible for the emplacement of granitic veins, faults and joints. D1 tectonic seem to be the main deformation style in the area, which developed the dominant schistosity (S1), regionally persistent in the terrain. The geochemical interpretation presented in this study has been used to decipher the tectonic evolution of metamorphic rocks of Negash study area. Rocks of intermediate to rhyolitic composition in Negash Tsaliet Group show calc-alkaline trends of evolution as confirmed by the chemical classification on various plots of geochemical data. On tectonic discrimination diagrams, the overall geochemical characteristics of Negash metavolcanic rocks provided evidence indicating that the area is most likely represents a part of volcanic island-arc tectonic setting. The field characteristics, petrography and geochemistry of Negash Tsaliet are similar to those of volcanic arcs described elsewhere in Northern Ethiopia. | en_US |
| dc.identifier.uri | http://10.90.10.223:4000/handle/123456789/23308 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Differentiating | en_US |
| dc.subject | Structures | en_US |
| dc.subject | Litho-Units | en_US |
| dc.subject | Tsaliet Group | en_US |
| dc.subject | Around Negash Area | en_US |
| dc.subject | Tigray | en_US |
| dc.subject | Northern Ethiopia | en_US |
| dc.title | Differentiating Structures and Litho-Units of the Tsaliet Group Around Negash Area, Tigray, Northern Ethiopia | en_US |
| dc.type | Thesis | en_US |