Developing Priliminary Conceptual Model of Eastern Shalla Geothermal Prospect on the Bases of Geological and Fluid Geochemichal Observation
| dc.contributor.advisor | Yirgu, Gezahagn (Professor) | |
| dc.contributor.author | Adem, Fetum | |
| dc.date.accessioned | 2020-10-01T11:54:20Z | |
| dc.date.accessioned | 2023-11-09T14:10:59Z | |
| dc.date.available | 2020-10-01T11:54:20Z | |
| dc.date.available | 2023-11-09T14:10:59Z | |
| dc.date.issued | 2019-06-06 | |
| dc.description.abstract | The thesis is focused on developing a preliminary conceptual model of Shalla geothermal prospect in the Main Ethiopian Rift (MER), Ethiopia on the bases of geological and water geochemical information. The Shalla prospect is one of the geothermal prospects in the Lakes district of the MER, which is located about 220 kms south of Addis Ababa. The area is largely occupied by Lake Shalla which has no surface outlet and receives discharge from Lakes Ziway, Langano and Abijata. Many hot and warm springs emerge along its eastern, southern and western shores. The most important and boiling thermal springs are located at the eastern part of the shore. The main objective of this study is to develop preliminary conceptual geothermal model of the prospect. For this purpose 7 hot spring water samples for geochemical analyses and 8 exposed rock samples for petrographic analysis were taken. Based on the petrographic descriptions four major lithologic types are identified. These are ignimbrites, rhyolite lavas, basaltic flows and lacustrine sediments. From the results of analyzed water samples, an estimate of the sub- surface temperature, the water type and the water rock interactions of the springs are proposed. Chemical evaluation using a Cl-SO4-HCO3 triangular diagram suggests that the existence of Na-Cl-HCO3 water types with a high, HCO3 and Na content and mature waters (Cl rich) in the study area. The sub-surface temperatures of the geothermal reservoirs were estimated by T-2 (Na-K), T-(K-Ca) and T-(K-Mg) geothermometers. The Na–K solute geothermometers provided reliable estimated temperatures of about 1400C and the K-Mg geothermometers gave temperature of about 2250C. But the K-Ca solute geothermometry provided very high temperature slightly greater than 5000C and this is considered not suitable. The Na/400-25 K/10-√Mg ternary diagram was also applied to evaluate the equilibrium of water with reservoir rock. It is indicated that all water samples have reached in the partial equilibrium or lie in mixed zone. The preliminary conceptual model shows the general geothermal system of the prospect that includes the probable heat source and reservoir, the cap rock, recharge zone and geothermal fluid flow circulation. | en_US |
| dc.identifier.uri | http://10.90.10.223:4000/handle/123456789/22542 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Conceptual Model | en_US |
| dc.subject | Eastern Shalla Geothermal Prospect | en_US |
| dc.subject | Geothermal Fluid | en_US |
| dc.subject | Geothermal System | en_US |
| dc.subject | Geothermometers | en_US |
| dc.subject | Hot Spring | en_US |
| dc.title | Developing Priliminary Conceptual Model of Eastern Shalla Geothermal Prospect on the Bases of Geological and Fluid Geochemichal Observation | en_US |
| dc.type | Thesis | en_US |