Stratigraphic, Petrographic and Geochemical Characteristics of the Gohatsion Formation in the Blue Nile Basin, Central Ethiopia: Implications for Paleoenviroment Reconstruction
| dc.contributor.advisor | Atnafu, Balemwal (PhD) | |
| dc.contributor.author | Getachew, Samuel | |
| dc.date.accessioned | 2019-08-28T07:05:26Z | |
| dc.date.accessioned | 2023-11-09T14:10:40Z | |
| dc.date.available | 2019-08-28T07:05:26Z | |
| dc.date.available | 2023-11-09T14:10:40Z | |
| dc.date.issued | 2018-06-02 | |
| dc.description.abstract | This thesis investigates the stratigraphic, petrographic and geochemical characteristics of the Gohatsion Formation in the Blue Nile Basin, central Ethiopia. In addition to detailed geological mapping and stratigraphic logging in the field, petrographic, mineralogical and major/trace element chemical analysis was performed on 27 samples by means of XRD, ICP-MS/AES analysis. The Formation consists cyclic intercalation of fine siliciclastic and evaporite beds and has been classified into 3 informal members namely, the Upper Mudrock Member, Gypsum Member and the Lower Mudrock Member. Four lithostratigraphic sections were constructed at the Gohatsion-Dejen, Mugher and Jemma localities. Lithofacies at an outcrop and petrographic scale indicates the presence of complex geological history. The Lower and Upper Mudrock Members were formed under tidal influenced environments such as intertidal, supratidal, lagoonal, back-barrier mudflats and tide dominated estuary. The Gypsum Member shows both subaqueous and subaerial facies formed under holomictic brine flux with both continental and marine influences. Geochemistry of mudrock samples showed lower compositional maturity and low weathering index (CIA and PIA values) which is indicative of first cycle deposition. Trace element analysis showed that the provenance composition for such rocks are felsic to intermediate metamorphic to plutonic rocks formed under an active continental arc setting. Diagenetic evolution of sandstone and dolomitic packstone rocks seem to be influenced by meteoric and late stage diagenetic processes whereas the gypsum recorded much of telogenetic processes. | en_US |
| dc.identifier.uri | http://10.90.10.223:4000/handle/123456789/18873 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Blue Nile Basin | en_US |
| dc.subject | Gohatsion Formation | en_US |
| dc.subject | Lithofacies | en_US |
| dc.subject | Provenance | en_US |
| dc.subject | Diagenesis | en_US |
| dc.title | Stratigraphic, Petrographic and Geochemical Characteristics of the Gohatsion Formation in the Blue Nile Basin, Central Ethiopia: Implications for Paleoenviroment Reconstruction | en_US |
| dc.type | Thesis | en_US |