Facies and Microfossil Analysis of Jurassic Carbonate Unit In Lemi Area (Jema Section) Northern Shewa; Central Ethiopia.

dc.contributor.advisorAtnafu, Balemwal (PhD)
dc.contributor.authorGecho, Geremu
dc.date.accessioned2019-10-18T12:20:48Z
dc.date.accessioned2023-11-09T14:10:53Z
dc.date.available2019-10-18T12:20:48Z
dc.date.available2023-11-09T14:10:53Z
dc.date.issued2018-05-30
dc.description.abstractA thick Jurassic carbonate succession of about 157m thickness was studied in Jema section, the Blue Nile basin; of the Northwestern Ethiopian Plateau. This study was mainly aimed on exploring the stratigraphy, paleontology, facies analysis, biostratigraphy and determination of the depositional environments of carbonate unit of the Jema section. Based on the petrographic study of 18 representative carbonate rock samples and 8 marl samples; the compositional and textural analysis of rocks were studied and grouped into six (6) microfacies associations and about 22 foraminiferal and 7 ostracodals species are identified; which characterizes for intertidal zone, shoal restricted marine and shelf facies to open circulation environments. The presences of micritic, bioclastic wackestone and peloidal grainstone microfacies in the Jema section indicate shoal to shelf facies deposits. The Pelsparite and algal stromatolite mudstone are indicators of carbonate intertidal to shoal deposits of shallow marine setting. Based on the presence of index fossils such as Kurnubia cf. morrisi, Alveosepta jaccardi and Kurnubia palastiniensis with their associations of Conicokurnubia orbitoliniformis, Valvulina lugeoni, and Nautiloculina oolithica; the age of carbonate succession was determined to an age from Callovian to Oxfordian. Paleontological study of the section in Abay basin shows the carbonate unit is rich in micro fossils and less in macro fossils that supply additional data for stratigraphic and Paleoenvironmental interpretations; particularly of foraminifers and ostracods explored. Among the macrofossils few groups of bivalves, gastropods brachiopods and echinoids are also identified. The carbonate deposits of the logged section are correlated with chronostratigrphically equivalent and lithostratigrphically similar basins in North western and Southeastern plateau of the country regionally and with the previously logged sections in the Bilu Nile Basin locally.en_US
dc.identifier.urihttp://10.90.10.223:4000/handle/123456789/19502
dc.language.isoenen_US
dc.publisherAddis Ababa Universityen_US
dc.subjectDepositional Environmenten_US
dc.subjectMicrofaciesen_US
dc.subjectFaciesen_US
dc.subjectMicrofossilsen_US
dc.subjectPaleoenvironmenten_US
dc.subjectBiostratigraphyen_US
dc.subjectCarbonate Uniten_US
dc.titleFacies and Microfossil Analysis of Jurassic Carbonate Unit In Lemi Area (Jema Section) Northern Shewa; Central Ethiopia.en_US
dc.typeThesisen_US

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