“Geology, Petrography and Geochemistry of Volcanic Rocks of Koma-Andabet Areas, North Western Ethiopian Large  Igneous Province”

Zemenu Molla

dc.contributor.author	Zemenu Molla
dc.date.accessioned	2023-05-02T12:16:07Z
dc.date.available	2023-05-02T12:16:07Z
dc.date.issued	2022-02
dc.identifier.uri	http://ir.bdu.edu.et/handle/123456789/15230
dc.description.abstract	This study is aimed to investigate the petrological, geological and geochemical characteristics of magmatic rocks in the study area. To achieve this objective, detailed field work, geological, lithostratigraphical, cross sectional mapping, petrographical and geochemical analyses of 15 and 10 samples respectively was done. The geology of the study area has been classified into five lithological units: Aphanitic and porphyritic basaltic rocks, Gabbroic rock units, felsic pyroclastic rocks and unwelded ignimbrites. The low Ti basalts of the study area display sub ophitic texture and together with the presence of glomerophyric aggregates of pyroxene and plagioclase minerals denote a tholeiitic tendency. The correlation of MgO and CaO is positive and is an indicative of co-fractionation of olivine and clinopyroxene. The chondrite normalized values of the REE pattern shows enrichment in LREE, (La/Yb)N of 9.4 to 18 than MREE ( La/Sm N =1.38-1.86) and HREE (Dy/Yb =1.39-1.72) and there is fractionation of these HREE and MREE. The Nb/U ratio of the study area largly ranged from 13.91 to 37.1, which is an indicator for the contamination nature of the outpouring magma from the source crustal materials. The Koma-Andabet magmatic suits have similar trace element patterns and trace element ratios as Zr/Nb (12.95-14.37), Zr/Ce (4.53-5.23) and Hf/La (0.26-0.33) indicating originated from the same magmatic source. The low CaO/Al2O3 ratio (0.50-0.80) and the relatively flat pattern of HREE ((Dy/Yb) =1.39-1.72) and the HREE value is above 10 times greater than the chondrite values is a clue for the source of the Koma-Andabet magmatic rocks to be spinel containing mantle rather than garnet sourced. N N	en_US
dc.language.iso	en	en_US
dc.subject	Petrology	en_US
dc.title	“Geology, Petrography and Geochemistry of Volcanic Rocks of Koma-Andabet Areas, North Western Ethiopian Large Igneous Province”	en_US
dc.type	Thesis	en_US