Browsing by Author "Berhe, Alemayehu"

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    Integrated Geophysical Methods in Base Met Al Expwration and Studies of Shear Structures in kAtta II, Wollega
    (Addis Ababa Universty, 1998-06) Berhe, Alemayehu; Mammo, Tilahwn (PhD)
    The Katta II area is situated in the western wonega, about 7 km east of the Nejo two. This area belongs to the Nejo series metasedimentry metavolcanic and intrusive rocks of the Upper Proterozoic metamorphosed in the greenschist facies. Phyllite, different types of schists including graphitic schist, quartzjte, gossaniferrous and metavolcanic are the prevalent rock types in Katta II. A large number of geological investigation and borehole dri1Iing in Katta II were canied out in the years between 1970 and 1982. As a result, occurrences of copper, zinc, lead, gold and cobalt are reported. The purpose of this paper is mainly to outline the concepts of using integrated geophysical data to delineate the position of structural features and identifY the base metal mineralization zone and thereby determining the most probable locations of economic importan.:e. For this purposes reevaluation of the existing IP/resistivity data and detailed magnetic and EM surveys were done. The results of the qualitative interpretation are presented and discussed in relation to the available geological, geochemical and borehole information. The interpretation is made on the bases of experimental, theoretical, and field model curves. Preliminary results show that shear structures control the mineralization. The investigation further indicates that the abundance of graphitic schist in the study area causes serious interpretational problem._ For thorough understanding of the anomalous zones and their qualitative description, frequency domain IP, gravity, radiometric surveys and quantitative interpretation of the magnetic data are proposed
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    Integrated Geophysical Methods in Base Metal Exploration and Studies of Shear Structures in Katta II, Wonega
    (AAU, 1998-06) Berhe, Alemayehu; Haile, Tigistu(Dr
    The Katta n area is situated in the western wollega, about 7 km east of the Nejo two. This area belongs to the Nejo series metasedimen1Iy metavolcanic and intrusive rocks of the Upper Proterozoic metamorphosed in the greenschist facies. Phyllite, different types of schists including graphitic schist, quartzite, gossaniferrous and metavolcanic are the prevalent rock types in K.atta n. A large number of geological investigation and borehole drilling in Katta n were carried out in the years between 1970 and 1982. As a result, occurrences of copper, nne, lead, gold and cobalt are reported. The purpose of this paper is mainly to outline the concepts of using integrated geophysical data to delineate the position of structw"al features and identify the base metal mineralization zone and thereby determining the most probable locations of economic importance. For this purposes reevaluation of the existing IP lresistivity data and detailed magnetic and EM surveys were done. The results of the qualitative interpretation are presented and discussed in relation to the available geological, geochemical and borehole infonnation. The interpretation is made on the bases of experimental, theoretical, and field model curves. Preliminary results show that shear structures control the mineralization. The investigation further indicates that the abundance of graphitic schist in the study area causes serious interpretational problem. For thorough understanding of the anomalous zones and their qualitative description, frequency domain IP, gravity, radiometric swveys and quantitative interpretation of the magnetic data are proposed.