Integrated Geophysical Methods in Base Metal Exploration and Studies of Shear Structures in Katta II, Wonega
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Date
1998-06
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AAU
Abstract
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.