Report for the mapping project carried out in area L within Igayaza Subcounty in Isingiro District in June/August, 2018

Abstract

In May/June a class of Geology and petroleum students from Makerere University camped in Igayaza area which is located 30km south of Mbarara in Isingiro district for two weeks to carry out geological mapping project in this area. This was aimed at acquainting students with necessary practical skills such as field data acquisition, mapping skills petrographic analysis and usage of geological equipment’s. Several materials and methods were applied in order to carry out the mapping exercise and these include; Global Positioning System (GPS), geological hammer for collecting samples, geological compass for location and taking structural measurements and so many others. Different geologic structures are encountered in area L and these include: joints, faults, bedding planes, lamination, and unconformity and micro folds. Joints and bedding planes were analyzed using stereonet-win-64 and found out that joints have two general trends (NW-SE and NE-SW) and bedding planes have one preferred orientation (NE-SW) in area L. Major minerals observed from the thin sections of the collected samples (L16, L11, L22, L7a, L7b and L19) include: quartz, clay minerals (probably illite and sericite) and iron oxide (probably hematite/ limonite). Wavy extinction is common in most of quartz grains (L11 and L7b) and this indicates low grade metamorphism whereas in some samples there is development of micas which could be indicating very low grade metamorphism. From the evidence observed in area L and other areas mapped by different groups, a regional synthesis was constructed to give geologic history of Karagwe-Ankolean system. Lastly, several conclusions have been made depending on the observations and analysis made both in the field and in the laboratory.