Geological mapping project report of Igayaza-isingiro district, Uganda.
Abstract
This report is a summary of the Geologic mapping course carried out in Gayaza, Isingiro district on the Gayaza synclinorium, within the Karagwe-Ankolean system of rocks. This excursion was aimed at equipping students with skills of geologic mapping such as recording field data, interpreting it and correctly representing it on a base map, measure and correctly interprets the different field structures, collect relevant samples and learn how to use field equipment such as the GPS and geologic compass. The report is comprised of a detailed geological study of area E that I mapped that is the mineralogy, metamorphism, stratigraphy, structural data and economic activities as well as the regional synthesis which covers Gayaza synclinorium and surrounding areas of Western Uganda within the Karagwe-Ankolean system. Area E is predominated by quartzite on top of the ridges, shale on the ridge slopes and valleys, as well as a few conglomerates. On addition to these, the rest of the Gayaza synclinorium contains slates, mudstones, schists, phyllites and granites in the arena. The metamorphism of the Gayaza area is largely of low grade and the metamorphism grade increases towards the arena due to the contact metamorphism resulting from granitic intrusion. Faulting and folding are the major tectonic events that occurred in this area and thus the common rock structures encountered are faults, joints, folds as well as bedding planes, laminations, boudins and quartz veins. There are two major fold trends in this region; the regional set generally trending North-westerly which predominates and the cross fold set trending North-easterly. The Gayaza Synclinorium is a cross fold with the axis plunging to the South-West. Weathering and erosion have also contributed greatly to the topography of this area such as the arena topography and the ridges. The major economic activities in this area are cattle keeping, farming in the fertile valleys and quarrying on the rock outcrops and exposures. Settlements are scarce in this area and it is largely in the valleys.