| dc.description.abstract | This project report is composed of a compilation of the introduction, goals, methodology, findings, interpretations, conclusions and recommendations from the geologic mapping exercise that took place in Gayaza-Isingiro district from 31st January to 8th February, 2022. It was found out that this area lies within the Karagwe-Ankolean system of rocks (ca. 1400-950 Ma) which is the northern most extension of the kibaran mobile belt.The exercise had a number of goals ranging from collecting field data to analyzing and interpreting the results and this was all for helping students gain skills about geologic mapping which also include learning how to use field equipment for example the GPS, geologic compass and many others as talked about in details under chapter one.
During the mapping exercise, I happened to work on area E and so this report consists of geological information obtained from this area that is the structural data, stratigraphy, metamorphism, mineralogy, regional synthesis (which covers the whole of the Igayaza synclinorium in relation to the rest of the Karagwe-Ankole rocks) and economic activities carried out in this area plus Gayaza area as a whole.
Lithologically, the area consisted of thin arenaceous formations that contained mainly of quartzites and also thick argillaceous formations that were made of shales, phyllites and schists. The quartzites were mainly found at the top of ridges occasionally with semi-persistent conglomerates while the shales were found along the flanks of ridges and in valleys. This results in a region of rugged topography.
And so therefore the different rocks found in the area mapped (area E) include sandstones which later metamorphosed into quartzites found on top of the ridges, shales on the ridge slopes and valleys between ridges, and then a few conglomerates were also found which are the youngest rock type found in the area . Other rocks found include slates, mudstones, schists, phyllites and granites found in the arena. These rocks are found to be Pre Cambrian in character due to lack of fossils. Structures found in the mapped area include beddings, laminations, joints, faults, quartz veins, folds, boudins. Beds and laminations were mostly found in shales.
The metamorphism of the area was primarily regional and of low grade and this was availed through the petrographic work or studies which also confirmed the presence of clay minerals which were the dominant minerals, quartz and some small amounts of micas, alkali feldspars, iron oxides were also found in certain rocks. Due to the contact metamorphism resulting from granitic intrusion, the metamorphism grade of the Gayaza area increases towards the arena. Deep, quiet and shallow water dynamic environments of deposition were proposed due to the presence of shale and quartzites and some structures such as beds and laminations in shales.
Folding is mainly of two major types i.e., regional folds whose fold axes trend in the NW-SE direction and the cross folds whose fold axes trend in the NE-SW direction.
The economic potential of the area is low since no economic minerals have been discovered but the major economic activities in this area are cattle keeping, farming in the fertile valleys and quarrying on the rock outcrops and exposures. People in this area mostly settled in valleys. | en_US |
