| dc.description.abstract | This report is a summary of the Geologic mapping project 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
interpret 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 A 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.
The area is generally characterized by a hilly topography with intervening areas of low relief (V-shaped valleys and the arenas) which could have evolved due to differential weathering. It is also characterized by parallel and dendritic drainage and savannah vegetation. Settlement in the area is generally linear with people settling along the roads and the area is difficult to
access because of its hilly nature. Land use is dominantly agriculture and quarrying stone for construction material.
Argillaceous and arenaceous rocks (shales, phyllites and quartzites) are characteristic of the area except for parts of granitic intrusions (arenas). As such, the area is placed in the middle part of the Karagwe-Ankolean system. Alternating conditions of low and high energy deposition are suggested for the deposition of the sediments in a possibly intercontinental
basin of the Precambrian times (conditions).
The major geologic structures encountered in the area are bedding and joints/fractures. Faults,folds, lamination being taken as minor structures. In the entire area, Beds dip to the SE and NW. In area-A the preferred orientation of the beds is NE-SW. The joints show two preferred trends in the NW-SE and NE-SW in the entire area corresponding to the regional and cross
fold trends of the area and moderate to steeply dipping. Folding is earlier than faulting and other structures in the area.
Petrographic results for area-A reveal that the is underlain by quartzites, ferruginous and micaceous-shales. However, phyllites, conglomerates and phyllititic shales are found in areas-
A. The type of metamorphism in the area is generally regional (due to burial) of low to very low grade. Dynamic metamorphism in fault zones evidenced by fault breccia’s was observed and contact metamorphism in areas near the granitic intrusions are also evident.
Metamorphism increases in grade towards the base of the unit and with increasing proximity to the areas of granitic intrusion (arena).
Lastly and conclusively, the area is part of the Karagwe -Ankolean system which is part of the Kibaran belt as seen from what has already been given and from the granitic intrusions and the tin mineralization areas visited during the field excursion part of the mapping project. | en_US |
