Geological and stratigraphic field study of Semiliki basin in the Albertine Graben, Ntoroko District, Western Uganda

Abstract

The field study was carried out in the Semiliki basin in the Albertine Graben, Ntoroko district, Western Uganda south of Lake Albert, at the footsteps of Rwenzori Mountains, aiming majorly at collecting and interpreting stratigraphic, sedimentological and structural data in relation to the petroleum system of this part of the basin.

In this report, details of data and interpretations from the whole field study with much emphasis on group 5 logging section inclusive of other areas; the Turaco wells and the Sempaya hot /Buranga geothermal prospect which involves the geophysical techniques, like resistivity, micro-earthquake and seismology.

The study was mainly on the surface geology and structural studies of the basement rocks and sediment deposits of the Kibuku area. The basement lithology comprised of weathered and altered granite gneisses, mafic and felsic rocks whereas for the sediments, it ranged from fluvial to lacustrine sandstones, siltstone and clay stones; where grain size, the level of sorting, grain shapes, grading especially for non-stratified beds, grain fabric that explains the transportation direction, the level of sediment maturity, primary and secondary structures in the strata were examined; with their provenance taken to be the Rwenzori. Interpreting the sedimentary environment was very important in order to determine the paleo-environment and current direction. From this study stratigraphic logs were drawn and interpreted and facies analysis was also used to interpret sedimentary successions.