Geophysics , lithologic units, structures in the basement rock and sediments of Semiliki basin (ALBERTINE GRABEN)
Abstract
The report comprises a detailed compilation of findings from the Semliki basin field study in the
Albertine area, Western Uganda. The materials and methodology used to achieve the main
objective; collection and interpretation of stratigraphic, petrographic, sedimentology and
structural data, have been outlined and discussed in a single chapter and the study results and
interpretations as well as discussions and conclusions about the petroleum system of the study
area clearly presented in the succeeding chapters that is a clear differentiation of the lithology and
stratigraphy of the basement rock and that of the overlying sediments, an integration of basin
analysis concepts in interpretations, facies analysis elements and facies analysis interpretations
from observed lithologic units, structures in the basement rock and sediments as well as
geophysics of the basin.
The Semliki basin is generally filled with Middle Miocene to recent age sediments exhibiting a
fining upward sequence (characteristic of fluvial systems) from conglomerates (overlying the
basement rock) to sands to silts to clays. It is structurally wedge shaped and majorly comprises
faults, joints, laminations and bedding planes, cross beds, foliations, quartz veins, unconformities,
soft sediment deformation structures among others. The southern part of this basin has the highest
elevation but the smallest thickness of accumulated sediments whereas the depocenter (5km
thickness of sediments) is in the northern part of the Semliki basin. The basin has a valid petroleum
system evidenced by the abundance of excellent reservoirs, regionally mature source rocks, traps,
intraformational and regional seals as well as hydrocarbon-migration pathways in the basin.