Implications on Gravity Anomaly Measurements Associated with Different Lithologies in Turkana South Subcounty ()
ABSTRACT
The use of gravity data has demonstrated capability for monitoring
lithological changes on a large scale as a consequence of differentiating
basement and sedimentary of buried valleys. Gravity anomalies are associated
with lateral contrasts in density and therefore deformation by faulting or
folding will be manifested if accompanied by lateral density changes, otherwise, the
vice versa is true. The study’s objective is to evaluate the effectiveness of
gravity method in establishing different lithologies in an area. The study has
revealed that regional anomaly gravity map presents high anomalies in the
Northern region in the NW-SE trend and low anomalies in the southern trend in
NW-SE, while the residual anomaly gravity map shows different trends for the
low and high gravity anomalies. The gravity anomalies are well interpreted in
line with the lithologies of the study area rather than the deformation of the
same lithologies. There are observed high values of gravity anomaly values (ranging from -880.2 to -501.2 g.u.) where there are eolian unconsolidated rocks overlying the basement compared to low
gravity anomaly values (ranging from -1338.9
to -1088.7 g.u.) where the andesites, trachytes and phonolites overly the
basement. The different regional gravity anomalies relate well with different
rock densities in the study area along the line profile for radially averaged
power spectrum. The gravity highs are noted in the eastern point and are
associated with andesites, trachytes, basalts and igneous rocks, while the
gravity lows are associated with sandstone, greywacke, arkose, and eolian
unconsolidated rock. The utilization of the information from the Power spectrum
analysis demonstrates that the depth to the deepest basement rock is 12.8 km
which is in the eastern flank, while the shallowest to the basement of 1.1 km
to the western flank.
Share and Cite:
Nyaberi, D. (2023) Implications on Gravity Anomaly Measurements Associated with Different Lithologies in Turkana South Subcounty.
Journal of Geoscience and Environment Protection,
11, 79-118. doi:
10.4236/gep.2023.111006.
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