TITLE:
Tele-Analytical Characterization of the Eburnean Tectonic Structures within the Birimian Formations of Mako Area, Eastern Senegal
AUTHORS:
Ibrahima Gassama, Moussa Dabo, Emmanuel Tama Samoura, Mamadou Ndiaye
KEYWORDS:
Eburnean, Kédougou, Tele-Analytic, Landsat-8 Images, Tectonic, Lineament
JOURNAL NAME:
International Journal of Geosciences,
Vol.13 No.1,
January
11,
2022
ABSTRACT: The tectonic structures of the Mako area in the Kédougou-Kéniéba inlier
(KKI) were mapped with tele-analytical investigation which is validated by
field data. This study is based on different images processing in particular: 1) the
colored combinations (1 to 5) and panchromatic (8) thematic mapping bands of
the Landsat-8 (ETM+) satellite; 2) Digital
Elevation Model (DEM) image of Space Shuttle Radar Topography Mission (SRTM); 3)
airborne geophysics (aeromagnetic and radiometric) images. In these images, four
major directions of lineaments NS, NNE-SSW, NW-SE and EW would be related to
the tectonic structures, have been identified and mapped. Field data confirm
these four structural directions and show that most of these lineaments are
related to faults, shear and/or thrust zones, or even basic rock dykes. N-S to
NE-SW oriented lineaments are more frequent followed by those NW-SE oriented.
These two directions of lineaments are generally in correlation with
trajectories of major sinistral shear zones in the Mako area. They would be
associated with the S2a and S2b schistosities relative to
the D2 Eburnean major deformation. They often intersect the E-W
oriented lineaments which are less frequent and sometimes folded and
crenulated. This E-W oriented lineament would
be prior and are associated with the S1 schistosity of the D1 Eburnean thrust phase of deformation. At the scale of the studied area, these
major linear structures (shear zones) are conjugated and create a partitioning
of deformation through an anastomosed network of mylonitic shear zones which
surround weakly deformed rock bodies. All these structures would be related to
the Eburnean or post-Eburnean orogenic events in this Mako area.