Application of wavelet multi-scale analysis in the separation of aeromagnetic data potential field

Abstract. This study was carried out in the Lom series in Cameroun, at the border with Central African Republic located between the latitudes 5°30′–6° N and the longitudes 13°30′–14°45′ E. A multi-scale analysis of aeromagnetic data combining tilt derivative, Euler deconvolution, upward continuation and the 2.75D modelling was used. The following conclusion were drawn: 1 – Several major families of faults were mapped. Their orientations are ENE-WSW, E-W, NW-SE, N-S with a NE-SW prevalence. The latter are predominantly sub-vertical with NW and SW dips and appear to be prospective for the future mining investigation. 2 – The evidence of compression, folding and shearing axis, was concluded from superposition of null contours of the tilt-derivative and Euler deconvolution. The evidence of the local tectonics principally due to several deformation episodes (D1, D2 and D4) associated with NE-SW, E-W, and NW-SE events respectively. 3 – Depths of interpreted faults ranges from 1000 to 3400 m. 4 – Several linear structures correlating with known mylonitic veins were identified. These are associated with the Lom faults and represent the contacts between the Lom series and the granito-gneissic rocks; we concluded the intense foldings caused by senestral and dextral NE-SW and NW-SE stumps; 5 – We propose a structural model of the top of the crust (schists, gneisses, granites) that delineates principal intrusions (porphyroid granite, garnet gneiss, syenites, micaschists, Graphite and Garnet gneiss) responsible for the observed anomalies. The 2.75D modelling revealed; many faults with a depth greater than 1200 m and confirmed the observations from RTE-TMI, Tilt derivative and Euler deconvolution; 6 – We developed lithologic profile of Betare Oya basin.

Download Full-text

Multi-scale analysis and modelling of aeromagnetic data over the Bétaré-Oya area in eastern Cameroon, for structural evidence investigations

Solid Earth ◽

10.5194/se-12-785-2021 ◽

2021 ◽

Vol 12 (4) ◽

pp. 785-800

Author(s):

Christian Emile Nyaban ◽

Théophile Ndougsa-Mbarga ◽

Marcelin Bikoro-Bi-Alou ◽

Stella Amina Manekeng Tadjouteu ◽

Stephane Patrick Assembe

Keyword(s):

Central African Republic ◽

Structural Model ◽

Scale Analysis ◽

Aeromagnetic Data ◽

Euler Deconvolution ◽

Multi Scale ◽

Tilt Derivative ◽

Local Tectonics ◽

Multi Scale Analysis ◽

Eastern Cameroon

Abstract. This study was carried out in the Lom series in Cameroon, at the border with Central African Republic, located between the latitudes 5∘30′–6∘ N and the longitudes 13∘30′–14∘45′ E. A multi-scale analysis of aeromagnetic data combining tilt derivative, Euler deconvolution, upward continuation, and 2.75D modelling was used. The following conclusions were drawn. (1) Several major families of faults were mapped. Their orientations are ENE–WSW, E–W, NW–SE, and N–S with a NE–SW prevalence. The latter are predominantly sub-vertical with NW and SW dips and appear to be prospective for future mining investigations. (2) The evidence of compression, folding, and shearing axis was concluded from superposition of null contours of the tilt derivative and Euler deconvolution. The principal evidence of the local tectonics was due to several deformation episodes (D1, D2, and D4) associated with NE–SW, E–W, and NW–SE events, respectively. (3) Depths of interpreted faults range from 1000 to 3400 m. (4) Several linear structures correlating with known mylonitic veins were identified. These are associated with the Lom faults and represent the contacts between the Lom series and the granito-gneissic rocks; we concluded the intense folding was caused by senestral and dextral NE–SW and NW–SE stumps. (5) We propose a structural model of the top of the crust (schists, gneisses, granites) that delineates principal intrusions (porphyroid granite, garnet gneiss, syenites, micaschists, graphite, and garnet gneiss) responsible for the observed anomalies. The 2.75D modelling revealed many faults with a depth greater than 1200 m and confirmed the observations from reduced-to-Equator total magnetic intensity (RTE-TMI), tilt derivative, and Euler deconvolution. (6) We developed a lithologic profile of the Bétaré-Oya basin.

Download Full-text