Geological models deduced from gravity data in the Garoua basin, Cameroon

Kamguia, Joseph; Manguelle-Dicoum, Eliézer; Tabod, Charles T.; Tadjou, Jean Marie

doi:10.1088/1742-2132/2/2/009

Cited by 35 publications

(31 citation statements)

References 6 publications

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“…However, this thinning has probably not resulted from the CVL but rather from other tectonic events. The crust beneath the coastal plain was likely thinned during the opening of the southern Atlantic Ocean, while the crust beneath the Garoua rift was likely thinned during the formation of the Benue Trough in the early Cretaceous (Stuart et al 1985; Baudin 1991; Kamguia et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Structure of the crust beneath Cameroon, West Africa, from the joint inversion of Rayleigh wave group velocities and receiver functions

Tokam

Tabod

Nyblade

et al. 2010

Geophysical Journal International

147

135

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S U M M A R YThe Cameroon Volcanic Line (CVL) consists of a linear chain of Tertiary to Recent, generally alkaline, volcanoes that do not exhibit an age progression. Here we study crustal structure beneath the CVL and adjacent regions in Cameroon using 1-D shear wave velocity models obtained from the joint inversion of Rayleigh wave group velocities and P-receiver functions for 32 broad-band seismic stations deployed between 2005 January and 2007 February. We find that (1) crustal thickness (35-39 km) and velocity structure is similar beneath the CVL and the Pan African Oubanguides Belt to the south of the CVL, (2) crust is thicker (43-48 km) under the northern margin of the Congo Craton and is characterized by shear wave velocities ≥4.0 km s −1 in its lower part and (3) crust is thinner (26-31 km) under the Garoua rift and the coastal plain. In addition, a fast velocity layer (V s of 3.6-3.8 km s −1 ) in the upper crust is found beneath many of the seismic stations. Crustal structure beneath the CVL and the Oubanguides Belt is very similar to Pan African crustal structure in the Mozambique Belt, and therefore it appears not to have been modified significantly by the magmatic activity associated with the CVL. The crust beneath the coastal plain was probably thinned during the opening of the southern Atlantic Ocean, while the crust beneath the Garoua rift was likely thinned during the formation of the Benue Trough in the early Cretaceous. We suggest that the thickened crust and the thick mafic lower crustal layer beneath the northern margin of the Congo Craton may be relict features from a continent-continent collision along this margin during the formation of Gondwana.

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Section: Discussionmentioning

confidence: 99%

Structure of the crust beneath Cameroon, West Africa, from the joint inversion of Rayleigh wave group velocities and receiver functions

Tokam

Tabod

Nyblade

et al. 2010

Geophysical Journal International

147

135

View full text Add to dashboard Cite

show abstract

“…Many geophysical and geological investigations carried out in this area were aimed at modeling the geological formations and its associated basins. Generally, the negative anomalies are attributed to Cretaceous sediments with thicknesses (Eyike & Ebbing, 2015;Eyike et al, 2010;Kamguia et al, 2005;Njandjock et al, 2006), while the positive residual Bouguer anomalies are due to the intrusions of igneous rocks or a shallow basement (Collignon, 1968;Ngounouno & Deruelle, 1997). Detailed analyses and interpretation realized by combining existing 2D reflection seismic and Gravity/Magnetic data of the Logone Birni Basin (LBB) in the West and Central African Rift System (WCAS) have revealed the distribution of buried volcanic bodies as well as their relationships with the structural and tectonic evolution of this basin.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Meaning of the Positive Bouguer Anomaly of Waza (Northernmost Cameroon, Central Africa)

Albert¹,

Antoine²,

Eugene³

et al. 2019

GEP

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Gravity and magnetic data were analyzed in conjunction with available geological data to determine the origin of observed positive gravity anomaly at Waza and its possible relationship to mafic intrusions. The data analysis includes the construction of a Bouguer gravity anomaly, isostatic residual gravity anomaly, total magnetic gradient and Euler solutions maps, and two and one-half dimensional gravity models. A positive gravity anomaly that occurs in Waza has amplitude of 35 mGal and can be separated into two parts. The top of the disturbing body causing the anomaly cannot be deeper than 4 km. We believe the anomaly is probably caused by a body of basaltic rocks lying at the upper surface of the Precambrian basement and originate from a self-propagating disturbance of magmatic loads on a pre-existing zone of lithospheric weakness. Melt migration might have been aided by tectonic and flexural stresses, such that the intrusion is limited in extent to the melting region of the plume and did not reach the surface. The model calculated to satisfy the observed anomaly consists of a 2.5 Km-thick slab underlain by a 10.5 km deep column. This model is interpreted to represent a sheet or saucer-like mafic intrusion that has a thick deep feeder. Detailed geophysical studies would be necessary to locate any possible economic occurrences.

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“…Therefore, the signals at the left on the filter are only those from the relatively shallower bodies and the contour map that they produce (lower preview in Figure 3) is not very different from the residual anomaly map obtained in Fourpot. The implication is that the chosen regional conforms to the relationship between the basement and the Asthenosphere in the area (Kamguia et al, 2005). On the filtered data that was contoured ( Figure 5) in Surfer 11.0, three profiles were then drawn and the data along the profiles used to model the basin in Grav2dc v2.06.…”

Section: Results and Interpretationmentioning

confidence: 99%

“…In the quest for oil and gas, the subsurface of most of Cameroon's basins have been thoroughly studied through the processing and interpretation of the gravity data (Fairhead et al, 1991;Kamguia et al, 2005;Ndougsa-Mbarga et al, 2007;Eyike et al, 2010;Oyoa et al, 2012;Mouzong et al, 2014). The study area which is the Mamfe basin is one of these basins and is a branch of the Benue Trough that extends into the South West Region of Cameroon.…”

Section: Introductionmentioning

confidence: 99%

Geometrical Characterisation of the Mamfe Basin, Cameroon, from the Earth, Gravitational Model (EGM 2008)

Lordon¹,

Yossa²,

Agyingi³

et al. 2018

ESR

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Gravimetric studies using the ETOPO1-corrected high resolution satellite-based EGM2008 gravity data was used to define the surface extent, depth to basement and shape of the Mamfe basin. The Bouguer anomaly map was produced in Surfer 11.0. The Fast Fourier Transformed data was analyzed by spectral analysis to remove the effect of the regional bodies in the study area. The residual anomaly map obtained was compared with the known geology of the study area, and this showed that the gravity highs correspond to the metamorphic and igneous rocks while the gravity lows match with Cretaceous sediments. Three profiles were drawn on the residual anomaly map along which 2D models of the Mamfe basin were drawn. The modeling was completed in Grav2dc v2.06 software which uses the Talwini's algorithm and the resulting models gave the depth to basement and the shape of the basement along the profiles. After processing and interpretation, it was deduced that the Mamfe basin has an average length and width of 77.6 km and 29.2 km respectively, an average depth to basement of 5 km and an overall U-shape basement. These dimensions (especially the depth) theoretically create the depth and temperature conditions for petroleum generation.

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Geological models deduced from gravity data in the Garoua basin, Cameroon

Cited by 35 publications

References 6 publications

Structure of the crust beneath Cameroon, West Africa, from the joint inversion of Rayleigh wave group velocities and receiver functions

Structure of the crust beneath Cameroon, West Africa, from the joint inversion of Rayleigh wave group velocities and receiver functions

Understanding the Meaning of the Positive Bouguer Anomaly of Waza (Northernmost Cameroon, Central Africa)

Geometrical Characterisation of the Mamfe Basin, Cameroon, from the Earth, Gravitational Model (EGM 2008)

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