Geodynamic insights of the Cameroon Volcanic Line (Western Africa) from isostatic gravity anomalies

Margat, Jean; Essi, Jean Marcel Abaté; Meli’i, Jorelle Larissa; Nouck, Philippe Njandjock; Mahamat, Abakar; Manguelle-Dicoum, Eliézer

doi:10.1016/j.jog.2018.07.002

Cited by 18 publications

(8 citation statements)

References 50 publications

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“…Our results reveal that under-compensation areas are situated under the Main volcanoes of the South-western CVL with a compensation rate lower than -1%. This result is in agreement with the findings of [24] who suggest that conditions of complete isostatic compensation are not fully satisfied with the high Mountainous of the CVL. Indeed, Mount Cameroon, the highest elevated area ( ~4000 m) of Southwest Cameroon, is particularly characterized by an isostatic compensation rate of -31%.…”

Section: Isostatic State and Geodynamic Insightssupporting

confidence: 92%

“…However, in Cameroon, there are very few regional studies dealing with the interpretation of isostatic maps and discussion about the isostatic state beneath the region [24,25], whereas isostatic map analysis and interpretation is common elsewhere. Even though [24] suggested that isostatic equilibrium is not satisfied for most of the mountain ranges observed over the Southern CVL, there is no direct relationship between isostasy and earthquakes made by the authors in light of historical and recent earthquake data [26][27][28][29]. However, such a study could be helpful to identify isostatic constraints causing natural disasters of seismic nature in the study area.…”

Section: Introductionmentioning

confidence: 99%

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Crustal Thickness Variations and Tectonic Settings in the Southwest Cameroon Inferred from Gravity and Topography Data

et al. 2022

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EIGEN 6C4 gravity anomalies are interpreted to determine the lateral and vertical variations in the crust and upper mantle structure and their influence on the isostasy of the coastal plain, transition zone between the Congo Craton (CC), the Pan-African Belt (PAB), and adjacent areas. The regional gravity anomalies have been inverted in an attempt to provide a Moho depth map. The inversion process was based on the Parker-Oldenburg method with a density contrast of 0.55 g/cm3 and an average depth reference of 39 km. In addition, various tests have been performed to validate the resulting Moho model and estimate the efficiency of the 3D gravity inversion by varying the density contrast for a fixed Moho reference depth. Inversion results reveal that the Moho depths generally agree with those obtained from previous geophysical studies. The computation of the isostatic models using the ETOPO1 digital elevation model (DEM) and its comparison with the Moho models obtained from gravity induce the following main conclusions: (1) an overcompensated crust beneath the coastal plain and the Yaounde Domain, (2) the crust beneath areas located in the southern end of the Adamawa-Yade Domain is thin and undercompensated, and (3) main volcanoes of the Southwestern Cameroon Volcanic Line (CVL) are isostatically undercompensated. This study also revealed that the local isostatic compensation law is not satisfied for most of the tectonic provinces of the study area, and we suggest alternative tectonic mechanisms to support topography below these tectonic features. Additionally, most seismic events (M>3.5) occurred in areas marked by abrupt changes in compensation amplitude. Thus, we concluded from this study that the northern limit of the CC, the Mount Cameroon, and its surroundings are tectonic extension areas that may play a crucial role in the occurrence of future earthquakes.

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Section: Isostatic State and Geodynamic Insightssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Crustal Thickness Variations and Tectonic Settings in the Southwest Cameroon Inferred from Gravity and Topography Data

et al. 2022

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“…EGM 2008 model associates terrestrial, airborne gravity, and altimetryderived data with a spatial resolution of five arc minutes (Pavlis, Holmes, Kenyon, & Factor, 2008). The 1 arc-minute ETOPO1 elevation data were used to correct the topographic effect, coupled with a density of 2,670 kg/m 3 for the Bouguer correction (Marcel et al, 2018a).…”

Section: Gravity Datamentioning

confidence: 99%

Integration of Landsat 8, gravity, and field data for exploration of gold mineralization in Gamba District, Northern Cameroon

et al. 2021

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Remote sensing is a robust and useful tool for providing high‐resolution image data and enabling reliable geological mapping during the initial stage of mineral exploration. One of its main applications is the extraction of lineaments and to locate alteration areas to target gold exploration. It has been long used in the Pan‐African belt of Cameroon to identify a hydrothermal alteration and a great number of lineaments associated with mineralizations. The study area located in the Pan‐African belt hosts numerous alluvial gold deposits where the primary mineralization was still largely poorly unknown until now, due to deep weathering. Therefore, remote sensing combined with field data is useful for targeting potential zones of primary gold resources involved in the hydrothermal and lineament systems. In this study, remote sensing data from Landsat 8 imagery were selected to map the distribution of hydrothermal minerals, and gravity data were interpreted for highlighting structural patterns related to the control of high‐potential zone for gold mineralization, generating a mineral prospect map. The lineaments network shows directions ranging from ENE‐WSW to E‐W, with main direction N45° and a secondary striking N275°. Image enhancement/processing techniques included the application of band ratio and principal component analysis that were helpful to demarcate potential alteration zones marked by iron oxide/hydroxides in which haematite and pyrite are used as proximal alterations and hydroxyl‐bearing minerals in which sericite (muscovite) is used as a marker of proximal alteration, while chlorite, epidote, biotite, quartz, and calcite are used as distal alteration zone, as described by field and petrographic data. The identified alteration zones display a high consistency with the known locations of gold occurrences (mining sites) and closely concordant with large‐scale gold mineralization in the study area. This study presents an integrated approach of Landsat 8 imagery with gravity data and field data for discovering primary mineral resources in a deep weathering area.

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“…Balogun and Akintokewa (2020), for instance, suggest that trends with wavelengths of 300-500 km in regional-scale gravity data are likely associated with a mantle upwelling, which they attribute to the African LLVP. Marcel et al (2018) showed positive gravity anomalies beneath Mount Cameroon, resulting from dense material at crustal depths, and they suggested that such anomalies are caused by mantle upwelling from depth.…”

Section: A Deep Mantle Source For the Cvlmentioning

confidence: 99%

Deep Mantle Influence on the Cameroon Volcanic Line

Saeidi

Hansen

Nyblade

2023

Geochem Geophys Geosyst

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Geodynamic insights of the Cameroon Volcanic Line (Western Africa) from isostatic gravity anomalies

Cited by 18 publications

References 50 publications

Crustal Thickness Variations and Tectonic Settings in the Southwest Cameroon Inferred from Gravity and Topography Data

Crustal Thickness Variations and Tectonic Settings in the Southwest Cameroon Inferred from Gravity and Topography Data

Integration of Landsat 8, gravity, and field data for exploration of gold mineralization in Gamba District, Northern Cameroon

Deep Mantle Influence on the Cameroon Volcanic Line

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