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International Journal of Geosciences 2013年第2期4卷 480-493页

作者： Arsène Meying Théophile Ndougsa Mbarga daniel gouet Patrick Assembe Stéphane Department of Physics Advanced Teacher’s Training College University of Yaoundé Yaoundé Cameroun Department of Physics Faculty of Science University of Yaoundé Yaoundé Cameroun School of Geology Mining and Mineral Processing University of Ngaoundéré Ngaoundéré Cameroun

The current study deals with an interpretation of audio-magnetotelluric (AMT) data collected in the Ayos/Nguelemendouka area, using a Stratagem EH4 unit. The study’s objective is to provide a better understanding of the area’s subsurface structure. Thus, AMT soundings were realised through seven profiles NE30° oriented, each profile made up of four stations. Data modelling highlights a SW-NE tectonic unevenness which seems to correlate with the Centre Cameroon Shear Zone. Moreover, this interpretation put into evidence an uplift of the basement at Lamba 2, a tabular structure at depth and an absence of discontinuities beneath 300 mdepth.

关键词： AMT Sounding Tectonic Unevenness Stratification Uplift Discontinuities

Clay Minerals Channels Identification in the Tindikala-Boutou Area (Eastern-Cameroon) along the Kadey River Using Direct Current (DC) Method

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Journal of Geoscience and Environment Protection 2015年第6期3卷 123-133页

作者： daniel Hervé gouet Arsène Meying Stéphane Patrick Assembe Théophile Ndougsa-Mbarga Department of Petroleum and Gas Explorations Institute of Mines and Petroleum Industries University of Maroua Maroua Cameroun Department of Applied Geophysics Geology and Mining Exploitation College University of Ngaoundéré Ngaoundéré Cameroun Department of Physics Faculty of Science University of Yaounde I Yaoundé Cameroon Department of Physics Advanced Teacher’s Training College University of Yaounde I Yaoundé Cameroon

To achieve the current study, geoelectrical surveys along six (06) profiles of 4 km long in a 100 m × 200 m grid defined according to the triangulation principle in the Tindikala-Boutou (Eastern-Cameroon) area along the Kadey River have been made through electrical sounding and profiling following Schlumberger array. The instrument is the resistive meter Syscal Junior 48 (IRIS Instrument). The data have been processed and modelled with Res2Dinv and Winsev softwares, and then interpolated with Surfer software. Investigation method used is the Direct Current (DC) method. Interpretations and analyses of results from the investigation method highlight weak zones or conductive discontinuities. The latter has been identified as shear zones within granitic structures of the Precambrian basement, according to the geologic and tectonic background of the area. The structural trend of these shear zones is E-W approximately. The mineralization characterized by conductive zones proves the presence of clay minerals disseminated in weathered quartz vein, which cross the shear zones. The intense activities of gold washers encountered in the studied area are able to attest the presence of clay minerals concentrations.

关键词： Geoelectrical Surveys Direct Current Method Resistivity Shear Zones Clay Minerals

2.5D Modelling of Aeromagnetic Data and their Mining Implications over the Ngaoundere Area (Adamawa Province, Cameroon)

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International Journal of Geosciences 2019年第2期10卷 173-192页

作者： Meying Arsène gouet daniel Hervé Ndougsa Mbarga Theophile Ndam Njikam Mouhamed Owono Amougou Olivier Ulrich Igor School of Geology and Mining Engineering University of Ngaoundere Meiganga Cameroon Department of Petroleum Mining & Groundwater Resources Exploration Faculty of Mines and Petroleum Industries University of Maroua Maroua Cameroun Department of Physics Advanced Teacher’s Training College University of Yaoundé I Yaoundé Cameroon Postgraduate School of Science Technologies & Geosciences University of Yaoundé I Yaoundé Cameroon

This study is based on the analysis and interpretation of aeromagnetic data using version 8.4 of the Geosoft Oasis Montaj Software, to map the subsurface or deep geological structures that affected the geological formations of the Ngaoundere area. The use of the standard aeromagnetic methods made it possible to draw up the maps of the residual magnetic field reduced to the equator (RTE), the horizontal gradient (HG), the analytical signal (AS) and that of the Euler solutions (ED) to find the main magnetic facies corresponding to these structures. The geological formations of the studied area thus appear to be intensely fractured by a NE-SW (N45°E) and ENE-WSW (N70°E) main orientation fault system, the depth of which has been estimated by combining the three-analytical methods HG, AS and ED. Advanced magmatic map analysis revealed dikes associated with vertical faults in the studied area. The development of an interpretative geological map taking into account the basic geology, the deep faults, the identified dikes and the mineralization index made it possible to extract a correlation between geological structures and mineralization of the studied area. The 2.5D modelling of two magnetic profiles plotted on the reduced residual map at the equator was performed to approximate the geometry and depth of the dikes sector, which are potential sources of mineralization here.

关键词： Aeromagnetic Data Analytical Methods Faults Mineralization 2.5D Modelling

Water Infiltration Study from Magnetotelluric Data in the Limestone Fault Network of Mintom (South Cameroon)

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International Journal of Geosciences 2015年第9期6卷 1007-1017页

作者： Harlin L. Ekoro Nkoungou daniel H. gouet Philippe Njandjock Nouck Eliézer Manguelle Dicoum Department of Physics Faculty of Science University of Yaounde I Yaounde Cameroon International Institute for Water and Environmental Engineering Ouagadougou Burkina Faso Institute of Mining and Petroleum Industries University of Maroua Maroua Cameroon

Magnetotelluric surveys have been conducted in the Mintom area in order to evaluate the water infiltration potential of the Dja river in a limestone deposit estimated at about 350 million?m3 laying on a network of faults compromising the exploitation of this limestone deposit. The interpretation of these data shows that this network of faults is clearly highlighted as 2D/3D structures consolidated showing a low potential water infiltration through these structures. This result is confirmed by the absence of confined and induced aquifer along all the profiles. From this finding, we concluded that the exploitation of this deposit is not conditioned by the water infiltration from the Dja River.

关键词： Limestone Fault Network Water Infiltration 2D Magnetotelluric Inversion

+-Evidence of Porphyry Deposits in the Ntem Complex: A Case Study from Structural and Hydrothermal Alteration Zones Mapping through Landsat-8 OLI, Aeromagnetic and Geological Data Integration in the Yaounde-Sangmelima Region (Southern Cameroon)

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Advances in Remote Sensing 2020年第2期9卷 53-84页

作者： Stephane Patrick Assembe Theophile Ndougsa Mbarga Françoise Enyegue A. Nyam Paul Claude Ngoumou Arsene Meying daniel Herve gouet Alain Zanga Jean daniel Ngoh Postgraduate School of Technology Science and Geoscience University of Yaounde 1 Yaounde Cameroon Department of Physics Higher Teachers Training College University of Yaounde 1 Yaounde Cameroon Department of Physics Faculty of Science University of Yaounde 1 Yaounde Cameroon School of Geology and Mining Engineering University of Ngaoundere Meiganga Cameroon Faculty of Mining and Petroleum Industries University of Maroua Kaele Cameroon Department of Physics Faculty of Science University of Douala Douala Cameroon

A semi-regional study was carried out in the Yaounde-Sangmelima area, a densely vegetated tropical region of southern Cameroon located in the Central Africa Fold Belt (CAFB)/Congo Craton (CC) transition zone. Towards structural lineaments and predictive hydrothermal porphyry deposits mapping, an integrated analysis of Landsat-8 OLI data, aeromagnetic, geological and mineral indices maps was performed. The Remote sensing using False colour composite images involving bands combinations and Crosta method (features oriented principal components analysis) enabled the mapping of the gneisses and schists domains without a clear differentiation between the Yaounde and Mbalmayo schists;despite the reflectance anomalies evidenced NW of Akonolinga, hydrothermal alterations in the study area failed to be detected. Besides, aeromagnetics depicted a moderately fractured northern zone (the CAFB) contrasting with a high densely fractured zone (the CC, known as Ntem complex). The Ntem complex displays signatures of a meta-igneous, an intrusive complex, greenstone relics south of Sangmelima and hydrothermal activity. Indeed, CET porphyry analysis tool detected many porphyry centres. In general, the study revealed many lineaments including contacts, fractures faults zones and strike-slips. The major aeromagnetics structures are SW-NE to WSW-ENE and WNW-ESE to NW-SE while those from Landsat-8 are NE-SW, WNW-ESE, NW-SE, WSW-ENE and NW-ESE to NNW-SSE. Together, these structures depict trans-compressions or trans-tensions corresponding to a broad NE-SW strike-slips channel that affect both the CAFB and the Ntem Complex, and they control the intrusions thus confirming a pervasive hydrothermal activity within the Ntem Complex. The proximity or coincidence of these porphyry centres with some mapped Iron-Gold affiliated mineral indices and porphyry granites indicate the possible occurrence of many hydrothermal ore deposits. These results show the high probability for the Ntem complex to host

关键词： Porphyry Centres Hydrothermal Ore Deposits Ntem Complex Remote sensing Aeromagnetics Southern Cameroon

Gold Mineralization Channels Identification in the Tindikala-Boutou Area (Eastern-Cameroon) Using Geoelectrical (DC &IP) Methods: A Case Study

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International Journal of Geosciences 2013年第3期4卷 643-655页

作者： daniel Hervé gouet Theophile Ndougsa-Mbarga Arsène Meying Stéphane P. Assembe Alphonse D. Man-Mvele Pepogo Department of Applied Geophysics Geology and Mining Exploitation College University of Ngaoundéré Ngaoundéré Cameroun Department of Earth Sciences Faculty of Science University of Yaoundé I Yaoundé Cameroon Department of Physics Advanced Teacher’s Training College University of Yaoundé I Yaoundé Cameroun Department of Physics Faculty of Science University of Yaoundé I Yaoundé Cameroun

To achieve the current study, geoelectrical surveys along six (06) profiles of 4 km long in a 100 m × 200 m grid defined according to the triangulation principle in the Ngoura area (Tindikala-Boutou villages) have been made through electrical sounding and profiling following Schlumberger array. The instrument is the resistivimeter Syscal Junior 48 (IRIS Instrument) which uses the electrical current. The data have been processed and modelled with Res2Dinv and Winsev softwares then interpolated with Surfer software. Electrical methods used are the Direct current (DC) and the Induced Polarization (IP). Interpretation and analyses of results from each investigation method highlight weak zones or conductive discontinuities and mineralized zones. Conductive zones have been identified as shear zones within granitic structures of the Precambrian basement, according to the geologic and tectonic background of the area. The structural trend of these shear zones is E-W. The mineralization within it is N-S and characterized by high values of chargeability, essentially in the eastern part of the area under study. This mineralization proves the presence of metalliferous or sulphide heaps disseminated in weathered quartz veins which cross shear zones. Also, the poor mineralization and conductive structures in shear zones characterize the groundwater zones. The intense activities of gold washers encountered in the area enable to link that mineralization to gold within quartz veins. The near surface gold mineralization is eluvial or alluvial, and in depth this mineralization is primary.

关键词： Geoelectrical Surveys Direct Current IP Method Resistivity Chargeability Shear Zones Gold Mineralization

Combined Geoelectrical Approach DC and IP Methods in the Identification of the Mineralized Bodies Parallel to the NE-SW Tectonic Line of Kadei River: Case of Quartz or Pegmatite Gold Bearing Veins of Ngoura Subdivision (East Cameroon)

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International Journal of Geosciences 2016年第7期7卷 891-903页

作者： daniel Hervé gouet Stéphane Patrick Assembe Arsène Meying Marcelin Bikoro Bialou Josué Kalaza Haskandi Théophile Ndougsa-Mbarga Department of Petroleum and Gas Explorations Institute of Mines and Petroleum Industries University of Maroua Maroua Cameroun Department of Physics Faculty of Science University of Bamenda Bambili Cameroon Department of Applied Geophysics Geology and Mining Exploitation College University of Ngaoundéré Ngaoundéré Cameroon Department of Earth Sciences Faculty of Science University of Maroua Maroua Cameroun Department of Earth Sciences Faculty of Science University of Ngaoundere Ngaoundere Cameroon Department of Physics Advanced Teacher’s Training College University of Yaounde I Yaounde Cameroon

A geophysical investigation of subsurface structures using the Syscal Junior 48 resistivity-meter was conducted in Ngoura subdivision (East Cameroon) following a combined geoelectrical direct current (DC) approach involving Resistivity and IP methods. This investigation was allowed to collect data on forty-five (45) profiling lines at three acquisition levels (AB = 100 m, MN = 10 m;AB = 200 m, MN = 20 m and AB = 500 m, MN = 50 m) and two electric panels L1 and L4, using the Schlumberger array. Processing, modeling and interpretation of data collected using the Winsev, Res2Dinv and Surfer software helped in highlighting a conductive and strongly mineralized discontinuity in granite formations, which lined up with the NE-SW Kadei tectonic line. It extends beyond 100 m depth over an average width of 600 m. The mineralization associated with this discontinuity is identified by a high concentration of disseminated metalliferous minerals in quartz or pegmatite veins. The mining reconnaissance works in the study area and those of several authors have characterized this anomaly to a lode gold quartz or large pegmatite. The results of this study correlate with geological and tectonic data for the region marked by NE-SW Kadei tectonic line. Therefore, they confirm the reliability of a geoelectrical DC investigation method combining Resistivity and IP to the identification of ore bodies.

关键词： Geoelectrical Investigation Direct Current IP Method Resistivity NE-SW Tectonic Line Mineralized Body Conductive Area