This study investigates the toposequential development of duricrusts formed on granite and gneiss in Meiganga, in the Adamawa Region of Central Cameroon. The area lies within a tropical upland characterized by duricrust outcrops. The methodology includes field investigations for duricrusts description and sampling for mineralogically and geochemically characterizations. Eleven samples were collected including six on granite and five on gneiss. Four main facies were identified: nodular and massive at both sites, vacuolar exclusively on granite, and brecciated only on gneiss. The study reveals a toposequential differentiation of the duricrusts with high-altitude positions (1150 m) displaying thick and mature duricrusts enriched in goethite and gibbsite, while mid and lower slope sites (1000 - 1050) show less indurated and kaolinite-rich materials. Geochemically, Fe2O3, the most important oxide, varied from 28.62% to 78.79%. It is followed by Al2O3 (3.06% - 32.6%). The SiO2 contents ranged from 0.95% to 22.48%. The alkali and alkaline earth elements are mostly low (0.1%). Most important trace elements identified are Ba (5 - 1191 ppm), V (108 - 1118 ppm) and Zr (9.6 - 529.4 ppm). LREE are more concentrated than HREE: 459.57 ppm and 39.44 ppm for granitic duricrusts; 722.45 ppm and 54.86 ppm for gneissic materials. The high CIA and MIA values (>99) confirm an intense duricrust weathering, leading to clay minerals development through ferruginization, monosialitization, and allitization. These results support a model of lateritic landscape evolution based on topography, lithology, and climatic conditions, which favored the understanding of duricrust processes in general and those of Adamawa region in particular.

Access to groundwater, particularly in the base zone, is a real problem. Located in the northwest of Benin, the structural and tectonic units of the Atacora chain are composed of fractured sedimentary and crystalline formations. The objective of this study is to dimension fractures on the scale of the Atacora Tectonic Unit and its foreland. The Landsat OLI 09 TIRS images have been processed in order to enhance the linear elements considered as lineaments. The lineaments obtained were compared with high-flow drilling data in order to identify fractures in the lineament network. In total, 417 fractures of various sizes (0.33 - 34.10 km) and orientations (NNE-SSW, NE-SW, ENE-OSO, ESE-ONO, SE-NO, and SSE-NNO) were identified. The distribution of fracture orientations shows a certain heterogeneity of fracturing in the study area. The statistical analysis shows that the fractures are numbered in the ESE-WNW directions: 146 fractures of length between 0.5 - 34.10 km and density between 7.87 × 10−5 - 2.50 × 10−3 km/km2; NE-SW, a total of 121 fractures with a length between 0.335 - 14.41 km and a density between 2.49 × 10−5 - 1.07 × 10−3 km/km2; ENE-OSO, 91 fractures with a length between 0.5 - 14.10 km and density between 3.78 × 10−5 - 1.04 × 10−3 km/km2; and for NNE-SSW, there are 39 fractures with a length between 0.33 - 6.74 km and a density between 2.88 × 10−5 - 5.01 × 10−3 km/km2. All the results contribute to a better understanding of fracture networks and the functioning of groundwater in the structural and tectonic units of the Atacora chain.

The Aptian-Albian age deposits are one of the most important reservoirs in Persian Gulf of Iran. These are equivalent to Shuaiba Formation in the southern part of the Persian Gulf. Microfacies, depositional environment and diagenetic processes of the studied reservoir formation have been investigated in studied field. Seven microfacies were identified in the studied interval including depositional environment ranged from lagoon to shoal and also open marine. Vertical and lateral facies changes were recognized and compared with modern and ancient depositional environments, showing that the sediments in this area were deposited in a homoclinal carbonate ramp. Variable diagenetic processes have been affected by this formation which has a notable impact on the reservoir quality. It is concluded that cementation, neomorphism and pyritization occluded the pore spaces and pore throat decreasing the reservoir porosity and permeability, while dolomitization, and fracturing increased the porosity and permeability and connection between the open spaces resulting in higher reservoir quality and most of the porosity consists of effective porosity in studied field which ranges between 9 to 18 percent and shows no major changes in the entire field. Considering the low volume of shale and good porosity most intervals of the studied reservoir formation show good reservoir quality in this field.

This study investigates the lithostratigraphic architecture and depositional environment of petroleum reservoirs in the Doba oil field, located in the Lake Chad Basin. Scientific research that exhibits the important geological and geophysical settings of this basin is lacking. The sedimentary fill of the Doba Basin spans from the Early Cretaceous to the Late Cretaceous, with some sequences extending into the Cenozoic. Hydrocarbon production in Doba Basin, particularly the northern boundary, for instance, has not yet succeeded due to the unawareness of its depositional environment. Understanding these geological characteristics is crucial for optimising the exploration and exploitation of petroleum resources. The research involves analysing geological, well log, core sample and petrophysical data from the oil wells to identify and correlate lithostratigraphic units across the oil field. The results show that the architecture, chronostratigraphic interval, lithostratigraphic units, and depositional environment are limited to the clay, sand, anhydrite, coal, sandstone, and limestone deposits from the base of the Cretaceous. These deposits exhibit spatio-temporal dispersion across the study area, influenced by local and/or regional tectonic controls. The identified reservoirs exhibit excellent porosity characteristics, ranging from 25% - 29.5%, and permeability generally is greater than 600 millidarcies (md). The results of this study will serve for the future prospector on the neighboring oil and gas fields of our study area. Significant advances have been made to ensure future exploration success.

The Fianga Massif belongs to the Pan-African Range of Central Africa in Chad. The Fianga Massif belongs to the Chadian sector of the Pan-African Range of Central Africa. The Fianga area has not been the subject of a detailed geological study. Many gaps remain in terms of the petrography and geochemistry of the massif. The Fianga Massif is composed of small, elongated NW-SE plutons. It consists of granitoids (granodiorites, hornblende and biotite granites, biotite granites and biotite microgranites) intruding into metamorphic rocks (quartz chlorite schists and massive amphibolites). These granitoids contain enclaves of metamorphic rocks and are cut by aplite and pegmatite veins. Geochemistry demonstrates that the Fianga granitoids are highly potassic and peraluminous. These studied rocks originate from a single magmatic source that evolved and differentiated by fractional crystallization in a magmatic reservoir. REE profiles show weakly enriched REEs (LaN/YbN = 0.69 - 40.29) while heavy REEs show a nearly flat profile (DyN/YbN = 0.52 - 1.13), and the La/Sm and Sm/Yb ratios led to the proposal that the Fianga rocks were derived from the partial melting of a mantle source enriched in spinel-garnet lherzolite. The partial melting of this mantle source is linked to large-scale movements along the Central Cameroon or Adamawa-Yadé shear zone and the Tchollire-Banyo shear zone, which controlled the emplacement of the pluton in the study area during the Pan-African period. This partial melting would be the origin of the emplacement of the granitoids of the Fianga massif. The high La/Nb (0.30 - 8.66) and low La/Ba (0.012 - 0.36) ratios of these granitoids are consistent with their origin by partial melting of the subcontinental lithospheric mantle modified by subduction. Pink granites (A/CNK = 0.91 - 0.96), pink microgranites (A/CNK = 0.98 - 0.07), syenites (A/CNK = 0.02), and granodiorites (A/CNK = 0.94 - 1.40) are metaluminous to perataluminous. The data suggest emplacement of this Fianga pluton in a subduction zone. The granitoids occur in the domains of volcanic arc granitoids and syn-collisional granites.

This study explores the dynamism of pollen dispersal and sedimentation on the Cameroonian continental shelf, influenced by marine currents and fluvial inputs, in particular those of the Sanaga River, crossing from NE to SW different plant successions ranging from savannah to humid forest. In addition, the monsoon and trade wind flows blow towards the continent, while the NE winds of the Harmattan directed towards the ocean hardly exceed the Savannah-Forest boundary. Through the analysis of 66 dredging samples, 43,131 pollens were identified, belonging to 381 taxa divided into 116 botanical families. The study reveals that the terrigenous inputs are essentially fluvial and concentrated at the front of the mouths. Marine currents play an important role in the distribution of pollen near the coast and offshore. It has been observed that large, flattened pollens are observed near the coasts, while small pollens can be transported easily to the open sea. In addition, Rhizophora pollens and spores, often recorded in fossil spectra, vary differently depending on the distance from areas of high mangrove production. The results provide a reference model for the reconstruction of past paleoenvironments and climates.

The work presented here deals with geographical-geological sites in the mountains of eastern Sinai in Egypt. The mountains of eastern Sinai, are characterized also by very interesting geological formations. The geological section in that region includes granite rocks on its basis, above which appear several formations of sandstones, above which appear also hard limestone rocks. The region of eastern Sinai is also located, at a meeting point between the two following big geomorphological structures, which are also in perpendicular directions. The Syrian-African rift valley, whose direction is north-south. The E Tih cliff crosses central Sinai in the east-west direction. As a consequence of those geological-geomorphological characteristics, we can see in the mountains of eastern Sinai, also combinations of deep canyons with variety of several types of rocks, isolated mountains, and also valleys with several kinds of sandstones.

The Dialafara area is part of the highly endowed Kédougou-Kéniéba Inlier (KKI), West-Malian gold belt, which corresponds to a Paleoproterozoic window through the West African Craton (WAC). This study presents, first of all, an integration of geophysical data interpretation with litho-structural field reconnaissance and then proposes a new litho-structural map of the Dialafara area. The Dialafara area shows a variety of lithology characterized by volcanic and volcano-sedimentary units, metasediments and plutonic intrusion. These lithologies were affected by a complex superposition of structures of unequal importance defining three deformation phases (DD1 to DD3) under ductile to brittle regimes. These features permit to portray a new litho-structural map, which shows that the Dialafara area presents a more complex lithological and structural context than the one presented in regional map of the KKI. This leads to the evidence that this area could be a potential site for exploration as it is situated between two world-class gold districts.

The aim of this study is to contribute to better targeting of gold prospecting areas using geospatial information. To this end, 3 mining sites were selected for the study. They are: the Sénoufo belt (Barrick Gold mine), the Yaouré complex (Perseus Mining mine) and the South Fetêkro belt (Bonikro, Hiré and Agbaou mines). For this study, a multi-scale approach was carried out at regional, mine and microscopic levels. At the regional scale, a comparative analysis of 1:200,000 scale geological maps revealed that 3 main lithologies are regularly repeated on and around the various mining sites. These are: undifferentiated volcanics, metagranodiorites and metasiltites dominated by meta-arenites. Most of these lithologies are affected by undifferentiated faults generally oriented NE-SW, N-S, ENE-WSW and WNW-ESE. In addition, gold and manganese occurrences are present on all the sites studied. At the mine scale, radarsat-1 images processing indicate that the main mining sites are generally located near or at the intersection of lineaments-oriented NE-SW or N-S on the one hand and E-W or ENE-WSW or WNW-ESE or again NW-SE on the other. These mines are also located at the interface between zones of high and low lineament density. At the microscopic scale, petrographic studies of undifferentiated volcanic samples from the various sites indicate that they consist of andesites, meta-andesites and tuffs.