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Conglomeratic, sandstone, siltstone, clay/shale and limestone facies cropping out in the East-West central part of Douala Basin along localities of Missolé II, Piti, Missolé I and Dibamba. (a) Gms facies (conglomerate sandstones with clay matrix without sedimentary structures). (b) Gmg facies (conglomerate with sandstone matrix "clast supported". (c and d) Ghi facies (coarse sandstone with imbricated elements noted the preferential orientation of quartz pebbles following their major axis). (e and f) Gt facies (crossbedding coarse sandstone). (g) Sm facies (coarse to medium-grained sandstones). (h) Sc facies (fine-grained sandstone with convoluted structures, associated to Sm facies). (i) Sh facies (fine to medium-grained sandstone showing horizontal lamination). (j) Sg facies (fine to mediumgrained sandstone). (k) Ss facies (fine to medium-grained cross-stratified sandstones). (l) St facies (medium to finegrained cross-bedded sandstones). (m) Vertical succession of Sh an Fl facies. (n) Fr facies (grey clays bioturbed, with massive structure). (o) Vertical succession of Fl and Fm facies. p) Fm (kaolinic spotted clays). (q) Fsf facies (grey to black clays, associated to Fl and Sg facies). (r) facies Fml (black laminated shale). (s) Fmlc facies (grey to black clays with some carbonaceous debris). (t) Fc facies (limestones very rich in animal debris)
Contexts in source publication
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... rock fragments of gravel size are also present. This facies has ferruginous cement and associated with convoluted Sandstone facies (Sc), coarse-grained sandstone Ghi). The Sg facies is organized in bars of several meters. It is made up of fine to medium and coarse-grained sandstones with a clay matrix, exhibiting traces of oxidation (Fig. 3g). The mm-scale grains are made up of angular to subangular quartz, with some feldspar. This facies is fairly homogeneous and poorly to well sorted and associated with horizontally bedded sandstone (Sh), cross bedded ferruginous coarse-Grained sandstone (Gt). It is showing in some place giant load casts at its basal boundary which is a simple local deformation. The St facies is composed of fine-grained sands coarsening-upward with thickness of about several meters. It consists of medium to coarse-grained, moderately to poorly sorted (Fig. 3h). Weathered surfaces show rubefaction trace, whereas fresh surfaces are white or light-pink. The coarse-grained sands have clays as its matrix. Grains are subangular to subrounded and in places the sands contains coarse-grained sandstones intraclasts formed from reworked sediments. This facies presents basal cross-stratification, which mostly form small scale troughs with low-angle. It is associated with kaolinic clay Facies (Fm), black clay Facies (Fmlc) and carbonate Facies (Fc). The Sh facies occurs in bars of several meters thickness, formed by medium to fine- grained sandstones (Fig. 3i). This facies shows a distinct horizontal lamination. It is associated with clayey siltstone Facies (Fl). The Ss facies is sorted medium to fine-grained sands occurring in a clay matrix with yellowish spots in some areas, which indicated a sign of rubefaction. This facies exhibit a distinct cross-stratification and some fragments of bivalve shells and traces of bioturbation (Fig. 3j). This facies generally has a thickness of several meters. The Sc facies is characterized by convoluted medium to fine-grained sandstones moderately sorted with thickness of about 0.5-1 m. This facies is associated with Sm facies (Fig. 3k). ...
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... rock fragments of gravel size are also present. This facies has ferruginous cement and associated with convoluted Sandstone facies (Sc), coarse-grained sandstone Ghi). The Sg facies is organized in bars of several meters. It is made up of fine to medium and coarse-grained sandstones with a clay matrix, exhibiting traces of oxidation (Fig. 3g). The mm-scale grains are made up of angular to subangular quartz, with some feldspar. This facies is fairly homogeneous and poorly to well sorted and associated with horizontally bedded sandstone (Sh), cross bedded ferruginous coarse-Grained sandstone (Gt). It is showing in some place giant load casts at its basal boundary which is a simple local deformation. The St facies is composed of fine-grained sands coarsening-upward with thickness of about several meters. It consists of medium to coarse-grained, moderately to poorly sorted (Fig. 3h). Weathered surfaces show rubefaction trace, whereas fresh surfaces are white or light-pink. The coarse-grained sands have clays as its matrix. Grains are subangular to subrounded and in places the sands contains coarse-grained sandstones intraclasts formed from reworked sediments. This facies presents basal cross-stratification, which mostly form small scale troughs with low-angle. It is associated with kaolinic clay Facies (Fm), black clay Facies (Fmlc) and carbonate Facies (Fc). The Sh facies occurs in bars of several meters thickness, formed by medium to fine- grained sandstones (Fig. 3i). This facies shows a distinct horizontal lamination. It is associated with clayey siltstone Facies (Fl). The Ss facies is sorted medium to fine-grained sands occurring in a clay matrix with yellowish spots in some areas, which indicated a sign of rubefaction. This facies exhibit a distinct cross-stratification and some fragments of bivalve shells and traces of bioturbation (Fig. 3j). This facies generally has a thickness of several meters. The Sc facies is characterized by convoluted medium to fine-grained sandstones moderately sorted with thickness of about 0.5-1 m. This facies is associated with Sm facies (Fig. 3k). ...
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... rock fragments of gravel size are also present. This facies has ferruginous cement and associated with convoluted Sandstone facies (Sc), coarse-grained sandstone Ghi). The Sg facies is organized in bars of several meters. It is made up of fine to medium and coarse-grained sandstones with a clay matrix, exhibiting traces of oxidation (Fig. 3g). The mm-scale grains are made up of angular to subangular quartz, with some feldspar. This facies is fairly homogeneous and poorly to well sorted and associated with horizontally bedded sandstone (Sh), cross bedded ferruginous coarse-Grained sandstone (Gt). It is showing in some place giant load casts at its basal boundary which is a simple local deformation. The St facies is composed of fine-grained sands coarsening-upward with thickness of about several meters. It consists of medium to coarse-grained, moderately to poorly sorted (Fig. 3h). Weathered surfaces show rubefaction trace, whereas fresh surfaces are white or light-pink. The coarse-grained sands have clays as its matrix. Grains are subangular to subrounded and in places the sands contains coarse-grained sandstones intraclasts formed from reworked sediments. This facies presents basal cross-stratification, which mostly form small scale troughs with low-angle. It is associated with kaolinic clay Facies (Fm), black clay Facies (Fmlc) and carbonate Facies (Fc). The Sh facies occurs in bars of several meters thickness, formed by medium to fine- grained sandstones (Fig. 3i). This facies shows a distinct horizontal lamination. It is associated with clayey siltstone Facies (Fl). The Ss facies is sorted medium to fine-grained sands occurring in a clay matrix with yellowish spots in some areas, which indicated a sign of rubefaction. This facies exhibit a distinct cross-stratification and some fragments of bivalve shells and traces of bioturbation (Fig. 3j). This facies generally has a thickness of several meters. The Sc facies is characterized by convoluted medium to fine-grained sandstones moderately sorted with thickness of about 0.5-1 m. This facies is associated with Sm facies (Fig. 3k). ...
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... rock fragments of gravel size are also present. This facies has ferruginous cement and associated with convoluted Sandstone facies (Sc), coarse-grained sandstone Ghi). The Sg facies is organized in bars of several meters. It is made up of fine to medium and coarse-grained sandstones with a clay matrix, exhibiting traces of oxidation (Fig. 3g). The mm-scale grains are made up of angular to subangular quartz, with some feldspar. This facies is fairly homogeneous and poorly to well sorted and associated with horizontally bedded sandstone (Sh), cross bedded ferruginous coarse-Grained sandstone (Gt). It is showing in some place giant load casts at its basal boundary which is a simple local deformation. The St facies is composed of fine-grained sands coarsening-upward with thickness of about several meters. It consists of medium to coarse-grained, moderately to poorly sorted (Fig. 3h). Weathered surfaces show rubefaction trace, whereas fresh surfaces are white or light-pink. The coarse-grained sands have clays as its matrix. Grains are subangular to subrounded and in places the sands contains coarse-grained sandstones intraclasts formed from reworked sediments. This facies presents basal cross-stratification, which mostly form small scale troughs with low-angle. It is associated with kaolinic clay Facies (Fm), black clay Facies (Fmlc) and carbonate Facies (Fc). The Sh facies occurs in bars of several meters thickness, formed by medium to fine- grained sandstones (Fig. 3i). This facies shows a distinct horizontal lamination. It is associated with clayey siltstone Facies (Fl). The Ss facies is sorted medium to fine-grained sands occurring in a clay matrix with yellowish spots in some areas, which indicated a sign of rubefaction. This facies exhibit a distinct cross-stratification and some fragments of bivalve shells and traces of bioturbation (Fig. 3j). This facies generally has a thickness of several meters. The Sc facies is characterized by convoluted medium to fine-grained sandstones moderately sorted with thickness of about 0.5-1 m. This facies is associated with Sm facies (Fig. 3k). ...
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... rock fragments of gravel size are also present. This facies has ferruginous cement and associated with convoluted Sandstone facies (Sc), coarse-grained sandstone Ghi). The Sg facies is organized in bars of several meters. It is made up of fine to medium and coarse-grained sandstones with a clay matrix, exhibiting traces of oxidation (Fig. 3g). The mm-scale grains are made up of angular to subangular quartz, with some feldspar. This facies is fairly homogeneous and poorly to well sorted and associated with horizontally bedded sandstone (Sh), cross bedded ferruginous coarse-Grained sandstone (Gt). It is showing in some place giant load casts at its basal boundary which is a simple local deformation. The St facies is composed of fine-grained sands coarsening-upward with thickness of about several meters. It consists of medium to coarse-grained, moderately to poorly sorted (Fig. 3h). Weathered surfaces show rubefaction trace, whereas fresh surfaces are white or light-pink. The coarse-grained sands have clays as its matrix. Grains are subangular to subrounded and in places the sands contains coarse-grained sandstones intraclasts formed from reworked sediments. This facies presents basal cross-stratification, which mostly form small scale troughs with low-angle. It is associated with kaolinic clay Facies (Fm), black clay Facies (Fmlc) and carbonate Facies (Fc). The Sh facies occurs in bars of several meters thickness, formed by medium to fine- grained sandstones (Fig. 3i). This facies shows a distinct horizontal lamination. It is associated with clayey siltstone Facies (Fl). The Ss facies is sorted medium to fine-grained sands occurring in a clay matrix with yellowish spots in some areas, which indicated a sign of rubefaction. This facies exhibit a distinct cross-stratification and some fragments of bivalve shells and traces of bioturbation (Fig. 3j). This facies generally has a thickness of several meters. The Sc facies is characterized by convoluted medium to fine-grained sandstones moderately sorted with thickness of about 0.5-1 m. This facies is associated with Sm facies (Fig. 3k). ...
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... Gms facies is a heterolithic conglomerate with a sandstone-clay matrix. The lithic elements of this conglomerate are 4-5 cm in diameter. These elements are rounded to subangular with quartz fragments being dominant. The unconsolidated matrix consists of coarse to medium-grained sandstones which is poorly sorted, mixed with clay and varies from grey to red, depending on the clay content (Fig. 3a). There is no graded bedding or other sedimentary structures and the bed varies from 1-12 m in thickness. The Gmg facies with 5 m thick is constituted by cm-scale rounded to subangular quartz grains (Fig. 3b). It is associated locally to Ghi facies. The matrix consists of medium to coarse-grained sands. It presents graded bedding and its basal surface is erosive. The Ghi facies is coarse- grained sandstones with quartz pebbles 3-4 cm in diameter in a clayey sandstone matrix (Fig. 3c). At the basal boundary of this facies, rounded quartz pebbles are slightly imbricated. This coarse-grained sandstone is poorly sorted and rests on an erosive surface. The bed has thickness of about 4-6 m. The Gt facies is ferruginous coarse-grained sandstone, with rounded quartz pebbles 4-5 cm in diameter ( Fig. 3d and e). These pebbles occur in a sandstone matrix poorly sorted and are associated to Sg facies. In some places, Gt facies shows cross bedding rarely multi- storey with pebbles lag at set base. The set has low- angle and oriented generally ...
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... Gms facies is a heterolithic conglomerate with a sandstone-clay matrix. The lithic elements of this conglomerate are 4-5 cm in diameter. These elements are rounded to subangular with quartz fragments being dominant. The unconsolidated matrix consists of coarse to medium-grained sandstones which is poorly sorted, mixed with clay and varies from grey to red, depending on the clay content (Fig. 3a). There is no graded bedding or other sedimentary structures and the bed varies from 1-12 m in thickness. The Gmg facies with 5 m thick is constituted by cm-scale rounded to subangular quartz grains (Fig. 3b). It is associated locally to Ghi facies. The matrix consists of medium to coarse-grained sands. It presents graded bedding and its basal surface is erosive. The Ghi facies is coarse- grained sandstones with quartz pebbles 3-4 cm in diameter in a clayey sandstone matrix (Fig. 3c). At the basal boundary of this facies, rounded quartz pebbles are slightly imbricated. This coarse-grained sandstone is poorly sorted and rests on an erosive surface. The bed has thickness of about 4-6 m. The Gt facies is ferruginous coarse-grained sandstone, with rounded quartz pebbles 4-5 cm in diameter ( Fig. 3d and e). These pebbles occur in a sandstone matrix poorly sorted and are associated to Sg facies. In some places, Gt facies shows cross bedding rarely multi- storey with pebbles lag at set base. The set has low- angle and oriented generally ...
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... Gms facies is a heterolithic conglomerate with a sandstone-clay matrix. The lithic elements of this conglomerate are 4-5 cm in diameter. These elements are rounded to subangular with quartz fragments being dominant. The unconsolidated matrix consists of coarse to medium-grained sandstones which is poorly sorted, mixed with clay and varies from grey to red, depending on the clay content (Fig. 3a). There is no graded bedding or other sedimentary structures and the bed varies from 1-12 m in thickness. The Gmg facies with 5 m thick is constituted by cm-scale rounded to subangular quartz grains (Fig. 3b). It is associated locally to Ghi facies. The matrix consists of medium to coarse-grained sands. It presents graded bedding and its basal surface is erosive. The Ghi facies is coarse- grained sandstones with quartz pebbles 3-4 cm in diameter in a clayey sandstone matrix (Fig. 3c). At the basal boundary of this facies, rounded quartz pebbles are slightly imbricated. This coarse-grained sandstone is poorly sorted and rests on an erosive surface. The bed has thickness of about 4-6 m. The Gt facies is ferruginous coarse-grained sandstone, with rounded quartz pebbles 4-5 cm in diameter ( Fig. 3d and e). These pebbles occur in a sandstone matrix poorly sorted and are associated to Sg facies. In some places, Gt facies shows cross bedding rarely multi- storey with pebbles lag at set base. The set has low- angle and oriented generally ...
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... Gms facies is a heterolithic conglomerate with a sandstone-clay matrix. The lithic elements of this conglomerate are 4-5 cm in diameter. These elements are rounded to subangular with quartz fragments being dominant. The unconsolidated matrix consists of coarse to medium-grained sandstones which is poorly sorted, mixed with clay and varies from grey to red, depending on the clay content (Fig. 3a). There is no graded bedding or other sedimentary structures and the bed varies from 1-12 m in thickness. The Gmg facies with 5 m thick is constituted by cm-scale rounded to subangular quartz grains (Fig. 3b). It is associated locally to Ghi facies. The matrix consists of medium to coarse-grained sands. It presents graded bedding and its basal surface is erosive. The Ghi facies is coarse- grained sandstones with quartz pebbles 3-4 cm in diameter in a clayey sandstone matrix (Fig. 3c). At the basal boundary of this facies, rounded quartz pebbles are slightly imbricated. This coarse-grained sandstone is poorly sorted and rests on an erosive surface. The bed has thickness of about 4-6 m. The Gt facies is ferruginous coarse-grained sandstone, with rounded quartz pebbles 4-5 cm in diameter ( Fig. 3d and e). These pebbles occur in a sandstone matrix poorly sorted and are associated to Sg facies. In some places, Gt facies shows cross bedding rarely multi- storey with pebbles lag at set base. The set has low- angle and oriented generally ...
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... Fl facies forms clayey siltstone and occurs in the form of an individual bar with a thickness of several meters and associated with horizontally bedded Sandstone facies (Sh), kaolinic claystone (Fm) and shale/mudstone Facies (Fml). It shows parallel laminations and weathered surfaces show traces of rubefaction, whereas fresh surfaces are white or light- pink. A few fragments of lignite were observed, bioturbation and plant root traces are common (Fig. 3l). This facies presented on the top rounded-sharp flute marks (Fig. 3m). The grey argillaceous Facies (Fr) with 2 m thick has massive structure and grey spotted with purple. Traces of bioturbation are frequently observed in this facies ( Fig. 3n and o). It is associated with horizontally bedded Sandstone (Sh). The multicoloured kaolinic clays Facies (Fm) has a thickness of several meters and associated with clayey siltstone (Fl), trough cross bedded Sandstone (St). This facies is massive and shows locally desiccation-cracks (Fig. 3p). Bioturbation, microorganism activity and plant root traces are also common (Fig. 3q). The black clay Facies (Fsf) is massive claystone with fossils content as moulds of bivalves and gastropod shells. There is also the presence of some coal debris. This facies is associated with clayey siltstone Facies (Fl) and fine to medium-grained Sandstone facies (Sg). The individual bed has thickness of about 15 m (Fig. 3r and s). The Fml facies consists of compacted, fissile black shale (Fig. 3t). These clays may be bioturbated in some areas. Many animal fossils are observed including shell moulds of molluscs (bivalves, gastropods), as well as Nautilus debris. Its thickness is estimated at more than ten meters. Towards the top of the bed, this facies is associated with clayey siltstone Facies (Fl). The massive or laminated black claystone Facies (Fmlc) shares the same features as Fml facies but contains some carbonaceous plant debris (Fig. 3u). It is associated with medium to coarse-grained Sandstone facies (Sm) and limestone Facies (Fc). The individual bed is about 40 m thick and presents at the top, some ferruginous nodules parallel to the stratification. The presence of parallel laminations is also noted at the bottom of the bed. The limestone Facies (Fc) occurs as a lenticular bed with thickness of about 0, 65 m thick. It is associated with Fmlc facies and in addition to numerous fragments of bivalves and gastropods; it also has siliciclastic elements such as subrounded to rounded quartz pebbles which sometimes show a ferruginous coating (Fig. ...
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... Fl facies forms clayey siltstone and occurs in the form of an individual bar with a thickness of several meters and associated with horizontally bedded Sandstone facies (Sh), kaolinic claystone (Fm) and shale/mudstone Facies (Fml). It shows parallel laminations and weathered surfaces show traces of rubefaction, whereas fresh surfaces are white or light- pink. A few fragments of lignite were observed, bioturbation and plant root traces are common (Fig. 3l). This facies presented on the top rounded-sharp flute marks (Fig. 3m). The grey argillaceous Facies (Fr) with 2 m thick has massive structure and grey spotted with purple. Traces of bioturbation are frequently observed in this facies ( Fig. 3n and o). It is associated with horizontally bedded Sandstone (Sh). The multicoloured kaolinic clays Facies (Fm) has a thickness of several meters and associated with clayey siltstone (Fl), trough cross bedded Sandstone (St). This facies is massive and shows locally desiccation-cracks (Fig. 3p). Bioturbation, microorganism activity and plant root traces are also common (Fig. 3q). The black clay Facies (Fsf) is massive claystone with fossils content as moulds of bivalves and gastropod shells. There is also the presence of some coal debris. This facies is associated with clayey siltstone Facies (Fl) and fine to medium-grained Sandstone facies (Sg). The individual bed has thickness of about 15 m (Fig. 3r and s). The Fml facies consists of compacted, fissile black shale (Fig. 3t). These clays may be bioturbated in some areas. Many animal fossils are observed including shell moulds of molluscs (bivalves, gastropods), as well as Nautilus debris. Its thickness is estimated at more than ten meters. Towards the top of the bed, this facies is associated with clayey siltstone Facies (Fl). The massive or laminated black claystone Facies (Fmlc) shares the same features as Fml facies but contains some carbonaceous plant debris (Fig. 3u). It is associated with medium to coarse-grained Sandstone facies (Sm) and limestone Facies (Fc). The individual bed is about 40 m thick and presents at the top, some ferruginous nodules parallel to the stratification. The presence of parallel laminations is also noted at the bottom of the bed. The limestone Facies (Fc) occurs as a lenticular bed with thickness of about 0, 65 m thick. It is associated with Fmlc facies and in addition to numerous fragments of bivalves and gastropods; it also has siliciclastic elements such as subrounded to rounded quartz pebbles which sometimes show a ferruginous coating (Fig. ...
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... Fl facies forms clayey siltstone and occurs in the form of an individual bar with a thickness of several meters and associated with horizontally bedded Sandstone facies (Sh), kaolinic claystone (Fm) and shale/mudstone Facies (Fml). It shows parallel laminations and weathered surfaces show traces of rubefaction, whereas fresh surfaces are white or light- pink. A few fragments of lignite were observed, bioturbation and plant root traces are common (Fig. 3l). This facies presented on the top rounded-sharp flute marks (Fig. 3m). The grey argillaceous Facies (Fr) with 2 m thick has massive structure and grey spotted with purple. Traces of bioturbation are frequently observed in this facies ( Fig. 3n and o). It is associated with horizontally bedded Sandstone (Sh). The multicoloured kaolinic clays Facies (Fm) has a thickness of several meters and associated with clayey siltstone (Fl), trough cross bedded Sandstone (St). This facies is massive and shows locally desiccation-cracks (Fig. 3p). Bioturbation, microorganism activity and plant root traces are also common (Fig. 3q). The black clay Facies (Fsf) is massive claystone with fossils content as moulds of bivalves and gastropod shells. There is also the presence of some coal debris. This facies is associated with clayey siltstone Facies (Fl) and fine to medium-grained Sandstone facies (Sg). The individual bed has thickness of about 15 m (Fig. 3r and s). The Fml facies consists of compacted, fissile black shale (Fig. 3t). These clays may be bioturbated in some areas. Many animal fossils are observed including shell moulds of molluscs (bivalves, gastropods), as well as Nautilus debris. Its thickness is estimated at more than ten meters. Towards the top of the bed, this facies is associated with clayey siltstone Facies (Fl). The massive or laminated black claystone Facies (Fmlc) shares the same features as Fml facies but contains some carbonaceous plant debris (Fig. 3u). It is associated with medium to coarse-grained Sandstone facies (Sm) and limestone Facies (Fc). The individual bed is about 40 m thick and presents at the top, some ferruginous nodules parallel to the stratification. The presence of parallel laminations is also noted at the bottom of the bed. The limestone Facies (Fc) occurs as a lenticular bed with thickness of about 0, 65 m thick. It is associated with Fmlc facies and in addition to numerous fragments of bivalves and gastropods; it also has siliciclastic elements such as subrounded to rounded quartz pebbles which sometimes show a ferruginous coating (Fig. ...
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... Fl facies forms clayey siltstone and occurs in the form of an individual bar with a thickness of several meters and associated with horizontally bedded Sandstone facies (Sh), kaolinic claystone (Fm) and shale/mudstone Facies (Fml). It shows parallel laminations and weathered surfaces show traces of rubefaction, whereas fresh surfaces are white or light- pink. A few fragments of lignite were observed, bioturbation and plant root traces are common (Fig. 3l). This facies presented on the top rounded-sharp flute marks (Fig. 3m). The grey argillaceous Facies (Fr) with 2 m thick has massive structure and grey spotted with purple. Traces of bioturbation are frequently observed in this facies ( Fig. 3n and o). It is associated with horizontally bedded Sandstone (Sh). The multicoloured kaolinic clays Facies (Fm) has a thickness of several meters and associated with clayey siltstone (Fl), trough cross bedded Sandstone (St). This facies is massive and shows locally desiccation-cracks (Fig. 3p). Bioturbation, microorganism activity and plant root traces are also common (Fig. 3q). The black clay Facies (Fsf) is massive claystone with fossils content as moulds of bivalves and gastropod shells. There is also the presence of some coal debris. This facies is associated with clayey siltstone Facies (Fl) and fine to medium-grained Sandstone facies (Sg). The individual bed has thickness of about 15 m (Fig. 3r and s). The Fml facies consists of compacted, fissile black shale (Fig. 3t). These clays may be bioturbated in some areas. Many animal fossils are observed including shell moulds of molluscs (bivalves, gastropods), as well as Nautilus debris. Its thickness is estimated at more than ten meters. Towards the top of the bed, this facies is associated with clayey siltstone Facies (Fl). The massive or laminated black claystone Facies (Fmlc) shares the same features as Fml facies but contains some carbonaceous plant debris (Fig. 3u). It is associated with medium to coarse-grained Sandstone facies (Sm) and limestone Facies (Fc). The individual bed is about 40 m thick and presents at the top, some ferruginous nodules parallel to the stratification. The presence of parallel laminations is also noted at the bottom of the bed. The limestone Facies (Fc) occurs as a lenticular bed with thickness of about 0, 65 m thick. It is associated with Fmlc facies and in addition to numerous fragments of bivalves and gastropods; it also has siliciclastic elements such as subrounded to rounded quartz pebbles which sometimes show a ferruginous coating (Fig. ...
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... Fl facies forms clayey siltstone and occurs in the form of an individual bar with a thickness of several meters and associated with horizontally bedded Sandstone facies (Sh), kaolinic claystone (Fm) and shale/mudstone Facies (Fml). It shows parallel laminations and weathered surfaces show traces of rubefaction, whereas fresh surfaces are white or light- pink. A few fragments of lignite were observed, bioturbation and plant root traces are common (Fig. 3l). This facies presented on the top rounded-sharp flute marks (Fig. 3m). The grey argillaceous Facies (Fr) with 2 m thick has massive structure and grey spotted with purple. Traces of bioturbation are frequently observed in this facies ( Fig. 3n and o). It is associated with horizontally bedded Sandstone (Sh). The multicoloured kaolinic clays Facies (Fm) has a thickness of several meters and associated with clayey siltstone (Fl), trough cross bedded Sandstone (St). This facies is massive and shows locally desiccation-cracks (Fig. 3p). Bioturbation, microorganism activity and plant root traces are also common (Fig. 3q). The black clay Facies (Fsf) is massive claystone with fossils content as moulds of bivalves and gastropod shells. There is also the presence of some coal debris. This facies is associated with clayey siltstone Facies (Fl) and fine to medium-grained Sandstone facies (Sg). The individual bed has thickness of about 15 m (Fig. 3r and s). The Fml facies consists of compacted, fissile black shale (Fig. 3t). These clays may be bioturbated in some areas. Many animal fossils are observed including shell moulds of molluscs (bivalves, gastropods), as well as Nautilus debris. Its thickness is estimated at more than ten meters. Towards the top of the bed, this facies is associated with clayey siltstone Facies (Fl). The massive or laminated black claystone Facies (Fmlc) shares the same features as Fml facies but contains some carbonaceous plant debris (Fig. 3u). It is associated with medium to coarse-grained Sandstone facies (Sm) and limestone Facies (Fc). The individual bed is about 40 m thick and presents at the top, some ferruginous nodules parallel to the stratification. The presence of parallel laminations is also noted at the bottom of the bed. The limestone Facies (Fc) occurs as a lenticular bed with thickness of about 0, 65 m thick. It is associated with Fmlc facies and in addition to numerous fragments of bivalves and gastropods; it also has siliciclastic elements such as subrounded to rounded quartz pebbles which sometimes show a ferruginous coating (Fig. ...
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... Fl facies forms clayey siltstone and occurs in the form of an individual bar with a thickness of several meters and associated with horizontally bedded Sandstone facies (Sh), kaolinic claystone (Fm) and shale/mudstone Facies (Fml). It shows parallel laminations and weathered surfaces show traces of rubefaction, whereas fresh surfaces are white or light- pink. A few fragments of lignite were observed, bioturbation and plant root traces are common (Fig. 3l). This facies presented on the top rounded-sharp flute marks (Fig. 3m). The grey argillaceous Facies (Fr) with 2 m thick has massive structure and grey spotted with purple. Traces of bioturbation are frequently observed in this facies ( Fig. 3n and o). It is associated with horizontally bedded Sandstone (Sh). The multicoloured kaolinic clays Facies (Fm) has a thickness of several meters and associated with clayey siltstone (Fl), trough cross bedded Sandstone (St). This facies is massive and shows locally desiccation-cracks (Fig. 3p). Bioturbation, microorganism activity and plant root traces are also common (Fig. 3q). The black clay Facies (Fsf) is massive claystone with fossils content as moulds of bivalves and gastropod shells. There is also the presence of some coal debris. This facies is associated with clayey siltstone Facies (Fl) and fine to medium-grained Sandstone facies (Sg). The individual bed has thickness of about 15 m (Fig. 3r and s). The Fml facies consists of compacted, fissile black shale (Fig. 3t). These clays may be bioturbated in some areas. Many animal fossils are observed including shell moulds of molluscs (bivalves, gastropods), as well as Nautilus debris. Its thickness is estimated at more than ten meters. Towards the top of the bed, this facies is associated with clayey siltstone Facies (Fl). The massive or laminated black claystone Facies (Fmlc) shares the same features as Fml facies but contains some carbonaceous plant debris (Fig. 3u). It is associated with medium to coarse-grained Sandstone facies (Sm) and limestone Facies (Fc). The individual bed is about 40 m thick and presents at the top, some ferruginous nodules parallel to the stratification. The presence of parallel laminations is also noted at the bottom of the bed. The limestone Facies (Fc) occurs as a lenticular bed with thickness of about 0, 65 m thick. It is associated with Fmlc facies and in addition to numerous fragments of bivalves and gastropods; it also has siliciclastic elements such as subrounded to rounded quartz pebbles which sometimes show a ferruginous coating (Fig. ...
Context 16
... Fl facies forms clayey siltstone and occurs in the form of an individual bar with a thickness of several meters and associated with horizontally bedded Sandstone facies (Sh), kaolinic claystone (Fm) and shale/mudstone Facies (Fml). It shows parallel laminations and weathered surfaces show traces of rubefaction, whereas fresh surfaces are white or light- pink. A few fragments of lignite were observed, bioturbation and plant root traces are common (Fig. 3l). This facies presented on the top rounded-sharp flute marks (Fig. 3m). The grey argillaceous Facies (Fr) with 2 m thick has massive structure and grey spotted with purple. Traces of bioturbation are frequently observed in this facies ( Fig. 3n and o). It is associated with horizontally bedded Sandstone (Sh). The multicoloured kaolinic clays Facies (Fm) has a thickness of several meters and associated with clayey siltstone (Fl), trough cross bedded Sandstone (St). This facies is massive and shows locally desiccation-cracks (Fig. 3p). Bioturbation, microorganism activity and plant root traces are also common (Fig. 3q). The black clay Facies (Fsf) is massive claystone with fossils content as moulds of bivalves and gastropod shells. There is also the presence of some coal debris. This facies is associated with clayey siltstone Facies (Fl) and fine to medium-grained Sandstone facies (Sg). The individual bed has thickness of about 15 m (Fig. 3r and s). The Fml facies consists of compacted, fissile black shale (Fig. 3t). These clays may be bioturbated in some areas. Many animal fossils are observed including shell moulds of molluscs (bivalves, gastropods), as well as Nautilus debris. Its thickness is estimated at more than ten meters. Towards the top of the bed, this facies is associated with clayey siltstone Facies (Fl). The massive or laminated black claystone Facies (Fmlc) shares the same features as Fml facies but contains some carbonaceous plant debris (Fig. 3u). It is associated with medium to coarse-grained Sandstone facies (Sm) and limestone Facies (Fc). The individual bed is about 40 m thick and presents at the top, some ferruginous nodules parallel to the stratification. The presence of parallel laminations is also noted at the bottom of the bed. The limestone Facies (Fc) occurs as a lenticular bed with thickness of about 0, 65 m thick. It is associated with Fmlc facies and in addition to numerous fragments of bivalves and gastropods; it also has siliciclastic elements such as subrounded to rounded quartz pebbles which sometimes show a ferruginous coating (Fig. ...
Context 17
... Fl facies forms clayey siltstone and occurs in the form of an individual bar with a thickness of several meters and associated with horizontally bedded Sandstone facies (Sh), kaolinic claystone (Fm) and shale/mudstone Facies (Fml). It shows parallel laminations and weathered surfaces show traces of rubefaction, whereas fresh surfaces are white or light- pink. A few fragments of lignite were observed, bioturbation and plant root traces are common (Fig. 3l). This facies presented on the top rounded-sharp flute marks (Fig. 3m). The grey argillaceous Facies (Fr) with 2 m thick has massive structure and grey spotted with purple. Traces of bioturbation are frequently observed in this facies ( Fig. 3n and o). It is associated with horizontally bedded Sandstone (Sh). The multicoloured kaolinic clays Facies (Fm) has a thickness of several meters and associated with clayey siltstone (Fl), trough cross bedded Sandstone (St). This facies is massive and shows locally desiccation-cracks (Fig. 3p). Bioturbation, microorganism activity and plant root traces are also common (Fig. 3q). The black clay Facies (Fsf) is massive claystone with fossils content as moulds of bivalves and gastropod shells. There is also the presence of some coal debris. This facies is associated with clayey siltstone Facies (Fl) and fine to medium-grained Sandstone facies (Sg). The individual bed has thickness of about 15 m (Fig. 3r and s). The Fml facies consists of compacted, fissile black shale (Fig. 3t). These clays may be bioturbated in some areas. Many animal fossils are observed including shell moulds of molluscs (bivalves, gastropods), as well as Nautilus debris. Its thickness is estimated at more than ten meters. Towards the top of the bed, this facies is associated with clayey siltstone Facies (Fl). The massive or laminated black claystone Facies (Fmlc) shares the same features as Fml facies but contains some carbonaceous plant debris (Fig. 3u). It is associated with medium to coarse-grained Sandstone facies (Sm) and limestone Facies (Fc). The individual bed is about 40 m thick and presents at the top, some ferruginous nodules parallel to the stratification. The presence of parallel laminations is also noted at the bottom of the bed. The limestone Facies (Fc) occurs as a lenticular bed with thickness of about 0, 65 m thick. It is associated with Fmlc facies and in addition to numerous fragments of bivalves and gastropods; it also has siliciclastic elements such as subrounded to rounded quartz pebbles which sometimes show a ferruginous coating (Fig. ...
Context 18
... Fl facies forms clayey siltstone and occurs in the form of an individual bar with a thickness of several meters and associated with horizontally bedded Sandstone facies (Sh), kaolinic claystone (Fm) and shale/mudstone Facies (Fml). It shows parallel laminations and weathered surfaces show traces of rubefaction, whereas fresh surfaces are white or light- pink. A few fragments of lignite were observed, bioturbation and plant root traces are common (Fig. 3l). This facies presented on the top rounded-sharp flute marks (Fig. 3m). The grey argillaceous Facies (Fr) with 2 m thick has massive structure and grey spotted with purple. Traces of bioturbation are frequently observed in this facies ( Fig. 3n and o). It is associated with horizontally bedded Sandstone (Sh). The multicoloured kaolinic clays Facies (Fm) has a thickness of several meters and associated with clayey siltstone (Fl), trough cross bedded Sandstone (St). This facies is massive and shows locally desiccation-cracks (Fig. 3p). Bioturbation, microorganism activity and plant root traces are also common (Fig. 3q). The black clay Facies (Fsf) is massive claystone with fossils content as moulds of bivalves and gastropod shells. There is also the presence of some coal debris. This facies is associated with clayey siltstone Facies (Fl) and fine to medium-grained Sandstone facies (Sg). The individual bed has thickness of about 15 m (Fig. 3r and s). The Fml facies consists of compacted, fissile black shale (Fig. 3t). These clays may be bioturbated in some areas. Many animal fossils are observed including shell moulds of molluscs (bivalves, gastropods), as well as Nautilus debris. Its thickness is estimated at more than ten meters. Towards the top of the bed, this facies is associated with clayey siltstone Facies (Fl). The massive or laminated black claystone Facies (Fmlc) shares the same features as Fml facies but contains some carbonaceous plant debris (Fig. 3u). It is associated with medium to coarse-grained Sandstone facies (Sm) and limestone Facies (Fc). The individual bed is about 40 m thick and presents at the top, some ferruginous nodules parallel to the stratification. The presence of parallel laminations is also noted at the bottom of the bed. The limestone Facies (Fc) occurs as a lenticular bed with thickness of about 0, 65 m thick. It is associated with Fmlc facies and in addition to numerous fragments of bivalves and gastropods; it also has siliciclastic elements such as subrounded to rounded quartz pebbles which sometimes show a ferruginous coating (Fig. ...
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For the Coulomb four-body problem, we show that there are finitely many isometry classes of planar central configurations (i.e., relative equilibria).
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... This surface corresponds to the top of the Middle Paleocene (Selandian), according to the chronostratigraphic chart of Robertson (2015). Bachirou et al. (2014) show that at outcrops this surface is represented by ferruginous concretions, with 10 centimeters thick. ...
... This period is mainly in uenced by tectonic activity which dominated the sea's forward and backward movements(Robertson, 1992 ;Lawrence et al., 2002). A subsidence phase from the Paleocene to the Early Eocene (Ypresian) consists of marine and continental deposits and an uplift phase at the Late Eocene, is composed of clastic shoreline deposits(Bachirou et al., 2014). ...
The present study aims to establish the stratigraphic architecture in order to understand the depositional history during the Paleocene- Early Eocene interval in the Douala Onshore Basin. The sequence stratigraphic analysis from gamma-ray logs and well cuttings was used to define stratigraphic surfaces and systems tracts based on the depositional sequence model. The results obtained show that the Paleocene-Early Eocene interval could be subdivided into three lithostratigraphic units (Unit 1, Unit 2, and Unit 3) of Middle Paleocene - Late Paleocene, Late Paleocene - Early Eocene, and Early Eocene age respectively. The sequence stratigraphic interpretation revealed three major stratigraphic surfaces : the sequence boundary (SB1) of the Middle Paleocene top, the transgressive surface (TS2) of the Late Paleocene, and the maximum flooding surface (MFS2) of the Early Eocene. The first highstand systems tracts (HST1) of the Middle Paleocene, the lowstand systems tract (LST2) of the Late Paleocene, the transgressive systems tract (TST2) of the Late Paleocene to Early Eocene, and the second highstand systems tracts (HST2) of the Early Eocene are the depositional sequences observed. The Paleocene-Eocene interval is therefore globally prograding, interrupted by a short transgressive episode of Late Paleocene to Early-Eocene age. Three cycles of base-level have been identified: the first cycle of base-level fall dated Middle Paleocene, the second cycle of rapid base-level rise which occurred between Late Paleocene to Early Eocene, and the third cycle of base-level fall dated Early Eocene. This observation confirms that the main factor which influenced the depositional history of Paleocene- Early Eocene succession in the Douala Onshore Basin was the eustatic sea-level changes due to the Cenozoic post-rift subsidence of the West African margin.
... The main oil and gas production in Cameroon is from the coastal and offshore Douala/Kribi-Campo and Rio del Rey Basins which are relatively well known (e.g. Nguene et al., 1992;Pauken, 1992;Loule et al., 1997;Brownfield and Charpentier, 2006;Ntamak-Nida et al., 2008;Mfayakouo et al., 2014;Agyingi et al., 2019). By contrast and with the exception of the Logone Birni and Mamfe Basins, onshore basins in Cameroon have been poorly studied. ...
The synrift Mayo Oulo‐Léré Basin in Northern Cameroon is located in the transition zone between the West and Central African Rift Systems. Structural and stratigraphic elements of the basin resemble those of the Yola Basin in NE Nigeria, an extension of the Upper Benue Trough. The Lower Cretaceous lacustrine shales with source rock potential which occur in nearby rift basins are also present in the Mayo Oulo‐Léré Basin. These shales were investigated at two outcrop locations (Badesi and Tchontchi), and samples collected (n = 60) were subjected to palynofacies and bulk geochemical analyses to evaluate their petroleum generation potential and to interpret their depositional environment. At the studied locations, shales were divided into two lithofacies: grey to black laminated shales containing algal‐bacterial OM together with common woody (phytoclast) debris (“facies Fml”); and cm‐bedded shales which had a higher content of algal‐bacterial OM but a lower phytoclast content (“facies Fmlc”). Palynological and bulk geochemical data indicate that the shales contain well‐preserved organic matter (OM) and locally display good to excellent oil generation potential. Average TOC contents are 2.7% and 1.4% for samples of the Fmlc and Fml facies shales respectively. HI values (94‐889 mg HC/g TOC and 131‐638 mg HC/g TOC respectively) suggest that the shales contain Types I to III kerogen. Organic material in the Fmlc facies shales is dominated by amorphous organic matter (AOM: 90% on average) with a low phytoclast content (6% on average); whereas samples of the Fml facies shales contain less AOM (74% on average) and have a higher phytoclast content (23% on average). AOM in the Fmlc shales is highly fluorescent; these shales are interpreted to have been deposited in dysoxic to anoxic conditions. The AOM in the Fml shales is weakly fluorescent and the shales were deposited under more oxic conditions. The kerogen in the shales ranges from immature to early oil window mature. Average values of the pyrolysis S2 yield are 15.5 mg HC/g of rock and 7 mg HC/g of rock for samples from Fmlc and Fml facies shales respectively. The shales increase in thickness northwards towards the Logone Birni Basin where they may have reached the oil window, as in neighbouring basins. The results of this study of lacustrine shales from the Mayo Oulo‐Léré Basin suggests that there may be potential for oil exploration in northern Cameroon.
... These outcrops of SW-NE direction, are composed by three main facies association: the gravelly dominated, the sandy dominated and the fine grained dominated. These facies associations have been well described in a previous work (Mfayakouo et al., 2014). For the palynological analysis, the sampling was targeted base on the facies changes on these outcrops. ...
... In the Missole I and Dibamba localities, three main facies associations were recognized in the previous study by (Mfayakouo et al., 2014). The summary of these facies are presented in table 2. The vertical evolution of these facies allowed us to define two virtual sequences that correspond to the paleoenvironment and paleogeographic evolution of a passive continental margin basin similar to those previously described by (Cojan and Renard, 2006) These includes (i) the transgressive virtual sequence, characterized by conglomerates, coarse-grained sandstone, finegrained sandstone, siltstone, claystone, marlstone, limestone and shale, and (ii) the regressive virtual sequence includes claystone, limestone, marlstone, siltstone, fine-grained sandstone and coarse-grained sandstone. ...
... The Missole I sediments were deposited in delta plain environment (see Mfayakouo et al., 2014). The association of palynomorph including continental and marine species with the dominance of monocotyledonous plant materials such as Spinizonocolpites baculatus and ...
The Douala basin in Cameroon is one of the West African basins created during the opening of the South Atlantic Ocean after the break-up of the Gondwana superstructure. Until now, no detailed studies of age and paleo-environmental evolution of this basin during the Cenozoic have been carried out, especially on outcrops sections. Palynological and sequence analyses have been performed on the outcrops in the Missole I and Dibamba localities in the central part of this basin. This integrated approach allow us propose a new age and paleo-environmental evolution of the Douala Basin. Three palynomorph assemblages have been identified: (i) the Paleocene-Eocene palynomorph assemblage (A) from the Missole I deposits; (ii) the Oligocene palynomorph assemblage (B) from the lower part of the Dibamba deposits; and (iii) the Lower to Middle Miocene palynomorph assemblages (C) from the upper part of the Dibamba deposits. Sequence analysis indicates four depositional sequences with a vertical succession, characterized by major transgressive depositional sequences (depositional sequence “a”, “b”, and “c”), and a minor regressive depositional sequence (“d”). The trangressive sequences were deposited in lagoon or marginal marine environments during Paleocene-Eocene, while the regressive sequence was deposited in prograding continental shelf during the Oligocene-Middle Miocene. The recognized depositional sequence and associated depositional environments were controlled by spasmodic subsidence, margin uplift and climatic variations. Climate evolved from a wet-dry subtropical to tropical during the Paleocene-Eocene and a warm humid subtropical during the Oligocene up to Lower Middle Miocene with overall shift of the Douala basin from the Southern to the Northern hemisphere. This study reveals the existence of Oligocene deposits (Souellaba Formation) in the outcrops and could be useful for future correlation with the offshore part of the Douala Basin.
... It has been subject to numerous paleoenvironmental studies from the Cretaceous to the Quaternary. Most of these studies were carried based on the sedimentological characteristics and/ or fossiliferous content of various deposits of the basin (Nguéné et al. 1992;Njiké Ngaha 2005;Tchouatcha 2005;Touomo Sime 2010;Mbesse et al. 2012;Mfayakouo et al. 2014;Ngon Ngon et al. 2016). ...
... The Bonepoupa and Mbanga outcrops belong to the Loungahé Formation (formerly called Logbadjeck Formation) of the Cenomanian age (Njiké Ngaha 1984;Njiké Ngaha and Eno Belinga 1987). The Missole 2 outcrops belong to the Miang Formation (formerly called N'kapa) constituted by Paleocene-Eocene deposits (Kenfack et al. 2012a, b;Mfayakouo et al. 2014;Mfayakouo 2016;Ngon Ngon et al. 2016;Fowé Kwéché et al. 2018). The Ngwan outcrops (at the boundary between the Matanda and Wouri formations) constituted by the Miocene-Pliocene deposits (Dumort 1968;Mfayakouo et al. 2014;Mfayakouo 2016), and the Japoma outcrops belong to the Wouri Formation and are composed of Pliocene to Pleistocene deposits (Dumort 1968;Njiké Ngaha 1984). ...
... The Missole 2 outcrops belong to the Miang Formation (formerly called N'kapa) constituted by Paleocene-Eocene deposits (Kenfack et al. 2012a, b;Mfayakouo et al. 2014;Mfayakouo 2016;Ngon Ngon et al. 2016;Fowé Kwéché et al. 2018). The Ngwan outcrops (at the boundary between the Matanda and Wouri formations) constituted by the Miocene-Pliocene deposits (Dumort 1968;Mfayakouo et al. 2014;Mfayakouo 2016), and the Japoma outcrops belong to the Wouri Formation and are composed of Pliocene to Pleistocene deposits (Dumort 1968;Njiké Ngaha 1984). ...
Reworked detrital sediments were discovered in the syn-rift to post-rift Cretaceous to Quaternary (Pleistocene) detrital deposits of the Douala coastal sub-basin in the eastern margin of the South Atlantic Ocean at West Cameroon. This contribution presents the geochemical, mineralogical, and sedimentological data to constrain the origin of these reworked sediments. The investigated samples are characterized by the high values of Plagioclase Index of Alteration (PIA, 97.83–99.90), Chemical Index of Alteration (CIA, 71.9–99.08), and Chemical Index of Weathering (CIW, 98.67–99.90). Data gleaned from these indices suggest that the reworked sediments and their potential source rocks experienced severe weathering. The A-CN-K plot along with the mineralogical indicates a probably post-depositional K-enrichment. The high light rare earth elements (LREE)/heavy rare earth elements (HREE) ratios (15.82–79.13) suggest that the reworked were mainly derived from felsic igneous rocks. This interpretation is further confirmed by the Zr versus TiO2, TiO2/Al2O3, Th/Co versus La/Sc, and La/Th versus Th/Yb plots, which indicate felsic igneous and silicic source rocks. Meanwhile, the high variability of LREE/HREE ratios (15.82–79.13) and the positive Eu anomalies (1.10–1.32) of studied samples could indicate a little contribution of mafic source rocks. Analysis of the distribution of the heavy minerals (e.g. tourmaline, aluminum silicate, and rutile) revealed that these felsic and silicic source rocks are mainly granite and gneiss, probably belonging to the Nyong Group and the Western part of the Neoproterozoic Yaounde Group. The morphoscopic analyses of the host rocks (very angular to angular shapes) have revealed that the reworked sediments have proximal to subproximal onshore origins, probably from former sedimentary deposits, as is indicated by variation of their color. The tectonic discriminant diagram indicates the Oceanic Island Arc and Active Continental Margin which are inconsistent with the geological history of the Douala coastal sub-basin and could be explained by the recycling effect experienced by studied sediments which have been deposited in the coastal plain to the fluvial environment in the Low System Track context.
... The Gmm facies, a lithounit of mostly granules and pebbles, supported by sandy silt, indicates deposition by hyperconcentrated or turbulent Cows that are formed due to the mass Cow (Meetei et al. 2007;Gao et al. 2018). The Gmg facies characterized by inverse to normal grading in the loosely packed, moderately supported gravel facies reCects its deposition by pseudoplastic debris Cow having low strength and viscosity (Miall 1996;Nemec and Steel 1988;Chavom et al. 2014;Tha et al. 2015). The matrix consisting of Bne sand to silty-clay, supporting pebbles and granules of loose and unpacked nature, suggests that the Cow was of constant nature during transportation (Fisher 1971). ...
... Similarly, southwest Kathmandu basin of Nepal also signiBes this facies, which is interpreted to be a product of viscous and pseudoplastic debris Cow (Tamrakar et al. 2009). Chavom et al. (2014) interpreted that the psedoplastic grain Cow processes are accountable for the deposition of matrix supported gravel beds with normal to reverse grading. Gao et al. (2018) also suggested the same environment, i.e., hyperconcentrated or turbulent mass for the deposition of the Gmg facies. ...
... The Gh facies marked by stratiBed, matrix supported gravel with horizontal beddings, moderate to poor imbrications, as of this facies, depicts sheet Cood, longitudinal bedforms, lag deposits and sieve deposits of comparatively high energy environment (Miall 1996;Uba et al. 2005;Adhikari and Wagreich 2011). Matrix support of coarse sand to granule, depicts various tractional processes of low energy condition (Miall 1977(Miall , 1978Rust 1978;Nilsen 1982;Chavom et al. 2014). Miall (1996) suggested that clasts dominated Gh facies, is formed as longitudinal bedform which is deposited by mass Cow of turbulent current. ...
Present work includes identification of lithofacies and reconstruction of depositional environments including controls of tectonics, and energy condition of the medium on sedimentation pattern of alluvial deposits of Purna basin, central India. The basin exhibits good development of dominantly areno-argillaceous sediments along with restricted occurrences of boulder-pebbly lithounits, covering together an area of 6,522 km2. These sediments are also characterized by preservation of various calcrete morphotypes, vertebrate remains and Youngest Toba Tuff (YTT) ash in certain stratigraphic units. The work is based on detailed field and lithological studies of 20 river-cut sections exposed along the course of Purna river, representing entire alluvial deposits in both vertical and lateral profiles. Three lithofacies associations have been identified, i.e., (1) gravelly facies association (FA-1), (2) sandy facies association (FA-2) and, (3) silty-clayey facies association (FA-3). These associations consist of total 10 lithofacies distributed as: (i) matrix supported massive gravelly (Gmm) facies, (ii) matrix supported gravelly (Gmg) facies, (iii) horizontally stratified gravelly (Gh) facies, (iv) planar stratified gravelly (Gp) facies (FA-1), (v) horizontal sandy (Sh) facies, (vi) planar cross stratified sandy (Sp) facies, (vii) low angle cross bedded sandy (Sl) facies, (viii) massive sandy (Sm) facies (FA-2), (ix) laminated sandy (Fl) facies, and (x) palaeosol (P) facies (FA-3). Various architectural elements have also been identified. Based on lateral and vertical profiling of the lithofacies architecture, it is interpreted that gravel dominated facies in the mountainous region of the basin area are deposited by medium to high energy debris flow,whereas sandy and silty-clayey facies in the plain area are because of saltation and suspension modes of deposition under medium to low energy condition of depositing medium. The tectonic and topographical controls are well reflected on the sedimentation pattern and the same has been illustrated by proposing a model. Discussions along with the model have also been made on the progressive development of bazada or, pediment zone along the northern margin of the basin marked by the foothills of Satpura mountain ranges.
... For the studied kaolins, the plot of log(K 2 O/ Al 2 O 3 )/log(MgO/Al 2 O 3 ) showed that the kaolins are dominantly of marine origin, except the Logbaba samples, which show a non-marine/deltaic environment (Figure 7). The Logababa samples are found in the Upper Cretaceous Logbaba Formation, which is believed to have sediments of lacustrine origin (Chavom et al., 2014). ...
The geochemistry and diagnostic evaluation of Cretaceous-Tertiary kaolins in the Douala Sub-Basin in Cameroon were carried out in order to determine their potential industrial applications. The mineralogical, physical, physico-chemical and geochemical
characteristics of the kaolins were determined. Quartz and kaolinite are the most dominant mineral phases in bulk kaolins (means of 45.25 and 33.90 wt%, respectively); whereas in the <2 μm fraction, kaolinite is the most dominant mineral phase (mean of 72.17 wt%). The texture of half of the samples is sandy loamy clay or sandy loam texture, and the colour from white to light reddish brown. The moisture content is generally <2 wt% in all the size fractions. The kaolins have an acidic pH, and the electrical conductivity is below 55 μS/cm. The major oxides geochemistry shows that the most abundant major oxides are silica and alumina, followed by iron oxide and titania. As physical, physico-chemical and geochemical characteristics of kaolins determine their potential industrial applications, these were inferred. Based on the interpretation of the results, the investigated kaolins could be used in the pharmaceutical, construction, pottery and cosmetics industries.
... The Gmm facies, a lithounit of mostly granules and pebbles, supported by sandy silt, indicates deposition by hyperconcentrated or turbulent Cows that are formed due to the mass Cow (Meetei et al. 2007;Gao et al. 2018). The Gmg facies characterized by inverse to normal grading in the loosely packed, moderately supported gravel facies reCects its deposition by pseudoplastic debris Cow having low strength and viscosity (Miall 1996;Nemec and Steel 1988;Chavom et al. 2014;Tha et al. 2015). The matrix consisting of Bne sand to silty-clay, supporting pebbles and granules of loose and unpacked nature, suggests that the Cow was of constant nature during transportation (Fisher 1971). ...
... Similarly, southwest Kathmandu basin of Nepal also signiBes this facies, which is interpreted to be a product of viscous and pseudoplastic debris Cow (Tamrakar et al. 2009). Chavom et al. (2014) interpreted that the psedoplastic grain Cow processes are accountable for the deposition of matrix supported gravel beds with normal to reverse grading. Gao et al. (2018) also suggested the same environment, i.e., hyperconcentrated or turbulent mass for the deposition of the Gmg facies. ...
... The Gh facies marked by stratiBed, matrix supported gravel with horizontal beddings, moderate to poor imbrications, as of this facies, depicts sheet Cood, longitudinal bedforms, lag deposits and sieve deposits of comparatively high energy environment (Miall 1996;Uba et al. 2005;Adhikari and Wagreich 2011). Matrix support of coarse sand to granule, depicts various tractional processes of low energy condition (Miall 1977(Miall , 1978Rust 1978;Nilsen 1982;Chavom et al. 2014). Miall (1996) suggested that clasts dominated Gh facies, is formed as longitudinal bedform which is deposited by mass Cow of turbulent current. ...
... It has been subject to numerous paleoenvironmental studies from the Cretaceous to the Quaternary. Most of these studies were carried based on the sedimentological characteristics and/ or fossiliferous content of various deposits of the basin (Nguéné et al. 1992;Njiké Ngaha 2005;Tchouatcha 2005;Touomo Sime 2010;Mbesse et al. 2012;Mfayakouo et al. 2014;Ngon Ngon et al. 2016). ...
... The Bonepoupa and Mbanga outcrops belong to the Loungahé Formation (formerly called Logbadjeck Formation) of the Cenomanian age (Njiké Ngaha 1984;Njiké Ngaha and Eno Belinga 1987). The Missole 2 outcrops belong to the Miang Formation (formerly called N'kapa) constituted by Paleocene-Eocene deposits (Kenfack et al. 2012a, b;Mfayakouo et al. 2014;Mfayakouo 2016;Ngon Ngon et al. 2016;Fowé Kwéché et al. 2018). The Ngwan outcrops (at the boundary between the Matanda and Wouri formations) constituted by the Miocene-Pliocene deposits (Dumort 1968;Mfayakouo et al. 2014;Mfayakouo 2016), and the Japoma outcrops belong to the Wouri Formation and are composed of Pliocene to Pleistocene deposits (Dumort 1968;Njiké Ngaha 1984). ...
... The Missole 2 outcrops belong to the Miang Formation (formerly called N'kapa) constituted by Paleocene-Eocene deposits (Kenfack et al. 2012a, b;Mfayakouo et al. 2014;Mfayakouo 2016;Ngon Ngon et al. 2016;Fowé Kwéché et al. 2018). The Ngwan outcrops (at the boundary between the Matanda and Wouri formations) constituted by the Miocene-Pliocene deposits (Dumort 1968;Mfayakouo et al. 2014;Mfayakouo 2016), and the Japoma outcrops belong to the Wouri Formation and are composed of Pliocene to Pleistocene deposits (Dumort 1968;Njiké Ngaha 1984). ...
... The N'kapa Fm. is considered as Paleocene -Eocene from Dumort (1968). Previous studies conducted in these outcrops by Bachirou et al. (2014) and Ngon Ngon et al (2016) provided facies analysis, depositional environments and geochemical charcteristics of Missole outcrops. However, no sequence stratigraphic study has been published for these outcrops since the building of the "Nationale 3" road in 1984. ...
Abstract
Missole facies description and sequence stratigraphy analysis allow a new proposal of depositional environments
of the Douala sub-basin eastern part. The sediments of Missole outcrops (N’kapa Formation) correspond to
fluvial/tidal channel to shallow shelf deposits with in some place embayment deposits within a warm and
semi-arid climate. Integrated sedimentologic, palynologic and mineralogical data document a comprehensive
sequence stratigraphy of this part of the Douala sub-basin. Five facies associations occur: (1) facies association I
is characterized by Floodplain deposits; (2) facies association II is Fluvial to mouth bar deposits; (3) facies
association III characterise Shallow Shelf deposits; (4) facies association IV represents Distal bay or Lacustrine
déposits; and (5) Facies association V is made of Fluvial channel deposits. Six depositional sequences were
identified. These sequences are composed of four progradational sequences and two retrogradational sequences
containing a fluvial channel portion represented by lag deposits at the base of retrogradational sequences. These
deposits represent the outset of the relative sea level rise period. In the study area, the N’kapa Formation is
composed of non-marine/coastal aggradational deposits representing the early stage of the regressive period. The
occurrence of the estuarine/bay deposits with paleosols development is interpreted as evidence of climate change
with significant relative base level fluctuation. The study of key minerals associated to sequence stratigraphy as
well as palynology demonstrated that sequence architecture has been controlled mostly by climate evolution and
outcrops are dated Paleocene – early Eocene.
Keywords: Facies, Sequence stratigraphy, Climate, N’kapa, Missole, Paleocene-early Eocene
... It is made up of Cretaceous-Recent Formations. This Sub-Basin is mainly known for hosting hydrocarbons (Brownfield and Charpentier, 2006;Ntamak-Nida et al., 2008;Chavom et al., 2014;Effoudou-Priso et al., 2014;Ngaha, 2005). Though the kaolin industry could be a profitable one, few studies have been carried out on those in this Sub-Basin (Ngon Ngon et al., 2012;Ekosse, 2012, 2013;Logmo et al., 2013;Ngon Ngon et al., 2014;Diko et al., 2016). ...
As a step in evaluating the quality of Cretaceous-Tertiary kaolins of the Douala Sub-Basin, their mineralogical characteristics were determined. The X-ray diffractometry technique was used to identify and quantify the mineral phases present in bulk and <2 μm fractions. Scanning electron microscopy was used to determine the micromorphology of <2 μm fractions kaolins. Thermal analyses (derivative thermal gravimetric analysis, thermal gravimetric analysis, and heat flow) were conducted to further characterise the kaolins. The main mineral phases present in the studied Cretaceous-Tertiary kaolins of the Douala Sub-Basin were kaolinite > smectite > illite, with mean values of 33.01 > 11.20 > 4.41 wt %; and 72.23 > 10.69 > 4.69 wt %, in bulk and <2 μm fractions, respectively. The kaolins, micromorphologically, consisted of pseudo-hexagonal and thin platy particles; swirl-textured particles; and books or stacks of kaolinite particles. Three main reactions occurred during heating of the kaolins: a low temperature endothermic reaction, observed between 48 and 109 °C; a second low temperature peak, observed between 223 and 285 °C; and a third endothermic peak was found between 469 and 531 °C. In addition, an exothermic reaction also occurred between 943 and 988 °C in some of the samples. The absence of primary minerals such as feldspars and micas in most of these kaolins is an indication of intensive weathering, probably due to the humid tropical climate of the region. The different morphologies suggested that these kaolins might have been transported. Therefore, a humid tropical climate was responsible for the formation of Cretaceous-Tertiary kaolins of the Douala Sub-Basin through intense weathering of surrounding volcanic and metamorphic rocks.
