This paper examines the geomorphology and hydrology of the Benin Region, Edo State, Nigeria. The major landform features and processes of the region are highlighted. This region is a strategic and significant landscap...This paper examines the geomorphology and hydrology of the Benin Region, Edo State, Nigeria. The major landform features and processes of the region are highlighted. This region is a strategic and significant landscape in Nigeria. Information was gathered on the various aspects of the landscape, including the Geology, Physiography (Relief) and Geomorphology, Geomorphic processes, Weathering, Drainage processes, Landforms, Surface Water Hydrology and Water Resources. The Benin Region is underlained by sedimentary formation of the South Sedimentary Basin. The geology is generally marked by top reddish earth, composed of ferruginized or literalized clay sand. Geologically, the Benin Region comprises of 1) the Benin formation;2) alluvium;3) drift/top soil and 4) Azagba-Ogwashi (Asuba-Ogwashi) formation. Several parts of the region are surrounded by the Benin historical moats. The region has been described as a tilled plain in the south western direction. The local relief of the region is 91 m. Boreholes records in the Benin Region show evidence of deep chemical weathering overtime. Soil profile reveals that the region is composed mainly of reddish brown sandy laterite. Intermittent layers of porous sands of sandy clays may reach a large depth as found in the borehole drilled in the region. These are products of deep chemical decay of the original parent rock materials. Three river systems drain the Benin Region. They are the Ikpoba River, the Ogba River and Owigie-Ogbovben River systems. The mean annual discharge of Ikpoba River for 1982-1983 and 1993-2002 was 1411 mm/yr, which was 1.019 × 10<sup>9</sup> m<sup>3</sup> with a mean annual baseflow of 1256.23 mm (0. 907 × 109 m<sup>3</sup>). This constitutes 87.65% of the total flow. It has a mean annual surface runoff of 225.18 mm (0.112 × 10<sup>9</sup> m<sup>3</sup>) or 24.4 % of the total discharge. The water resources of the region include surface water and underground water.展开更多
The article discusses regularity of the formation of high-altitude zones on the mountain territories of Tenir-Too and their relationship with geomorphological complexes and the relief steps. The main purpose was to cl...The article discusses regularity of the formation of high-altitude zones on the mountain territories of Tenir-Too and their relationship with geomorphological complexes and the relief steps. The main purpose was to classify geomorpho-logical complexes and to concretize their morphological characteristics. The belt structure consisting of two mixed rows is analyzed. Excess, elevated, medium-moistened, semi-moistened, semi-arid, and arid types of altitudinal belts were proposed.展开更多
An analysis of the formation of karst and karst-suffosion forms on the territory of the West Kazakhstan region is presented in this paper. Numerous literary sources were used as the information database for the analys...An analysis of the formation of karst and karst-suffosion forms on the territory of the West Kazakhstan region is presented in this paper. Numerous literary sources were used as the information database for the analysis of the relief features of the West Kazakhstan region. Evaluation of the morphometric features of the collapsed new formations on the basis of materials of our own field research is presented here for the first time. According to the research objectives there were defined localization places of the karst-collapsed phenomena where the reconnaissance field surveys were carried out. Survey points’ localization has been carried out by means of GPS system with the help of 12-channel GPS-receiver of Garmin eTrex model. Geoinformational technology, based on MapInfo 9.5 and ArcGIS 9.2 packages was used for the building of the information and cartographic database. Original thematic maps compiled on the basis of the research results’ analysis have been obtained in this research. The features of the Caspian Basin’s karst landscapes, formed as a result of salt-dome tectonic manifestations (Inder Mountains, Malaya Bogdo Mountain, Bish-Chokho hill) are described in this paper. The important elements of the Caspian Basin salt-dome landscapes are landforms of the karst origin from large karst depressions of the karst-tectonic origin to modern forms of the sulfate karst: sinkholes, wells, polje, knobs (“Kurgantau”), arches, caves and grottoes. Some karst formations have a non-salt-dome origin. Three areas with the collapsed forms that have the karst-suffosion origin have been identified (near Konyr village, Berezovka village and Zhanatalap village). The mechanism of the sinkholes formation is due to the changes of the groundwater regime and the displacement of limestone eluvium as a result of active anthropogenic impacts. The sinkholes occurence near Zhanatalap village, which is located near the Karachaganak oil and gas field, is probably due to the anthropogenic initiation of karst-suffosion processes.展开更多
文摘This paper examines the geomorphology and hydrology of the Benin Region, Edo State, Nigeria. The major landform features and processes of the region are highlighted. This region is a strategic and significant landscape in Nigeria. Information was gathered on the various aspects of the landscape, including the Geology, Physiography (Relief) and Geomorphology, Geomorphic processes, Weathering, Drainage processes, Landforms, Surface Water Hydrology and Water Resources. The Benin Region is underlained by sedimentary formation of the South Sedimentary Basin. The geology is generally marked by top reddish earth, composed of ferruginized or literalized clay sand. Geologically, the Benin Region comprises of 1) the Benin formation;2) alluvium;3) drift/top soil and 4) Azagba-Ogwashi (Asuba-Ogwashi) formation. Several parts of the region are surrounded by the Benin historical moats. The region has been described as a tilled plain in the south western direction. The local relief of the region is 91 m. Boreholes records in the Benin Region show evidence of deep chemical weathering overtime. Soil profile reveals that the region is composed mainly of reddish brown sandy laterite. Intermittent layers of porous sands of sandy clays may reach a large depth as found in the borehole drilled in the region. These are products of deep chemical decay of the original parent rock materials. Three river systems drain the Benin Region. They are the Ikpoba River, the Ogba River and Owigie-Ogbovben River systems. The mean annual discharge of Ikpoba River for 1982-1983 and 1993-2002 was 1411 mm/yr, which was 1.019 × 10<sup>9</sup> m<sup>3</sup> with a mean annual baseflow of 1256.23 mm (0. 907 × 109 m<sup>3</sup>). This constitutes 87.65% of the total flow. It has a mean annual surface runoff of 225.18 mm (0.112 × 10<sup>9</sup> m<sup>3</sup>) or 24.4 % of the total discharge. The water resources of the region include surface water and underground water.
文摘The article discusses regularity of the formation of high-altitude zones on the mountain territories of Tenir-Too and their relationship with geomorphological complexes and the relief steps. The main purpose was to classify geomorpho-logical complexes and to concretize their morphological characteristics. The belt structure consisting of two mixed rows is analyzed. Excess, elevated, medium-moistened, semi-moistened, semi-arid, and arid types of altitudinal belts were proposed.
文摘An analysis of the formation of karst and karst-suffosion forms on the territory of the West Kazakhstan region is presented in this paper. Numerous literary sources were used as the information database for the analysis of the relief features of the West Kazakhstan region. Evaluation of the morphometric features of the collapsed new formations on the basis of materials of our own field research is presented here for the first time. According to the research objectives there were defined localization places of the karst-collapsed phenomena where the reconnaissance field surveys were carried out. Survey points’ localization has been carried out by means of GPS system with the help of 12-channel GPS-receiver of Garmin eTrex model. Geoinformational technology, based on MapInfo 9.5 and ArcGIS 9.2 packages was used for the building of the information and cartographic database. Original thematic maps compiled on the basis of the research results’ analysis have been obtained in this research. The features of the Caspian Basin’s karst landscapes, formed as a result of salt-dome tectonic manifestations (Inder Mountains, Malaya Bogdo Mountain, Bish-Chokho hill) are described in this paper. The important elements of the Caspian Basin salt-dome landscapes are landforms of the karst origin from large karst depressions of the karst-tectonic origin to modern forms of the sulfate karst: sinkholes, wells, polje, knobs (“Kurgantau”), arches, caves and grottoes. Some karst formations have a non-salt-dome origin. Three areas with the collapsed forms that have the karst-suffosion origin have been identified (near Konyr village, Berezovka village and Zhanatalap village). The mechanism of the sinkholes formation is due to the changes of the groundwater regime and the displacement of limestone eluvium as a result of active anthropogenic impacts. The sinkholes occurence near Zhanatalap village, which is located near the Karachaganak oil and gas field, is probably due to the anthropogenic initiation of karst-suffosion processes.
