This study reports on the first investigation into the potential of luminescence dating to establish a chronological framework for the depositional sequences of the Sperchios delta plain, central Greece. A series of t...This study reports on the first investigation into the potential of luminescence dating to establish a chronological framework for the depositional sequences of the Sperchios delta plain, central Greece. A series of three borehole cores(20 m deep) and two shallow cores(4 m deep), from across the delta plain, were extracted, and samples were collected for luminescence dating. The luminescence ages of sand-sized quartz grains were obtained from small aliquots of quartz, using the Single-Aliquot Regenerative-dose(SAR) protocol.The equivalent dose determination included a series of tests and the selection of the Minimum Age Model(MAM) as the most appropriate statistical model. This made it possible to confirm the applicability of quartz Optically Stimulated Luminescence(OSL) dating to establish absolute chronology for deltaic sediments from the Sperchios delta plain.Testing age results of the five cores showed that the deltaic sediments were deposited during the Holocene.A relatively rapid deposition is implied for the top14 m possibly as a result of the deceleration in the rate of the sea-level rise and the transition to terrestrial conditions, while on the deeper parts, the reduced sedimentation rate may indicate a lagoonal or coastal environment.展开更多
The name of Vertisol is derived from Latin “vertere” meaning to invert. This case restricts development of soil horizons in profile. These soils have the capacity to swell and shrink, inducing cracks in the upper pa...The name of Vertisol is derived from Latin “vertere” meaning to invert. This case restricts development of soil horizons in profile. These soils have the capacity to swell and shrink, inducing cracks in the upper parts of the soil and distinctive soil structure throughout the soil. The formation of these specific features are caused by a heavy texture, a dominance of swelling clay in the fine fraction and marked changes in moisture content. The swell-shrink behavior is attributed to the wetting and drying of the soil mass. In this study, morphology, physico-chemical characteristics and classification of vertisols that were formed on alluvial delta plains, were investigated. Those soils formed on the Bafra Plain found in the K?z?l?rmak Delta and located in the central Black Sea region of Turkey. All studied Vertisols are characterised by a dark colour in surface soil, a heavy clayey texture, hardpan formation under top soil (high bulk density a high compaction) and very high COLE values. In addition, they have deep wide-opened desiccation cracks at the surface, slickensides at the middle part of the profiles and a poor differentiation of their horizons. Physico-chemically, the studied soils are slightly basic to very basic, non-saline and poor in organic matter, which is slightly higher in the surface horizon. In addition, cation exchange capacity, sum of exchangeable bases and base saturation of soils are very high. On the basis of morphological and physicochemical analysis, soil profiles were classified as Sodic Haplustert, Typic Calciaquert, Sodic Calciustert according to Soil Taxonomy (Soil Survey Staff, 1975 and 1999) and as Sodic Vertisol and Calcic Vertisol according to FAO/ISRIC (2006) classification systems.展开更多
In the Fuyu Reservoir of Songliao Basin, there occur a series of well-developed peculiar shallow lake delta facies, which can be divided to such three ones as the upper delta plain subfacies, the lower delta plain sub...In the Fuyu Reservoir of Songliao Basin, there occur a series of well-developed peculiar shallow lake delta facies, which can be divided to such three ones as the upper delta plain subfacies, the lower delta plain subfacies, and the delta front subfacies. Among them the upper delta plain subfacies mainly grows proximal distributary channels; the lower delta plain subfacies mainly grows distal ones. The entire Fuyu Reservoir has mainly developed 7 kinds of distributary channel patterns： proximal/ distal meandering type distributary channels, proximal/distal low-sinuosity type distributary channels, proximal/distal straight type distributary channels, and subaqueous distributary channels. Among these patterns, the proximal and distal meandering type distributary channels have bigger thickness of point bar and better sorting and low content of mud; moreover, they are the major reservoirs and occur in the bottom of Quan-4th member. The sandbars of the subaqueous distributary channels have higher mud content, and serve as the poorer reservoirs, and mainly occur in the top of Quan-4th member.展开更多
The hydraulic properties of deeper Coastal Plain Sands, which form the main aquifer in the Niger Delta, were investigated around Eleme, Rivers State. The intent was to find out if frequent well failure was as a result...The hydraulic properties of deeper Coastal Plain Sands, which form the main aquifer in the Niger Delta, were investigated around Eleme, Rivers State. The intent was to find out if frequent well failure was as a result of the aquifer not having enough transmitting capacity to sustain the huge withdrawal necessary for Eleme and its environs where demand for groundwater withdrawal is very high because Eleme axis serves as a major industrial axis of River State or whether the frequent well failure was due to inefficient well construction practice. Constant discharge pumping tests were conducted in 8 deep borehole (250 - 310 m). Data generated during the test were analysed using Cooper-Jacob’s straight line method. The calculated transmissivity of the aquifers ranged from 1324 m2/day - 5815 m2/day. These values when compared with transmissivity values elsewhere indicate that the aquifers in the study area have excellent water yielding properties, plotting within the range of “Very Good” in water transmitting capacity scale. Coefficient of permeability ranged from 13.65 m/d - 59.9 m/d. Coefficient of Storage ranged from 28.2 × 10-5 - 29.1 × 10-5 while the Specific capacities of the wells ranged from 48.75 3 - 78.13 m3/d/m. It is concluded that the deep aquifers of the Niger Delta do possess the capacity to produce and sustain large groundwater withdrawal. It is further recommended that competent drilling contractors be engaged in deep well construction in the area.展开更多
基金supported by the Greek General Secretariat of Research and Technology through ESPA-KRIPIS Project: "Development of an integrated management framework of river basins and associated coastal and marine zone"
文摘This study reports on the first investigation into the potential of luminescence dating to establish a chronological framework for the depositional sequences of the Sperchios delta plain, central Greece. A series of three borehole cores(20 m deep) and two shallow cores(4 m deep), from across the delta plain, were extracted, and samples were collected for luminescence dating. The luminescence ages of sand-sized quartz grains were obtained from small aliquots of quartz, using the Single-Aliquot Regenerative-dose(SAR) protocol.The equivalent dose determination included a series of tests and the selection of the Minimum Age Model(MAM) as the most appropriate statistical model. This made it possible to confirm the applicability of quartz Optically Stimulated Luminescence(OSL) dating to establish absolute chronology for deltaic sediments from the Sperchios delta plain.Testing age results of the five cores showed that the deltaic sediments were deposited during the Holocene.A relatively rapid deposition is implied for the top14 m possibly as a result of the deceleration in the rate of the sea-level rise and the transition to terrestrial conditions, while on the deeper parts, the reduced sedimentation rate may indicate a lagoonal or coastal environment.
文摘The name of Vertisol is derived from Latin “vertere” meaning to invert. This case restricts development of soil horizons in profile. These soils have the capacity to swell and shrink, inducing cracks in the upper parts of the soil and distinctive soil structure throughout the soil. The formation of these specific features are caused by a heavy texture, a dominance of swelling clay in the fine fraction and marked changes in moisture content. The swell-shrink behavior is attributed to the wetting and drying of the soil mass. In this study, morphology, physico-chemical characteristics and classification of vertisols that were formed on alluvial delta plains, were investigated. Those soils formed on the Bafra Plain found in the K?z?l?rmak Delta and located in the central Black Sea region of Turkey. All studied Vertisols are characterised by a dark colour in surface soil, a heavy clayey texture, hardpan formation under top soil (high bulk density a high compaction) and very high COLE values. In addition, they have deep wide-opened desiccation cracks at the surface, slickensides at the middle part of the profiles and a poor differentiation of their horizons. Physico-chemically, the studied soils are slightly basic to very basic, non-saline and poor in organic matter, which is slightly higher in the surface horizon. In addition, cation exchange capacity, sum of exchangeable bases and base saturation of soils are very high. On the basis of morphological and physicochemical analysis, soil profiles were classified as Sodic Haplustert, Typic Calciaquert, Sodic Calciustert according to Soil Taxonomy (Soil Survey Staff, 1975 and 1999) and as Sodic Vertisol and Calcic Vertisol according to FAO/ISRIC (2006) classification systems.
文摘In the Fuyu Reservoir of Songliao Basin, there occur a series of well-developed peculiar shallow lake delta facies, which can be divided to such three ones as the upper delta plain subfacies, the lower delta plain subfacies, and the delta front subfacies. Among them the upper delta plain subfacies mainly grows proximal distributary channels; the lower delta plain subfacies mainly grows distal ones. The entire Fuyu Reservoir has mainly developed 7 kinds of distributary channel patterns： proximal/ distal meandering type distributary channels, proximal/distal low-sinuosity type distributary channels, proximal/distal straight type distributary channels, and subaqueous distributary channels. Among these patterns, the proximal and distal meandering type distributary channels have bigger thickness of point bar and better sorting and low content of mud; moreover, they are the major reservoirs and occur in the bottom of Quan-4th member. The sandbars of the subaqueous distributary channels have higher mud content, and serve as the poorer reservoirs, and mainly occur in the top of Quan-4th member.
文摘The hydraulic properties of deeper Coastal Plain Sands, which form the main aquifer in the Niger Delta, were investigated around Eleme, Rivers State. The intent was to find out if frequent well failure was as a result of the aquifer not having enough transmitting capacity to sustain the huge withdrawal necessary for Eleme and its environs where demand for groundwater withdrawal is very high because Eleme axis serves as a major industrial axis of River State or whether the frequent well failure was due to inefficient well construction practice. Constant discharge pumping tests were conducted in 8 deep borehole (250 - 310 m). Data generated during the test were analysed using Cooper-Jacob’s straight line method. The calculated transmissivity of the aquifers ranged from 1324 m2/day - 5815 m2/day. These values when compared with transmissivity values elsewhere indicate that the aquifers in the study area have excellent water yielding properties, plotting within the range of “Very Good” in water transmitting capacity scale. Coefficient of permeability ranged from 13.65 m/d - 59.9 m/d. Coefficient of Storage ranged from 28.2 × 10-5 - 29.1 × 10-5 while the Specific capacities of the wells ranged from 48.75 3 - 78.13 m3/d/m. It is concluded that the deep aquifers of the Niger Delta do possess the capacity to produce and sustain large groundwater withdrawal. It is further recommended that competent drilling contractors be engaged in deep well construction in the area.
