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C O Okogbue - One of the best experts on this subject based on the ideXlab platform.
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Performance of pyroclastic rocks from Abakaliki Metropolis (southeastern Nigeria) in road construction projects
Bulletin of Engineering Geology and the Environment, 2013Co-Authors: C O Okogbue, O. P. AghameluAbstract:A total of 15 samples from the Abakaliki pyroclastic rock bodies were subjected to petrographic and mechanical analyses to determine the suitability of the rock type as a road aggregate. Results indicate that the Abakaliki pyroclastic rock yield aggregates with marginal performance in road projects. Although the aggregates meet a number of road stone requirements (i.e., ten percent fines and their ability to absorb water), they fail to meet other key road stone requirements. Whilst their aggregate impact values, Los Angeles abrasion values, and flakiness index are generally above the recommended limits, petrographic analyses reveal appreciable amounts of shaley to muddy Lithic Fragment and volcanic glassy groundmass. These detrimental constituents and marginal laboratory test results would likely translate to long term poor field performance where the pyroclastic aggregate is used for road construction. This study suggests that utilization of the Abakaliki pyroclastic rock as an aggregate, especially for road construction, requires informed caution, particularly when the material is exposed to climatic extremes (high volume of rainfall and high and fluctuating temperature) as is the case in the tropics.
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Some Geological Considerations and Durability Analysis on the Use of Crushed Pyroclastics from Abakaliki (Southeastern Nigeria) as Concrete Aggregate
Geotechnical and Geological Engineering, 2013Co-Authors: Okechukwu Pius Aghamelu, C O OkogbueAbstract:Samples of pyroclastic rocks from Abakaliki area (Nigeria) were subjected to geological and geochemical tests to determine the suitability and durability of the rocks as concrete aggregate. Petrographic analysis shows fine-grained texture and predominance of plagioclase (21–60 %) and shaley-muddy Lithic Fragment, while geochemical analysis classifies the rocks as alkaline. Analysis indicates that the pyroclastics would likely perform marginally well as concrete aggregates, especially in heavy Portland cement concrete and bituminous concrete. This is due to appreciably high values of natural moisture content, low bulk density, relative density and specific gravity, which suggests low durability, high voids and less aggregate absorption in concrete and bitumen mixes. The rocks are rated as moderate to high strength material on the basis of their unconfined compressive strength values, but are very likely to have low durability as buttressed by poor sulphate soundness test results, probably due to high amount of weak minerals. Analyses reveal that the Abakaliki Pyroclastics are not completely satisfactory as concrete aggregates source, despite their origin, texture, strength and economic availability. Hence, caution is required when they are used in concrete projects.
Okechukwu Pius Aghamelu - One of the best experts on this subject based on the ideXlab platform.
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Some Geological Considerations and Durability Analysis on the Use of Crushed Pyroclastics from Abakaliki (Southeastern Nigeria) as Concrete Aggregate
Geotechnical and Geological Engineering, 2013Co-Authors: Okechukwu Pius Aghamelu, C O OkogbueAbstract:Samples of pyroclastic rocks from Abakaliki area (Nigeria) were subjected to geological and geochemical tests to determine the suitability and durability of the rocks as concrete aggregate. Petrographic analysis shows fine-grained texture and predominance of plagioclase (21–60 %) and shaley-muddy Lithic Fragment, while geochemical analysis classifies the rocks as alkaline. Analysis indicates that the pyroclastics would likely perform marginally well as concrete aggregates, especially in heavy Portland cement concrete and bituminous concrete. This is due to appreciably high values of natural moisture content, low bulk density, relative density and specific gravity, which suggests low durability, high voids and less aggregate absorption in concrete and bitumen mixes. The rocks are rated as moderate to high strength material on the basis of their unconfined compressive strength values, but are very likely to have low durability as buttressed by poor sulphate soundness test results, probably due to high amount of weak minerals. Analyses reveal that the Abakaliki Pyroclastics are not completely satisfactory as concrete aggregates source, despite their origin, texture, strength and economic availability. Hence, caution is required when they are used in concrete projects.
Vysetti Balaram - One of the best experts on this subject based on the ideXlab platform.
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petrography and geochemistry of sands from the chachalacas and veracruz beach areas western gulf of mexico mexico constraints on provenance and tectonic setting
Journal of South American Earth Sciences, 2015Co-Authors: John S Armstrongaltrin, Vysetti Balaram, R Nagarajan, Olmedo NatalhypinedaAbstract:Abstract Compositional and geochemical analyses of sands collected from the Chachalacas (CHA) and Veracruz (VER) beach areas along the western Gulf of Mexico were studied to determine the provenance and tectonic setting of the source region. The modal composition showed that the proportion of quartz (Q) is lower in CHA than in VER sands. The average quartz-feldspar-Lithic Fragment (QFL) ratios for the CHA and VER sands are Q 75 F 8 L 17 and Q 86 F 4 L 10 , respectively. The X-ray diffractometer (XRD) and Scanning Electron Microscope equipped with EDAX spectrometer (SEM-EDS) data revealed that the CHA sands were abundant in heavy minerals like magnetite, ilmenite, and zircon. The rare earth element concentration (REE) is higher in CHA than in VER sands, which is due to the concentration of heavy minerals in CHA sands. The weathering indices such as chemical index of alteration (CIA), plagioclase index of alteration, and A–CN–K (A = Al 2 O 3 , CN = CaO ∗ + Na 2 O, K = K 2 O) plot suggested that the intensity of weathering in the source area was low to moderate. The index of chemical variability (ICV) for the CHA (∼1.9–3.0) and VER (∼0.82–1.33) sands indicated that the compositional maturity was higher for the VER sands. The concentrations of Co, Cr, Ni, and V are lower in VER sands than in CHA sands, indicating that the CHA sands were derived from the intermediate source rocks. Provenance modelling revealed that the CHA sands were associated with the mixture of basalt, andesite, dacite, and trachyandesite in the ratio of 5:20:25:50. The VER sands were best matched with a mixture having 75–90% dacite and 25–10% andesite compositions. The provenance difference between the two beach areas suggested that longshore current play a less significant role in mixing and homogenization of sands. The multidimensional tectonic discrimination diagrams revealed rift and collision settings for the VER and CHA beach areas, respectively, which is consistent with the general geology of the study areas.
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geochemistry of beach sands along the western gulf of mexico mexico implication for provenance
Chemie Der Erde-geochemistry, 2012Co-Authors: John S Armstrongaltrin, Yong Il Lee, Daniel Garcia, Vysetti Balaram, Juan Jose Kasperzubillaga, Arturo Carranzaedwards, Nelson G Eby, Norma Liliana CruzortizAbstract:This paper contributes to understanding the intractable problems in provenance study due to hydraulic sorting and geochemical heterogeneity in medium, fine, and very fine sands. For this purpose, detrital modes, major, trace, and rare earth element (REE) compositions of recent sands from the Playa Azul, Tecolutla, and Nautla beach areas of the western Gulf of Mexico have been investigated. Marked geochemical and petrographic differences occur among the three beach sands, even though they are separated just by 45 km. The average quartz-feldspar-Lithic Fragment (QtFL) ratios for the Playa Azul, Tecolutla, and Nautla sands are respectively Qt69–F10–L21, Qt57–F11–L32, and Qt37–F5–L58. The volcanic Lithic Fragment (Lv) − sedimentary Lithic Fragment (Ls) − [plutonic Lithic (Lp) + metamorphic Lithic Fragments (Lm)] ternary diagram indicates that the Nautla sands are dominated by volcanic detritus, while the Tecolutla sands are dominated by sedimentary and volcanic detritus. The Playa Azul sands are dominated largely by sedimentary detritus. Geochemically, the three beach sands are quite distinctive from each other. The Playa Azul sands are higher in SiO2 content (∼64–84 wt.%) than in the Tecolutla sands (SiO2 = ∼47–69 wt.%). The Nautla sands are very low in SiO2 content (<46 wt.%). The contrasting geochemical compositions among the three beach areas are also confirmed by significant variations in Al2O3/TiO2, Na2O/K2O, K2O/Al2O3, Rb/Al2O3, and Cr/Ni ratios. The CIA values (∼39–69; chemical index of alteration) for the three beach areas suggest low to moderate weathering nature. In the three beach sands studied, the decrease in grain size is accompanied by a gradual decrease in SiO2 content and an increase in TiO2, Al2O3, Fe2O3, MgO, Zr, Hf, Cr, and V contents. Similarly, the ∑REE content increases with decreasing grain size. However, very fine sands in the Playa Azul and Nautla beaches are different in ∑REE content. This observation suggests that the provenance is more important in controlling the geochemical composition of beach sands than the grain size. The zirconium concentration in beach sands, however, is not related to the grain size. The comparison of REE patterns of beach sands with those of source rocks located relatively close to the study areas suggests that the Playa Azul sands were derived from felsic rocks, whereas a mixed provenance with contributions from felsic and intermediate rocks is more likely for the Tecolutla sands. In contrast, the REE distribution patterns of Nautla sands resemble those derived from basalt and basaltic andesite. However, selective concentration of magnetite grains in beach sands increases the LREE content and fractionates Eu resulting in a europium anomaly that is more negative than that displayed by Nautla sands. All of the above observations suggest that rivers delivering sands to the beaches are the important factors in controlling the composition of beach sands and that longshore currents play a less significant role.
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Geochemistry of beach sands along the western Gulf of Mexico, Mexico: Implication for provenance
Geochemistry, 2012Co-Authors: John S. Armstrong-altrin, Yong Il Lee, Juan José Kasper-zubillaga, Arturo Carranza-edwards, Daniel Garcia, G. Nelson Eby, Vysetti Balaram, Norma Liliana Cruz-ortizAbstract:This paper contributes to understanding the intractable problems in provenance study due to hydraulic sorting and geochemical heterogeneity in medium, fine, and very fine sands. For this purpose, detrital modes, major, trace, and rare earth element (REE) compositions of recent sands from the Playa Azul, Tecolutla, and Nautla beach areas of the western Gulf of Mexico have been investigated. Marked geochemical and petrographic differences occur among the three beach sands, even though they are separated just by 45 km. The average quartz-feldspar-Lithic Fragment (QtFL) ratios for the Playa Azul, Tecolutla, and Nautla sands are respectively Qt69–F10–L21, Qt57–F11–L32, and Qt37–F5–L58. The volcanic Lithic Fragment (Lv) − sedimentary Lithic Fragment (Ls) − [plutonic Lithic (Lp) + metamorphic Lithic Fragments (Lm)] ternary diagram indicates that the Nautla sands are dominated by volcanic detritus, while the Tecolutla sands are dominated by sedimentary and volcanic detritus. The Playa Azul sands are dominated largely by sedimentary detritus. Geochemically, the three beach sands are quite distinctive from each other. The Playa Azul sands are higher in SiO2 content (∼64–84 wt.%) than in the Tecolutla sands (SiO2 = ∼47–69 wt.%). The Nautla sands are very low in SiO2 content (
Daniel Garcia - One of the best experts on this subject based on the ideXlab platform.
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geochemistry of beach sands along the western gulf of mexico mexico implication for provenance
Chemie Der Erde-geochemistry, 2012Co-Authors: John S Armstrongaltrin, Yong Il Lee, Daniel Garcia, Vysetti Balaram, Juan Jose Kasperzubillaga, Arturo Carranzaedwards, Nelson G Eby, Norma Liliana CruzortizAbstract:This paper contributes to understanding the intractable problems in provenance study due to hydraulic sorting and geochemical heterogeneity in medium, fine, and very fine sands. For this purpose, detrital modes, major, trace, and rare earth element (REE) compositions of recent sands from the Playa Azul, Tecolutla, and Nautla beach areas of the western Gulf of Mexico have been investigated. Marked geochemical and petrographic differences occur among the three beach sands, even though they are separated just by 45 km. The average quartz-feldspar-Lithic Fragment (QtFL) ratios for the Playa Azul, Tecolutla, and Nautla sands are respectively Qt69–F10–L21, Qt57–F11–L32, and Qt37–F5–L58. The volcanic Lithic Fragment (Lv) − sedimentary Lithic Fragment (Ls) − [plutonic Lithic (Lp) + metamorphic Lithic Fragments (Lm)] ternary diagram indicates that the Nautla sands are dominated by volcanic detritus, while the Tecolutla sands are dominated by sedimentary and volcanic detritus. The Playa Azul sands are dominated largely by sedimentary detritus. Geochemically, the three beach sands are quite distinctive from each other. The Playa Azul sands are higher in SiO2 content (∼64–84 wt.%) than in the Tecolutla sands (SiO2 = ∼47–69 wt.%). The Nautla sands are very low in SiO2 content (<46 wt.%). The contrasting geochemical compositions among the three beach areas are also confirmed by significant variations in Al2O3/TiO2, Na2O/K2O, K2O/Al2O3, Rb/Al2O3, and Cr/Ni ratios. The CIA values (∼39–69; chemical index of alteration) for the three beach areas suggest low to moderate weathering nature. In the three beach sands studied, the decrease in grain size is accompanied by a gradual decrease in SiO2 content and an increase in TiO2, Al2O3, Fe2O3, MgO, Zr, Hf, Cr, and V contents. Similarly, the ∑REE content increases with decreasing grain size. However, very fine sands in the Playa Azul and Nautla beaches are different in ∑REE content. This observation suggests that the provenance is more important in controlling the geochemical composition of beach sands than the grain size. The zirconium concentration in beach sands, however, is not related to the grain size. The comparison of REE patterns of beach sands with those of source rocks located relatively close to the study areas suggests that the Playa Azul sands were derived from felsic rocks, whereas a mixed provenance with contributions from felsic and intermediate rocks is more likely for the Tecolutla sands. In contrast, the REE distribution patterns of Nautla sands resemble those derived from basalt and basaltic andesite. However, selective concentration of magnetite grains in beach sands increases the LREE content and fractionates Eu resulting in a europium anomaly that is more negative than that displayed by Nautla sands. All of the above observations suggest that rivers delivering sands to the beaches are the important factors in controlling the composition of beach sands and that longshore currents play a less significant role.
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Geochemistry of beach sands along the western Gulf of Mexico, Mexico: Implication for provenance
Geochemistry, 2012Co-Authors: John S. Armstrong-altrin, Yong Il Lee, Juan José Kasper-zubillaga, Arturo Carranza-edwards, Daniel Garcia, G. Nelson Eby, Vysetti Balaram, Norma Liliana Cruz-ortizAbstract:This paper contributes to understanding the intractable problems in provenance study due to hydraulic sorting and geochemical heterogeneity in medium, fine, and very fine sands. For this purpose, detrital modes, major, trace, and rare earth element (REE) compositions of recent sands from the Playa Azul, Tecolutla, and Nautla beach areas of the western Gulf of Mexico have been investigated. Marked geochemical and petrographic differences occur among the three beach sands, even though they are separated just by 45 km. The average quartz-feldspar-Lithic Fragment (QtFL) ratios for the Playa Azul, Tecolutla, and Nautla sands are respectively Qt69–F10–L21, Qt57–F11–L32, and Qt37–F5–L58. The volcanic Lithic Fragment (Lv) − sedimentary Lithic Fragment (Ls) − [plutonic Lithic (Lp) + metamorphic Lithic Fragments (Lm)] ternary diagram indicates that the Nautla sands are dominated by volcanic detritus, while the Tecolutla sands are dominated by sedimentary and volcanic detritus. The Playa Azul sands are dominated largely by sedimentary detritus. Geochemically, the three beach sands are quite distinctive from each other. The Playa Azul sands are higher in SiO2 content (∼64–84 wt.%) than in the Tecolutla sands (SiO2 = ∼47–69 wt.%). The Nautla sands are very low in SiO2 content (
John S Armstrongaltrin - One of the best experts on this subject based on the ideXlab platform.
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petrography and geochemistry of sands from the chachalacas and veracruz beach areas western gulf of mexico mexico constraints on provenance and tectonic setting
Journal of South American Earth Sciences, 2015Co-Authors: John S Armstrongaltrin, Vysetti Balaram, R Nagarajan, Olmedo NatalhypinedaAbstract:Abstract Compositional and geochemical analyses of sands collected from the Chachalacas (CHA) and Veracruz (VER) beach areas along the western Gulf of Mexico were studied to determine the provenance and tectonic setting of the source region. The modal composition showed that the proportion of quartz (Q) is lower in CHA than in VER sands. The average quartz-feldspar-Lithic Fragment (QFL) ratios for the CHA and VER sands are Q 75 F 8 L 17 and Q 86 F 4 L 10 , respectively. The X-ray diffractometer (XRD) and Scanning Electron Microscope equipped with EDAX spectrometer (SEM-EDS) data revealed that the CHA sands were abundant in heavy minerals like magnetite, ilmenite, and zircon. The rare earth element concentration (REE) is higher in CHA than in VER sands, which is due to the concentration of heavy minerals in CHA sands. The weathering indices such as chemical index of alteration (CIA), plagioclase index of alteration, and A–CN–K (A = Al 2 O 3 , CN = CaO ∗ + Na 2 O, K = K 2 O) plot suggested that the intensity of weathering in the source area was low to moderate. The index of chemical variability (ICV) for the CHA (∼1.9–3.0) and VER (∼0.82–1.33) sands indicated that the compositional maturity was higher for the VER sands. The concentrations of Co, Cr, Ni, and V are lower in VER sands than in CHA sands, indicating that the CHA sands were derived from the intermediate source rocks. Provenance modelling revealed that the CHA sands were associated with the mixture of basalt, andesite, dacite, and trachyandesite in the ratio of 5:20:25:50. The VER sands were best matched with a mixture having 75–90% dacite and 25–10% andesite compositions. The provenance difference between the two beach areas suggested that longshore current play a less significant role in mixing and homogenization of sands. The multidimensional tectonic discrimination diagrams revealed rift and collision settings for the VER and CHA beach areas, respectively, which is consistent with the general geology of the study areas.
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geochemistry of beach sands along the western gulf of mexico mexico implication for provenance
Chemie Der Erde-geochemistry, 2012Co-Authors: John S Armstrongaltrin, Yong Il Lee, Daniel Garcia, Vysetti Balaram, Juan Jose Kasperzubillaga, Arturo Carranzaedwards, Nelson G Eby, Norma Liliana CruzortizAbstract:This paper contributes to understanding the intractable problems in provenance study due to hydraulic sorting and geochemical heterogeneity in medium, fine, and very fine sands. For this purpose, detrital modes, major, trace, and rare earth element (REE) compositions of recent sands from the Playa Azul, Tecolutla, and Nautla beach areas of the western Gulf of Mexico have been investigated. Marked geochemical and petrographic differences occur among the three beach sands, even though they are separated just by 45 km. The average quartz-feldspar-Lithic Fragment (QtFL) ratios for the Playa Azul, Tecolutla, and Nautla sands are respectively Qt69–F10–L21, Qt57–F11–L32, and Qt37–F5–L58. The volcanic Lithic Fragment (Lv) − sedimentary Lithic Fragment (Ls) − [plutonic Lithic (Lp) + metamorphic Lithic Fragments (Lm)] ternary diagram indicates that the Nautla sands are dominated by volcanic detritus, while the Tecolutla sands are dominated by sedimentary and volcanic detritus. The Playa Azul sands are dominated largely by sedimentary detritus. Geochemically, the three beach sands are quite distinctive from each other. The Playa Azul sands are higher in SiO2 content (∼64–84 wt.%) than in the Tecolutla sands (SiO2 = ∼47–69 wt.%). The Nautla sands are very low in SiO2 content (<46 wt.%). The contrasting geochemical compositions among the three beach areas are also confirmed by significant variations in Al2O3/TiO2, Na2O/K2O, K2O/Al2O3, Rb/Al2O3, and Cr/Ni ratios. The CIA values (∼39–69; chemical index of alteration) for the three beach areas suggest low to moderate weathering nature. In the three beach sands studied, the decrease in grain size is accompanied by a gradual decrease in SiO2 content and an increase in TiO2, Al2O3, Fe2O3, MgO, Zr, Hf, Cr, and V contents. Similarly, the ∑REE content increases with decreasing grain size. However, very fine sands in the Playa Azul and Nautla beaches are different in ∑REE content. This observation suggests that the provenance is more important in controlling the geochemical composition of beach sands than the grain size. The zirconium concentration in beach sands, however, is not related to the grain size. The comparison of REE patterns of beach sands with those of source rocks located relatively close to the study areas suggests that the Playa Azul sands were derived from felsic rocks, whereas a mixed provenance with contributions from felsic and intermediate rocks is more likely for the Tecolutla sands. In contrast, the REE distribution patterns of Nautla sands resemble those derived from basalt and basaltic andesite. However, selective concentration of magnetite grains in beach sands increases the LREE content and fractionates Eu resulting in a europium anomaly that is more negative than that displayed by Nautla sands. All of the above observations suggest that rivers delivering sands to the beaches are the important factors in controlling the composition of beach sands and that longshore currents play a less significant role.