Laser diffraction spectrometry allows for efficiently obtaining high-resolution grain size data. However, pretreatment and dispersion of aggregates in sediment samples are essential pre-requisites for acquiring accurate results using this method. This study evaluates the effectiveness of five dispersing agents in deflocculating the investigated fluvial sediments and the resulting grain size distribution obtained by laser diffraction spectrometry. We also examine the ability of the different dispersing agents to deflocculate sediment samples treated by thermal combustion. Distilled water presented a low efficiency in deflocculating the samples and yielded a near-zero clay content for samples with an expected clay content. The other chemical dispersants were effective in dispersing aggregates and yielding clay, albeit with different efficiencies. Calgon had the highest dispersing ability, followed closely by sodium tripolyphosphate. The performance of chemical treatment with sodium oxalate approaches that of sodium tripolyphosphate. However, it leads to the formation of precipitates in the samples, obscuring the actual grain size data. Sodium pyrophosphate derived the least amount of deflocculation among the four chemical dispersants. Furthermore, all the chemical dispersants were found to be ineffective in dispersing aggregates in samples treated by thermal combustion.
Floodplains of Sokoto Basin with covering about 280,000 hectares of land was assessed for its shallow groundwater potentials. Data on pumping test of tube wells, logs and drilled tube wells were utilized for this study. Storativity was determined from known lithology of tube wells. Results of this study gives the ranges and averages of Hydraulic parameters for the shallow alluvial aquifers of hydraulic conductivity, transmissivity, specific capacity and storativity to be 6. -5 -6×10 -3 and 5×10 -4 respectively, While the Yields range of 0.3-7 l/s was obtained with 90% of tube wells evaluated having yields of 2.2 l/s and above. Lithologic Aquiferous units vary from medium sands, sands, coarse sands to gravel with thickness range of between 0.3 to 15 m. Computed hydraulic conductivity indicates the aquifer materials to be gravels and alluvial sands of high permeability. Specific capacity values indicated the wells to be of high productivity when compared with standard values, Transmissivity average revealed the area to be of high groundwater transmission potentials. Overall assessment of the yields of tube wells studied indicated that 90% of the wells have yields that are above the minimum required for irrigation; the low average drawdown of 0.41 m recorded is an indication that the aquifers have high efficiency and high performance as regards storage and transmission of water. Recharge of the alluvial aquifers is mainly through surface river flow and precipitation, climate change have recently threaten the recharge potential s owing to the drying up of some of these streams and rivers at the peak of dry season as well reduction in rainfall. Statistical analysis has shown a good linear relationship between Specific capacity with yield, Transmissivity and hydraulic conductivity while Transmissivity is linearly related with yield and Conductivity. Generally the study revealed that the Sokoto basin Fadama land to be of high groundwater potentials, with storage coefficient values of confined and high yielding aquifers with capabilities of sustaining withdrawals for long period without recharge from external sources. Standard procedures are highly recommended to reduce or avoid the case of drilling abortive or low yielding wells.
The sulfur isotope composition of pyrite in marine sedimentary rocks is often difficult to interpret due to a lack of precise isotopic constraints for coeval sulfate. This study examines pyrite and barite in the Late Devonian Canol Formation (Selwyn Basin, Canada), which provides an archive of δ34S and δ18O values during diagenesis. Scanning electron microscopy (SEM) has been combined with microscale secondary ion mass spectrometry (SIMS) analysis (n = 1,032) of pyrite (δ34S) and barite (δ34S and δ18O) on samples collected from nine stratigraphic sections of the Canol Formation. Two paragenetic stages of pyrite and barite formation have been distinguished, both replaced by barium carbonate and feldspar. The δ34Sbarite and δ18Obarite values from all sections overlap, between +37.1‰ and +67.9‰ (median = +45.7‰) and +8.8‰ and +23.9‰ (median = +20.0‰), respectively. Barite morphologies and isotopic values are consistent with precipitation from diagenetically modified porewater sulfate (sulfate resupply << sulfate depletion) during early diagenesis. The two pyrite generations (Py-1 and Py-2) preserve distinct textures and end-member isotopic records. There is a large offset from coeval Late Devonian seawater sulfate in the δ34Spyrite values of framboidal pyrite (-29.4‰ to -9.3‰), consistent with dissimilatory microbial sulfate reduction (MSR) during early diagenesis. The Py-2 is in textural equilibrium with barite generation 2 (Brt-2) and records a broad range of more positive δ34SPy-2 values (+9.4‰ to + 44.5‰). The distinctive highly positive δ34Spyrite values developed from sulfate limited conditions around the sulfate methane transition zone (SMTZ). We propose that a combination of factors, including low sulfate concentrations, MSR, and sulfate reduction coupled to anaerobic oxidation of methane (SR-AOM), led to the formation of highly positive δ34Spyrite and δ34Sbarite values in the Canol Formation. The presence of highly positive δ34Spyrite values in other Late Devonian sedimentary units indicate that diagenetic pyrite formation at the SMTZ may be a more general feature of other Lower Paleozoic basins.
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