scholarly journals Comparison of hydraulic conductivities by grain-size analysis, pumping, and slug tests in Quaternary gravels, NE Slovenia

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Tatjana Pucko ◽  
Timotej Verbovšek

AbstractHydraulic conductivities (K) can be obtained from pumping and slug tests as well as grain size analysis. Although empirical methods for such estimations are longstanding, there is still insufficient comparison of K values among the various approaches. Six grain-size analysis methods were tested on coarse-grained alluvial sediments from 12 water wells in NE Slovenia. Values of K from grainsize methods were compared to those of pumping tests and slug tests. Six grain-size methods (USBR, Slichter, Hazen, Beyer, Kozeny-Carman, and Terzaghi) were used for comparison with the Theis and Neuman pumping test method and the Bouwer-Rice method for slug tests. The results show that the USBR (US Bureau of Reclamation) method overestimates K values and there is no correlation with other results, so its use is not advised. Conversely, whilst the Slichter method gives much lower estimates of K, it is the only one to completely fulfill the grain size requirements. Other methods (Hazen, Beyer, Kozeny- Carman, and Terzaghi) result in intermediate values and are similar to the Slichter method; however they should be used for smaller-sized sediments. Due to their high transmissivity and small radius of inffiuence, slug tests should be avoided in the analysis of gravels, as they only test a small portion of the aquifer compared to pumping tests. This is confirmed by the low correlation coefficients between hydraulic conductivities obtained from pumping tests and slug tests.

Geologos ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 51-73 ◽  
Author(s):  
Asma A. Ghaznavi ◽  
M.A. Quasim ◽  
A.H.M. Ahmad ◽  
Sumit K. Ghosh

Abstract Grain size analysis is an important sedimentological tool used to unravel hydrodynamic conditions, mode of transportation and deposition of detrital sediments. For the present study, detailed grain size analysis was carried out in order to decipher the palaeodepositional environment of Middle–Upper Jurassic rocks of the Ler Dome (Kachchh, western India), which is further reinforced by facies analysis. Microtextures were identified as grooves, straight steps and V-shaped pits, curved steps and solution pits suggesting the predominance of chemical solution activity. Grain size statistical parameters (Graphic and Moment parameters) were used to document depositional processes, sedimentation mechanisms and conditions of hydrodynamic energy, as well as to discriminate between various depositional environments. The grain size parameters show that most of the sandstones are medium- to coarse-grained, moderately to well sorted, strongly fine skewed to fine skewed and mesokurtic to platykurtic in nature. The abundance of medium- to coarse-grained sandstones indicates fluctuating energy levels of the deposition medium and sediment type of the source area. The bivariate plots show that the samples are mostly grouped, except for some samples that show a scattered trend, which is either due to a mixture of two modes in equal proportion in bimodal sediments or good sorting in unimodal sediments. The linear discriminant function analysis is predominantly indicative of turbidity current deposits under shallow-marine conditions. The C-M plots indicate that the sediments formed mainly by rolling to bottom suspension and rolling condition in a beach subenvironment. Log probability curves show that the mixing between the suspension and saltation populations is related to variable energy conditions.


Grain size analysis of Turonian Amasiri Sandstone in southern Benue Trough has been undertaken to determine the controversial depositional environment of the formation. The formation was first studied on outcrops and 26 representative samples were collected and subjected to particle size analysis in line with standard procedures for dry sieving. Various methods of environmental interpretation of grain size distribution data were applied to constrain the depositional of the sandstones. The result indicates that the sands are medium and coarse-grained with mean size ranging from 0.15 to 1.87φ and averaging 0.96 φ. The sandstones are moderately to poorly sorted with standard deviation values ranging from 0.72 to 1.38 φ and averaging 1.07 φ. They exhibit a wide range of distribution from strongly coarse skewed to strongly fine skewed with skewness values ranging from -2.31 to 1.52 φ and averaging -0.04 φ but indicate a narrow range of kurtosis from mesokurtic to leptokurtic distribution with values ranging from 0.99 to 3.49 φ and an average of 2.06 φ. The sediments have bimodal with minor polymodal and unimodal distribution with primary modal size of 1.2 φ. The bivariate plots of size statistical parameters indicate fluvial environment of deposition. However, linear discriminant function analysis and the interpretations of log-probability plots indicate deposition in a fluvial, beach, and shallow marine settings, and thus suggesting a possible deposition in high-energy transitional environment. The C-M pattern of the samples indicates that sediments were transported mainly by rolling and suspension with subordinate fractions moved by rolling as well as suspension. Thus, it is deduced that Amasiri Sandstone was deposited in fluvial, beach, and agitated shallow marine environments.


2021 ◽  
Author(s):  
Conner O'Reilly ◽  
Catherine C. Beck ◽  
Jeroen H. van der Lubbe ◽  
Craig S. Feibel ◽  
Bruce Wegter ◽  
...  

<p>The Turkana Basin in northern Kenya contains a robust record of hominin fossils, including Nariokotome Boy (discovered from the NK3 site), the most complete H. erectus specimen found to date. Understanding the paleoenvironmental context in which hominins such as H. erectus evolved has been an objective of decades of research in eastern Africa. Here, we present a study using grain size analyses to infer the paleoenvironmental conditions responsible for the deposition of the sedimentary sequences directly associated with NK3. We resampled a ~14 m interval at from the West Turkana Kaitio (WTK13) core, collected as part of the Hominin Sites and Paleolakes Drilling Project. This interval ties directly to the outcrop where Nariokotome Boy was recovered. By sampling continuously at 0.5 cm intervals (~7 yrs/sample), we document the paleoenvironment in ultra high-resolution (i.e. a scale relevant to a hominin life) that directly correlates to the NK3 site. Over 350 sediment samples were pre-treated to remove carbonate, biogenic silica, and other organic material from detrital material. Grain size distributions were measured on a Malvern Mastersizer 3000 using wet suspension. Based on these analyses, the interval was dominated by silt, which was further investigated using end-member modeling. A four end-member solution explained on average 99% of the population variability. The bottom of the interval was more coarse-grained, with an abrupt fining transition at 38.83 meter below surface (mbsf), which corresponds with the transition out of a tuffaceous interval (Natoo tuff) and into a pedogenically modified interval. This correlation is significant as the top of this tuff is the surface upon which Nariokotome Boy was recovered. Previous facies and grain size analyses revealed and quantified Turkana’s dynamic lake level history. However, our grain size analysis provides unprecedented resolution for the paleoenvironment during which Nariokotome Boy lived. Our 0.5 cm sampling resolution enables us to quantify depositional changes on a scale comparable with previous descriptive facies analyses and to refine transitions between paleosols, fluvial deposits, and lacustrine deposition at the interface of these three paleoenvironments enabling us to reconstruct a dynamic lakeshore environment during the lifetime of the Nariokotome Boy.</p>


2020 ◽  
Vol 24 (5) ◽  
pp. 943-974
Author(s):  
O.A. Ilegieuno ◽  
E.J. Ighodaro ◽  
R.O. Sunny

The sedimentary rock in the Auchi area of Edo State constitutes part of the Upper Cretaceous Deposits of the Anambra Basin, which has its  depocentre in Eastern Nigeria. Lithostratigraphic and Sedimentological studies carried out on twenty eight (28) selected samples from a section of a road–cut show that the sediments range from fine through medium to coarse grained. Sorting is poor to moderate. Grain size analysis shows that the sediments are strongly fine skewed and they exhibit mesokurtic to platykurtic kurtosis. These coupled with the various colours observed in the sediment, ranging from whitish sand through yellowish brown, pink and reddish brown possibly indicate a non–marine environment and a fluviatile to deltaic environment of sedimentation is suggested. The sediments might have been transported in a fairly high energy medium and deposited under a slightly fluctuating velocity. Keywords: Sedimentology, Cretaceous, Paleogeography, Grain size, Anambra Basin


Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 28
Author(s):  
Srećko Bevandić ◽  
Rosie Blannin ◽  
Jacqueline Vander Auwera ◽  
Nicolas Delmelle ◽  
David Caterina ◽  
...  

Mine wastes and tailings derived from historical processing may contain significant contents of valuable metals due to processing being less efficient in the past. The Plombières tailings pond in eastern Belgium was selected as a case study to determine mineralogical and geochemical characteristics of the different mine waste materials found at the site. Four types of material were classified: soil, metallurgical waste, brown tailings and yellow tailings. The distribution of the mine wastes was investigated with drill holes, pit-holes and geophysical methods. Samples of the materials were assessed with grain size analysis, and mineralogical and geochemical techniques. The mine wastes dominantly consist of SiO2, Al2O3 and Fe2O3. The cover material, comprising soil and metallurgical waste is highly heterogeneous in terms of mineralogy, geochemistry and grain size. The metallurgical waste has a high concentration of metals (Zn: 0.1 to 24 wt.% and Pb: 0.1 to 10.1 wt.%). In the tailings materials, Pb and Zn vary from 10 ppm to 8.5 wt.% and from 51 ppm to 4 wt.%, respectively. The mining wastes comprises mainly quartz, amorphous phases and phyllosilicates, with minor contents of Fe-oxide and Pb- and Zn-bearing minerals. Based on the mineralogical and geochemical properties, the different potential applications of the four waste material types were determined. Additionally, the theoretical economic potential of Pb and Zn in the mine wastes was estimated.


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