Quartz Sand Samples Research Articles

Micro-hole and multigrain quartz luminescence dating of Paleodeltas at Lake Fryxell, McMurdo Dry Valleys (Antarctica), and relevance for lake history

Relict (perched) lacustrine deltas around the perennially ice-covered lakes in the Taylor Valley, Antarctica, imply that these lakes were up to 40 times larger in area than at present since the last glacial maximum (LGM). These deltas have been used to constrain ice-margin positions in Taylor Valley, and the boundaries of the proposed LGM ice-damned Glacial Lake Washburn. The timing of these high lake levels has depended on 14C chronologies of algal layers within relict lacustrine deltas. To provide additional geochronometric data for the post-LGM lake-level history, we applied photon-stimulated-luminescence (PSL) sediment dating to polymineral fine silt and sand-size quartz from 7 perched-delta and 3 active-delta sites of different elevations along 3 major meltwater streams entering Lake Fryxell. Our PSL dating of 4 quartz-sand samples from core tops in the seasonal ice-free moat of Lake Fryxell (elevation ∼18 m a.s.l.) and two core-top moat samples from the seasonal moat of Lake Vanda in nearby Wright Valley establish that adequate PSL clock zeroing (by daylight) occurs in regional, modern shoreline deposits. Minimum-age micro-hole PSL results from the moats are consistently near 100 a. Minimum-age micro-hole age estimates for the deltas range from ∼50 to 100 a near the present lake level up to 13.4 ± 1.3 ka at 240 m. These are systematically younger than the comparable, reservoir-uncorrected, 14C ages that range from 7 ka (cal yr BP) to 13 ka (cal yr BP) near lake level up to 20 ka (cal yr BP) at 220–240 m elevation. Our results indicate the occurrence of a dramatic discrepancy between PSL minimum-age and 14C age estimates that is presently unresolved.

Bench-scale flotation of chrysocolla with n-octanohydroxamate

Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, atomic absorption spectroscopy (AAS) and X-ray photoelectron spectroscopy (XPS) have been employed to characterise the surface layer and compound formation during the interaction of n-octanohydroxamate with chrysocolla and malachite surfaces. The flotation response of a single mineral chrysocolla–quartz sand sample and mixed chrysocolla–malachite–quartz sand sample using n-octanohydroxamate collector has been investigated. Recoveries of 95% were achieved in bench-scale flotation testing, with the best Cu grades achieved at pH>9. Long conditioning times adversely affected flotation performance. Moderate recovery of impurity minerals in the mineral and sand was also observed.

Analysis of influencing factors on infrared spectroscopic determination of the content of free silica in quartz sand

To find a suitable method for detecting SiO2 in quartz sand and to analyze the influencing factors on infrared spectroscopic determination of the content of free silica in quartz sand. The infrared spectroscopy was used to detect the free silica content of quartz sand, the various factors of influencing the results were analyzed and the control scheme was proposed. The number of particles less than 5 um and the proportion of free silica content increased with the grinding time. When the grinding time was 10-20 min, the results of detecting the free silica content tended to be stable. When the ashing temperature was below 550 degrees C, there was no effect on the free silica content. Although the silica content decreased slightly at ashing temperature 600 degrees C as compared to ashing temperature 550 degrees C, the difference of the free silica content between 550 degrees C and 600 degrees C was not significant (P > 0.05). When the ashing temperature was 600 degrees C, the free silica content in quartz sand samples did not change obviously in 1 h (F = 4.231, P > 0.05). The free silica content in quartz sand samples decreased significantly at 2 h of ashing time, as compared with 2 h of ashing time (F = 10.231, P < 0.05). The average content of free silica was 88.56% +/- 5.75% by pyrophosphate determination, which was significantly higher than that (21.23% +/- 11.25%) by infrared determination (P < 0.05). There was no significant correlation of the average content of free silica between pyrophosphate determination and infrared determination (r = 0.411, P > 0.05). The free silica contents detected by pyrophosphate determination were significantly higher than those detected by infrared determination for the same quartz sand samples. It is suggested that the method of detecting the free silica contents in quartz sand samples prefers the pyrophosphate determination to infrared determination.

Investigation of Hydration Heat of Slag in Portland Cement Environment

The hydration of slag in Portland cement is studied by considering the interaction between the hydrations of slag and Portland cement clinker. The slag hydration heat value that the different dosage of slag is in Portland cement is measured with isothermal calorimetry method as quartz sand sample contrast. The kinetic analysis was used to obtain parameters, which were employed to find out the influence of the slag content on the reaction rate constant value. The reaction stages have been analyzed and explained in accordance with kinetic models. The model predictions show that as the slag proportions in the blended cement changes, water retention in the hydration products changes only slightly if compared to that of Portland cement, The investigations have shown that the addition of silica fume of more than 30 mass% reduces the duration of the phase boundary interaction as a rate-determined process resulting in the fast diffusion rate-determining process. The results of this study have also revealed evidence of the accelerator effect of slag during the first 24 h of hydration when it still exists as chemically inert filler.

Thermal conductivity measurement of the synthetic samples of bottom sediments containing methane hydrates

The experimental setup is described, which makes it possible to simulate the quartz sand samples, containing methane hydrates, and to measure their thermal conductivity, using a needle probe of constant power. The method and results of measurements at different temperatures and pressures are considered. It is established that under the P-T-conditions close to the equilibrium for methane hydrate, the measurements result in the essential overestimation of the thermal conductivity the samples, i.e., to an anomalous increase in its calculated values. This is because of the dissociation (with the heat consumption) of the part of hydrates near the needle probe under the action of its heater. It is possible to conclude that this feature (the anomalous increase in the calculated values of thermal conductivity) is certain evidence for the presence of a noticeable quantity of hydrates in the sediments. This observation offers a new possibility of utilization of the geothermal method for prospecting the subsea gas hydrate accumulations. Our conclusions are confirmed by the results of measurements in situ of the thermal conductivity of the bottom sediment of the Black Sea [Kutas et al., 2005].

Age limits on Middle Pleistocene glacial sediments from OSL dating, north Norfolk, UK

The lowland region of north Norfolk contains some of the best preserved evidence for glacial deposition during the Middle Pleistocene in northwest Europe. Despite the importance of these deposits, there is limited chronological control and it is debated whether they belong to a single glaciation, equated to the Anglian Glaciation (Marine Isotope Stage 12), or represent deposition over a number of Middle Pleistocene cold stages. In order to develop an improved chronology for glaciation in this region, we obtained 18 samples for optical stimulated luminescence (OSL) dating from glacial outwash facies. Samples of coarse-grained quartz sand were measured using the SAR (single aliquot regenerative-dose) protocol. The low radioactive isotope concentrations in sediments of this region enable the traditionally accepted age limit of luminescence dating to be extended. The form of the dose response curves, pre-heat plateaux tests, and dose recovery experiments also indicate that laboratory doses can be reliably measured in these samples. Age overestimation due to partial bleaching is thought to be insignificant. The OSL ages suggest that the glacial sediments studied were deposited during MIS 12 rather than in different post MIS 12 stages.

Analysis of Heavy Metal Pollution in Soil Using Transversely Excited Atmospheric CO2 Laser-Induced Plasma by Trapping the Soil in Microstructured Holes on Metal Subtargets

A unique technique for direct analysis of soil samples utilizing a special advantage of a transversely excited atmospheric (TEA) CO(2) laser-induced plasma generated at atmospheric pressure on a metal target has been developed. In this technique, a metal subtarget, such as nickel plate, structured with intentional microholes on its surface, each with dimensions of around 100 microm in diameter and depth, was used to selectively trap small sized soil particles by immersing the metal plate subtarget into the polluted soil sample. The trapped small soil particles on the metal subtarget were irradiated by a TEA CO(2) laser (10.6 microm, 1.5 J, 200 ns) at atmospheric pressure under defocused condition with a spot size of 3 mm x 3 mm. This trapping and confining scheme substantially suppresses the blowing off effect; thus, the trapped soil particles can effectively be dissociated and atomized in the microstructured holes. Using this method of a microstructured metal plate subtarget, quantitative analysis was carried out on loam soil samples polluted by Pb. A linear calibration curve was obtained with a detection limit of approximately 50 mg/kg. Preliminary quantitative studies were carried out for a quartz sand sample containing Cr and Hg, resulting in linear calibration curves with detection limits of approximately 25 mg/kg and 10 mg/kg, respectively, at this stage. This technique is promising as a potential field screening tool for soil analysis.

A laboratory study to determine the effect of iron oxides on proton NMR measurements

Using laboratory methods, we investigate the effect of the presence and mineralogic form of iron on measured proton nuclear magnetic resonance (NMR) relaxation rates. Five samples of quartz sand were coated with ferrihydrite, goethite, hematite, lepidocrocite, and magnetite. The relaxation rates for these iron-oxide-coated sands saturated with water were measured and compared to the relaxation rate of quartz sand saturated with water. We found that the presence of the iron oxides led to increases in the relaxation rates by increasing the surface relaxation rate. The magnitude of the surface relaxation rate was different for the various iron-oxide minerals because of changes in both the surface-area-to-volume ratio of the pore space, and the surface relaxivity. The relaxation rate of the magnetite-coated sand was further increased because of internal magnetic field gradients caused by the presence of magnetite. We conclude that both the concentration and mineralogical form of iron can have a significant impact on NMR relaxation behavior.

Total soluble Fe in soil solutions of chemically different soils

Until now not much about Fe concentrations in soil solutions is known because of difficulties to extract the soil solution and to determine the low Fe concentration in them. Therefore a technique was elaborated by which a mixture of 1:1 soil–quartz sand sample with a soil moisture of 80% of maximum water holding capacity was spread in a Buchner funnel and after an incubation time of 3 days extracted under vacuum (− 50 kPa). In comparison with other water extracts for the determination of soluble Fe our method had a low water/sample ratio and therefore anaerobic conditions were avoided. Anaerobiosis leads to the reduction of Fe(III) and thus to a high release of soluble Fe 2+. The Fe(III) in solution obtained by our method was reduced by hydroxylamine hydrochloride to Fe 2+ and bound to ferrozine both reacting to form a colored complex with a maximum absorption at 562 nm. The reliability of the method was tested by adding a solution with known Fe concentration to extracted samples and by mixing samples with known Fe concentrations. These tests proved a high reproducibility. By this technique 32 soils differing in texture and pH were analyzed. The Fe concentrations found differed in a range from few μM Fe to about 200 μM Fe. These concentrations were not related to any soil characteristics.Calcareous soils had high Fe concentrations. All Fe concentrations found were high enough to meet the plants' demand. The high Fe concentrations found in the calcareous soils prove that the Fe chlorosis of plants on such soils is not a question of the Fe availability in soils. Fifty to 90% of the Fe found in the solutions was complexed by organic molecules (i.e., siderophores). The percentage of organic Fe complexes was correlated with the soil pH ( r = 0.93). The relative Fe buffer power in the soil solution differed much and was high in calcareous soils. In the discussion it is argued that the Fe concentrations found in the extracts from soil–quartz sand mixture reflect the actual Fe concentration in the soil solution at 80% of maximum water holding capacity. From the results it is concluded that rather soil organic matter and its turnover than inorganic Fe relationships in soils are decisive for the bioavailability of Fe in soils. This is in line with not yet published results obtained by us showing that the Fe concentrations in soil solution depend much on the microbial activity in soils.

OSL chronology for a sediment core from the southern Baltic Sea: A continuous sedimentation record since deglaciation

A chronology based on optically stimulated luminescence (OSL) dating is presented for the late- and post-glacial evolution of the southern Baltic Sea (∼15 ka to present). During this period, large water level and salinity changes occurred in the Baltic Basin due to opening and closing of connections to the North Atlantic. Previous attempts to establish a chronology for these palaeoenvironmental changes have mainly been conducted in coastal settings where organic material for 14C dating is abundant. Many of these records are, however, discontinuous due to the large water level fluctuations. In contrast, in the relatively deep water of the Arkona Basin, the sediment record is expected to be more or less continuous. The single aliquot regenerative dose (SAR) procedure was used to date 32 samples of fine quartz sand from a 10.86 m long sediment core from the centre of this basin (45 m water depth). Tests of luminescence characteristics confirmed the suitability of the material for OSL dating and the ages agree well with the available AMS 14C ages on shells. The Baltic Ice Lake drainage to the North Atlantic appears to occur ∼11.6 ka, agreeing with other published evidence. However, we suggest that the main marine Littorina transgression appears in the Arkona Basin at about 6.5 ka, rather than at 8.5 ka, as previously thought.

Laboratory deformation of granular quartz sand: Implications for the burial of clastic rocks

We explore the influence of mechanical deformation in natural sands through experiments on water-saturated samples of quartz sand. Stresses, volumetric strain, and microseismicity (or acoustic emission, AE) rates were monitored throughout each test. Deformation of quartz sand at low stresses is accommodated by granular flow without significant grain breakage, whereas at high stresses, granulation and cataclastic flow are dominant. Sands deformed under isotropic conditions show compactive strains with an inverse power-law dependence of macroscopic crushing strength on mean grain size. Triaxial compression at high effective pressures produces compactive strain and a high AE rate associated with considerable particle-size reduction. Triaxial compression at low effective pressure produces dilatant granular flow accommodated by grain boundary frictional sliding and particle rotation. On the basis of experiment results, we predict the evolution of porosity and macroscopic yield strength as a function of depth for extensional and contractional basins. Sand strength increases linearly with depth for shallow burial, whereas for deep burial, strength decreases nonlinearly with depth. At subyield stresses, porosity evolves as a function of applied mean stress and is independent of distortional stress. Our predictions are in qualitative agreement with observations of microfracture density obtained from laboratory creep-compaction experiments and with natural sandstones of the Gulf of Mexico basin. Mechanical deformation contributes as much as a 30% increase to fluid pressure evolution, which has particular application to sedimentary systems that display zones of fluid overpressure. Furthermore, deformational strains cannot be fully recovered during uplift, erosion, and unloading of a sedimentary basin.

Paramagnetic Effects of Iron(III) Species on Nuclear Magnetic Relaxation of Fluid Protons in Porous Media

The 1H NMR spin–lattice relaxation time, T1, of saturated sands depended on the chemistry of the pore fluid, pore size distribution, and relaxivity of the surface. In the absence of paramagnetic impurities, surface relaxivities of quartz sand and silica gel samples of known porosity and surface area at any pH were lower than any previously reported values. Relaxation rate of the bulk pore fluid increased linearly with increasing Fe(III) concentration and varied with speciation of the ion. With only 0.01% of the silica surface sites occupied by sorbed Fe(III) ions, surface relaxivity increased by an order of magnitude. In addition, low concentrations of Fe(III)-bearing solid phases present as surface coatings or as separate mineral grains increased surface relaxation as much as two orders of magnitude. We believe that observations of relatively constant surface relaxivity in rocks by previous researchers were the result of consistently high surface concentrations of paramagnetic materials.

Prospects of Developing Obskii Alluvial and Watershed Sands in West Siberia

Quartz sand samples from alluvial deposits in Khanty-Mansiiskii Autonomous District are studied. It is proposed to build a concentration enterprise using the principles of integrated processing of initial loose masses.

Comminution of geological samples using Syalon based milling vessels: comparison with established sample preparation methods

The productivity and reputation of analytical laboratories are in part underpinned by the standards of efficiency and quality applied when preparing samples for analysis. Sample milling vessels constructed from Syalon 101 (an aluminium–silicon–oxynitride alloy) have recently become available. This paper describes an assessment of their efficiency and contamination characteristics to assist the evaluation of Syalon as a possible alternative to agate for sample preparation prior to multi-element geochemical analysis. Samples of crushed quartz, quartz sand, garnet-bearing schist and marble were milled in Syalon vibrating-cup and planetary ball mill vessels to compare their comminuting efficiency with that of conventional hardened chromium steel and agate vessels. Contamination during milling was estimated by comparison with samples comminuted in agate vessels only, because metallic preparation equipment is known to introduce contaminants including Fe, Cr, W, Mn, Ni and Co to the sample. The comminuting efficiency of Syalon is superior to that of agate. Although some contamination does occur it may be less analytically critical than that derived from metallic comminution equipment.

Effects of substrate mineralogy on the biodegradability of fuel components

AbstractExperiments were carried out to determine the effects of mineralogy on the biodegradability of components of a whole fuel by a soil microbial consortium. Samples of quartz sand (Fischer Sea Sand) and illite clay (API 35) were spiked with marine diesel fuel, aged, slurried, and inoculated, and concentrations of fuel components were monitored over time. To help distinguish biotic from abiotic processes, identical samples were poisoned with mercuric chloride and were run in parallel. While there was chromatographic and biomarker evidence of n‐alkane biodegradation in the sand samples, illite samples showed no evidence of biogenic loss of aliphatic components. Polycyclic aromatic hydrocarbons, on the other hand, were lost equivalently on both minerals and in both cases were lost to a much greater extent than were total petroleum hydrocarbons (TPHs). These results suggest that under our experimental conditions, illite inhibited the bioavailability of some TPH components to the soil microbial consortium.

The influence of impurities contained in quartz sand on the catalytic reduction of nitric oxide by carbon monoxide

The catalytic activity of a natural sand, pure quartz and different quartz sand samples were tested on the reduction of nitric oxide by carbon monoxide in a fixed bed flow reactor. The natural sand shows a very high conversion of nitric oxide to nitrogen whereas pure quartz has no catalytic activity. The activity of the quartz sand samples depends on the amount of impurities present. The pollutants are not only responsible for the catalytic reaction but also for a deactivation of the catalyst at temperatures higher than 800°C. The reason for it was investigated by inverse gas chromatography, IR spectroscopy, temperature programmed desorption and differential thermal analysis, indicating a surface transformation.

EFFECTS OF SUBSTRATE MINERALOGY ON THE BIODEGRADABILITY OF FUEL COMPONENTS

Experiments were carried out to determine the effects of mineralogy on the biodegradability of components of a whole fuel by a soil microbial consortium. Samples of quartz sand (Fischer Sea Sand) and illite clay (API 35) were spiked with marine diesel fuel, aged, slurried, and inoculated, and concentrations of fuel components were monitored over time. To help distinguish biotic from abiotic processes, identical samples were poisoned with mercuric chloride and were run in parallel. While there was chromatographic and biomarker evidence of n-alkane biodegradation in the sand samples, illite samples showed no evidence of biogenic loss of aliphatic components. Polycyclic aromatic hydrocarbons, on the other hand, were lost equivalently on both minerals and in both cases were lost to a much greater extent than were total petroleum hydrocarbons (TPHs). These results suggest that under our experimental conditions, illite inhibited the bioavailability of some TPH components to the soil microbial consortium.

Correlating quartz dissolution kinetics in pure water from 25 to 625°C

Results for quartz dissolution kinetics in pure water from five different experimental apparatuses in this study were correlated with measurements from ten previous investigations. A simple global equation with an Arrhenius rate constant formulation satisfactorily represented experimental data spanning temperatures from 25 to 625°C obtained from crushed quartz crystals, quartz sand, and quartz slab samples. Geometric and BET-derived surface areas were successfully used to normalize dissolution rates. An Arrhenius expression describing a kinetic dissolution rate constant with an average activation energy of 89 ± 5 kJ/mol was regressed from the set of dissolution rate data covering eleven orders of magnitude in variation from about 4 × lO −14 mol/m 2s at 25°C to 1 × 10 −3 mol/m 2s at 625°C on a geometric area basis.

Distribution of REE and trace elements in size and mineral fractions of high-purity quartz sands

Eight sample sets — raw quartz sand, quartz fraction, < 2- μm clay fraction, 2–20-μm fraction and heavy minerals — of the Cretaceous quartz sand deposits of Haltern and Weferlingen (central Germany) and the Tertiary quartz sand of Frechen (western Germany) were studied to characterize the distribution of REE and trace elements and to get genetic information about provenance and sedimentologic history of the sediments. The quartz sand samples from different localities have rather similar trace-element distribution and REE patterns with enriched LREE and negative Eu anomalies. However, these relations can be modified by local changes in syn- or postsedimentary geochemical conditions. Adsorption of REE and trace elements on humic substances under reducing conditions and postsedimentary weathering in the quartz sand of Weferlingen resulted in significantly modified element abundances. The concentration of trace elements is most important in the < 2- μm fraction and in the heavy-mineral fraction where they may be enriched by a factor of up to 100. The chondrite-normalized REE distribution of the < 2- μm fraction is quite similar to those in the North American Shale (NAS) with average Eu/Sm ratios of 0.21 and ( La Yb ) cn of 6.1. Low trace-element abundances in the < 2- and 2–20-μm fractions were attributed to quartz dilution and quantified. Among the common minerals in the heavy-mineral fractions, especially zircon and the Fe/1bTi-oxides (rutile, ilmenite, magnetite) influence the trace-element distribution. Investigations concerning the provenance of the quartz sands illustrate that the host sediments have a rather homogeneous geochemical signature due to their sedimentological history. Taking into account Th/Ta variations the quartz sands of Weferlingen and Haltern can be distinguished from the Frechen quartz sand. Additionally, discriminations based on element ratios within the quartz fraction (Th/Sc, Ba/Sc, Ba/Co, Cs/Sc or Li/Sc) seem to be promising.

Radiocarbon and thermoluminescence dating of the Old Alluvium from a coastal site in Perak, Malaysia

Exposures of the ‘Old Alluvium’ in Pantai Mine and Sinar Manjung Mine in Perak, Peninsular Malaysia, reveal woody peat layers interbedded with angular sands and gravels. Eight samples from peat within the Pantai Mine were dated using accelerator mass spectrometry (AMS) radiocarbon dating, together with a near-surface shell sample. Five samples of quartz sand from the Pantai Mine and three samples of similar sand from Sinar Manjung Mine were dated by thermoluminescence (TL) dating. While for several samples both dating techniques were at the limits of their detection, results from the upper strata of the northwestern face of the Pantai Mine indicate agreement between the two independent dating techniques. The age of the Old Alluvium, known as the Simpang Formation in Perak, is confirmed as Late Pleistocene at this site. The measured ages range from 28,000 years B.P. to 67,000 years B.P., but the lower units are older than this and appear at this site to be beyond the range of both dating techniques.