Distribution and Influence of Iron Phases the Physico—Chemical Properties of Phyllosilicates

Clay minerals from different Cretaceous stratigraphic successions of Egypt were investigated using XRD,DTA,dissolution analysis(DCB),IR,Moessbauer and X-ray Electron Spin Resonance(ESR) spectroscopes.The purity of the samples and the degree of their structural order were determined by XRD.The location of Fe in the octahedral sheet is characterized by absorption bands at-875cm^-1 assigned as Al-OH-Fe which persist after chemical dissolution of free iron.The Moessbauer spectra of these clays show two doublets with isomer shift and quadrupole splitting typical of octahedrally coordinated Fe^3 ,in addition to third doublet with hyperfine parameter typical of Fe^2 in the spectra of Abu-Had kaolinite (H) sample.Six-lines magnetic hyperfine components which are consistent with those of hematite are confirmed in the spectra of both Isel and Rish kaolinite samples.Goethite was confirmed by both IR and DTA.Multiple nature of ESR of these clays suggested structural Fe in distorted octahedral symmetry as well as non-structural Fe.Little dispersion and low swelling indices as well as incomplete activation of the investigated montmorillonite samplas by NaCO3 appear to be due to incomplete disaggregation of montmorillonite particles.This can be explained by the ability of Fe-gel to aggregate the montmorillonite into pseudo-particles and retard the rigid-gel structure.However,extraction of this ferric amorphous compound by dithonite treatment recovers the surface properties of the montmorillonite samples.On the other hand,the amount and site occupation of Fe associated with kaolinite samples show an inverse correlation with the parameters used to describe the degree of crystallinity perfection,color,brightness and vitrification range of these kaolinite samples.     

利用瞬变电磁和多频电磁方法监测地下水位及其对Hawara遗址的影响

利用瞬变电磁（TEM）和地面电磁（GEM）方法,本文研究了埃及Hawara遗址区的地下水对遗址的影响.这个遗址包括Hawara金字塔、北区墓地、以及被称作“迷宫”的南区墓葬场所.现今Hawara遗址已经完全荒废,被耕作区和Bahr Wahba运河包围.地表水和地下水会破坏Hawara金字塔和“迷宫”遗址的地基,现在金字塔入口已被淹没至地面下约6 m深处.本文在耕作区、金字塔以及“迷宫”等三个地区进行了TEM勘察;在“迷宫”地区进行了GEM勘察.综合分析以上两种勘察数据,我们发现,农业灌溉是浸入到地下的水的主要来源;本地区地下水位随着观测点及海拔的不同,在地面以下2~7 m之间变化.     

Influence of Salinity on pH and Aluminum Concentration on the Interaction of Acidic Red Soil with Seawater

Contamination of acidic red soil in the coastal areas of Okinawa Islands is a serious environmental problem. This study was conducted to examine the effects of the salinity on pH and aluminum concentration when the acidic red soil interacts with seawater. Acidic red soil from Gushikawa recreation center was fractionated into bulk soil, coarse sand and silt + clay. Different weights of each fraction were equilibrated with seawater solutions. The pH and concentrations of Al³⁺, Na⁺, K⁺, Ca²⁺ and Mg²⁺ were then analyzed in the extracts. The results showed a decreasing trend of pH with increasing soil to solution ratio while the extracted Al³⁺ revealed an increasing trend. The lowest pH values were 3.85, 4.06, 4.41, 4.66 and their corresponding highest Al³⁺ concentrations were 2.50, 1.01, 0.062 and 0.036 mmolL⁻¹ in the seawater extracts, one-tenth seawater extracts, one-hundredth seawater extracts and one-thousandth seawater solution extracts, respectively. Mostly, the concentrations of Na⁺, Ca²⁺, Mg²⁺ and especially K⁺ decreased with increasing soil weight in the high salinities but showed the opposite trend in the low salinity samples. Potassium concentration decreased by 39%, 53% and 40% in the seawater extracts, one-tenth and one-hundredth seawater extracts but increased by 200% in one-thousandth seawater extracts. The coincidence of the increase in Al³⁺ and H⁺ concentrations, and the decrease of Na⁺, K⁺, Ca²⁺ and Mg²⁺ concentrations in the solutions suggests ion exchange/adsorption, while the increased patterns, particularly at low salinity could be attributed to the dissolution of the species from the soils.     

Solidification of Tank Bottom Sludge

Tank bottom oily sludge (S) is collected from tank bottoms during cleaning operations and contaminated soil is collected after spills and leakages. Disposal of tank sludge is a significant item of tank maintenance for producers, refiners and transporters of petroleum materials. The objective of this paper is to investigate the use of various additives in the solidification of tank bottom sludge. The sludge was solidified using various combinations of additives including ordinary Portland cement (OPC), cement by-pass dust (CBPD) and quarry fines (QF). Geotechnical and leachability properties of the mixtures were determined. The use of OPC alone as a solidifying agent yielded the best results. This was followed by blends S:OPC:QF of 1:0.5:1.5 and S:CBPD of 1:2. Economically, the latter two mixtures would be considered more cost-effective in solidifying the sludge as the additives are waste by-product materials. The Toxicity Characteristic Leaching Procedure (TCLP) results indicated that no extracts exceeded the threshold TCLP limits established by U.S. Environmental Protection Agency (USEPA). The solidified material can be used in construction of roads, embankments and landfill layers.     

Hornblende barometry of the Galway batholith,Ireland: an empirical test

Summary The application of four hornblende geobarometers, two empirical and two experimental, to the 400 Ma Galway Granite, Ireland gives a pressure of crystallization of the zoned hornblende cores in the western parts of the granite of 2.62 ± 1.2 kb falling to < 1.53 ±1.02 kb at the hornblende rims whereas in the more eastern part of the batholith the value of 4.30 ± 0.70 kb is obtained from unzoned hornblendes. These results are consistent with field and petrographic evidence which indicates a much deeper level of early crystallization of the granite in the central and eastern area with larger K-feldspar phenocrysts (up to 6 cm). Although some of the uplift is related to late upward faulting, the main uplift of the centre of the granite in the east was due to late magmatic differential slip against the marginal granite which became vertically foliated. In the west the crystallization of hornblende started and completed at lower pressures than in the east with final hornblende crystallization at the limit of the field of igneous hornblende and at depth of < 5 km. Hornblende geobarometry reveals: (1) that different parts of some batholiths crystallized at very different pressures (and therefore depths) and have been juxtaposed at the present level of erosion (2) that at least the early part of the crystallization of some granites took place at significantly greater depths than the final crystallization and emplacement position; (3) in zoned hornblendes crystallization occurred during magma movement.

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Hornblende-Barometrie des Galway-Batholithen, Irland: Ein empirischer Test

Zusammenfassung Vier Hornblende-Geobarometer, zwei empirische and zwei experimentelle wurden auf den 400 m.y. alten Galway-Granit, Irland, angewendet and ergeben ähnliche Resultate. Der Durchschnitt der Berechnungen gibt einen Kristallisationsdruck der zonierten Hornblendekerne in den westlichen Teilen des Granits von 2.62 ± 1.2 kbar. Diese Werte fallen auf weniger als < 1.53 ± 1.02 kbar in den Hornblenderändern, während in den östlichen Teilen des Batholithen ein Wert von 4.30 ± 0.70 kbar von nicht zonierten Hornblenden erhalten wurde. Diese Ergebnisse stimmen gut mit Geländebeobachtungen und petrographischen Daten überein, die darauf hinweisen, daß der Granit im zentralen und östlichen Bereich in größerer Tiefe kristallisiert ist. Dabei erreichten K-Feldspat Kristalle Maximumlängen von 6 cm, verglichen mit nur 3 cm im Westen und am Rand. Obwohl ein Teil der Hebung auf späte Verwerfungen zurückgeht, war die Haupthebung zentraler Teile des Granites im Osten durch spätmagmatische, differentielle Gleitung gegenüber den randlichen Granitzonen bedingt, wobei letztere vertikal gefältelt wurden. Im Westen begann die Kristallisation der Hornblende bei niedrigeren Drucken als im Osten, wobei die späteste Hornblende-Kristallisation an der Grenze des Feldes magmatischer Hornblende und in Tiefe von < als 5 km stattfand. Hornblende-Geobarometrie zeigt, daß 1. verschiedene Teile des gleichen Batholithen unter verschiedenen Drucken (und somit in verschiedenen Tiefen) kristallisierten und erst im gegenwärtigen Erosions-Niveau nebeneinander gestellt wurden; 2. daß wenigstens die Frühkristallisation einiger Granite in signifikant größeren Tiefen als die Endkristallisation, und die Position der Platznahme lagen; 3. in zonierten Hornblenden Kristallisation während magmatischer Bewegung stattfand.

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With 2 Figures

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Formerly Oum-toub, Skikda, BP56, 21450, Algeria     

TDR detection of nonaqueous phase liquids in sandy soils using the eigendecomposition method

In this study, the presence of nonaqueous phase liquids (NAPL) in sandy soils are detected using a TDR probe system and the eigendecomposition method of analysis. As a demonstration, five NAPLs with different physicochemical properties (acetone, benzene, heptane, trichloroethylene, and xylene; Table 1) were used. Samples were prepared in such a way that the soil pore fluid has different contents of deionized water and NAPLs. For each experiment, a pulse signal with known characteristics was used and reflected signals were captured by an oscilloscope and analyzed using the eigendecomposition method. Autoregressive modeling and singular value decomposition were used to calculate the eigenvalues. The most significant eigenvalues were identified based on their power spectrum. The relative eigenvalue of the first mode (Eow), which is a measure of the power carried by the signal, was calculated and correlated to NAPL type and content, and octanol water partition coefficient (log Kow). The results indicated that for the same NAPL content, as log Kow increases, Eow decreases due to increase of hydrophobicity. For the same log Kow, as the organic content in soil pore fluid increases, Eow increases due to decrease of dielectric properties of the pore fluids.     

Eigendecomposition of TDR waveforms: a novel method to determine water content and pore fluid concentration of sandy soils

In this study, an incident pulse signal of several harmonics (i.e., multiples of the fundamental frequency) was used as a source in the time domain reflectometry (TDR) probing technique. Reflected signals were captured by an oscilloscope and their characteristics were determined via eigendecomposition. Autoregressive modeling and singular value decomposition were used to calculate the eigenvalues and the most significant ones were identified based on power spectrum. A multivariate statistical analysis was performed for the two most dominant eigenvalues, which are dependent on water content and salt concentrations, and regression equations were obtained. To determine the water content and salt concentrations in terms of the first and second eigenvalues, a modified Powell hybrid algorithm was used to solve the obtained system of nonlinear equations. Actual and predicted results are in agreement indicating that the developed method is very successful in predicting water content and salt concentrations. Furthermore, on comparing the eigendecomposition method with Fourier spectral analysis, one can observe that the former is superior in predicting water content and salt concentrations.     

Effect of groundwater and sea weathering cycles on the strength of chalk rock from unstable coastal cliffs of NW France

The aim of this paper is to evaluate the role of groundwater and sea weathering on the strength of the chalk rocks exposed on the coastline of the English Channel in Normandy, NW France. We present a study of the rock strength variations of three representative chalk units (Lewes Chalk, Seaford Chalk and Newhaven Chalk) exposed at various locations on the coastal chalk cliffs. The combination of UCS tests and SEM observations have been used (1) on dry natural chalk samples, (2) on chalk samples at various moisture contents, (3) on dry chalk samples submitted to a 10-day cycle of alternating wetting and drying by distilled water and by sea water. Dry chalk samples show low UCS strength (3.46–4 MPa) indicative of very weak rocks. When chalk samples are submitted to progressive water wetting, they present a decrease of UCS strength and Young's modulus of 40% to 50%. This behaviour begins at low values of water content within the chalk, i.e., for a degree of water saturation ranging between 10% and 17%. When chalk samples are submitted to an artificial weathering cycle with distilled water, a decrease in strength is observed, whereas the Young's modulus increases. SEM observations indicate the occurrence of microcracks and particle aggregates in the sample. When chalk samples are submitted to an artificial weathering with sea water, the decrease of UCS strength and Young's modulus achieves a minimum. SEM observations indicate salt crystals within the chalk. On the coastal cliffs of NW France, weathering processes depend both on chalk lithology, which show a range of sensitivity to weathering and on the location of the chalk in the coastal area. Processes allied to the degree of weathering (e.g., salt crystallisation or fresh water disaggregation) differ in the chalk massif, on the cliff face and on the shore platform.     

Assessment of crushed shales for use as compacted landfill liners

The possibility of using crushed shales as landfill liners is investigated in this study. Two types of shales were studied by performing the following laboratory tests: hydraulic conductivity, compaction, swelling, consolidation, X-ray diffraction (XRD), scanning electron microscope (SEM) and chemical analysis. For both compacted shales, the hydraulic conductivity was in order of 10^− 7 cm/s or less which satisfies the specifications for landfill liners. The results of XRD and SEM support the low values of the hydraulic conductivity. Because of the dominant presence of low-activity kaolinite, there was no significant change in the hydraulic conductivity when the compacted shales are exposed to calcium chloride solution. The compressibility of the compacted clay was low and no serious post-construction settlement is expected. The shear strength of the compacted shales was within the usual expected range for earthen liners and, therefore, should pose no challenges with respect to shear strength. The crushed shales also satisfy the other criteria related to Atterberg limits and grain size.