Journal articles on the topic 'Kaolinite-rich soils'
To see the other types of publications on this topic, follow the link: Kaolinite-rich soils.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Kaolinite-rich soils.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Melo, V. F., B. Singh, C. E. G. R. Schaefer, R. F. Novais, and M. P. F. Fontes. "Chemical and Mineralogical Properties of Kaolinite-Rich Brazilian Soils." Soil Science Society of America Journal 65, no. 4 (July 2001): 1324–33. http://dx.doi.org/10.2136/sssaj2001.6541324x.
Full text
2
Arocena, J. M., and P. Sanborn. "Mineralogy and genesis of selected soils and their implications for forest management in central and northeastern British Columbia." Canadian Journal of Soil Science 79, no. 4 (November 1, 1999): 571–92. http://dx.doi.org/10.4141/s98-071.
Full textAbstract:
Soil properties in central and northeastern British Columbia are strongly influenced by parent materials because of geologically young till, glaciolacustrine, and glaciofluvial deposits. We examined pedogenesis on various parent materials to support studies of long-term forest productivity. We sampled nine pedons developed on till (Bobtail, Lucille Mountain, Skulow Lake, Log Lake, Topley, and Kiskatinaw), glaciofluvial (Bowron), and glaciolacustrine (Aleza Lake 1, 2) deposits. The Skulow Lake pedon is distinctive in the occurrence of talc, while the Lucille Mountain pedon has the only clay fraction in which kaolinite is absent. Other pedons on till contain mica, kaolinite, chlorite, smectite, and vermiculite. The Bowron pedon has mica, kaolinite, and chlorite, while the Aleza Lake pedons have mica, kaolinite, chlorite, and 2:1 expanding minerals. In pedons with low amount of 2:1 expanding clays in the C horizon, mica and chlorite appear to degrade into 2:1 expanding clays, while in pedons with C horizons containing 2:1 expanding clays, mica and chlorite seem stable and the formation of hydroxy-interlayered clays is the predominant process. Podzolization and lessivage are major pedogenic processes, while redoximorphic processes are observed in some pedons with illuvial Bt horizons. Significant soil compaction hazards are presented by the medium and fine soil surface textures. Although clay-rich Bt horizons may benefit soil nutrient regimes, conservation of nutrient-rich forest floors is important, given the low S contents in mineral soils. High contents of feldspars in these soils provide a large reserve of nutrients such as Ca and K. Key words: Clay minerals, parent material, podzolization, lessivage
3
Muhs, Daniel R. "Evolution of Soils on Quaternary Reef Terraces of Barbados, West Indies." Quaternary Research 56, no. 1 (July 2001): 66–78. http://dx.doi.org/10.1006/qres.2001.2237.
Full textAbstract:
AbstractSoils on uplifted Quaternary reef terraces of Barbados, ∼125,000 to ∼700,000 yr old, form a climo-chronosequence and show changes in physical, chemical, and mineralogical properties with terrace age. Parent materials are dust derived from the Sahara, volcanic ash from the Lesser Antilles island arc, and detrital carbonate from the underlying reef limestone. Although some terrace soils are probably eroded, soils or their remnants are redder and more clay-rich with increasing terrace age. Profile-average Al2O3 and Fe2O3 content increases with terrace age, which partially reflects the increasing clay content, but dithionite-extractable Fe also increases with terrace age. Profile-average K2O/TiO2, Na2O/TiO2, and P2O5/TiO2 values decrease with terrace age, reflecting the depletion of primary minerals. Average SiO2/Al2O3 values also decrease with terrace age and reflect not only loss of primary minerals but also evolution of secondary clay minerals. Although they are not present in any of the parent materials, the youngest terrace soils are dominated by smectite and interstratified kaolinite-smectite, which gradually alter to relatively pure kaolinite over ∼700,000 yr. Comparisons with other tropical islands, where precipitation is higher and rates of dust fall may be lower, show that Barbados soils are less weathered than soils of comparable age. It is concluded that many soil properties in tropical regions can be potentially useful relative-age indicators in Quaternary stratigraphic studies, even when soils are eroded or changes in soil morphology are not dramatic.
4
Vasquez Torres, Oscar Oswaldo, Laura Carmona-Saldarriaga, and Jorge I. Tobón. "Cement production with pozzolans from residual tropical soils formed from paragneiss with a high silicon oxide content." DYNA 87, no. 213 (April 1, 2020): 69–74. http://dx.doi.org/10.15446/dyna.v87n213.83208.
Full textAbstract:
The manufacture of cement demands a lot of energy and gives off large amounts of CO2. Calcined clays need less energy and emit water instead of CO2, which has drawn attention to them, especially those rich in kaolinite. However, their use has been discouraged due to their location and high market price. Hence, the present study focuses on calcined clays with a low kaolinite content, specifically those derivedfrom paragneiss. In Colombia they are located in weathering horizons with depths of up to 40 meters. The results showed contents of 20%Al2O3, less than 14% Fe2O3, more than 60% SiO2, less than 40% kaolinite, 20% illite and more than 30% quartz. Calcined at 750 °C, they were used in mortars, obtaining SAI values of between 80 and 100% after 28 days, which, added to the results of Frattini tests, show that their use as a supplementary cementing material is feasible.
5
Farias, Wisley M., Éder S. Martins, and Patrícia F. Machado. "Benzene Concentration in the Phases of Tropical Soils." Soils and Rocks 32, no. 3 (September 1, 2010): 135–40. http://dx.doi.org/10.28927/sr.323135.
Full textAbstract:
This work evaluates tropical soil adsorption capacity of a hydrophobic compound (benzene). With such purpose, a lateritic soil poor in organic matter and a hydromorphic soil rich in kaolinite with a higher organic content were studied. The lateritic soil, rich in Al and Fe oxides, presented a higher sorption capacity in grain size terms for having a higher clay fraction which consequently favored a greater surface contact area, and in mineralogical terms for containing micro-aggregates of Al and Fe oxides, which may confine hydrophobic compounds. This study also compared the lateritic soil retardation factor with Batch Test sorption data. It is shown that the retardation factor for benzene may overestimate the concentration of the adsorbed phase, and thus underestimates the concentration in the effective dissolved phase. Also, a simplified model is presented to calculate benzene concentration in the various phases (free, dissolved and adsorbed) and in the pore-fluid of a lateritic soil in a saturated environment.
6
Arthur, Emmanuel, Markus Tuller, Trine Norgaard, Per Moldrup, and Lis W. de Jonge. "Improved estimation of clay content from water content for soils rich in smectite and kaolinite." Geoderma 350 (September 2019): 40–45. http://dx.doi.org/10.1016/j.geoderma.2019.05.018.
Full text
7
Singh, Balwant, and Susan Heffernan. "Layer charge characteristics of smectites from Vertosols (Vertisols) of New South Wales." Soil Research 40, no. 7 (2002): 1159. http://dx.doi.org/10.1071/sr02017.
Full textAbstract:
Premature senescence in cotton has been attributed to K deficiency in the cotton soils of Australia. The availability, release, and fixation of K+ in soils are mainly dependent on the clay mineralogy and layer charge characteristics of 2 : 1 clay minerals. There is a little information on the mineralogy and charge characteristics of the cotton growing soils (Vertosols) of Australia. The aims of this study were to determine the clay mineralogy, the layer charge density, and layer charge distribution of some cotton growing soils by chemical and X-ray diffraction methods.Most soil clays contain abundant smectite associated with small amounts of mica, kaolinite, and an interstratified mineral. The total layer charge as determined by the alkylammonium method ranged between 0.55 and 0.67 mol(–)/(O10(OH)2), indicating a high interlayer charge density. The layer charge of smectites from different valleys and for different size fractions was similar. The Greene-Kelly test showed that most of the charge originated in the tetrahedral sheet. The chemical analysis indicates that the smectite is an iron-rich beidellite, which has possibly formed from the weathering of mica.
8
Fernandes, Kathleen Lourenço, Adriana Aparecida Ribon, José Marques Junior, Angélica Santos Rabelo de Souza Bahia, and João Tavares Filho. "Magnetic and spectral signatures of Cerrado soils in the state of Goiás, Brazil." Pesquisa Agropecuária Brasileira 52, no. 10 (October 2017): 923–32. http://dx.doi.org/10.1590/s0100-204x2017001000012.
Full textAbstract:
Abstract: The objective of this work was to estimate the iron oxide contents (hematite and goethite) and to characterize the color and the spectral and magnetic signatures of Cerrado soils in the state of Goiás, Brazil. Six Oxisols and one Inceptisol were studied. Spectral and magnetic signatures were determined by diffuse reflectance spectroscopy (DRS) and magnetic susceptibility, respectively. Then, the spectral curves and the second derivative calculations were used to determine hematite and goethite contents, as well as soil color after conversion into tristimulus values. Hematite and goethite contents were also obtained by x-ray diffractometry, and soil color was also defined in the field (Munsell color chart). The values for the isomorphic substitution of iron by aluminum and the degree of redness were also determined. DRS can be used to estimate hematite and goethite contents, as well as the color of Cerrado soils in the state of Goiás. The spectral signature can point out the main soil properties related to the contents of organic matter, iron oxides, kaolinite, and gibbsite. The magnetic signature, characteristic of soils rich in iron oxides (hematite and goethite), shows the predominance of pedogenic minerals.
9
Budhu, Muniram, R. F. Giese Jr., George Campbell, and Lynn Baumgrass. "The permeability of soils with organic fluids." Canadian Geotechnical Journal 28, no. 1 (February 1, 1991): 140–47. http://dx.doi.org/10.1139/t91-015.
Full textAbstract:
Permeability measurements, using a consolidometer, were made for kaolinite, montmorillonite, and a clay-rich soil (the Lockport clay) with a variety of organic liquids and water as permeants. These data, along with selected values from the literature, were used to evaluate several theories that have been proposed as explanations for the general observation that permeabilities of clay soils with organic fluids as the permeants are higher than with water as the permeant. Of the several obvious differences in physical properties between water and organic liquids (e.g., dielectric constant, viscosity, dipole moment, specific gravity, and surface tension), only the dielectric constant provided a consistent correlation with the permeabilities used in this study. The permeabilities for the organic chemicals used in this study can be predicted using the measured permeability for the soil with water as the permeant and the dielectric constant of the organic by way of an exponential equation. For mixtures of acetone–water and methanol–water, the permeabilities did not vary linearly with the composition; the permeabilities remained close to values for pure water until approximately 70% (by volume) of the fluid was organic. Key words: permeability, organics, dielectric constant, soils.
10
Bleeker, P., and R. Sageman. "Surface charge characteristics and clay mineralogy of some variable charge soils in Papua New Guinea." Soil Research 28, no. 6 (1990): 901. http://dx.doi.org/10.1071/sr9900901.
Full textAbstract:
Clay mineralogy and charge characteristics of two lowland volcanic ash soils (Andepts or Andisols) and two strongly weathered soils (Oxisols) have been studied. The clay mineralogy of the Oxisols is strongly related to the composition of the parent material, one profile on ultrabasic rocks being dominated by goethite and the other, developed on basaltic rocks, having kaolinite as the major clay mineral. In contrast, the clay minerals of the soils developed on volcanic ash deposits are dominated by hydroxy Al-interlayered vermiculite which, in one soil, is most likely formed as an alteration product of biotite. In the other profile, however, in the absence of mica, the vermiculite may have formed as an alteration product of feldspars. Charge characteristics for each of the four profiles studied show a characteristic set of curves related to organic matter content, clay mineralogy and exchangeable aluminium at low pH. The results clearly show that organic manuring within the root zone and/or rejuvenation of silica-rich ash showers can be very beneficial in retaining the chemical fertility levels of soils that contain both variable and permanent charge colloids.
11
Garcia-Gonzalez, MT, and FJ Aragoneses. "Relationship between mineralogy and elemental composition in strongly developed soils using principal components analysis." Soil Research 30, no. 4 (1992): 395. http://dx.doi.org/10.1071/sr9920395.
Full textAbstract:
The distribution rate of major, minor and trace elements in different size fractions of highly developed soils of central Spain was determined and related to the mineralogy of the soils. Analysis of variance, factor analysis and contingency tables were used. The principal trace element carriers were the 2 : 1 phyllosilicates and the Fe and Mn-oxides; kaolinite did not play a role in this regard. Factor analysis indicated that the principal difference is found between samples rich in clay-kaoliniteAl2O3 and samples rich in quartz-SiO2. Alkaline and alkaline-earth elements (K, Na, Rb, Ba and Sr) show a similar behaviour, being directly related to the contents of illite and feldspars. Co and Pb contents are found to be related to the Mn-oxides, while Cu and Zn showed a relatively erratic distribution. Vanadium content was clearly associated with the Fe-oxides, but other metals, such as Cr, Ni and La, showed distinct associations depending on particle size.
12
Zhang, Qingzhong, Claudia Keitel, and Balwant Singh. "Evaluation of the Influence of Individual Clay Minerals on Biochar Carbon Mineralization in Soils." Soil Systems 3, no. 4 (December 3, 2019): 79. http://dx.doi.org/10.3390/soilsystems3040079.
Full textAbstract:
Although association between mineral and biochar carbon have been speculated in some studies, still there is no direct evidence for the influence of individual clay minerals on the mineralization of biochar carbon in soils. To address this, we conducted an incubation study using monomineralic soils constituted by separately mixing pure minerals, i.e., smectite, kaolinite, and goethite, with a sandy soil. Switch grass biochar (400 °C) was added to the artificial soils and samples were incubated for 90 days at 20 °C in the laboratory. The CO2-C mineralized from the control, and biochar amended soil was captured in NaOH traps and the proportion of C mineralized from biochar was determined using δ13C isotopic analysis. The clay minerals significantly decreased the cumulative total carbon mineralized during the incubation period, whereas biochar had no effect on this. The least amount of total C was mineralized in the presence of goethite and biochar amended soil, where only 0.6% of the native soil organic carbon (SOC) (compared to 4.14% in control) and 2.9% of the biochar-C was mineralized during the 90 days incubation period. Native SOC mineralization was significantly reduced in the presence of biochar and the three minerals. Goethite was most effective in stabilizing both biochar and the native soil organic carbon. The short-term data from this study demonstrate that biochar application in Fe oxide rich soils may be an effective strategy to sequester biochar carbon, as well as to stabilize native soil carbon.
13
Długosz, Jacek, Barbara Kalisz, and Andrzej Łachacz. "Mineral matter composition of drained floodplain soils in north-eastern Poland." Soil Science Annual 69, no. 3 (September 1, 2018): 184–93. http://dx.doi.org/10.2478/ssa-2018-0019.
Full textAbstract:
Abstract Soils in two river valleys (Rozoga and Omulew) in north-eastern Poland were investigated. The valleys are located on a sandy outwash plain formed during the Vistulian (Weichelian) Glaciation. The soils are drained, used as meadows and classified as Fluvic Umbric Gleysol, Fluvic Mollic Gleysol, and Eutric Fluvic Histic Gleysol (IUSS Working Group WRB 2015). The aim of the study was to identify the composition of mineral matter and to determine the types of clay minerals and intermediate stages of clay minerals by means of the X-ray diffraction (XRD). The studied floodplain soils are rich in organic matter and contain considerable mineral alluvial admixtures. The content of clay fraction (< 2.0 μm) is low (0.02–5.61% of total mineral matter). Higher content of clay fraction was noted in soils with elevated content of organic matter, which can be evidence of simultaneous accumulation of both components. In deeper depressions occurring in river valleys (oxbow lakes), a specific deposit termed silty telmatic mud (16–24% TOC, 50–75% silt, 3.1–5.6% clay fraction content) was accumulated. On the other hand, in shallow depressions, a muddy deposit was accumulated (5.7–7.7% TOC, sandy texture). The main identified clay minerals were smectite, vermiculite, illite and kaolinite as well as variety of mixed-layer clays. Alluvial clay admixture in studied soil formations showed mineralogical similarity to typical floodplain mineral soils (Fluvisols). Mineral fraction of studied soils is mostly of allochthonous origin.
14
Löhr, S. C., M. Grigorescu, and M. E. Cox. "Iron nodules in ferric soils of the Fraser Coast, Australia: relicts of laterisation or features of contemporary weathering and pedogenesis?" Soil Research 51, no. 2 (2013): 77. http://dx.doi.org/10.1071/sr12372.
Full textAbstract:
The genesis of ferruginous nodules and pisoliths in soils and weathering profiles of coastal southern and eastern Australia has long been debated. It is not clear whether iron (Fe) nodules are redox accumulations, residues of Miocene laterite duricrust, or the products of contemporary weathering of Fe-rich sedimentary rocks. This study combines a catchment-wide survey of Fe nodule distribution in Poona Creek catchment (Fraser Coast, Queensland) with detailed investigations of a representative ferric soil profile to show that Fe nodules are derived from Fe-rich sandstones. Where these crop out, they are broken down, transported downslope by colluvial processes, and redeposited. Chemical and physical weathering transforms these eroded rock fragments into non-magnetic Fe nodules. Major features of this transformation include lower hematite/goethite and kaolinite/gibbsite ratios, increased porosity, etching of quartz grains, and development of rounded morphology and a smooth outer cortex. Iron nodules are commonly concentrated in ferric horizons. We show that these horizons form as the result of differential biological mixing of the soil. Bioturbation gradually buries nodules and rock fragments deposited at the surface of the soil, resulting in a largely nodule-free ‘biomantle’ over a ferric ‘stone line’. Maghemite-rich magnetic nodules are a prominent feature of the upper half of the profile. These are most likely formed by the thermal alteration of non-magnetic nodules located at the top of the profile during severe bushfires. They are subsequently redistributed through the soil profile by bioturbation. Iron nodules occurring in the study area are products of contemporary weathering of Fe-rich rock units. They are not laterite duricrust residues nor are they redox accumulations, although redox-controlled dissolution/re-precipitation is an important component of post-depositional modification of these Fe nodules.
15
Andrews, Julian E. "Jurassic clay mineral assemblages and their post-depositional alteration: upper Great Estuarine Group, Scotland." Geological Magazine 124, no. 3 (May 1987): 261–71. http://dx.doi.org/10.1017/s0016756800016289.
Full textAbstract:
AbstractClay minerals from Middle Jurassic lagoonal mudrocks, siltstones and silty fine-grained sandstones of the upper Great Estuarine Group (Bathonian) are divided into four assemblages. Assemblage 1, the most common assemblage, is rich in mixed-layer illite–smectite with attendant illite and kaolinite. Assemblage 2 is dominated by smectitic clay. These assemblages are indicative of primary Jurassic deposition. Illite and kaolinite were probably derived from the weathering of older rocks and soils in the basin hinterland and were deposited in the lagoons as river-borne detritus. The majority of smectite and mixed-layer illite–smectite is interpreted as the argillization product of Jurassic volcanic dust, also deposited in the lagoons by rivers. Near major Tertiary igneous intrusions these depositional clay mineral assemblages have been altered. Assemblage 3 contains smectite-poor mixed-layer illite–smectite, whilst Assemblage 4 contains no smectitic clay at all. Destruction of smectite interlayers occurred at relatively shallow burial depths (< 2500 m) due to enhanced geothermal gradients and local convective hot-water circulation cells associated with the major Tertiary igneous intrusions.
16
Prasetyo, B. H. "PERBEDAAN SIFAT-SIFAT TANAH VERTISOL DARI BERBAGAI BAHAN INDUK." Jurnal Ilmu-Ilmu Pertanian Indonesia 9, no. 1 (November 28, 2017): 20–31. http://dx.doi.org/10.31186/jipi.9.1.20-31.
Full textAbstract:
Vertisols is black and fertile soils, derived from various parent materials, dominated by smectite clay minerals, and charasterize by crack formation during dry season. Six soil profiles consisted of thirty two soil samples from dIfferent location were analyzed for their chemical and mineralogical composition at the laboratories of Soil Research Center for soil characteristics. Results indicate that the color matrix of Vertisols varies, hue range from 2.5Y to 10YR, color value varies from 2 to 6, and chroma range from 0 to 4. Clay mineral composition of Vertisols is dominated by smectite. Other clay minerals founded in the Vertisols are kaolinite, illite and vermiculite. The mineralogy composition of sand fraction is varies, some of them rich in weatherable minerals like andesine, amfibole, orthoclase, sanidin and the others are dominated by resistant minerals such as quartz and opaque. The mineralogical composition of Vertisols dependent on their parent material. The dominant cations in Vertisols are Ca++ and Mg++. Vertisols from volcanic materials is dominated by Ca++ and followed by Mg++ cations, Vertisols from limestone is dominated by Ca++, while Vertisols from peridotite is dominated by Mg++. All of the Vertisols studied have a high cation exchange capacity with pH’s range from 5.5 to 7.4. In using Vertisols for food plantation, should be consider the high content of Ca++, Mg++ and the water management. The soils should be atleast always in moist condition, otherwise soils become very hard and cracks when dry.
17
Taylor, K. G. "Berthierine from the non-marine Wealden (Early Cretaceous) sediments of south-east England." Clay Minerals 25, no. 3 (September 1990): 391–99. http://dx.doi.org/10.1180/claymin.1990.025.3.13.
Full textAbstract:
AbstractA thin (15–20 cm) Fe-rich intraformational conglomerate in the fresh- to brackish-water Early Cretaceous succession of south-east England contains pisoids and pseudo-ooids of a green clay mineral which has been identified as berthierine. The pisoids (up to 0·5 cm in size) are concentrically laminated, have complex structure, and are frequently nucleated around a sandstone fragment. They show evidence of weathering due to a change in their environment after formation. The ooids have well to moderately well developed concentric lamination, are very often multi-nucleated and do not always completely cover the nucleus. They suggest formation as a result of mineral precipitation as opposed to agitation and accretion. The climate and environment during the Wealden were suited to the formation of Fe-rich soils and it is likely that the pisoids and ooids were originally composed of iron oxyhydroxide and kaolinite, having formed in soil in the Weald Basin. They were then eroded and deposited in the base of a large scour structure as part of the conglomerate. On burial, and the attainment of low Eh conditions, berthierine formed by diagenetic transformation of the pre-existing minerals.
18
Delvaux, B., A. J. Herbillon, L. Vielvoye, and M. M. Mestdagh. "Surface properties and clay mineralogy of hydrated halloysitic soil clays. II: Evidence for the presence of halloysite/smectite (H/Sm) mixed-layer clays." Clay Minerals 25, no. 2 (June 1990): 141–60. http://dx.doi.org/10.1180/claymin.1990.025.2.02.
Full textAbstract:
AbstractSix clays from volcanic ash soils at different stages of weathering differ in their relative halloysite content with respect to kaolinite and several surface properties, namely CEC, and exchange selectivity for K+. These three parameters are related to each other in that they all decrease with increasing soil weathering stage. XRD data show that the hydrated 1:1 layer-silicates in these clays combine with smectite to form interstratified H/Sm clay minerals. In these mixed-layers, the content and layer charge of smectitic units decrease as the relative halloysite content in the clay decreases. These clays thus depict a weathering sequence that is parallel to the weathering sequence of the soils from which they originate. It is also shown that the smectites in the H/Sm minerals have the distinctive composition and ESR spectrum of Fe-rich 2:1 clay minerals belonging to the beidellite-nontronite series. The information obtained explains why these clays have high CEC and distinct affinities for K+. It is hoped that this study will help to clarify the controversy concerning the CEC and related surface properties attributed to hydrated halloysite.
19
Bravard, S., and D. Righi. "Characteristics of clays in an Oxisol-Spodosol toposequence in Amazonia (Brazil)." Clay Minerals 23, no. 3 (September 1988): 279–89. http://dx.doi.org/10.1180/claymin.1988.023.3.05.
Full textAbstract:
AbstractThe clay fraction of soils from a toposequence developed on a sandy clay Tertiary sediment in the Brazilian Amazonia was studied. Clayey Acrorthox located at the upper part of the sequence have transformed progressively into sandy Tropohumods down the slope. Along the slope important chemical and mineralogical changes linked to modifications in the weathering conditions were observed. In the Acrorthox the hydrolysis process largely prevails and the clay fraction is composed mainly of Fe-rich kaolinite. Fe and Al amorphous compounds become increasingly abundant along the slope. In the Spodosols, hydrolysis and acidocomplexolysis processes have both been effective, and the clay fractions contain not only more gibbsite, but also amorphous materials which are particularly abundant in the Bh horizons.
20
Huggett, J. M., A. S. Gale, and N. Clauer. "The nature and origin of non-marine 10 Å clay from the Late Eocene and Early Oligocene of the Isle of Wight (Hampshire Basin), UK." Clay Minerals 36, no. 3 (September 2001): 447–64. http://dx.doi.org/10.1180/000985501750539526.
Full textAbstract:
AbstractVariegated palaeosols, which formed from weathering of clays, silts and brackish to freshwater limestones, are present in the Late Eocene–Early Oligocene Solent Group of the Hampshire Basin, southern UK. The composition and origin of the clay in three segments of the lower part of the Solent Group have been investigated by X-ray diffraction, microprobe analysis, inductively coupled plasma-mas spectrometry, K/Ar dating, high resolution scanning electron microscopy, analytical transmission electron microscopy and wet chemistry. The detrital clay mineral suite is dominated by illite and smectite with minor kaolinite and chlorite. Seasonal wetting and drying in gley soils has resulted in replacement of smectite by Fe-rich, or illite-rich illitesmectite. Illite has also formed with gypsum and calcite in ephemeral hypersaline alkaline lakes that periodically dried out. This illite may have precipitated directly from solution. X-ray diffraction data and probe analyses indicate that the neoformed illite is Fe-rich. The K and Fe for the illitization are thought to be derived from weathered glauconite reworked from the underlying Bracklesham Group and Barton Beds.
21
Bishop, J. L., M. D. Lane, M. D. Dyar, and A. J. Brown. "Reflectance and emission spectroscopy study of four groups of phyllosilicates: smectites, kaolinite-serpentines, chlorites and micas." Clay Minerals 43, no. 1 (March 2008): 35–54. http://dx.doi.org/10.1180/claymin.2008.043.1.03.
Full textAbstract:
AbstractCoordinated visible/near-infrared reflectance/mid-infrared reflectance and emissivity spectra of four groups of phyllosilicates were undertaken to provide insights into the differences within and among groups of smectites, kaolinite-serpentines, chlorites and micas. Identification and characterization of phyllosilicates via remote sensing on Earth and Mars can be achieved using the OH combination bands in the 2.2–2.5 μm region and the tetrahedral SiO4 vibrations from ~8.8–12 μm (~1140–830 cm–1) and ~20–25 μm (500–400 cm–1). The sharp and well resolved OH combination bands in the 2.2–2.5 μm region provide unique fingerprints for specific minerals. Al-rich phyllosilicates exhibit OH combination bands near 2.2 μm, while these bands are observed near 2.29–2.31, 2.33–2.34 μm and near 2.35–2.37 μm for Fe3+-rich, Mg-rich and Fe2+-rich phyllosilicates, respectively. When a tetrahedral substitution of Al or Fe3+ for Si occurs, the position of the Si(Al,Fe)O4 stretching mode absorption shifts. Depending on the size of the cation, the Si(Al,Fe)O4 bending mode near 500 cm–1 is split into multiple bands that may be distinguished via hyperspectral remote sensing techniques. The tetrahedral SiO4 vibrations are also influenced by the octahedral cations, such that Al-rich, Fe-rich and Mg-rich phyllosilicates can be discriminated in reflectance and emissivity spectra based on diagnostic positions of the stretching and bending bands. Differences among formation conditions for these four groups of phyllosilicates are also discussed. Hyperspectral remote sensing can be used to identify specific phyllosilicates using electronic and vibrational features and thus provide constraints on the chemistry and formation conditions of soils.
22
Bentz, Jennifer L., and Ronald C. Peterson. "Authigenic Phyllosilicates in Sand Layers from the Mudflats of Saline Lakes in the Northern Great Prairies, Saskatchewan." Canadian Mineralogist 60, no. 1 (December 6, 2021): 101–20. http://dx.doi.org/10.3749/canmin.1900065.
Full textAbstract:
ABSTRACT The mudflats of saline lakes are amenable to authigenic clay formation due to the high ionic strength of the solutions driven by evaporative concentration and due to the fluctuating wet/dry cycles. However, the mudflats of saline lakes have received relatively little study given the challenges in sampling unstable sediments coupled with post-depositional alterations that make direct relationships to the climate difficult. In an effort to gain a better understanding of the authigenic phyllosilicates present, the mudflats of 17 sulfate-rich saline lake basins across southern Saskatchewan were sampled. The <2 μm fraction was separated from the sediments and analyzed utilizing X-ray diffraction (XRD), scanning electron microscopy, bulk chemical analysis via digestion and inductively coupled optical emission spectroscopy, and visible and near-infrared reflectance spectroscopy. The mudflat sediments were characterized as highly variable and were classified based on particle size into sediment classes A (clay-rich), B (unsorted till), and C (sand). Despite the high variability in sorting and thickness of the sedimentary layers, the phyllosilicates were distinctive within each class independent of the basin. Phyllosilicates in sediment class A were characterized by well-crystalline dioctahedral (Al) clays similar to the surrounding soils with smectite > illite > kaolinite > chlorite. Phyllosilicates from sediment class B displayed highly variable characteristics ranging between classes A and C. Clays from sediment class C were dominated by illite with decreasing proportions of smectite, kaolinite, and chlorite. The illite in the sand lenses was poorly formed, with broad reflections in the XRD patterns indicative of small crystallite size or high disorder, which is consistent with an authigenic nature. The clays in class C were rich in iron (Fe) and magnesium (Mg) and displayed lath-like morphologies common with authigenic illite forming in sandy porous sediments. The sand lenses of mudflats represent viable targets for finding authigenic clay minerals in detrital-rich sediments to use in understanding past climates on Earth and Mars.
23
Hewson, RD, and GR Taylor. "An investigation of the geological and geomorphological features of Fowlers Gap using thermal infrared, radar and airborne geophysical remote sensing techniques." Rangeland Journal 22, no. 1 (2000): 105. http://dx.doi.org/10.1071/rj0000105.
Full textAbstract:
This study summarises the application of several remote sensing techniques to investigate various components of a land surface in the semi-arid environment of Fowlers Gap. These remote sensing techniques included NASA's Thermal Infrared Multispectral Scanner (TIMS) and CSIRO's Mid-Infrared Airborne CO, Laser Spectrometer (MIRACO,LAS), NASA's AIRSAR radar and geophysical airborne radiometrics. Linear spectral unmixing of extracted emissivities from the TIMS data produced four endmembers: quartz, clay minerals, dry vegetation (cellulose) in fine soils, and green vegetation/moisture. MIRAC0,LAS data identified spectral signatures similar to the spectra of endmembers derived from TIMS data. The sensitivity of both thermal infrared remote sensing techniques to the quartzklay contents and textures of the soils and sediments was confirmed by detailed laboratory spectral measurements. Surface roughness information from AIRSAR's band C radar backscatter assisted the discrimination of alluvial and colluvial quartz and clay-rich deposits from the outcropping geological units. In particular the C band AIRSAR radar discriminated the coarse grained sandstone and quartzite scree within the colluvial pediments, from the finer grained quartz-rich 'radar smooth' alluvium in the scalds. Airborne radiometrics were also found useful for further discriminating potassium and thorium- bearing phyllosilicate/clay minerals, within shales and ghyllites, from the kaolinite and montmorillonite- rich alluvium. This study found that TIMS data could identify some of the geomorphological features at Fowlers Gap, such as colluvial pediments, depositional scalds and gilgai landforms, that characterise some of the land systems in the Lowlands and Plains relief class of the Fowlers Gap land system classification. Thermal infrared remote sensing techniques also proved capable of discriminating areas of cellulose-rich dry vegetation and fine grained soils within the Plains relief class. The sensitivity of AIRSAR radar for topographic relief and surface roughness suggests that it is useful for distinguishing land systems in the Ranges relief class. Radiometrics appeared useful for land system definition when outcropping argillaceous units and alluvium assisted their classification. Key words: remote sensing, Fowlers Gap, thermal infrared, land system, spectral unmixing
24
Beyer, Steve R., Kurt Kyser, Tom G. Kotzer, Kevin Ansdell, and David Quirt. "Exploration geochemistry of surficial media over the high-grade McArthur River uranium deposit, Saskatchewan, Canada." Canadian Mineralogist 59, no. 5 (September 1, 2021): 913–45. http://dx.doi.org/10.3749/canmin.2000081.
Full textAbstract:
ABSTRACT An orientation survey using surficial media was performed over the high-grade McArthur River unconformity-related U deposit (Saskatchewan, Canada) to test whether or not secondary dispersion of elements related to the ore body or alteration zone can be detected at the surface more than 500 m above the deposit. Organic-rich Ah-horizon soils, Fe-rich B-horizon soils, C-horizon soils, tree cores of Jack pine (Pinus banksiana), and glacially dispersed boulders of Manitou Falls Formation sandstone that host the U deposit were collected in four sampling grids near the mine site. Two of the grids overlaid the trace of the P2 fault that hosts the deposit and extends nearly to the surface, one grid overlaid both the P2 fault and one of the high-grade ore bodies (Zone 4), and one grid was located 2.5 km away from the ore body surface trace in the barren hanging wall of the P2 fault. The grid overlying the Zone 4 ore body had the highest proportion of samples with elevated U and low 207Pb/206Pb ratios, the latter indicative of radiogenic Pb from a high-U source, measured in two size fractions of Ah-horizon soils using Na pyrophosphate leach, pine tree cores using total digestion, and sandstone boulders using 2% HNO3 leach. A handful of pathfinder elements, such as As, Co, Ni, and Pb, are variably associated with the U and radiogenic Pb. Sandstone boulders with an assemblage of dravite + kaolinite ± illite, determined using shortwave infrared (SWIR) spectroscopy and matching the alteration mineralogy in the Manitou Falls Formation above the U deposit, were prevalent in the grid above the Zone 4 ore body and in the adjacent grid in the direction of glacial dispersion. A coarse fraction of the B-horizon soils, leached with 5% HNO3, highlighted the grid above the Zone 4 ore body to a lesser extent, whereas HNO3 leaches and aqua regia digests of C-horizon soil separates did not highlight the P2 fault or ore body trace due to influence by parent till mineralogy. Results of environmental monitoring at the mine site, which was active at the time of sampling, suggest that dust containing U, Pb, and radionuclides from waste rock piles and a ventilation shaft could influence A-horizon soil geochemistry near the mine site, and that U and radiogenic Pb anomalies in B- and C-horizon soils near the water table are close to a treated mine effluent discharge point. However, older trees that record elevated U and radiogenic Pb in annual rings that pre-date mining activity, and alteration mineralogy and geochemistry of boulders that are less susceptible to the influences of mining activity, add confidence that the geochemical anomaly in diverse surficial media above the Zone 4 ore body represents secondary dispersion from the underlying U deposit.
25
Luther, S. M., L. Poulsen, M. J. Dudas, and P. M. Rutherford. "Fluoride sorption and mineral stability in an Alberta soil interacting with phosphogypsum leachate." Canadian Journal of Soil Science 76, no. 1 (February 1, 1996): 83–91. http://dx.doi.org/10.4141/cjss96-012.
Full textAbstract:
A by-product of phosphate fertilizer production is phosphogypsum (PG). Relatively high F concentrations occur in the solid phase and in the highly acidic process water (PW) that initially fills its pores. The present research addresses the fate of F and the effects on mineral stability as phosphogypsum leachate (PGL) interacts with calcareous (Ck) soil and non-calcareous (Bt) soil. In a sequential batch equilibration, soils were exposed to fresh PGL during 30 d-long extractions. Major ions, pH and electrical conductivity (EC) were monitored. At 28 d, F concentration decreased from 31 mg L−1 in the PGL to 11 mg L−1 in the Bt-PGL mixture and 22 mg L−1 in the Ck-PGL mixture. Saturation indices (SIs) for fluorite ranged from 2.1 to −3.6. Extracts were closer to saturation with fluorite than with the other F minerals studied. Using alternative geochemical constants, fluorapatite was predicted to be stable in Bt-PGL extracts. The day 28 Bt-PGL extract was also near equilibrium with alunite, basaluminite, jurbanite, gypsum, amorphous silica, and quartz. Of the phyllosilicates in the soil-PGL mixtures at day 28, only kaolinite was predicted to be stable in only the Bt-PGL mixture. The potential for clay mineral instability and accelerated dissolution in F-rich PGL needs to be considered m the design of PG repositories. Key words: Fluoride, phosphogypsum, waste management, leachates, geochemical modeling, mineral stability
26
Schaefer, C. E. G. R., J. D. Fabris, and J. C. Ker. "Minerals in the clay fraction of Brazilian Latosols (Oxisols): a review." Clay Minerals 43, no. 1 (March 2008): 137–54. http://dx.doi.org/10.1180/claymin.2008.043.1.11.
Full textAbstract:
AbstractThis review focuses on the clay mineralogy of the most important Brazilian soils: the Latosols, which cover >60% of the country by area, and occur in association with other soils. They are typically deep, highly-weathered soils, dominated by low-activity 1:1 clay minerals and Fe and Al oxyhydroxides, with varying proportions of these minerals, depending on parent material and weathering intensity. They are usually of low fertility, although eutric types also occur. Latosols are generally correlated with Oxisols (American soil taxonomy) and Ferralsols (WRB system). Clay mineralogy is typically monotonous: kaolinite, gibbsite, hematite, goethite, maghemite and Ti minerals (mainly ilmenite and anatase) are the prominent mineral phases in the clay fraction. Some Latosols developing on basalt from southern Brazil contain significant amounts of hydroxyl-interlayed vermiculite. Among the pedogenic oxides the most frequent are goethite (α-FeOOH), indicated by yellowish colours (2.5Y–10YR; in the absence of hematite), and hematite (α-Fe2O3), which imbues reddish colors (2.5YR–5R), even when present in very minor amounts. Maghemite (γ-Fe2O3) is less frequent; it imparts a reddish-brown colour (5YR–2.5YR) and magnetic properties. Both goethite and hematite show Al-substitution, with a greater relative proportion in soil goethites. Hence, in similar drainage conditions, goethite is less prone to dissolution than hematite. Most reddish Latosols also contain maghemite, due to partial or complete oxidation of magnetite, which generally occurs naturally or is fire-induced. Magnetite and/or maghemite are associated with trace elements which are important in plant nutrition, such as Cu, Zn and Co. The contents of gibbsite in Latosols are extremely variable, from a complete absence in brown Latosols, to 54% in red Latosols from mafic rocks. Relatively large amounts of gibbsite are found in the clay fraction of these soils and this mineral is important in P sorption in deeply weathered Latosols in association with goethite and hematite. Even though most Latosols are dystrophic, some are eutrophic, revealing an unusually large base saturation in areas under ustic regimes where the parent material is particularly rich in bases, such as basalts. This eutrophic nature is attributed to the protecting role of micro-aggregates in ferric red Latosols, which retard baseleaching from the inner aggregate. At the other extreme, some Brazilian Latosols are acric and positively-charged in sub-surface horizons, as revealed by the relationship pH KCl > pH H2O. These acric Latosols are the result of long-term weathering and intensive leaching, during which pH tends to increase to values close to the zero point charge of Fe and Al oxides (between 6 and 7), greatly increasing P adsorption, which is mainly attributed to gibbsite, goethite and hematite. Soil kaolinites in Brazilian Latosols are mostly of low crystallinity, with Hughes and Brown indexes of between 6 and 15. In this review we have discussed the role of these clay-fraction minerals in soil genesis and fertility, highlighting the marked role of inheritance from deeply-weathered parent material. Latosols typically retain large amounts of Fe oxides, some of which are magnetic, with spontaneous magnetization >1 J T–1 kg–1. In this regard, reddish Latosols developed from mafic rocks are the most representative magnetic soils, and cover as much as 3.9% of Brazil. An overview of magnetic soils on four representative examples of mafic lithologies is presented, together with some aspects of their Fe-oxide mineralogy and related field and laboratory technqiues.
27
Rodriguez-Navarro, Carlos, Fulvio di Lorenzo, and Kerstin Elert. "Mineralogy and physicochemical features of Saharan dust wet deposited in the Iberian Peninsula during an extreme red rain event." Atmospheric Chemistry and Physics 18, no. 13 (July 16, 2018): 10089–122. http://dx.doi.org/10.5194/acp-18-10089-2018.
Full textAbstract:
Abstract. The mineralogy and physicochemical features of Saharan dust particles help to identify source areas and determine their biogeochemical, radiative, and health effects, but their characterization is challenging. Using a multianalytical approach, here we characterized with unprecedented level of detail the mineralogy and physicochemical properties of Saharan dust particles massively wet deposited ( ∼ 18 g m−2) following an extreme red rain event triggered by a northern African cyclone that affected the southern Iberian Peninsula during 21–23 February 2017. Abundant palygorskite and illite, and relatively high carbonate contents, well-known northern and north-western Saharan dust indicators, along with low chlorite content and significant amounts of smectites and kaolinite, whose abundance increases southwards in the western Sahara, complemented by satellite imagery and back/forward trajectories, show that the most probable dust source areas were (i) southern/central Algeria, northern Mali, and northwestern Niger, and (ii) northern Algeria, southern Tunisia, and northwestern Libya. Scanning and transmission electron microscopy analyses, including Z-contrast high angle annular dark field (HAADF) imaging and analytical electron microscopy (AEM), show that clay minerals include abundant structural Fe (55 % of the total Fe) and typically form nanogranular aggregates covered or interspersed with amorphous/poorly crystalline iron oxyhydroxide nanoparticles (ferrihydrite), which account for ∼ 18 % of the free Fe, the rest being goethite and hematite. These nanogranular aggregates tend to form rims lining large silicate and carbonate particles. Such internally mixed iron-containing phases are the main contributors to the observed absorption of solar and thermal radiation, and along with the abundant coarse/giant particles ( > 10 µm) strongly affect the dust direct radiative forcing. The lack of secondary sulfates in aggregates of unaltered calcite internally mixed with clays/iron-rich nanoparticles shows that iron-rich nanoparticles did not form via atmospheric (acid) processing but were already present in the dust source soils. Such iron-rich nanoparticles, in addition to iron-containing clay (nano)particles, are the source of the ∼ 20 % soluble (bioavailable) iron in the studied desert dust. The dust particles are a potential health hazard, specifically the abundant and potentially carcinogenic iron-containing palygorskite fibers. Ultimately, we show that different source areas are activated over large desert extensions, and large quantities of complex dust mixtures are transported thousands of kilometers and wet-deposited during such extreme events, which dwarf any other Saharan dust event affecting southwestern Europe. The past, present, and future trends, as well as impacts, of such extreme events must be taken into account when evaluating and modeling the manifold effects of the desert dust cycle.
28
Bentabol, Maria, Maria Dolores Ruiz Cruz, Francisco Javier Huertas, and Jose Linares. "Hydrothermal synthesis of Mg-rich and Mg-Ni-rich kaolinite." Clays and Clay Minerals 54, no. 6 (December 1, 2006): 667–77. http://dx.doi.org/10.1346/ccmn.2006.0540602.
Full text
29
Samuel, Zerihun Asmelash, Tilahun Seyoum Workneh, Cristina Trois, and Fekadu Fufa Feyessa. "Removal of Cr(VI) from contaminated water using soil rich in kaolinite - ferrinatrite, coffee husk ash and soil rich in kaolinite – goethite: characteristic, isotherm and kinetic study." DESALINATION AND WATER TREATMENT 105 (2018): 250–54. http://dx.doi.org/10.5004/dwt.2018.21785.
Full text
30
Delvaux, B., M. M. Mestdagh, L. Vielvoye, and A. J. Herbillon. "XRD, IR and ESR study of experimental alteration of Al-nontronite into mixed-layer kaolinite/smectite." Clay Minerals 24, no. 4 (December 1989): 617–30. http://dx.doi.org/10.1180/claymin.1989.024.4.05.
Full textAbstract:
AbstractThe formation of kaolinite from Al hydroxy interlayered Garfield nontronite has been carried out at 225°C in hydrothermal conditions. The kaolinitization process, which proceeds through mixed-layer kaolinite/smectite intermediates, was followed by XRD, IR and ESR spectroscopy, chemical analysis and charge properties. The smectite content of the clay products decreases regularly with the duration of the hydrothermal treatment. The CEC and the structural Fe content of the deferrated products show a similar trend. IR features specific to nontronite disappear and are barely detectable as the smectite content of the mixed-layer clay falls below 30%. In contrast, the ESR spectrum of nontronite is characterized by a broad g2 signal that remains even after prolonged hydrothermal treatment. The calibration of the g2 ESR signal, due to Fe-smectite, shows that the synthetic kaolinites have low Fe contents (∼ 1% Fe2O3) indicating that the kaolinitization process involves destruction of the 2:1 layers and the subsequent neoformation of kaolinite and Fe oxides. As illustrated by the study of deferrated soil clay samples, representing a weathering sequence Fe-smectite → kaolinite + Fe oxides, ESR spectroscopy proved to be a powerful Fe probe for detecting Fe-rich smectite in kaolinite/Fe-smectite mixed-layer clays.
31
Kemp, Simon J., Michael A. Ellis, Ian Mounteney, and Sev Kender. "Palaeoclimatic implications of high-resolution clay mineral assemblages preceding and across the onset of the Palaeocene–Eocene Thermal Maximum, North Sea Basin." Clay Minerals 51, no. 5 (December 2016): 793–813. http://dx.doi.org/10.1180/claymin.2016.051.5.08.
Full textAbstract:
AbstractUnderstanding the composition of clay-rich sediments and their transportation into proximal marine basins allows us to better decipher hydroclimatic changes before and within the Palaeocene–Eocene Thermal Maximum (PETM). Only a limited number of such studies exists from the North Sea Basin, which was proximal to the volcanic activity and early rifting hypothesized to have triggered the PETM. The present study examines core material from well 22/10a-4, UK North Sea, as it exhibits an exceptionally expanded and almost stratigraphically complete fine-grained sedimentary sequence suitable for high-resolution analysis.QuantitativeNewmod-for-Windows™-modelled clay mineral assemblages, rather than traditional semi-quantitative estimates, are dominated by smectite-rich, interlayered illite-smectite that probably developed from volcanogenic deposits on continental landmasses. Soil development before the PETM is consistent with the existence of a seasonal tropical climate with a prolonged dry season. A striking rise and fall of kaolinite content within the PETM onset, prior to the principal carbon-isotope excursion, is reported here. This variation is interpreted as a signal of an enhanced hydrologic cycle producing an increase in erosionally derived kaolinite, followed by a dampening of this detrital source as sea-levels rose. Global variations in PETM kaolinite concentrations are consistent with a latitudinal shift in patterns of precipitation in models of global warming.
32
Tobo, Y., P. J. DeMott, T. C. J. Hill, A. J. Prenni, N. G. Swoboda-Colberg, G. D. Franc, and S. M. Kreidenweis. "Organic matter matters for ice nuclei of agricultural soil origin." Atmospheric Chemistry and Physics Discussions 14, no. 7 (April 11, 2014): 9705–28. http://dx.doi.org/10.5194/acpd-14-9705-2014.
Full textAbstract:
Abstract. Heterogeneous ice nucleation is a~crucial process for forming ice-containing clouds and subsequent ice-induced precipitation. The importance for ice nucleation of airborne desert soil dusts composed predominantly of minerals is relatively well understood. On the other hand, the potential influence of agricultural soil dusts on ice nucleation has been poorly recognized, despite recent estimates that they may account for up to ∼25% of the global atmospheric dust load. We have conducted freezing experiments with various dusts, including agricultural soil dusts derived from the largest dust source region in North America. Here we show evidence for the significant role of soil organic matter (SOM) in particles acting as ice nuclei (IN) under mixed-phase cloud conditions. We find that the ice nucleating ability of the agricultural soil dusts is similar to that of desert soil dusts, but is reduced to almost the same level as that of clay minerals (e.g., kaolinite) after either H2O2 digestion or dry heating to 300 °C. In addition, based on chemical composition analysis, we show that organic-rich particles are more important than mineral particles for the ice nucleating ability of the agricultural soil dusts at temperatures warmer than about −36 °C. Finally, we suggest that such organic-rich particles of agricultural origin (namely, SOM particles) may contribute significantly to the ubiquity of organic-rich IN in the global atmosphere.
33
Lottermoser, Bernd G. "Natural enrichment of topsoils with chromium and other heavy metals, Port Macquarie, New South Wales, Australia." Soil Research 35, no. 5 (1997): 1165. http://dx.doi.org/10.1071/s96108.
Full textAbstract:
Total heavy metal concentrations [cobalt (Co), chromium (Cr), copper(Cu), iron (Fe), mangnese (Mn), nickel (Ni), lead (Pb), and zinc (Zn)]were determined in surface soil samples from Port Macquarie, New South Wales,Australia. Composite topsoil samples (0–10 cm depth) had mean values(per kg) of 13 mg Co, 1020 mg Cr, 59 mg Cu, 136·7 g Fe, 719 mg Mn, 149mg Ni, 20 mg Pb, and 47 mg Zn. The topsoils were generally characterised by alow pH (3·8–5·2) and a mineralogy dominated by haematite,magnetite, quartz, and kaolinite. Chromium was predominantly present in thetopsoils as Cr3+ in microcrystalline chromite(FeCr2O4) and, to a lesser degree,in kaolinite and haematite. Differences in Cr soil concentrations with depthwere due to variations in the relative abundance of the various soilcomponents, rather than Cr3+ mobility within the soilprofile. The elevated heavy metal concentrations are the result of soildevelopment over metal-rich bedrock (serpentinite matrix melange) andassociated enrichment of relatively immobile elements (Cr, Fe, Ni) in theresidual soil profile. The ANZECC and NH&MRC (Australian and New ZealandEnvironment and Conservation Council and National Health & MedicalResearch Council) environmental investigation limits were exceeded for100% of the sample sites for Cr, 47% for Cu, 61% for Mn,and 58% for Ni.
34
Curry, B. Brandon. "Absence of Altonian Glaciation in Illinois." Quaternary Research 31, no. 1 (January 1989): 1–13. http://dx.doi.org/10.1016/0033-5894(89)90081-1.
Full textAbstract:
AbstractIllinois was free of glacier ice from about 130,000 to 25,000 yr B.P. Deposits of this time interval in northeastern Illinois, represented by core samples from test-hole ISGS S-30, are composed of leached, nonglacigenic, stratified, or pedoturbated silty sediments that typically are organic-rich and pedogenically modified. These deposits overlie the Sangamon Soil, which is identified by its stratigraphic position, soil morphology, and distinct alteration products in the clay-mineral fraction, including a variably swelling vermiculite-like phase and a randomly interstratified kaolinite/10 Å phase. The regional extent of these deposits suggests that if Altonian ice existed in the Lake Michigan basin, it did not extend westward beyond the cuesta of Silurian dolomite that rims the southwestern shore of Lake Michigan.
35
Tineo, David Eric, Marcos Alejandro Comerio, Luis Hernán Vigiani, Germán Sebastián Kürten Moreno, and Daniel Gustavo Poiré. "Tectonic and paleoclimatic controls on the composition of inland wetland deposits, Chaco foreland basin, Central Andes." Journal of Sedimentary Research 92, no. 2 (February 8, 2022): 112–33. http://dx.doi.org/10.2110/jsr.2021.033.
Full textAbstract:
ABSTRACT In recent decades, the growing interest in wetlands highlights the fundamental role of these complex ecosystems. Integrated sedimentological and geochemical studies that refer to wetlands appear more frequently in the literature, since such approaches provide a window into understanding the functions they have played through geologic time. The Miocene Yecua Formation (Chaco foreland basin, Central Andes, Bolivia) presents sedimentological features that show how siliciclastic, chemical, and biological processes lead to lithofacies and compositional features that are distinctive of wetlands related to back-bulge settings. The succession is composed of shallowing-upward parasequences with various compositional characteristics controlled by tectonic and climatic factors. Data integration obtained from paleocurrents, petrography, and clay mineralogy show the influence of the Central Andes fold and thrust belt located to the west of the basin as a principal source area. The high compositional maturity of sandstones reflects the tectonic control as the main allocyclic variable associated with reworking of already mature sediment sources and transport factors in relation to the distal position of the basin (back-bulge), combined with climatic and paleoenvironmental conditions. XRD and SEM-EDS analyses show that illitic clays represent the main mineral phase of the clay assemblages, and have a detrital origin related to physical weathering processes in the source area. Al-rich smectitic minerals have an authigenic origin and were likely formed by alteration of volcanic detritus as well as from precursor minerals such as illite and feldspars. Kaolinite is determined to be detrital and likely derived from the erosion of floodplains with soil development. Throughout the parasequences, illite–smectite–kaolinite minerals are arranged in different proportions, showing a general vertical trend (from base to top) in which the illitic clays decrease at the expense of the increase in Al-rich smectite and kaolinite. The increase in smectite is accompanied by mixed siliciclastic–carbonate sedimentation, which points to a reduction in the clastic contribution linked to drier conditions. This vertical compositional arrangement reveals a paleoclimatic control, influenced by middle-term wet and dry periods. This work demonstrates that source-rock composition and transport distance (tectonic processes) are the key factors influencing quartz-rich sandstones and illite-rich clay mineral suites in distal positions of continental foreland basins. The long-term tropical to subtropical climate favored the development of inland wetlands and played a secondary role in the final composition of these depositional systems.
36
Środoń, J., J. Szulc, A. Anczkiewicz, K. Jewuła, M. Banaś, and L. Marynowski. "Weathering, sedimentary and diagenetic controls of mineral and geochemical characteristics of the vertebrate-bearing Silesian Keuper." Clay Minerals 49, no. 4 (September 2014): 569–94. http://dx.doi.org/10.1180/claymin.2014.049.4.07.
Full textAbstract:
AbstractMudstones and claystones from the southern marginal area of the European Upper Triassic, midcontinental Keuper basin (Silesia, southern Poland) were investigated using XRD, organic and inorganic geochemistry, SEM, K-Ar of illite-smectite, AFT, and stable isotopes of O and C in carbonates in order to unravel the consequent phases of the geological history of these rocks, known for abundant fossils of land vertebrates, and in particular to evaluate the diagenetic overprint on the mineral composition. The detected and quantified mineral assemblage consists of quartz, calcite, dolomite, Ca-dolomite, illite, mixed-layer illite-smectite, and kaolinite as major components, plus feldspars, hematite, pyrite, chlorite, anatase, siderite, goethite as minor components. Palygorskite, gypsum, jarosite and apatite were identified in places.The K-Ar dates document a post-sedimentary thermal event, 164 Ma or younger, which resulted in partial illitization of smectite and kaolinite. The maximum palaeotemperatures were estimated from illite-smectite as ∼125°C. Apatite fission track data support this conclusion, indicating a 200–160 Ma age range of the maximum temperatures close to 120°C, followed by a prolonged period of elevated temperatures. These conclusions agree well with the available data on the Mesozoic thermal event, which yielded Pb-Zn deposits in the area. Organic maturity indicators suggest the maximum palaeotemperatures <110°C.Palygorskite was identified as authigenic by crystal morphology (TEM), and calcite by its accumulation in soil layers and by its isotopic composition evolving with time, in accordance with the sedimentary and/or climatic changes. Dolomite isotopic composition indicates more saline (concentrated) waters. Palygorskite signals a rapid local change of sedimentary conditions, correlated with algal blooms. This assemblage of authigenic minerals indicates an arid climate and the location at the transition from a distal alluvial fan to mudflat.Fe-rich smectite, kaolinite, and hematite were products of chemical weathering on the surrounding lands and are therefore mostly detrital components of the investigated rocks. Kaolinite crystal morphology and ordering indicates a short transport distance. Hematite also crystallizedin situ, in the soil horizons. A large variation in kaolinite/2:1 minerals ratio reflects hydraulic sorting, except of the Rhaetian, where it probably signals a climatic change, i.e. a shift in the weathering pattern towards kaolinite, correlated with the disappearance of hematite. Quartz, 2M1illite, and minor feldspars and Mg-chlorite were interpreted as detrital minerals. The documented sedimentation pattern indicates that in more central parts of the Keuper playa system, where an intense authigenesis of the trioctahedral clays (chlorite, swelling chlorite, corrensite, sepiolite) took place, illite and smectite were the dominant detrital clay minerals.Cr/Nb and Cr/Ti ratios were found as the best chemostratigraphic tools, allowing for the correlation of all investigated profiles. A stable decrease of these ratios up the investigated sedimentary sequence is interpreted as reflecting changes in the provenance pattern from more basic to more acidic rocks.
37
Torres Sánchez, R. M., and E. L. Tavani. "Temperature effects on the point of zero charge and isoelectric point of a red soil rich in kaolinite and iron minerals." Journal of Thermal Analysis 41, no. 5 (May 1994): 1129–39. http://dx.doi.org/10.1007/bf02547202.
Full text
38
Kew, G. A., and R. J. Gilkes. "Properties of regolith beneath lateritic bauxite in the Darling Range of south Western Australia." Soil Research 45, no. 3 (2007): 164. http://dx.doi.org/10.1071/sr06128.
Full textAbstract:
A morphological key has been developed for regolith that is exposed during mining of lateritic bauxite in the Darling Range of south Western Australia. The key distinguishes materials with different mineralogical and chemical properties. Iron oxide cemented (Zh) regolith has a gibbsitic matrix, quartz-rich (Zm) regolith has a gibbsite and kaolin matrix, and clay-rich (Zp) regolith has a kaolin matrix. An Si affinity element map (Si, Hf, Th) and a K affinity element group (K, Ba, Rb) are associated with granitic quartz-rich regolith and an Al/Fe element affinity group (Al, Fe, Ti, P, Ni, Co, Cu, Mn, Zn, Ga, Cr, V) is associated with clay and iron rich regolith. Doleritic regolith is generally associated with the Al/Fe affinity group. Although granite and granitic regolith exhibit similar element affinity groups, the abundance of elements within each is highly variable, which reflects the diversity in composition of granite within the region. The degree of euhedral character of clay-size platy crystals (kaolinite/gibbsite) does not differ for materials distinguished by the key, as both quartz-rich (Zm) and clay-rich (Zp) regolith and both granitic and doleritic saprolite contain subhedral kaolin crystals. The crystal size of platy kaolin (approximately 0.5 µm) is similar for different mine pits and for different regolith materials (Zm and Zp) within mine pits. There is a difference in halloysite tube length (0.52–1.18 µm) between mine pits, which may be related to the presence of weathered mica or to the alteration of halloysite in gibbsite-rich regolith. The internal and external diameters of halloysite tubes (about 0.11 and 0.24 µm) are similar for different mine pits and different regolith types within mine pits. The resin used during thin section preparation contains chlorine, so that determination of chlorine by EMPA provides a measure of the porosity of regolith material. A systematic negative relationship exists between chlorine concentration and total oxide weight % of porous regolith matrix determined by EMPA; both measurements provide an indication of the porosity of the clay matrix in regolith.
39
Wira Etika, Adhe Phoppy, and Rahmat Hasan. "Effect of Mineral and Humic Substances on Tailing Soil Properties and Nutrient Uptake by Pennisetum purpureum Schumach." JOURNAL OF TROPICAL SOILS 20, no. 2 (May 10, 2016): 101. http://dx.doi.org/10.5400/jts.2015.v20i2.101-109.
Full textAbstract:
Tin mining produces a by-product sand tailing from soil leaching with characteristic low pH and total organic carbon, and can be reclaimed by providing a suitable ameliorant. When available in situ, ameliorant materials can be economically used as they are required in large amounts. Fortunately, Bangka Belitung has sample stock of such kaolinite-rich minerals that can be utilized for improving soil chemical properties. Extracted organic materials, such as humic substances, can also be utilized as they influence the complex soil reactions, and promote plant growth. Thus, this study aimed to assess the effects of mineral, humic materials and interaction of both material on soil chemical properties and nutrient uptake of Pennisetum purpureum Schumach. A completely randomized design with 2 factors and 3 replications each was employed. Factor 1 was mineral matter is 0; 420; 840; 1.260 Mg ha-1 while Factor 2 was humic material is 0; 0.46; 0.92; 1.38 kg C ha-1. Air-dried samples of tailing were applied with oil palm compost then mixed evenly with mineral and humic materials. Penissetum purpureum Schumach was planted after 4 weeks incubation, and maintained for another 4 weeks. The results demonstrated that the addition of mineral matter significantly increased soil organic carbon content, total N, exchangeable K, Fe, Mn and boosted nutrient - total Ca, Mg and Mn – uptake of the plant. But the application of humic material increased only soil organic carbon content. The interaction of both materials only lowered soil pH.
40
Blaise, Bertrand. "Clay-Mineral Assemblages from Late Quaternary Deposits on Vancouver Island, Southwestern British Columbia, Canada." Quaternary Research 31, no. 1 (January 1989): 41–56. http://dx.doi.org/10.1016/0033-5894(89)90084-7.
Full textAbstract:
AbstractOn Vancouver Island, the Dashwood Drift, Cowichan Head Formation, Quadra Sand, and Vashon Drift were deposited during late Pleistocene glacial and interstadial periods and show large variations in clay-mineral contents partly related to changing climatic conditions. Glacial deposits are characterized by iron-rich chlorite, illite (both well crystallized), and smectite with a morphology reflecting rapid derivation from volcanic rocks. The clay mineralogy of nonglacial deposits is more complex, and is marked by the presence of vermiculite, kaolinite, halloysite, and irregular mixed-layer minerals. Nonglacial clay minerals are poorly preserved and show a higher state of alteration due to pedogenesis. Large variations in nonglacial deposits compared to glacial deposits are also due to secondary factors such as selective sorting, soil and rock source variations, differences in sedimentary environment, and diagenesis. These secondary factors do not seem to obliterate significantly the climatic imprint on the clay minerals. These studies also permit the recognition of glacially reworked sediments, the determination of relationships between two units in the same section, and the establishment of the conditions of clay-mineral formation.
41
Huggett, J. M., and J. Cuadros. "Glauconite formation in lacustrine/palaeosol sediments, Isle of Wight (Hampshire Basin), UK." Clay Minerals 45, no. 1 (March 2010): 35–49. http://dx.doi.org/10.1180/claymin.2010.045.1.35.
Full textAbstract:
AbstractThe clay mineralogy and chemistry of a green lacustrine marl that has been pedogenically modified in the upper part was investigated in order to better understand the formation of low-temperature Fe-rich 10 Å clay. Twelve samples in a vertical sequence have been investigated using X-ray diffraction (XRD), chemical analysis, scanning electron microscopy (SEM) and laser particle size analysis. The clay assemblage has a range of overall illite-smectite (I-S) compositions (64–100%) resulting from several I-S phases that, for the sake of modelling, have been simplified to one to three I-S phases of increasing illitic content. Where the lacustrine marl has been pedogenically modified, the smectite-rich I-S is much reduced in abundance or absent and the 10 Å -rich component is both more abundant and more illitic. These assemblages are a consequence of illitization of detrital I-S in the lake and soil, and dissolution of other clays (kaolinite and chlorite) in the hypersaline lake. Interlayer K, octahedral Fe and octahedral + interlayer Mg increase with intensity of illitization (increase range 0.32–0.63, 0.68–1.67, 0.18–0.24 per O10(OH)2, respectively), first in the increasingly saline lake, and latterly as a result of wetting and drying in a gley soil. In the soil environment, reduction of Fe(III) to Fe(II) resulted in increased layer charge but, as by this stage very few smectite interlayers remained, this did not result in an equivalent increase in illite. Laser particle-size analysis, supported by SEM observation, shows the existence of a bimodal distribution of clay particle size (maxima at 0.2 and 1.5–1.8 μm) in which the finer fraction increases largely in the pedogenically affected samples, probably due to particle break-up caused by seasonal wetting and drying. This ‘dual action’ illitization, first in a hypersaline lake and latterly through wetting and drying, may be responsible for both the intensity of illitization and exceptionally high (for the Solent Group) Fe content of the authigenic illite. The chemical characteristics of the illitic I-S and the illite end-member correspond to glauconite. Hence, this is an example of onshore, non-pelletal glauconite formation.
42
He, Jie, Eduardo Garzanti, Tao Jiang, Marta Barbarano, Alberto Resentini, Entao Liu, Si Chen, Guanzhong Shi, and Hua Wang. "Mineralogy and geochemistry of modern Red River sediments (North Vietnam): Provenance and weathering implications." Journal of Sedimentary Research 92, no. 12 (December 20, 2022): 1169–85. http://dx.doi.org/10.2110/jsr.2022.045.
Full textAbstract:
Abstract This study illustrates the clay mineralogy and sedimentary geochemistry of the Red River and its major tributaries and distributaries in northern Vietnam and shows how these methods can be used to unravel grain size, provenance, hydraulic-sorting, and chemical weathering effects. All sand samples are SiO2-rich and consequently depleted in most chemical elements (but Sn and Pb) relative to the upper continental crust (UCC). The order of element mobility indicated by αAlE values, which estimate the degree of depletion in mobile element E relative to the UCC standard, is Ca ≥ Na > Sr > Mg > Ba ≥ K ≥ Rb. In mud fractions, SiO2 decreases, and other elements consequently increase. The grain size-dependent intrasample chemical variability of fluvial sediments reflects the grain size distribution of detrital minerals, which is strictly controlled in turn by the settling-equivalence principle. The 87Sr/86Sr ratio in Red River sands varies widely between 0.716 and 0.748, and εNd ranges from −8.5 to −13.8. The negative εNd values and high 87Sr/86Sr ratios point at a significant contribution from Precambrian crystalline basement, directly or through recycling of Triassic siliciclastic strata. Clay-mineral assemblages, dominated by illite and smectite with subordinate kaolinite and minor chlorite, suggest largely physical erosion in the upper catchment and stronger weathering in the monsoon-drenched lower catchment. Extremely intense weathering is demonstrated by a Quaternary soil sample from the Red River valley in northernmost Vietnam, which is a pure quartzose sand yielding a tourmaline-dominated heavy-mineral suite and a kaolinite-dominated clay-mineral assemblage. In the humid landscapes of northern Vietnam, no detrital mineral, excepting quartz, muscovite, tourmaline, prismatic sillimanite, anatase, and zircon, can resist even shallow early pedogenesis.
43
Van Cromphaut, C., E. Van Ranst, V. G. De Resende, R. E. Vandenberghe, E. De Grave, and G. Lambiv Dzemua. "Characterization by Mössbauer spectroscopy of Fe phases in highly weathered serpentinitic soil from southern Cameroon." Clay Minerals 43, no. 1 (March 2008): 117–28. http://dx.doi.org/10.1180/claymin.2008.043.1.09.
Full textAbstract:
AbstractWeathered soil material derived from tectonically emplaced serpentinized ultrabasic intrusive rocks of southern Cameroon has received considerable attention from mining companies due to its extractable-metal (i.e. Ni, Co) potential. As these cations can be incorporated into Fe oxides, it was deemed appropriate to study the mineralogical assemblage of a highly weathered serpentinite soil profile from the area. This study focuses on the different Fe-oxide phases, which were investigated using 57Fe Mössbauer spectroscopy, showing goethite and hematite as the dominant Fe oxides throughout the weathering profile. These minerals, in association with gibbsite and kaolinite, indicate an advanced degree of weathering. The clay fraction of the ‘Lower Limonite’ layer, above the saprolite and at a depth of 7 m, is very rich in goethite, whereas hematite and magnetite are almost absent. Above this layer, the hematite content in the fine-earth and clay fractions increases upwards, while the goethite content remains constant. The significant substitution and change in the particle size of the goethite and the poor crystallinity of hematite, as indicated by the hyperfine parameters and XRD, suggest that the upper material evolved under different pedological conditions compared to the deeper layers. The mixed composition of the upper layers (above 7 m), which contain muscovite and a relatively chaotic distribution of trace elements, suggests ancient mica-schist capping and possibly different cycles of erosion and pedimentation.
44
Costa, Marcondes Lima da, Dirse Clara Kern, Alice Helena Eleotério Pinto, and Jorge Raimundo da Trindade Souza. "The ceramic artifacts in archaeological black earth (terra preta) from lower Amazon region, Brazil: mineralogy." Acta Amazonica 34, no. 2 (2004): 165–78. http://dx.doi.org/10.1590/s0044-59672004000200004.
Full textAbstract:
Several archaeological black earth (ABE) sites occur in the Amazon region. They contain fragments of ceramic artifacts, which are very important for the archaeological purpose. In order to improve the archaeological study in the region we carried out a detailed mineralogical and chemical study of the fragments of ceramic artifacts found in the two ABE sites of Cachoeira-Porteira, in the Lower Amazon Region. Their ceramics comprise the following tempers: cauixi, cariapé, sand, sand +feldspars, crushed ceramic and so on and are composed of quartz, clay equivalent material (mainly burned kaolinite), feldspars, hematite, goethite, maghemite, phosphates, anatase, and minerals of Mn and Ba. Cauixi and cariapé, siliceous organic compounds, were found too. The mineralogical composition and the morphology of their grains indicate a saprolite (clayey material rich on quartz) derived from fine-grained felsic igneous rocks or sedimentary rocks as source material for ceramic artifacts, where silica-rich components such cauixi, cariapé and/or sand (feldspar and rock fragments) were intentionally added to them. The high content of (Al,Fe)-phosphates, amorphous to low crystalline, must be product of the contact between the clayey matrix of pottery wall and the hot aqueous solution formed during the daily cooking of animal foods (main source of phosphor). The phosphate crystallization took place during the discharge of the potteries put together with waste of organic material from animal and vegetal origin, and leaving to the formation of the ABE-soil profile.
45
Séa, Frédéric, Pierre Trudel, and Marc G. Tanguay. "Géochimie des horizons d'oxydes ferro-manganésifères noirs enrichis en or dans la latérite de Misséni, au Mali." Canadian Journal of Earth Sciences 31, no. 12 (December 1, 1994): 1791–805. http://dx.doi.org/10.1139/e94-160.
Full textAbstract:
The laterite overlying the Misséni gold occurrence in Mali is characterized by the presence of remarkable black layers of ferro-manganiferous oxides. In an attempt to study the origin of the concentrations in these layers, 56 rock and soil samples were collected from three wells and from a borehole near the occurrence. The bedrock of the area is composed of Lower Proterozoic volcano-sedimentary formations, within which primary gold is associated with copper and iron sulphides disseminated in crushed and silicified zones in andesites and andesitic volcaniclastites. The general profile of the laterite at Misséni, from bottom to top is as follows: (i) saprolite (including the Fe–Mn oxides rich layers), (ii) ferruginous hardpan, (iii) ferruginous cuirasse, and (iv) eluvium. The mineralogical composition of the layers rich in Fe–Mn oxides is dominated by geothite, hematite, psilomelane, and quartz enveloped in a kaolinite matrix. There is a significant increase of the following elements in these layers: (i) trace elements: Au, Cu, Co, Ba, W, Pb, V, Be, As, Sb, Cs, Se, U, and Th; (ii) rare-earth elements: La, Ce, Sm, Yb, Eu, Lu, and Tb. The average gold content measured in these layers of black Fe–Mn oxides is 672 ppb. These gold concentrations are three times higher than the amount of gold found in the saprolite (233 ppb) surrounding these layers and six times superior to the gold content measured in the country rock (109 ppb) hosting the auriferous zone. The gold content of oxide grains derived from the black layers range from 0.25 to 7.7 ppm. The black layers of Fe–Mn oxides of Misséni are probably related to the remnants of an old phreatic surface, above which the oxides of Fe–Mn were deposited as a result of the prevailing oxidation conditions in this environment. The gold would have precipitated synchronously, by reduction from gold thiosulphate and its adsorption on the newly formed oxides. [Journal Translation]
46
Bakker, Eleanor, Fabien Hubert, Michelle M. Wander, and Bruno Lanson. "Soil Development under Continuous Agriculture at the Morrow Plots Experimental Fields from X-ray Diffraction Profile Modelling." Soil Systems 2, no. 3 (August 6, 2018): 46. http://dx.doi.org/10.3390/soilsystems2030046.
Full textAbstract:
Impact of continuous cropping on clay mineralogy was assessed on a collection of unfertilized soil samples from the Morrow Plots experimental fields covering 110 years of long crop rotations. Evolution of mineralogy was quantitatively determined by fitting X-ray diffraction (XRD) patterns from four size fractions (50–2, 2–0.2, 0.2–0.05 and <0.05 µm) of the surface horizon (0–20 cm). The mineralogy of the three clay subfractions (2–0.2 µm, 0.2–0.05 µm and <0.05 µm) consists mainly of coexisting illite-smectite-chlorite whose compositions range from discrete illite (in the 2–0.2 µm subfraction) to discrete smectite (in the <0.05 µm subfraction). Mixed layers of similar compositions were used to fit XRD data from all clay subfractions. With decreasing size fractions, both the size of the coherent scattering domains and the proportion of illite-rich mixed layers decrease, thus accounting for the higher cation exchange measured in the <0.05 µm subfraction compared to other clay subfractions. The analysis of fine clay subfractions (<0.2 µm or lower) provided key information and constraints to a complete and accurate description of the bulk <2 µm fraction. Additional constraints derived from chemical treatments (K-saturation and heating) proved to be especially useful to propose a reliable structure model for these fine clay subfractions because of their weakly modulated diffraction signature. Mineralogy of all subfractions considered is essentially stable over the studied period (1904–2014), with the relative proportion of the different clay layer types (illite, smectite, kaolinite, chlorite) showing no significant evolution in the bulk <2 µm fraction. A century of continuous cropping thus results essentially in an increase of fine clay particles (<0.05 µm) and a decrease of the 0.2–0.05 µm subfraction, indicative of clay mineral dissolution and consistent with observed increase of cation exchange capacity with time. The relative proportion of the bulk <2 µm fraction is nearly constant over the studied period, indicative of minimal export of clay phases.
47
Kadİr, S., M. Eren, T. Külah, N. Önalgİl, M. Cesur, and A. Gürel. "Genesis of Late Miocene-Pliocene lacustrine palygorskite and calcretes from Kırşehir, central Anatolia, Turkey." Clay Minerals 49, no. 3 (June 2014): 473–94. http://dx.doi.org/10.1180/claymin.2014.049.3.09.
Full textAbstract:
AbstractThis paper addresses the mineralogy, geochemistry, and genesis of palygorskite and associated calcretes in the Kırşehir region. In this area, the Quaternary calcretes are present within and/or on lacustrine mudstones of the Kızılırmak Formation (Late Miocene-Pliocene). The calcretes occur in the form of nodules, tubes, fracture-infills, and hard laminated crusts (hardpans). Calcrete samples are predominantly composed of calcite associated with smectite, quartz, feldspar, and minor palygorskite. The lacustrine mudstone samples consist mainly of smectite and palygorskite with minor calcite, quartz, feldspar, illite, kaolinite and amorphous material. Petrographic studies revealed that the calcrete samples are predominantly micrites that were partially converted to microsparites by recrystallization. Scanning and transmission electron microscopy images indicate that palygorskite fibres formed authigenically on and between calcite rhombs in the calcrete samples and at the edges of smectite flakes of host rocks adjacent to the calcretes. The oxygen and hydrogen stable isotope values of the calcite suggest that it precipitated from meteoric water under arid or seasonally arid climatic conditions. Calcite precipitation occurred in the vadose zone, as evidenced by desiccation cracks and vadose pisolites. The enrichment of Rb+Ba±Sr and Light Rare Earth Elements (LREE) relative to Heavy Rare Earth Elements (HREE)with a distinct negative Eu anomaly are responses to the fractionation of volcanogenic feldspar and hornblende under the influence of meteoric water. The palygorskite associated with calcretes was precipitated from alkaline water rich in Si, Al and Fe and low in Mg. The palygorskite precipitation occurred at increased temperatures, characterising the advanced stage of calcrete formation which lowers the Ca content in the soil water. The required chemical elements for palygorskite and calcite were most likely derived from the dissolution of smectitic clays, ignimbrites and carbonate minerals.
48
Ryan, Adrienne L., and Stephen R. Cattle. "Do sand dunes of the lower Lachlan floodplain contain the same dust that produced parna?" Soil Research 44, no. 8 (2006): 769. http://dx.doi.org/10.1071/sr06051.
Full textAbstract:
Æolian dust deposits are known to be widespread in south-eastern Australia, with the dominant model being that of ‘parna’, an aggregated material comprising clay, calcium carbonate, and silt-sized quartz. Despite a general acceptance of the parna model, there is surprisingly little evidence of silt-sized clay aggregates remaining in parna profiles. To investigate a relatively pure æolian dust deposit within the proposed zone of parna distribution, we examined the various phases of 3 source-bordering sand dunes on the lower Lachlan River floodplain of south-western NSW. In each dune exists an upper-slope phase of coarse brown sand, a mid-slope layer of reddish, clay-enriched sand, and a lower-slope phase of coarse sand dominated by an accumulation of carbonate glaebules. Granulometric analyses of the clay-enriched phase(s) of each dune identified a conspicuous particle population in the 20–60 μm range, and another in the fine-silt/clay range (<10 μm). Mineralogical characterisation revealed an abundance of illite and kaolinite in the upper 2 dune phases, coupled with a minor amount of smectite, further suggesting an allochthonous æolian origin, as the surrounding floodplain is smectite-rich and relatively poor in illite. Micromorphological features within the clay-enriched phase, including abundant argillans and laminar bands of well-sorted fine quartz grains, indicate that this clay is a depositional feature, illuviated from surface horizons and re-deposited at depth. A similar illuvial origin is suggested by the fine crystalline nature of the calcium carbonate accumulation, ubiquitously coating the matrix mineral grains of the lower dune phase. No discrete clay aggregates were identified; however, all the assumed components of parna (silt-sized quartz grains, clay, and calcium carbonate) were identified, spatially separated within each dune. The consistency of these features among the 3 dunes indicates an analogous æolian dust accession, but it is not clear whether the clay component of this dust was transported as coatings on quartz grains, or as silt-sized clay aggregates accompanied by silt-sized quartz grains.
49
Worthy, Soleil E., Anand Kumar, Yu Xi, Jingwei Yun, Jessie Chen, Cuishan Xu, Victoria E. Irish, Pierre Amato, and Allan K. Bertram. "The effect of (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> on the freezing properties of non-mineral dust ice-nucleating substances of atmospheric relevance." Atmospheric Chemistry and Physics 21, no. 19 (October 4, 2021): 14631–48. http://dx.doi.org/10.5194/acp-21-14631-2021.
Full textAbstract:
Abstract. A wide range of materials including mineral dust, soil dust, and bioaerosols have been shown to act as ice nuclei in the atmosphere. During atmospheric transport, these materials can become coated with inorganic and organic solutes which may impact their ability to nucleate ice. While a number of studies have investigated the impact of solutes at low concentrations on ice nucleation by mineral dusts, very few studies have examined their impact on non-mineral dust ice nuclei. We studied the effect of dilute (NH4)2SO4 solutions (0.05 M) on immersion freezing of a variety of non-mineral dust ice-nucleating substances (INSs) including bacteria, fungi, sea ice diatom exudates, sea surface microlayer substances, and humic substances using the droplet-freezing technique. We also studied the effect of (NH4)2SO4 solutions (0.05 M) on the immersion freezing of several types of mineral dust particles for comparison purposes. (NH4)2SO4 had no effect on the median freezing temperature (ΔT50) of 9 of the 10 non-mineral dust materials tested. There was a small but statistically significant decrease in ΔT50 (−0.43 ± 0.19 ∘C) for the bacteria Xanthomonas campestris in the presence of (NH4)2SO4 compared to pure water. Conversely, (NH4)2SO4 increased the median freezing temperature of four different mineral dusts (potassium-rich feldspar, Arizona Test Dust, kaolinite, montmorillonite) by 3 to 9 ∘C and increased the ice nucleation active site density per gram of material (nm(T)) by a factor of ∼ 10 to ∼ 30. This significant difference in the response of mineral dust and non-mineral dust ice-nucleating substances when exposed to (NH4)2SO4 suggests that they nucleate ice and/or interact with (NH4)2SO4 via different mechanisms. This difference suggests that the relative importance of mineral dust to non-mineral dust particles for ice nucleation in mixed-phase clouds could potentially increase as these particles become coated with (NH4)2SO4 in the atmosphere. This difference also suggests that the addition of (NH4)2SO4 (0.05 M) to atmospheric samples of unknown composition could potentially be used as an indicator or assay for the presence of mineral dust ice nuclei, although additional studies are still needed as a function of INS concentration to confirm the same trends are observed for different INS concentrations than those used here. A comparison with results in the literature does suggest that our results may be applicable to a range of mineral dust and non-mineral dust INS concentrations.
50
Linsel, Adrian, Sebastian Wiesler, Jens Hornung, and Matthias Hinderer. "High-resolution analysis of the physicochemical characteristics of sandstone media at the lithofacies scale." Solid Earth 11, no. 4 (August 13, 2020): 1511–26. http://dx.doi.org/10.5194/se-11-1511-2020.
Full textAbstract:
Abstract. The prediction of physicochemical rock properties in subsurface models regularly suffers from uncertainty observed at the submeter scale. Although at this scale – which is commonly termed the lithofacies scale – the physicochemical variability plays a critical role for various types of subsurface utilization, its dependence on syndepositional and postdepositional processes is still subject to investigation. The impact of syndepositional and postdepositional geological processes, including depositional dynamics, diagenetic compaction and chemical mass transfer, onto the spatial distribution of physicochemical properties in siliciclastic media at the lithofacies scale is investigated in this study. We propose a new workflow using two cubic rock samples where eight representative geochemical, thermophysical, elastic and hydraulic properties are measured on the cubes' faces and on samples taken from the inside. The scalar fields of the properties are then constructed by means of spatial interpolation. The rock cubes represent the structurally most homogeneous and most heterogeneous lithofacies types observed in a Permian lacustrine-deltaic formation that deposited in an intermontane basin. The spatiotemporal controlling factors are identified by exploratory data analysis and geostatistical modeling in combination with thin section and environmental scanning electron microscopy analyses. Sedimentary structures are well preserved in the spatial patterns of the negatively correlated permeability and mass fraction of Fe2O3. The Fe-rich mud fraction, which builds large amounts of the intergranular rock matrix and of the pseudomatrix, has a degrading effect on the hydraulic properties. This relationship is underlined by a zonal anisotropy that is connected to the observed stratification. Feldspar alteration produced secondary pore space that is filled with authigenic products, including illite, kaolinite and opaque phases. The local enrichment of clay minerals implies a nonpervasive alteration process that is expressed by the network-like spatial patterns of the positively correlated mass fractions of Al2O3 and K2O. Those patterns are spatially decoupled from primary sedimentary structures. The elastic properties, namely P-wave and S-wave velocity, indicate a weak anisotropy that is not strictly perpendicularly oriented to the sedimentary structures. The multifarious patterns observed in this study emphasize the importance of high-resolution sampling in order to properly model the variability present in a lithofacies-scale system. Following this, the physicochemical variability observed at the lithofacies scale might nearly cover the global variability in a formation. Hence, if the local variability is not considered in full-field projects – where the sampling density is usually low – statistical correlations and, thus, conclusions about causal relationships among physicochemical properties might be feigned inadvertently.