Effect of slope aspect on transformation of clay minerals in Alpine soils

AbstractTwo soil profile sequences on paragneiss debris in the Val di Rabbi (Northern Italy) along an altitude gradient ranging from 1200 to 2400 m a.s.l. were studied to evaluate the effect of aspect on the weathering of clay minerals. All the soils had a coarse structure, a sandy texture and a low pH. Greater weathering intensities of clay-sized phyllosilicates (greater content of smectites) were observed in soils on the north-facing slope. On the south-facing slope, smectite was found only in the surface horizon of the soil profile at the highest altitude. Hot citrate treatment of north-facing soils revealed the presence of low-charged 2:1 clay minerals, the expansion of which was hindered in the untreated state by interlayered polymers. However, the hot citrate treatment encountered some problems with the samples of the south-facing soils: as confirmed by Fourier transform infrared spectroscopy, the hot citrate treatment was unable to remove all interlayer Al polymers. The 2:1 phyllosilicates were not expanded by ethylene glycol solvation in several samples, although thermogravimetric analyses indicated the presence of clay minerals with interlayer H2O. At the same time, the collapse of clay minerals to 1.0 nm following K-saturation was evident. Theoretically, this should indicate that 2:1 phyllosilicates had no evident substitution of trioctahedral cations (Mg2+, Fe2+) by dioctahedral cations (Al3+ and Fe3+). X-ray diffraction analysis of the d060 region and determination of the layer charge of clay minerals by the long-chain (C18) alkylammonium ion, however, did not confirm this. A transformation from trioctahedral to dioctahedral species was observed and low-charge clay minerals (ξ ~0.30) were identified in the surface horizons of the south-facing sites. In the south-facing soils, the podzolization process was less pronounced because of a lower water flux through the soil and probably less complexing organic molecules that would remove the interlayer polymers. Besides the eluviation process, clay minerals underwent a process of ionic substitutions in the octahedral sheet that led to the reduction of the layer charge. This process was more obvious in the north-facing sites.

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THE CLAY MINERALS IN SOME BRITISH COLUMBIA SUBSOILS

Canadian Journal of Soil Science ◽

10.4141/cjss62-039 ◽

1962 ◽

Vol 42 (2) ◽

pp. 296-301 ◽

Cited By ~ 2

Author(s):

J. S. Clark ◽

J. E. Brydon ◽

H. J. Hortie

Keyword(s):

British Columbia ◽

Diffraction Analysis ◽

Clay Minerals ◽

Clay Mineralogy ◽

X Ray Diffraction ◽

The South ◽

Parent Materials ◽

X Ray ◽

Northeastern Part ◽

Montmorillonitic Clay

X-ray diffraction analysis was used to identify the clay minerals present in fourteen subsoil samples that were selected to represent some more important clay-bearing deposits in British Columbia. The clay mineralogy of the subsoils varied considerably but montmorillonitic clay minerals tended to predominate in the water-laid deposits of the south and illite in the soil parent materials of the Interior Plains region of the northeastern part of the Province.

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Influence of slope aspect on the microbial properties of rhizospheric and non-rhizospheric soil on the Loess Plateau, China

10.5194/se-2017-137 ◽

2018 ◽

Author(s):

Ze Min Ai ◽

Jiao Yang Zhang ◽

Hong Fei Liu ◽

Sha Xue ◽

Guo Bin Liu

Keyword(s):

Loess Plateau ◽

Microbial Biomass Carbon ◽

Phospholipid Fatty Acid ◽

Slope Aspect ◽

Research Station ◽

Rhizospheric Soil ◽

The Loess Plateau ◽

The South ◽

Microbial Properties ◽

The North

Abstract. Slope aspect is an important topographic factor, but its effect on the microbial properties of grassland rhizospheric soil (RS) and non-rhizospheric soil (NRS) remain unclear. A field experiment was conducted at the Ansai Research Station on the Loess Plateau in China to test the influence of slope aspects (south-facing, north-facing, and northeast-facing slopes, all with Artemisia sacrorum as the dominant species) on RS and NRS microbial biomass carbon (MBC) and phospholipid fatty acid (PLFA) contents, and the rhizospheric effect (RE) of various microbial indices. MBC content differed significantly among the slope aspects in RS but not in NRS, and RE for MBC content in the south-facing slope was larger than that in the north-facing slope. RS total, bacterial, and gram-positive bacterial PLFA contents in the south-facing slope were significantly lower than those in the north- and northeast-facing slopes, and RS gram-negative bacterial (G-) and actinomycete PLFA contents in the south-facing slope were significantly lower than those in the north-facing slope. Differently, NRS total, bacterial, and G- PLFA contents in the north-facing slope were significantly higher than those in the south- and northeast-facing slopes, and NRS fungal and actinomycete PLFA contents in the north- and south-facing slopes were significantly higher than those in the northeast-facing slope. RE for all PLFA contents except fungal in the northeast-facing slope were higher than those in the south-facing slope. Slope aspect significantly but differentially affected the microbial properties in RS and NRS, and the variable influence was due an evident RE for most microbial properties.

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Sedimentology, Mineral Facies, and Petrofabric of the Meaford–Dundas Formation (Upper Ordovician) in Southern Ontario

Canadian Journal of Earth Sciences ◽

10.1139/e73-175 ◽

1973 ◽

Vol 10 (12) ◽

pp. 1790-1804 ◽

Cited By ~ 2

Author(s):

K. Czurda ◽

C. G. Winder ◽

R. M. Quigley

Keyword(s):

Clay Minerals ◽

Heavy Minerals ◽

Carbonate Content ◽

The South ◽

Upper Ordovician ◽

Quartz Content ◽

Southern Ontario ◽

The North ◽

Bedding Planes ◽

Diffraction Patterns

The Meaford–Dundas Formation in southern Ontario is a medium gray shale with good fissility and resistant interbeds of gray fossiliferous limestones and siltstones. The hard layers are up to 20 cm in thickness and comprise 10 to 20% of the formation. The shale layers vary in thickness from 50 cm to 2 m.The clay minerals are principally illite, iron-chlorite, and small amounts of vermiculite and mixed-layer types. The carbonate content seems constant across the area at about 4 to 5% of the formation, except for the southwestern area where the carbonate increases to 20 or 25%. This increase is chiefly in dolomite content, a feature which reflects such factors as original conditions of deposition and possibly diagenesis subsequent to burial. The quartz content in the shale beds, and especially in the hard interbeds, increases towards the north to an average of 35 to 40% compared with 10 to 15% in the south. Framboids (aggregates of pyrite grains in spheroidal clusters) are a striking feature of the shale beds of the Meaford–Dundas Formation in the Meaford area.Fabric studies by means of X-ray diffraction patterns and scanning electron photomicrographs reveal, in most cases, high parallelism of clay platelets in the bedding planes, resulting in the good fissility of the shale.The principal source rock areas are the Appalachian orogen in the east (Taconic Mountains), which probably supplied most of the clay minerals and some quartz, and the Canadian Shield in the north, which provided the basin of sedimentation in the south with heavy minerals and additional quartz.

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Nickel-containing montmorillonites and chlorites from Brazil, with remarks on schuchardtite

Mineralogical Magazine ◽

10.1180/minmag.1975.040.310.04 ◽

1975 ◽

Vol 40 (310) ◽

pp. 141-152 ◽

Cited By ~ 21

Author(s):

G. W. Brindley ◽

Jefferson V. De Souza

Keyword(s):

Structural Formula ◽

Layer Charge ◽

Basal Spacing ◽

Chemical Compositions ◽

X Ray Diffraction ◽

Octahedral Sheet ◽

X Ray ◽

Crystalline Forms ◽

Polytype Structure ◽

Good Agreement

SummaryClay-like, hydrous nickel silicates from Niquelandia, Goias, Brazil, and from Jacupiranga, São Paulo, Brazil, arc examined by X-ray diffraction, chemical analysis, and thermogravimetric methods. The nickel silicates from Niquelandia are ferric iron montmorillonites, with nickel in the octahedral positions and, to a lesser extent, in interlayer positions. The chemical compositions of samples dried at 110°C average (Mg0.15Ni0.08Ca0.015Na0.005) (Fe0.92IIIFe0.025IIAl0.55Mg0.37Ni0.22) (Si3.88Al0.12)O10(OH)2(H2O)0.93. The layer charge originates largely in the octahedral sheet. The cation-exchange capacities average 107 me/100 g clay (110°C). These minerals differ from non-tronites, in which the layer charge originates mainly in the tetrahedral sheets.The nickel silicates from Jacupiranga resemble chlorites, with a non-expanding basal spacing of 14·2-14·3 Å. The better crystalline forms give X-ray data in good agreement with a la polytype structure, which is consistent with their formation by low-temperature processes. Chemical formulae derived on the basis of O10(OH)8 give an average of 5·47 cations in octahedral positions. Thermogravimetric measurements show up to 4% H2O lost between 110 and 500 °C. These results suggest a partial vermiculitization of the interlayer sheets. A new method of calculating a structural formula is developed that gives an interlayer composition of the form R1.75(OH)3.75(H2O)1.14, with (OH + H2O)/R = 2·80, which approaches the ratio for a dioctahedral sheet structure.A comparison of these defect chlorites with available data on schuchardtites shows many similarities; however, schuchardtite is not yet sufficiently well denned for the Jacupiranga chlorites to be given this name.

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Weathering of glauconites: reversal of the glauconitization process in a soil profile in western France

Clay Minerals ◽

10.1180/claymin.1981.016.3.02 ◽

1981 ◽

Vol 16 (3) ◽

pp. 231-243 ◽

Cited By ~ 30

Author(s):

C. Courbe ◽

B. Velde ◽

A. Meunier

Keyword(s):

Aqueous Solution ◽

Clay Minerals ◽

Mixed Layer ◽

Electron Microprobe ◽

Soil Profile ◽

X Ray Diffraction ◽

X Ray ◽

Polarizing Microscope

AbstractPolarizing microscope, electron microprobe and X-ray diffraction examination of minerals in a soil profile developed on a glauconite sand indicate that destabilization of glauconite can be a progressive process which appears to be the reverse of glauconitization. Glauconite in these soils appears to be destabilized into a mixed-layer glauconite-nontronite phase, which crystallizes as a plasma mineral. This material in turn is transformed into smectite+kaolinite+oxides. Loss of K and Fe is evident in whole rock as well as microprobe analyses of the samples. Thus glauconite can lose both Fe and K to aqueous solution during weathering, leaving aluminous clay minerals in the soil.

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Clay mineral transformations in podzolized tills in central Finland

Clay Minerals ◽

10.1180/claymin.1997.032.4.04 ◽

1997 ◽

Vol 32 (4) ◽

pp. 531-544 ◽

Cited By ~ 19

Author(s):

D. Righi ◽

M. L. Räisänen ◽

F. Gillot

Keyword(s):

Ethylene Glycol ◽

Sea Level ◽

Clay Minerals ◽

X Ray Diffraction ◽

Fine Silt ◽

Land Uplift ◽

X Ray ◽

Mixed Layers ◽

Low Charge ◽

Mineral Transformations

AbstractTransformations of clay minerals were studied in a sequence of podzols (Entic Cryorthods) of increasing age (5500-10000 years BP) developed from till materials in central Finland. The age of the soils was estimated according to altitude above the present sea level, with reference to the age of ancient shorelines and the rate of land uplift. Clay minerals in fine (<0.1 µm), coarse (0.1-2 µm) clay and fine silt (2-5 µm) fractions were studied by X-ray diffraction. The layer charge of expandable minerals was estimated on the basis of their re-expansion with ethylene glycol following K-saturation and heating to 110°C Pedogenic transformations of clay minerals occur essentially in the E horizons of the podzols. Smectites and illite-smectite mixed-layers are the dominant clay minerals in the E horizons of soils older than 6500 years. The number of mixed-layers decreases with evolution of the soil, leaving a nearly pure smectite phase in the oldest soil (10000 years). The smectites are dioctahedral with a tetrahedral charge. Groups of low-charge and highcharge interlayers are both present in the samples, but low-charge smectite layers were found only in the two older soils (9500-10000 years). This suggests alteration with time of the high-charge smectites.

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RELIEF AND MICROCLIMATE AS RELATED TO SOIL PROPERTIES

Canadian Journal of Soil Science ◽

10.4141/cjss78-049 ◽

1978 ◽

Vol 58 (3) ◽

pp. 421-438 ◽

Cited By ~ 22

Author(s):

T. M. MACYK ◽

J. D. LINDSAY ◽

S. PAWLUK

Keyword(s):

Redox Potential ◽

Soil Temperature ◽

Soil Properties ◽

Exchange Capacity ◽

Moisture Regime ◽

X Ray Diffraction ◽

The South ◽

The North ◽

Soil Moisture Regime ◽

Soil Temperatures

This study was undertaken to determine the influence of relief and microclimate on soil properties. Seven sites were chosen at different positions on the north- and south-facing slopes of a moderately rolling till knob. Physical, chemical and mineralogical analyses were conducted to characterize the soils at each of the sites. The vegetation of the area was described and soil temperatures and moisture were monitored at four depths. Redox potential and pH were measured to detect seasonal variations. Data for oxalate and dithionite-extractable iron and aluminum, cation exchange capacity, and X-ray diffraction showed only minor differences among the seven pedons along the slope faces. Soil temperature was higher on the south-facing slope than on the north-facing slope and air temperature was usually higher than soil temperature at the 10-cm depth. Soil moisture regime varied with position in the landscape. The soil on the north-facing slope was generally more moist than the soil on the south-facing slope. Redox potential varied seasonally and appeared to be related to the moisture content of the soil.

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Characterization of a Mg-rich and low-charge saponite from the Neogene lacustrine basin of Eskisşehir, Turkey

Clay Minerals ◽

10.1180/claymin.2007.042.4.10 ◽

2007 ◽

Vol 42 (4) ◽

pp. 541-548 ◽

Cited By ~ 4

Author(s):

M. Yeniyol

Keyword(s):

Thermal Analyses ◽

Structural Formula ◽

Layer Charge ◽

Octahedral Sheet ◽

Rational Series ◽

Powder Samples ◽

Basal Reflection ◽

Xrd Patterns ◽

Low Charge

AbstractThe saponite examined occurs as two 0.1 m thick layers in a Pliocene sequence consisting of dolomite and dolomitic marl. To characterize this material, mineralogical and structural analyses (XRD, SEM and FTIR), thermal analyses (DTA, TG) and chemical analyses (ICP-ES) were performed. From XRD patterns of randomly-oriented powder samples, the first basal reflection appears as an asymmetric and broad peak with d001 values varying between 16.55 and 17.32 Å. In oriented and air-dried samples, this reflection occurs between 14.45 and 16.42 Å and is fairly symmetrical with FWHM of 2.7º2θ. Oriented and ethylene glycol-solvated samples produce a rational series of basal reflections, where 001 occurs at ~17.8 Å as an intense, narrow (1.1º2θ) and fairly symmetrical reflection. Upon solvation with glycerol, the 001 reflection shifts to ~18.7 Å.The chemical composition of this saponite is similar to stevensite. However, the structural formula of Na0.114Ca0.013K0.003(Mg2.957Al0.004Fe0.028Ti0.004)(Si3.826Al0.174)O10(OH)2 indicates that vacancies in the octahedral sheet do not exist. The negative layer charge arises nearly entirely from the substitutions in the tetrahedral sheet, with the net layer charge of –0.148, smaller than for common smectites.Due to the XRD characteristics and particularly the layer-charge distribution, it was concluded that this mineral is a Mg-rich saponite with low layer charge. The saponite was formed by direct precipitation in an alkaline lake environment from Mg- and Si-rich solutions at high pH.

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Influence of slope aspect on the microbial properties of rhizospheric and non-rhizospheric soils on the Loess Plateau, China

Solid Earth ◽

10.5194/se-9-1157-2018 ◽

2018 ◽

Vol 9 (5) ◽

pp. 1157-1168 ◽

Cited By ~ 3

Author(s):

Ze Min Ai ◽

Jiao Yang Zhang ◽

Hong Fei Liu ◽

Sha Xue ◽

Guo Bin Liu

Keyword(s):

Loess Plateau ◽

Phospholipid Fatty Acid ◽

Slope Aspect ◽

Research Station ◽

Rhizospheric Soil ◽

The Loess Plateau ◽

The South ◽

Microbial Properties ◽

The North ◽

Microbial Indices

Abstract. Slope aspect is an important topographic factor in the micro-ecosystem environment, but its effect on the microbial properties of grassland rhizospheric soil (RS) and non-rhizospheric soil (NRS) remain unclear. A field experiment was conducted at the Ansai Research Station on the Loess Plateau in China to test the influence of slope aspects (south-facing, north-facing, and northwest-facing slopes, all with Artemisia sacrorum as the dominant species) on RS and NRS microbial biomass carbon (MBC) contents, phospholipid fatty acid (PLFA) contents, and the rhizospheric effect (RE) of various microbial indices. Soil samples were collected from the three slope aspects, including rhizospheric and non-rhizospheric region, and analyzed to determine the various related microbial indices. The results showed that MBC content differed significantly among the slope aspects in RS but not in NRS, and the RE for MBC content in the south-facing slope was larger than that in the north-facing slope. RS total, bacterial, and Gram-positive bacterial PLFA contents in the south-facing slope were significantly lower than those in the north- and northwest-facing slopes, and RS Gram-negative bacterial (G−) and actinomycete PLFA contents in the south-facing slope were significantly lower than those in the north-facing slope. In contrast, NRS total, bacterial, and G− PLFA contents in the north-facing slope were significantly higher than those in the south- and northwest-facing slopes, and NRS fungal and actinomycete PLFA contents in the north- and south-facing slopes were significantly higher than those in the northwest-facing slope. RE for all PLFA contents except fungal in the northwest-facing slope were higher than those in the south-facing slope. Slope aspect significantly but differentially affected the microbial properties in RS and NRS, and the variable influence was due to an evident RE for most microbial properties.

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Prostorska analiza kmetijskih zemljišč v zaraščanju v Sloveniji

Acta agriculturae Slovenica ◽

10.14720/aas.2017.109.2.10 ◽

2017 ◽

Vol 109 (2) ◽

pp. 261 ◽

Cited By ~ 1

Author(s):

Matjaž Glavan ◽

Aljaž Malek ◽

Marina Pintar ◽

Helena Grčman

Keyword(s):

Land Use ◽

Agricultural Land ◽

Natura 2000 ◽

Slope Aspect ◽

The South ◽

North East ◽

The North ◽

Natural Factors ◽

South West ◽

Flooded Areas

In this study we performed a spatial analysis to determine the influence of selected environmental factors (forests share, elevation a.s.l., slope, aspect, flooding) and the management status of an area on the spatial distribution of the abandoned agricultural land (land use class 1410), and agricultural land with forest trees (land use class 1800) in Slovenia. All these natural factors influence the management decisions of landowners. We found out that land use class 1410 is distributed over the entire country, along the south-west to the north-east axis. The majority of the land use class 1800 can be found in the south-western part of the country. On municipality level, the link between the forest and studied land uses was weak. The percentage of land use classes 1410 and 1800 grows with increasing altitude a.s.l. and slope. Land use class 1400 is more frequent in flooded areas. The percentage of the abandoned agricultural land is greater in areas with special management status (e.g. Natura 2000 areas). A strict, professional and fast implementation of the Agricultural Land Act is needed to improve the situation and prevent further agricultural land losses.

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