scholarly journals Mixed-Layer Illite-Smectite in Pennsylvanian-Aged Paleosols: Assessing Sources of Illitization in the Illinois Basin

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 108
Author(s):  
Julia A. McIntosh ◽  
Neil J. Tabor ◽  
Nicholas A. Rosenau
Keyword(s):  
Mixed Layer ◽  
Acid Leaching ◽  
Soil Formation ◽  
Illinois Basin ◽  
Formation Processes ◽  
X Ray Diffraction ◽  
Diagenetic Alteration ◽  
Mineral Alteration ◽  
Diffraction Patterns ◽  
The Impact

Mixed-layer illite-smectite (I-S) from a new set of Pennsylvanian-aged Illinois Basin underclays, identified as paleosols, are investigated to assess the impact of (1) regional diagenesis across the basin and (2) the extent to which ancient environments promoted illitization during episodes of soil formation. Interpretations from Reichweite Ordering and Δ° 2θ metrics applied to X-ray diffraction patterns suggest that most I-S in Illinois Basin paleosols are likely the product of burial diagenetic processes and not ancient soil formation processes. Acid leaching from abundant coal units and hydrothermal brines are likely diagenetic mechanisms that may have impacted I-S in Pennsylvanian paleosols. These findings also suggest that shallowly buried basins (<3 km) such as the Illinois Basin may still promote clay mineral alteration through illitization pathways if maximum burial occurred in the deep past and remained within the diagenetic window for extended periods of time. More importantly, since many pedogenic clay minerals may have been geochemically reset during illitization, sources of diagenetic alteration in the Illinois Basin should be better understood if Pennsylvanian paleosol minerals are to be utilized for paleoclimate reconstructions.

Preparation by solution mixing and characterization of condensation type poly(dimethyl siloxane)/graphene nanoplatelets composites

2021 ◽  
pp. 002199832110558
Author(s):  
Panayiotis Ketikis ◽  
Efthimios Damopoulos ◽  
Georgios Pilatos ◽  
Panagiotis Klonos ◽  
Apostolos Kyritsis ◽  
...  
Keyword(s):  
Graphene Nanoplatelets ◽  
Matrix Composites ◽  
Dielectric Relaxation Spectroscopy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Melting Temperatures ◽  
Dimethyl Siloxane ◽  
Diffraction Patterns ◽  
The Impact

The impact of the incorporation of graphene nanoplatelets (GN) on the properties of hydroxyl-terminated poly(dimethylsiloxane) (PDMS) matrices was investigated. The composites were prepared by solution mixing, using tetrahydrofuran (THF) as a solvent. Brookfield viscosimetry, implemented during the vulcanization process, revealed that GN increases the viscosity of the system, compared to pristine PDMS, proportionally to its concentration. X-ray diffraction patterns suggested an efficient dispersion of GN in the polysiloxane matrix. The D and G bands ratio (ID/IG) calculation, based on RAMAN spectra of GN/PDMS specimens, revealed more defects in graphene nanoplatelets when incorporated in the PDMS matrix. By differential scanning calorimetry (DSC), a marginal increase in crystallization, glass transition and melting temperatures of PDMS in GN/PDMS composites was observed. Improvement of the thermal stability of LMW PDMS composites, especially for higher GN concentrations (3 and 5 phr), was noticed by thermogravimetric analysis (TGA). Additionally, GN enhanced the tensile strength of composites, up to 73% for the 3 phr GN/LMW PDMS composite. A significant increase in the elongation at break was recorded, whereas no effect on the modulus of elasticity was recorded. The decrease in toluene-swelling, for the LMW PDMS matrix composites, was attributed to the increase in the tortuosity path because of the efficient dispersion of GN. A decrease in oxygen permeability of 55–65% and 44–58% was measured in membranes made of PDMS composites containing 0.5 phr and 1 phr GN, respectively. Dielectric relaxation spectroscopy (DRS) measurements recorded a significant increase in the conductivity of the higher graphene content composites.

scholarly journals MICROMORPHOLOGY AND PEDOGENESIS OF MOUNTAINOUS INCEPTISOLS IN THE MANTIQUEIRA RANGE (MG)

2015 ◽  
Vol 39 (5) ◽  
pp. 455-462 ◽  
Author(s):  
Leandro Campos Pinto ◽  
Yuri Lopes Zinn ◽  
Carlos Rogério de Mello ◽  
Phillip Ray Owens ◽  
Lloyd Darrell Norton ◽  
...  
Keyword(s):  
Soil Formation ◽  
Intermediate Stage ◽  
Mineral Weathering ◽  
Southeastern Brazil ◽  
Native Forest ◽  
Subtropical Climate ◽  
Formation Processes ◽  
Severe Reduction ◽  
Mineral Alteration ◽  
Quartz Grains

ABSTRACTUnderstanding soil formation processes across different landscapes is needed to predict how soil properties will respond to land use change. This study aimed to characterize mountainous Inceptisols (Cambisols) under high altitude subtropical climate in southeastern Brazil, by soil physical, chemical and micromorphological analyses, under native forest and pasture. The soil under pasture had a greater bulk density than under forest, resulting in a severe reduction of macroporosity. At two depths, coarse quartz grains are angular, suggesting absence of transportational processes, thus confirming an autochthonous pedogenesis from the underlying gneissic rock. Most feldspars were weathered beyond recognition, but mineral alteration was commonly seen across cleavage plans and edges of micas. The micromorphological results suggest an intermediate stage of mineral weathering and soil development, which is in accordance with properties expected to be found in Inceptisols.

Impacts of clay mineralogy and physiographic units on the distribution of potassium forms in calcareous soils in Iran

Clay Minerals ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 327-337 ◽  
Author(s):  
S. Rezapour ◽  
A. A. Jafarzadeh ◽  
A. Samadi ◽  
S. Oustan
Keyword(s):  
Calcareous Soils ◽  
Clay Mineralogy ◽  
Soil Formation ◽  
Alluvial Plain ◽  
X Ray Diffraction ◽  
Piedmont Plain ◽  
Physiochemical Properties ◽  
Exchangeable K ◽  
North West ◽  
Diffraction Patterns

AbstractThe potassium pools of five major physiographic units of the Urmia region situated in western Azerbaijan province, north-west Iran, were studied to determine the distribution of K forms as functions of clay mineralogy and physiographic units. Soil samples from horizons of ten pedons were selected and analysed for physiochemical properties, clay mineralogy and forms of K. X-ray diffraction patterns revealed that the soils were similar in clay-mineral compositions, consisting of illite, smectite, chlorite, and kaolinite, for the different physiographic units, but vary in the relative amounts of these minerals. The illite content was highest in piedmont plain (P.P) followed by plateau (Pl), river alluvial plain (R.A.P), colluvial alluvial plain (C.A.R) and lowland (L.L) units. Smectite content was highest in Pl followed by P.P, L.L, R.A.P and C.A.P units. Several processes, such as the diversity of weathering rate, biocyclying processes of K accumulation, geomorphologic conditions and soil formation processes, caused significant differences in most K forms in the soils. A wide variation in total K (HF-extractable K) (0.54–1.1%), non-exchangeable K (280–450 mg kg–1) and exchangeable K (217–330 mg kg–1) occurred among the physiographic units, corresponding to variations in their mineralogical compositions, mainly the abundance of illite. Significant differences (P ⩽ 0.05) were found for K, HNO3-extractable K and non-exchangeable K between the soils with large illite contents (30–50%) and with small illite contents (10–30%). A significant positive relationship existed between mineral K and illite content (r2 = 0.85, P ⩽ 0.001) and non-exchangeable K and illite content (r2 = 0.84, P ⩽ 0.001). The results indicated that these pools of K are mainly released from the frayed edges and wedge zones of illite.

Mafic phyllosilicates in low-grade metabasites. Characterization using deconvolution analysis — discussion

Clay Minerals ◽  
1995 ◽  
Vol 30 (1) ◽  
pp. 67-73 ◽  
Author(s):  
S. Hillier
Keyword(s):  
Mixed Layer ◽  
Low Grade ◽  
X Ray Diffraction ◽  
Deconvolution Analysis ◽  
Xrd Pattern ◽  
Strong Reflection ◽  
Diffraction Patterns ◽  
Xrd Patterns ◽  
Layer Mineral ◽  
Trioctahedral Smectite

AbstractAny X-ray diffraction (XRD) pattern of mixed-layered maximum R1 ordered chlorite-smectite has an exact equivalent R0 smectite-corrensite or R0 chlorite-corrensite. The identification of a mineral as chlorite (0.8)-smectite R1 is, therefore, not evidence that the fundamental layers in such an interstratified structure are actually chlorite and smectite. Furthermore, there are no obvious differences between XRD patterns of R0 and R1 chlorite-smectite at high or low smectite contents. Therefore the frequently supposed identification of R0 chlorite-smectite with high smectite contents is also questionable. It follows that the identification of R1 chlorite (0.8)-smectite by Robinson & Bevins (1994) and of R0 chlorite (≈0.2)-smectite in an earlier publication (Robinson et al.,1993) cannot be used as evidence regarding the debate over the nature of the component layers in interstratified minerals intermediate between trioctahedral smectite and chlorite.Diffraction patterns of natural mixed-layer chlorite minerals from metabasites often show a strong reflection at 31 Å yet a lack of resolution of other mixed-layer peaks from those of discrete chlorite. These features cannot be matched by any single mixed-layer mineral consisting of layers of chlorite and smectite and were matched by Robinson & Bevins (1994) using a mixture of different chlorite-smectite minerals. However, they can be matched by a single chlorite-corrensite mineral in which there is an element of segregation of layer types. These different possibilities need to be investigated further.

A rectorite-pyrophyllite-chlorite-illite assemblage in pelitic rocks from Colombia

Clay Minerals ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 425-434 ◽  
Author(s):  
B. Brattli
Keyword(s):  
Grain Size ◽  
Mixed Layer ◽  
Low Pressure ◽  
X Ray Diffraction ◽  
Illite Crystallinity ◽  
X Ray ◽  
Diffraction Patterns ◽  
The Stability ◽  
Pelitic Rocks

AbstractIn samples of slate from the Fomeque Formation near Bogota, Colombia, pyrophyllite was found to occur together with mixed-layered illite-smectite, chlorite and illite. Other minerals were quartz, K-feldspar, dolomite and pyrite. X-ray diffraction patterns revealed that the mixed-layer represents an R1 ordered rectorite with 80–90% illite layers. The microfabric is developed as a closely spaced cleavage in the phyllosilicate-rich rocks, and grades into a fracture cleavage with coarsening of the grain size. No cleavage was observed in the interbedded siltstones. It is suggested that the microfrabrics developed in these rocks correspond to high diagenetic to anchizonal conditions. The illite crystallinity from the slate has been measured on glycolated samples and ranges from 0.47 to 0.55°Δ2θ with a mean of 0.52°Δ2θ Based on the stability of R1 ordered rectorite, the illite crystallinity and the microfabric development, it is proposed that the rocks have been subjected to a temperature of ∼200°C at low pressure. At this temperature, pyrophyllite can only be stabilized at the expense of kaolinite and quartz if aH2O ≪ 1.

scholarly journals Mineralogy of recent pelitic sediments from the Fiskenæsset region, southern West Greenland

1976 ◽  
Vol 73 ◽  
pp. 100-108
Author(s):  
D Heling
Keyword(s):  
Chemical Weathering ◽  
Clay Fraction ◽  
Soil Formation ◽  
Mineralogical Composition ◽  
Climatic Conditions ◽  
Formation Processes ◽  
Grab Sampling ◽  
West Greenland ◽  
Fast Transport ◽  
Mineral Alteration

Recent muds were sampled during the summer of 1973 from different fjords and lakes in the Fiskenæsset region of southern west Greenland. The samples were analysed for their mineralogical composition in order to study sorting effects and possibie mineral alteration by transport action under subarctic climatic conditions. In an investigation of the composition of sands from the Fiskenæsset region Kalsbeek et al. (1974) revealed a close correspondence between the mineralogical composition of the coarser clastic components and that of the bedrock. Such relationships occur when chemical weathering of the sediment material is negligibie due to low temperatures and in connection with fast transport (high relief) and corresponding high sedimentation rates. All these influencing factors are active in southern west Greenland. Sampling was undertaken in Buksefjorden, Sermilik, Grædefjord, Fiskenæsfjorden, Bjørnesund and at the margin of Frederikshåbs Isblink. Further bottom samples were taken from the lakes marked in fig. 45. A total of 121 samples were recovered from depths ranging from Oto 275 m using grab sampling devices. Almost the entire sediment material under consideration has been produced by glacial abrasion and only a negligibie proportion by soil formation processes. Both bed load and suspension load are brought by melt water streams from beneath the glaciers. The melt waters run into glaciaIly eroded lakes, where most of the coarse sediment material and some of the clay fraction is trapped. Most of the clay fraction remains in suspension, however, and is transported downstream to sea level. Considerable amounts of clay in suspension are carried far into the fjords.

Bodenschutz im Wald – Annäherung an ein Wahrnehmungsproblem (Essay) | Soil protection in forests – approaching a problem of perception (essay)

2010 ◽  
Vol 161 (12) ◽  
pp. 482-488
Author(s):  
Franz Borer
Keyword(s):  
Forest Management ◽  
Sustainable Forest Management ◽  
Soil Formation ◽  
Timber Harvesting ◽  
High Tech ◽  
Soil Protection ◽  
Formation Processes ◽  
Soil System ◽  
Protection Measures ◽  
The Impact

Sustainable forest management is totally dependent on an intact production base such as the soil. Today's soil has been shaped by soil formation processes over hundreds and thousands of years in the context of various natural cycles. In contrast to these very slow soil formation processes, timber harvesting methods have evolved within a few decades from manual harvesting to high-tech harvesting with heavy machinery. The impact of these on the soil structure is comparable to that of the ice sheets during the last glaciation. The consequences of this development are not easily visible to the eye. But there is the threat of irreversible damages in the form of soil compaction. Now what about sustainability, this fundamental requirement that wood production can be maintained over many tree generations keeping the production base intact? What about the responsibility of forest owners and managers for future forest stands to the coming generations of people? The knowledge exists about the soil processes and the possible damages caused by overstraining the natural limits of the soil system. There are also guidelines for careful forest management even with modern machinery. Rejecting wood harvesting techniques with integrated state-of-the-art soil protection measures purely on economic grounds is incompatible with sustainable thinking.

Sign in / Sign up

Export Citation Format

Share Document