scholarly journals PESTRÉ SEDIMENTY OTTNANGU V BRNĚ-KOHOUTOVICÍCH

2018 ◽  
Vol 25 (1-2) ◽  
Author(s):  
Pavla Tomanová Petrová ◽  
David Buriánek ◽  
Karel Kirchner ◽  
Oldřich Krejčí ◽  
František Laufek ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Clay Minerals ◽  
Heavy Fraction ◽  
Parent Rock ◽  
Fine Grained ◽  
Sediment Layers

The reddish coloured sediment layers (up to 5 m thick) were found within building pit in the Brno-Kohoutovice on the Libušina třída Avenue (NW part of Brno). These sediments were assigned to the Ottnangian based on characteristic pseudoassociation of microfossils. Smectite or illite/smectite dominates over kaolinite among the clay minerals. Minerals typomorphic for granitoids of the Brno Massif, i.e. epidote, amphibole and altered titanite, absolutely dominate (99 mod. %) within the assemblage of translucent heavy fraction. Minerals like garnet and staurolite which are typical for the Ottnangian sediments in this region, are presented only in accessoric amount. The chemical composition of the studied sediments is located between the chemical composition of granodiorites of the Brno Massif and Neogene clays. Relatively high content of Zr, Hf and HREE, which is interpreted as result of presence of very fine grained zircon in studied sediments, is characteristic. High content of SiO2 and comparatively low contents of Al2O3 and Fe2O3 indicates non-lateritic type of weathering. The chemical composition of studied sediments reflects semiarid to humid paleoclimate that the granitoids of the Brno Massif as parent rock have undergone.

scholarly journals Synrift sandstones and clayey rocks: bulk chemical composition and location on a number of discriminant paleogeodynamic diagrams

2019 ◽  
pp. 439-465
Author(s):  
A. V. Maslov ◽  
V. N. Podkovyrov ◽  
E. Z. Gareev ◽  
A. D. Nozhkin
Keyword(s):  
Chemical Composition ◽  
Continental Margins ◽  
Bulk Chemical Composition ◽  
East European ◽  
Fine Grained ◽  
Sedimentary Deposits ◽  
Data Points ◽  
Bulk Chemical ◽  
Clayey Rocks ◽  
Active Continental Margins

The bulk chemical composition of synrift sandstones and associated clayey rocks has been analized, and the distribution of the fields they form has been studied on discriminant paleogeodynamic SiO2K2O/Na2O [Roser, Korsch, 1986] and DF1DF2 [Verma, Armstrong-Altrin, 2013] diagrams. The studied sandstones in terms of bulk chemical composition mainly correspond to greywacke, lititic, arkose and subarkose psammites; Sublitites and quartz arenites are also found. A significant part in the analyzed data massif consists of psammites, in which log(Na2O/K2O)-1.0; missing on the Pettijohn classification chart. This confirms our conclusion, based on the results of mineralogical and petrographic studies, that the sedimentary infill of rift structures unites immature sandstones, the detrital framework of which was formed due to erosion of local sources, represented by various magmatic and sedimentary formations. Synrift clayey rocks, compared with sandstones, are composed of more mature fine-grained siliciclastics. As follows from the distribution of figurative data points of clayey rocks on the F1F2 diagram [Roser, Korsch, 1988], its sources were mainly sedimentary deposits. The content of most of the main rock-forming oxides in the synrift sandstones is almost the same as in silt-sandstone rocks present in the Upper Precambrian-Phanerozoic sedimentary mega-complex of the East European Plate, but at the same time differs significantly from the Proterozoic and Phanerozoic cratonic sediments, as well as from the average composition upper continental crust. It is shown that the distribution of the fields of syntift sandstones and clayey rocks on the SiO2K2O/Na2O diagram does not have any distinct features, and their figurative data points are localized in the areas of terrigenous rocks of passive and active continental margins. On the DF1DF2 diagram, the fields of the studied psammites and clayey rocks are located in areas of riftogenous and collisional environments. We have proposed a different position of the border between these areas in the diagram, which will require further verification.

Nouvelles observations sur les roches vertes de l'anticlinal de Laniscat-Merleac (Cotes-du-Nord)

1963 ◽  
Vol S7-V (5) ◽  
pp. 844-851 ◽  
Author(s):  
Jean Nicolas ◽  
Jean Paul Sagon
Keyword(s):  
Chemical Composition ◽  
Chemical Analysis ◽  
Rock Sample ◽  
Coarse Grained ◽  
Northern Flank ◽  
Fine Grained ◽  
Rock Supports

Abstract Observations on the dolerites of the northern flank of the E-W-trending Laniscat-Merleac anticline in NW France suggest that the rocks were emplaced as coulees. A well-marked granular differentiation in the rock supports this hypothesis; the coarse-grained rocks are in contact with Devonian rocks at the bottom of the coulee and the fine-grained rocks are in contact with Dinantian rocks at the top. Chemical analysis shows that there is a diminishing of Na <sub>2</sub> O and an augmentation of the percentage of CaO ranging from the boundary of the coarse-grained rock to that of the fine-grained. Overlying the green rocks are green schists of comparable chemical composition attributed to former tuffs which were subject to regional epimetamorphism. Finally, a coarse-grained, green rock sample has been traced to the spilite family.

Jurassic clay mineral assemblages and their post-depositional alteration: upper Great Estuarine Group, Scotland

1987 ◽  
Vol 124 (3) ◽  
pp. 261-271 ◽  
Author(s):  
Julian E. Andrews
Keyword(s):  
Clay Minerals ◽  
Clay Mineral ◽  
Mixed Layer ◽  
Middle Jurassic ◽  
Water Circulation ◽  
Hot Water ◽  
Geothermal Gradients ◽  
Fine Grained ◽  
Igneous Intrusions ◽  
Mineral Assemblages

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.

Sediment contamination by heavy metals in a lock-regulated section of the River Neckar

1995 ◽  
Vol 46 (1) ◽  
pp. 101 ◽  
Author(s):  
U Kern ◽  
B Westrich
Keyword(s):  
Heavy Metals ◽  
Principal Component ◽  
Coarse Grained ◽  
Acid Neutralizing Capacity ◽  
High Concentration ◽  
Fine Grained ◽  
Neutralizing Capacity ◽  
Sediment Fraction ◽  
Sediment Layers ◽  
Different Sources

For a lock-regulated reach of the River Neckar at Lauffen, Germany, results from sediment core analysis are presented. It is observed that sediment layers with a high concentration of heavy metals, especially cadmium, are covered by younger, less polluted sediment layers. A principal component analysis separated the parameters measured into three groups: heavy metals from human activities (Cd, Cr, Ni, Pb, Zn), metals from natural sources (Co, Fe, Mn), and inorganic carbon. Within the fine-grained sediment fraction containing particles smaller than 20 μm, a higher concentration of anthropogenic trace metals was found in fine-grained samples than in coarse-grained samples, whereas Co, Fe and Mn showed the opposite tendency. Obviously, this is due to two different sources of fine-grained material: sewage flocs and natural erosion particles. Acid-producing capacity (APC) and acid-neutralizing capacity (ANC) are calculated for both pore water and particulate matter of the sediment. At a depth of 20 cm, APC and ANC are controlled by the sediment matrix. ANC, which is due to calcium carbonate, is 20 times higher than APC, which is predominantly due to reduced sulfur components. Therefore, oxidation of sediment of the River Neckar does not lead to acidification.

Anti-termite and anti-fungal bio-sourced wood preservation ingredients from Dacryodes edulis (G. Don) H.J. Lam resin

Holzforschung ◽  
2020 ◽  
Vol 74 (8) ◽  
pp. 745-753
Author(s):  
Walter Fiacre Bédounguindzi ◽  
Kévin Candelier ◽  
Prosper Edou Engonga ◽  
Stéphane Dumarçay ◽  
Marie-France Thévenon ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Chemical Composition ◽  
Essential Oil ◽  
Heavy Fraction ◽  
Wood Preservation ◽  
Gas Chromatography Mass Spectrometry ◽  
Wood Protection ◽  
Anti Fungal ◽  
Dacryodes Edulis

AbstractDacryodes edulis (G. Don) H.J. Lam resin was hydro-distilled to recover essential oil (EO), and further purified to produce a heavy fraction constituting less volatile compounds. Chemical composition was investigated by gas chromatography-mass spectrometry (GC-MS), and indicated that different monoterpenes and triterpenes were present depending on the analyzed fraction. Bioassays were performed on the different fractions to evaluate their anti-fungal and anti-termite properties. Results indicated that crude resin, its heavy fraction and its EO all had proved termicidal properties, which decrease on drying for EO and crude resin due to evaporation of monoterpenes. Conversely, no anti-fungal properties were observed for any fraction. Dacryodes edulis resin is therefore a new valuable bioactive ingredient for the formulation of wood protection products with anti-termite properties.

Smectite, chlorite and a regular interlayered chlorite-vermiculite in soils developed on a small serpentinite body Massif Central, France

Clay Minerals ◽  
1976 ◽  
Vol 11 (2) ◽  
pp. 121-135 ◽  
Author(s):  
J. Ducloux ◽  
A. Meunier ◽  
B. Velde
Keyword(s):  
Chemical Composition ◽  
Clay Minerals ◽  
Closed System ◽  
Soil Profile ◽  
Crystalline Rocks ◽  
Soil Profiles ◽  
Massif Central ◽  
Three Stages ◽  
Image Position ◽  
Chemical Migration

AbstractThree soil profiles developed on a serpentinite body (La Rochel'Abeille, near Limoges) show three stages of weathering. All soils contain iron-rich smectites and secondary chlorites. The latter are very silica-rich, more so than 14 Å chlorites from crystalline rocks. In the (B)1g horizon of the hydromorphic profile, these minerals seem to give a reaction of the type:This reaction, typical of a closed system, appears to be operative in a soil profile which is certainly, in part, open to chemical migration. The chemistry of the weathered serpentinite and the chemical composition of newly formed minerals as well as those of the serpentinite are used to indicate the chemiographic relations of clay minerals formed in the weathering profiles.

scholarly journals Spectral stratigraphy and clay minerals analysis in parts of Hellas Planitia, Mars

2014 ◽  
Vol XL-8 ◽  
pp. 419-422
Author(s):  
I. C. Das ◽  
J. Joseph ◽  
S. K. Subramanian ◽  
V. K. Dadhwal
Keyword(s):  
Chemical Composition ◽  
Clay Minerals ◽  
Absorption Feature ◽  
Crater Wall ◽  
Spectral Variability ◽  
Origin And Evolution ◽  
Different Types ◽  
Surface Alteration ◽  
Alteration Minerals ◽  
Absorption Features

Absorption features that occur in reflectance spectra are a sensitive indicator of mineralogy and chemical composition for a wide variety of materials. The investigation of the mineralogy and chemical composition of surfaces give information about the origin and evolution of planetary bodies. On Mars, the processes of formation of different types of clay minerals result from different types of wet conditions viz. hydrothermalism, subsurface/groundwater weathering, surface alteration etc. The image analyzed in the present study was frt000947f- 164-trr3 (&minus;27.87N&ndash;65.06E). Through the spectral stratigraphic characterization along a crater wall, eight (8) different layers were identified considering the spectral variability and their position. In Hellas Planitia, the alteration minerals identified by CRISM based on distinctive absorptions from 0.4 to3.9 μm include Al-rich smectite, montmorillonite, phyllosilicate mineral at 2.2 μm and 2.35 μm, including strong absorption feature noticed at 1.9 μm. We conclude that the layers exposed in the crater wall help characterize the compositional stratigraphy for confirming the presence of hydrated minerals in this region as an outcome of geohydrological weathering process.

scholarly journals Evolução do Manto de Intemperismo Laterítico Rico em Fosfatos na Ilha de Itacupim (PA) - Mineralogia, Micromorfologia e Geoquímica

2006 ◽  
Vol 33 (2) ◽  
pp. 109 ◽  
Author(s):  
MARIA CRISTINA MOTTA DE TOLEDO ◽  
SONIA BARROS DE OLIVEIRA ◽  
MARCONDES LIMA DA COSTA ◽  
CAMILA PASSOS ◽  
HENRIQUE DINIZ DE ALMEIDA
Keyword(s):  
Chemical Composition ◽  
Parent Rock ◽  
Ultramafic Rocks ◽  
Altered Rock ◽  
Island State ◽  
Northern Brazil ◽  
Bottom To Top

The lateritic mantle overlying ultramafic rocks at Itacupim Island (state of Pará, northern Brazil) comprises 5 horizons. From bottom to top they are: (1) altered rock (hornblende, phlogopite, apatite, magnetite, fissural wavellite, and smaller amounts of smectite or kaolinite), (2) a smectitic saprolite (smectite, wavellite, goethite, and traces of hornblende), a kaolinitic saprolite (kaolinite, wavellite, goethite, and traces of phlogopite), a phosphatic duricrust (crandallite, goethite and hematite), and a ferruginous duricrust (hematite, goethite and crandallite). The mineralogical and chemical composition of the saprolitic and duricrust horizons indicate a discontinuity in the weathering evolution: the P-rich crandallitic duricrusts cannot be derived from the P-poor wavellitic saprolites. Most probably, the duricrusts developed during an earlier stage of the weathering evolution, under a drier climate, when the hypogene phosphates (wavellite and apatite) transformed into crandallite. Under subsequent more humid conditions, the weathering alteration of the parent rock led to the dissolution of the hypogene phosphates, resulting in the P-depleted saprolites.

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