scholarly journals Clay minerals associations in palaeoweathering profiles from Central Spain: genesis and implications

Clay Minerals ◽  
2012 ◽  
Vol 47 (1) ◽  
pp. 117-129 ◽  
Author(s):  
M. Doval ◽  
R. Martín-García ◽  
Á. La Iglesia ◽  
A. M. Alonso-Zarza
Keyword(s):  
Clay Minerals ◽  
Iron Oxides ◽  
Primary Structure ◽  
Metamorphic Rocks ◽  
Progressive Decrease ◽  
Central Spain ◽  
Central System ◽  
Weathering Processes ◽  
Spanish Central System ◽  
Mixed Layers

AbstractThis study examines part of the thick palaeoweathering mantle that formed on the northern area of the Spanish Central System. The study of a compound profile indicates that despite weathering processes, the primary structure of the metamorphic rocks is preserved, and is only partially lost in some intervals of the upper part of the compound profile. Macro/micromorphology, mineralogy and geochemical changes within the profiles revealed two weathering paths. In the first path, Fe-chlorite weathered to chlorite-smectite mixed-layer/smectite/kaolinite+ iron oxides. In the second path, biotite and/or muscovite weathered to kaolinite + iron oxides. The profiles show a progressive decrease, from base to top, in mica and mixed-layers and an increase in smectite and kaolinite. Thus, the profiles only comprise the lower or intermediate zones of the weathering mantle. The weathering occurred under humid climates; the lower zones of the profiles were poorly drained, whereas the topmost zones were better drained and more oxidizing. The results obtained indicate that detailed mineralogical studies are very useful to reconstruct the characteristics of the weathering mantles, and as palaeogeographic and palaeoclimatic indicators.

scholarly journals Clay mineral genesis and chemical evolution in the Miocene sediments of Somosaguas, Madrid Basin, Spain

Clay Minerals ◽  
2007 ◽  
Vol 42 (2) ◽  
pp. 187-201 ◽  
Author(s):  
O. Fesharaki ◽  
E. García-Romero ◽  
J. Cuevas-González ◽  
N. López-Martínez
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clay Minerals ◽  
Analytical Electron Microscopy ◽  
Source Area ◽  
Alluvial Fan ◽  
Granitic Rocks ◽  
Central System ◽  
Transmission Electron ◽  
Spanish Central System

AbstractA mineralogical and microtextural study of Somosaguas Miocene deposits, located in the Madrid Basin (western Madrid, Spain), was carried out using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and optical microscopy, whereas crystal chemistry data were obtained by analytical electron microscopy-transmission electron microscopy and electron icroprobe analysis. Four stratigraphic sections were studied, compising detrital rocks representing intermediate and distal facies from alluvial fan deposits. The predominant source area of these sediments was the granitic rocks of the Spanish Central System with a lesser contribution of metamorphic rocks. Clayey arkoses are the most abundant rocks of these sections, typical of granite alteration under warm, semi-arid climates. The mineralogy is characterized by phyllosilicates, followed by feldspars and quartz. The data obtained reveal mineral mixtures of detrital (quartz, feldspars, kaolinite, micas and chlorite), transformed (illite and beidellite) and neoformed (montmorillonite) origin. Clay minerals resulted from interactions between detrital minerals and meteoric waters. Two trends of degradation of micas are detected. The first shows a transition from muscovites and dioctahedral illites, to beidellites. The other trend is defined by the biotite degradation to beidellites with different layer charge and octahedral Fe content. Montmorillonites were neoformed from the hydrolysis and weathering of primary minerals (feldspars and muscovite). Magnesian clay minerals such as sepiolite, palygorskite and trioctahedral smectites, extremely abundant in the centre of the basin, were not detected in Somosaguas sediments.

scholarly journals Determination of present-day stress tensor and neotectonic interval in the Spanish Central System and Madrid Basin, central Spain

1996 ◽  
Vol 266 (1-4) ◽  
pp. 405-424 ◽  
Author(s):  
G. De Vicente ◽  
J.L. Giner ◽  
A. Muñoz-Martín ◽  
J.M. González-Casado ◽  
R. Lindo
Keyword(s):  
Stress Tensor ◽  
Central Spain ◽  
Central System ◽  
Spanish Central System

Crustal density structure in the Spanish Central System derived from gravity data analysis (Central Spain)

2005 ◽  
Vol 403 (1-4) ◽  
pp. 131-149 ◽  
Author(s):  
D. Gómez-Ortiz ◽  
R. Tejero-López ◽  
R. Babín-Vich ◽  
A. Rivas-Ponce
Keyword(s):  
Data Analysis ◽  
Gravity Data ◽  
Density Structure ◽  
Central Spain ◽  
Central System ◽  
Crustal Density ◽  
Spanish Central System

scholarly journals Nano-Sized Minerals from Lower Cretaceous Sandstones in Israel Observed by Transmission Electron Microscopy (TEM)

2021 ◽  
Author(s):  
Nurit Taitel-Goldman ◽  
Vladimir Ezersky
Keyword(s):  
Clay Minerals ◽  
Iron Oxides ◽  
Lower Cretaceous ◽  
Fine Fraction ◽  
Anatase Tio2 ◽  
Rutile Tio2 ◽  
Transmission Electron ◽  
Quartz Arenite ◽  
Dark Violet ◽  
Hematite Fe2o3

Fine fraction in quartz arenite sandstones from Lower Cretaceous Hatira formation in Israel was observed by Transmission electron microscope (TEM). Samples were collected from Hatira and Ramon craters located in southern part of Israel and from Manara cliff from the northern part of Israel. The additional phases cause yellow, red, dark red and dark violet colors of the layered sandstones. The motivation was to identify the minerals of the fine factions that cause the variations in the colors. The minerals observed were clay minerals, mainly kaolinite (Al4Si4O20(OH)8), some illite (K0.65Al2.0[Al0.65Si3.35O10](OH)2) and smectite. Iron oxides were goethite (FeOOH) and hematite (Fe2O3), Titanium-iron oxides observed was ilmenite (FeTiO3), and Titanium-oxides were rutile (TiO2), and anatase (TiO2). Sulphates observed were jarosite (KFe3(SO4)2(OH)6) and alunite (KAl3(SO4)2(OH)6). Some of the hematite was formed by recrystallization of goethite. Ilmenite disintegrated into small iron oxides mainly hematite. Euhedral to sub-hedral rutile (TiO2) and anatase (TiO2) were preserved in clay-minerals. Crystals of alunite and jarosite were observed in sandstones in both craters. They probably crystallized due to some transgression of the Thetis Sea.

scholarly journals Clay Minerals Variations in Quaternary Sediments of Basrah City-Iraq

2017 ◽  
Vol 6 (2) ◽  
pp. 41
Author(s):  
Mohanad Hamid Al-Jaberi
Keyword(s):  
Clay Minerals ◽  
Mineralogical Composition ◽  
Silty Sand ◽  
Recent Sediment ◽  
Quaternary Sediments ◽  
Marine Transgression ◽  
Fine Grain ◽  
Clayey Silt ◽  
Marine Facies ◽  
Mixed Layers

Mineralogical and chemical analysis of two well cutting in quaternary sediments at Basrah city. This study have been focused on the quaternary clay minerals variations which give a clear indication to marine transgression and or / regression in Hammar formation. Kaolinite, Illite, Palygoreskite, Illite-Palygorestike mixed layer, Chlorite, Montmorillonite, Vermiculte, and mixed layers of Illite- Smectite are the most quantitatively important phyllosilicates in soil studies in both boreholes. The mineralogical composition of cutting sediments shows significant variability in the different size fractions and depth distribution. Chlorite and kaolinite minerals were increase in the fine grain size especially in the clayey silt, whereas montmoriolllinite and vermiculite minerals were increase in coarse grains especially in silty sand texture. Kaolinite decrease in abundance with depth, which give indicative of a transition from non-marine in quaternary recent sediment ( fresh or brackish water silt) to marine facies in quaternary Hammar formation ( marine shelly silt) during last transgression of quaternary. Palygoreskite mineral percentages increasing at depths 27 and 28 meter , after decreased at 30, 32, 35 , and 40 m respectively , which give data indication that early quaternary marine transgression happened in 32m , and center of quaternary marine transgression detected in 27 and 28 meters , while late marine transgression detected in 17 m , and all of these represent by Hammar formation. Soil ageing also caused to downward increase of montmorillonite suggest to climate became more arid during the early quaternary. Variations ratio of montmorillonite versus kaolinite can be indicated to climatic fluctuation. Illite-Semectite featured indicates changes in both sediment source and paleoclimate. Illite transformation for Illite-Palygoreskite mixed layers with ageing. Vermiculite has strong susceptibility to increase with age. SiO₂, Al₂O₃, CaO, MgO, K₂O, and Fe₂O₃ were the major oxides that identified in present study and used as indicated of clay minerals in studied sediments.

An occurrence of polymorphic halloysite in granite saprolite of the Bayerischer Wald, Germany

Clay Minerals ◽  
1978 ◽  
Vol 13 (1) ◽  
pp. 67-77 ◽  
Author(s):  
B.-M. Wilke ◽  
U. Schwertmann ◽  
E. Murad
Keyword(s):  
Trace Elements ◽  
Clay Minerals ◽  
Iron Oxides ◽  
Aqueous Phase ◽  
Mixed Layer ◽  
Thin Plates ◽  
Low Crystallinity

AbstractXRD, DTA and IR patterns showed clay veins filling fissures in a granite of the Bayerischer Wald (eastern Bavaria) to consist mainly of hydrated halloysite of low crystallinity with traces of gibbsite, 2:1 (mixed layer) clay minerals and iron oxides. The halloysite forms thin plates which exhibit varying degrees and types of enrolment, resulting in platy, tubular and spheroidal crystals within the same sample. Concentrations of the trace elements Rb, Sr, Ba, Zr, Y, Ce, Pb, Zn and Cu indicate halloysite formation to have taken place via an aqueous phase under the influence of vadose waters circulating in fissures.

Thermal study of some manganese oxide minerals

1950 ◽  
Vol 29 (210) ◽  
pp. 239-251 ◽  
Author(s):  
J. Laurence Kulp ◽  
Jose N. Perfetti
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Manganese Oxide ◽  
Clay Minerals ◽  
Iron Oxides ◽  
Theoretical Background ◽  
Thermal Study ◽  
The Past ◽  
Considerable Success ◽  
Oxide Minerals

In the past decade, differential thermal analysis has developed into a very useful mineralogical technique. The theoretical background for this method has been treated by Speil, Berkelhamer, Pask, and Da vies (1945) and has been modified by Kerr and Kulp (1948, 1949). The application of the method to the clay minerals has been carried out with considerable success by a number of workers in Europe and America. In particular, Grim and co-workers (1942, 1947, 1948) have produced a number of significant papers dealing with the thermal analysis of clays. The method has been extended to other mineral groups such as the carbonates (Faust, 1949; Beck, 1946; Kerr and Kulp, 1947; Cuthbert and Rowland, 1947; Kulp, Kent, and Kerr, 1950), phosphates (Manly, 1950), sulphates (Kulp and Adler, 1950), quartz (Faust, 1948), and the hydrous iron oxides (Kulp and Trites, 1950).

A fluid-inclusion study and genetic model of wolframite-bearing quartz veins, Garganta de los Montes, Spanish Central System

1990 ◽  
Vol 54 (375) ◽  
pp. 267-278 ◽  
Author(s):  
E. Ouilez ◽  
J. Sierra ◽  
E. Vindel
Keyword(s):  
Genetic Model ◽  
Fluid Inclusion Study ◽  
Central System ◽  
Quartz Veins ◽  
Low Salinity ◽  
Third Stage ◽  
Inclusion Study ◽  
Moderate Salinity ◽  
Spanish Central System

AbstractWolframite-bearing quartz veins from Garganta de los Montes, Madrid province, are hosted by banded gneisses that have undergone intense migmatization processes. The ore deposit is closely related to the La Cabrera granitic batholith. The veins strike 075° and dip 75°S. The mineral association includes wolframite, quartz and minor amounts of scheelite and sulphides (sphalerite, chalcopyrite, pyrrhotite, stannite and marcasite). The fluid phases associated with quartz from the vein margin (early barren quartz) and from the vein centre (late wolframite-bearing quartz) have been studied using microthermometry, scanning electron microscopy and crushing test analyses. Four hydrothermal stages have been distinguished.The earliest fluids, only recognized in the barren quartz, contain brine, daughter phase (halite) and trapped minerals. The second hydrothermal stage is characterized by complex carbonic-aqueous inclusions of low salinity (3 to 7 wt.% eq. NaC1) and low density (0.4 to 0.7 g.cm−3). They mainly homogenize into liquid between 300 and 420°C. The third stage is represented by low to moderate salinity inclusions (<9 wt. % eq. NaCl) of moderate density (0.8 to 0.96 g.cm−3), homogenizing between 120° and 330°C. The latest fluids correspond to aqueous solutions of higher salinities (H2O-NaCl, with Ca2+ and Mg2+) and densities (>1 g.cm−3), with TH ranging between 50 and 130°C. The role of the complex-carbonic aqueous fluids in the transport and precipitation of tungsten is highlighted.

Sodium-fluoride pH of South-Western Australian soils as an indicator of P-sorption

Soil Research ◽  
1994 ◽  
Vol 32 (4) ◽  
pp. 755 ◽  
Author(s):  
RJ Gilkes ◽  
JC Hughes
Keyword(s):  
Clay Minerals ◽  
Iron Oxides ◽  
Sorption Capacity ◽  
Sodium Fluoride ◽  
Secondary Importance ◽  
P Sorption ◽  
Soil Constituent ◽  
Western Australian ◽  
Soil Constituents ◽  
Measuring Ph

Phosphate sorption by the surface horizon of 228 acid to neutral Western Australian (W.A.) soils is more closely related (r(2) = 0.76) to the content of oxalate-extractable aluminium than to any other soil constituent. This fraction corresponds to poorly ordered inorganic and organic Al compounds that release considerable amounts of OH- to NaF solution. Thus the abundance of these compounds in soil may be estimated by measurement of the pH of a NaF extract (pH((NaF)) This association enables the rapid and moderately accurate prediction in the field of the P-sorption capacity of soils (r(2) = 0.72) by measuring pH(NaF) With a. simple, portable pH meter. For many W.A. soils, it is probable that well crystalline aluminium and iron oxides, clay minerals and other soil constituents are of secondary importance in determining P-sorption and that most P-sorption is due to poorly ordered and organically complexed forms of Al.

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