Soil genesis, mineralogy and chemical composition in a steatite outcrop under tropical humid climate in Brazil

CATENA ◽  
2019 ◽  
Vol 183 ◽  
pp. 104234 ◽  
Author(s):  
Emerson Ferreira Vilela ◽  
Alberto Vasconcellos Inda ◽  
Yuri Lopes Zinn
Keyword(s):  
Chemical Composition ◽  
Humid Climate ◽  
Soil Genesis

scholarly journals On soil genesis in temperate humid climate. VIII. The formation of a "udalfic" eutrochrepi.

1970 ◽  
Vol 18 (3) ◽  
pp. 207-214 ◽  
Author(s):  
J. Van Schuylenborgh ◽  
S. Slager ◽  
A.G. Jongmans
Keyword(s):  
Biological Activity ◽  
Clay Minerals ◽  
Redox Processes ◽  
Humid Climate ◽  
Soil Genesis ◽  
Fe Oxide ◽  
The Holocene ◽  
Differential Movement ◽  
The Difference ◽  
Soil Forming Processes

The active soil-forming processes occurring in a Holocene alluvial deposit were: the formation, along voids, of illuvial cutans consisting of clay minerals, Fe oxide and fine matric components (matriferriargillans), differential movement of clay minerals, kaolinite being most mobile; partial transformation of smectites into kandites; disturbance of cutans by biological activity resulting in the formation of papules; redox processes leading to the formation of micro-segregation of Fe oxide. The difference in character and location of matriferriargillans and ferriargillans is discussed. The former are thought to have been synthesized in the Holocene period and the latter in Pleistocene times. The soil is classifiable as a dystric eutrochrept, but as plasma movement generally occurs only in "dystric" (decalcified) material, the soil could be classified as a "udalfic" eutrochrept. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals On soil genesis in temperate humid climate. IV. The "low humus podzols".

1964 ◽  
Vol 12 (4) ◽  
pp. 291-296
Author(s):  
J. Van Schuylenborgh
Keyword(s):  
Humid Climate ◽  
Soil Genesis ◽  
Reducing Conditions

"Low humus podzols" do not possess a spodic horizon; podzol formation in conjunction with predominantly reducing conditions give rise to an eluviated profile. Low humus podzols have an umbric epipedon, the Fe and Al contents of the B horizon are intermediate between those of the A and C horizon, and their humus is mostly dispersed. Psammic Umbraquepts is proposed as a fifth subgroup for these soils. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals On soil genesis in temperate humid climate. VII. The formation of a glossaqualf in a silt-loam terrace deposit.

1969 ◽  
Vol 17 (4) ◽  
pp. 261-271
Author(s):  
J. Bouma ◽  
J. Van Schuylenborgh
Keyword(s):  
Thin Layer ◽  
Soil Profile ◽  
Parent Material ◽  
Silt Loam ◽  
Humid Climate ◽  
Soil Genesis ◽  
Thin Sections ◽  
Reduction Processes ◽  
Physical Chemical ◽  
Terrace Deposit

The physical, chemical and micromorphological properties of a poorly drained soil profile developed on clayey parent material covered by a thin layer of loess are described. Clay skins on peds were absent in the B-horizon which is considered to be of Pleistocene age. In thin sections, however, oriented clay was observed inside peds occurring undisturbed as free grain and channel argillans, and disturbed by pedoturbation as quasicutans and papules. Clay was leached vertically through the B horizon along planar voids between prisms, leaving accumulations of skeleton grains. Some clay was also leached from the A2 horizon. Kaolinite was more mobile than illite or smectite. Reduction processes resulted in strongly bleached areas around prisms and in well developed mangans on ped faces and around channels. The profile was classified as an aerie glossaqualf. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals On soil genesis in temperate humid climate. V. The formation of the "albic" and "spodic" horizon.

1965 ◽  
Vol 13 (3) ◽  
pp. 267-279
Author(s):  
J. Van Schuylenborgh ◽  
M.G.M. Bruggenwert
Keyword(s):  
Stability Constants ◽  
Solubility Product ◽  
Humid Climate ◽  
Soil Genesis ◽  
Parent Materials ◽  
Model Substance ◽  
Fe Complexes ◽  
The Stability ◽  
Insoluble Compounds ◽  
Hydrolysis Of

With the aid of parahydroxybenzoic acid as a model substance, some suggestions are given on the formation of the albic and spodic horizons under well-aerated conditions in very poor and acid parent materials. The acid forms soluble complexes with Fe, while insoluble compounds are formed with Al. The stability constants of the Fe complexes and the solubility product of the Al complex were determined. Hydrolysis of the Fe complexes formed in the A horizon, and formation of an insoluble Al complex are the most important mechanisms in the formation of the B2ir and B2h horizons, respectively. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals On soil genesis in temperate humid climate. II. The behaviour of the non-clay fraction in some soil groups.

1963 ◽  
Vol 11 (1) ◽  
pp. 10-12
Author(s):  
J. Van Schuylenborgh
Keyword(s):  
Organic Acids ◽  
Clay Minerals ◽  
Clay Fraction ◽  
Humid Climate ◽  
Soil Genesis ◽  
Amp Clay ◽  
Soil Groups

The SiO2, A12O3 & Fe2O3 contents of the non-clay fraction of podzol, gray-brown podzolic, brown podzolic, acid brown earth & gley soils were calculated from the soil & clay composition. Results which are tabulated with the silica-ses-quioxide ratios show that the translocation of Fe & Al is fundamentally the same process. Although Al migrates with the clay minerals, if there is clay eluviation, weathering resulting in the liberation of A12O3 & Fe2O3, and subsequent translocation by organic acids are more important. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals On soil genesis in temperate humid climate. 1. Some soil groups in the Netherlands.

1962 ◽  
Vol 10 (2) ◽  
pp. 127-144
Author(s):  
J. Van Schuylenborgh
Keyword(s):  
The Netherlands ◽  
Parent Material ◽  
Humid Climate ◽  
Soil Genesis ◽  
Podzolic Soils ◽  
Soil Groups

Profiles of humus-iron and humus podzols, gray-brown podzolic soils, acid brown earths, brown podzolic soils and gley soils are described. Podzols developed on very poor acid parent material (low in silt and low in clay, i.e.

The Origin of the Moon

1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
The Moon ◽  
The Earth ◽  
The Difference ◽  
Origin Of The Moon

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.

On the Inhomogeneity of Chemical Composition over the Surface of 21 Per

1976 ◽  
Vol 32 ◽  
pp. 343-349
Author(s):  
Yu.V. Glagolevsky ◽  
K.I. Kozlova ◽  
V.S. Lebedev ◽  
N.S. Polosukhina
Keyword(s):  
Chemical Composition ◽  
Spectral Line ◽  
Variable Star ◽  
Radial Velocities ◽  
Crimean Astrophysical Observatory ◽  
Line Intensities ◽  
Magnetic Variable

SummaryThe magnetic variable star 21 Per has been studied from 4 and 8 Å/mm spectra obtained with the 2.6 - meter reflector of the Crimean Astrophysical Observatory. Spectral line intensities (Wλ) and radial velocities (Vr) have been measured.

Structural Studies on Mitotic Spindle Fibres

1978 ◽  
Vol 36 (3) ◽  
pp. 615-626
Author(s):  
J.R. Mcintosh
Keyword(s):  
Chemical Composition ◽  
Mitotic Spindle ◽  
Structural Studies ◽  
Mitotic Apparatus ◽  
Chemical Studies ◽  
Medical Interest ◽  
Spindle Fibres

The mitotic apparatus is a structure of obvious biological and medical interest, but it has proved to be a difficult cellular machine to understand. The chemical composition of the spindle is only slightly elucidated, largely because of the difficulties in preparing useful isolates of the structure. Chemical studies of the mitotic spindle have been reviewed elsewhere (Mcintosh, 1977), and will not be discussed further here. One would think that structural studies on the mitotic apparatus (MA) in situ would be straightforward, but even with this approach there is some disagreement in the results obtained with various methods and by different investigators. In this paper I will review briefly the approaches which have been used in structural studies of the MA, pointing out the strengths and problems of each approach. I will summarize the principal findings of the different methods, and identify what seem to be fruitful avenues for further work.

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