This paper demonstrates that on the glacial foreland at Storbreen, chemical weathering and associated soil development trends show significant elevational influences. Thus the research objectives in this study were to determine the effects
Chemicalalteration ; Pleistocene ; Quaternary ; South Africa ; Weathering
The extensive angular Pleistocene debris covers of the western Cape have been attributed to cryoclastic origin. However, evidence of chemical weathering and lichen growth is presented suggesting further research is necessary. - (AJC)
Chemicalalteration ; Crystalline rocks ; Geochemistry ; Geomorphogenesis ; Maryland ; Model ; Periglacial features ; United States ; Weathering
The possible impact of periglacial climates on the rate of chemical weathering of a coarse-grained plagioclase-muscovite-quartz schist has been determined for a small watershed near Baltimore, Maryland. The results suggested by the chemical
REE, while the extremely altered residual products are especially depleted in the heavy REE. Mobilisation of the REE probably results from PH changes of soil and ground waters as they encounter different chemical environments while fractionation may
The rare earth elements (REE) have been mobilised and fractionated during supracrustal alteration of the Torrongo granodiorite. Compared with the parent granodiorite, incipiently and moderately altered rocks are particularly enriched in the heavy
largely result from mineralogical controls. Submarine and subaerial weathering processes may affect REE similarly, producing intensively weathered materials appreciably depleted in the REE. Spilitisation and hydrothermal alteration processes may affect
Chemical pollution ; Ecosystem ; Environment ; Floodplain ; Human impact ; Humid environment ; Netherlands (The) ; Pollution ; Vegetation ; Water pollution
, are pollutants transported (and retarded or chemicallyaltered) towards the river plain, is regeneration of upward seepage a good restoration measure?. - (AGD)
Chemical erosion ; Colorado ; Geochemistry ; Mineralogy ; United States of America ; Weathering
The AA. present results from a study of two sites located on the 1.65 Ga Boulder Creek Granodiorite near Boulder, Colorado, USA, in which weakly chemicallyaltered saprock derived from tonalitic and granodioritic–tonalitic bedrock records volumetric
strains on the order of 7.6%–8.5% and 7.9%–8.2% respectively. They show that dilation is likely due to the alteration of biotite to vermiculite during the early stages of weathering, and is associated with an expansion normal to the {001} cleavage of ~ 40
origins : (1) an inherent variability in soils owing to geological and genetic constraints, and (2) an alteration of soil physical and chemical properties by the vegetation.
the weathering to be of preglacial origin. The rapakivi saprolites are of grus type. The weathering has caused both mechanical and chemicalalteration of the parent rock. The residual topography comprises small tor-like features.
Besides the elaboration of erosion surfaces and the positioning of the hydrographic network, the result of chemicalalterations is important in relief building. Evacuation of the running products and denudation of the unaltered rocks are the major
Sand composition and Chemical Index of Alteration (CIA) of parent rocks, soil and fluvial sand of the Savuto River watershed, Calabria (Italy), were used to evaluate the modifications of source rocks through different sections of the basin
, characterized by different geomorphic processes, in a sub-humid Mediterranean climate. The study area provides a good opportunity to study some of the processes (i.e. chemical weathering, slope instability and erosion) controlling landscape development
Mineralogical and geo-chemical characterization of a diapiric formation in the North of Spain
The AA. study a diapiric zone located in the Miranda-Treviño Depression, in the southern part of the Basque-Cantabrian Basin. They have selected 7 profiles : 3 soils formed on basic rock of volcanic origin (ophite) and rich in alterable minerals, 3
others formed on clay marl and one soil formed on gypsiferous marl. The profiles have been analyzed for the mineralogy and the chemical composition of original materials, soils developed above them and clay fractions. Fundamentally, it is the semiarid
Physical, chemical, and mineralogical analyses of undisturbed drill cores of pelitic schist from a landslide area in Japan clarified the mechanisms of chemical weathering of pelitic schist. Oxidizing surface water percolates downward and reaches
an oxidation front, where chlorite is altered to Al-vermiculite, graphite and pyrite are oxidized and depleted, and goethite precipitates. Pyrite oxidation yields sulphuric acid, which penetrates further downward, interacting with and weakening the rocks
. In addition to this chemical weakening, stress release and shearing along schistosities form an incipient shear zone, which propagates to a sliding zone that forms the rupture surface of a landslide. Once a sliding zone has developed, it inhibits downward
this to a depth of up to 60 mm. This zone of alteration coincides with chemical changes. Salt weathering is a threshold phenomenon where decay is manifest only when a stress/strength threshold is crossed. Consequently, in a structurally and mineralogically
Analysis of two clay-rich sandstone blocks from a temperate maritime, urban environment indicates that, although structural changes such as scaling and flaking affect only the outer 10-20 mm of stone, the zone of alteration extends well beyond