Journal ArticleDOI
The Weathering of Serpentinite by Lecanora Atra
TLDR
A study of the weathering phenomena brought about by the growth of Lecanora alra on a substrate of magnesium silicate minerals (serpentinite) has been carried out mainly by X-ray diffraction and scanning electron microscopy as mentioned in this paper.Abstract:
A study of the weathering phenomena brought about by the growth of Lecanora alra on a substrate of magnesium silicate minerals (serpentinite) has been carried out mainly by X-ray diffraction and scanning electron microscopy. The lichen thallus contains appreciable amounts of crystalline magnesium oxalate dihydrate, which occurs as an insoluble extra-cellular precipitate and derives from the decomposition of magnesium silicates (particularly chrysotile) by oxalic acid secreted by the mycobiont. In theory magnesium oxalate dihydrate should be capable of incorporating large amounts of heavy metal ions into its structure, as indeed the electron probe evidence indicates has happened, thus suggesting a mechanism for enabling some lichens to cope with environments that are high in these generally harmful ions. The only weathering product detected in the lichen weathering crust is an X-ray amorphous silica gel which often retains the fibrous morphology of the chrysotile from which it forms.read more
Citations
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Journal ArticleDOI
Weathering of rocks induced by lichen colonization — a review
TL;DR: In this paper, the effects of lichens on their mineral substrates can be attributed to both physical and chemical processes, such as hyphal penetration, expansion and contraction of lichen thallus, swelling action of the organic and inorganic salts originating from lichen activity.
Journal ArticleDOI
Weathering of the primary rock-forming minerals: processes, products and rates
TL;DR: In this article, the authors describe the ways in which the major rock-forming primary minerals (olivine, pyroxenes, amphiboles, feldspars, micas and chlorites) break down during weathering, the products that develop during this breakdown and the rates at which this breakdown occurs.
Journal ArticleDOI
Weathering of rocks and neogenesis of minerals associated with lichen activity
Paola Adamo,P. Violante +1 more
TL;DR: In this paper, the authors reviewed the role of lichens on rocks and the biogeophysical and biogeochemical alteration of rock-forming minerals, their influence in dissolution and precipitation reactions and in bioformation of new minerals.
Book ChapterDOI
Role of Biologicaland Biochemical Factors in Soil Mineral Weathering
M. Robert,J. Berthelin +1 more
Journal ArticleDOI
Biologically versus inorganically mediated weathering reactions: relationships between minerals and extracellular microbial polymers in lithobiontic communities
TL;DR: In the case of amphibole syenite, a specialized weathering microenvironment around each mineral grain initially produces minute phyllosilicate crystallites and a rind of clay minerals forms around the dissolving parent phase, eventually culminating in abundant 5-10 μm diameter polymer-bound aggregates of face-to-face oriented clay minerals of homogeneous composition as discussed by the authors.
References
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Journal ArticleDOI
Weathering of a Basalt by Pertusaria Corallina
TL;DR: The weathering phenomena resulting from the encrustation of basalt by Pertusaria corallina have been studied by scanning electron microscopy and a variety of other techniques as discussed by the authors.
Journal ArticleDOI
Glushinskite, a naturally occurring magnesium oxalate
TL;DR: In this article, Glushinskite, a dihydrate of magnesium oxalate, occurs at the lichen/rock interface on serpentinite colonized by Lecanora atra at Mill of Johnston, near Iusch in north-east Scotland.
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Weathering of rocks and neogenesis of minerals associated with lichen activity
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