scholarly journals The Importance of Mechanical Transport, Rock Texture, and Mineral Chemistry in Chemical Weathering of Granites: The Melechov Massif, Czech Republic

2020 ◽  
Author(s):  
Václav Procházka ◽  
Miroslav Žáček ◽  
Petr Sulovský ◽  
Tomáš Vaculovič ◽  
Lenka Rukavičková ◽  
...  
Keyword(s):  
Czech Republic ◽  
Chemical Weathering ◽  
Mineral Chemistry ◽  
Rock Texture

Multiple alteration events in the history of a sub-Huronian regolith at Lauzon Bay, Ontario

1992 ◽  
Vol 29 (3) ◽  
pp. 432-445 ◽  
Author(s):  
S. J. Sutton ◽  
J. B. Maynard
Keyword(s):  
Clay Minerals ◽  
Chemical Weathering ◽  
Analytical Techniques ◽  
Mineral Chemistry ◽  
White Mica ◽  
Low Grade ◽  
Plagioclase Feldspar ◽  
Fine Grained ◽  
History Of ◽  
Greenschist Facies Metamorphism

Confusion exists over the usefulness of chemical data from Precambrian weathering profiles in constraining models of atmospheric evolution. One difficulty is in correctly identifying ancient weathering effects and isolating them from numerous other processes that are likely to have affected such ancient rocks. In this study of a middle Precambrian granitic weathering profile, we have used several analytical techniques to separate weathering-related chemical and mineralogical changes from those resulting from other processes. The profile is exposed beneath the Huronian at Lauzon Bay in the Blind River area of Ontario and has a complex history of alteration events, addition of allochthonous material, and low-grade metamorphism. Much of this history can be deciphered, and changes in mineralogy and bulk and mineral chemistry can be assigned to separate alteration events. Specifically, the granite has undergone preweathering albitization, resulting in Na enrichment, followed by chemical weathering that corroded K-feldspar and nearly destroyed plagioclase feldspar and mica in the regolith. Clay minerals replaced feldspars, resulting in enrichment in Al, Ti, and Zr and depletion in Na, Ca, Sr, and K. Fe has also been leached. After weathering, a fine-grained 0.5 m layer of strongly weathered allochthonous material was deposited on the regolith, followed by deposition of the Matinenda Formation. Sometime after Matinenda deposition, K- and Rb-metasomatim affected the regolith and overlying sediments, converting some clays to illite and depositing secondary K-feldspar. Greenschist-facies metamorphism probably postdated this metasomatism and converted clay minerals to white mica and chlorite.

scholarly journals Migrace alkalických kovů ve zvětralinových profilech migmatitů ze svrateckého krystalinika a moldanubika

2020 ◽  
Vol 27 (1-2) ◽  
Author(s):  
David Buriánek ◽  
Martin Soukup ◽  
Martin Ivanov
Keyword(s):  
Czech Republic ◽  
Soil Profile ◽  
Alkali Metals ◽  
Chemical Weathering ◽  
The Other ◽  
Soil Profiles ◽  
Sand Fraction ◽  
The Czech Republic ◽  
Physical And Chemical ◽  
Weathering Process

The purpose of this study was to characterize four soil profiles derived from migmatites were studied in the Moldanubicum and Svratka Crystalline Unit (eastern part of the Czech Republic). Both physical and chemical weathering biotite to muscovite-biotite migmatites produces 100 to 80 cm thick soil profiles. The silt (43–88 %) was the dominant fraction in all of the studied soil profiles. The weathering process studied migmatites start with biotite replaced to chlorite and continue decomposition plagioclase to the kaolinite. On the other hand, K-feldspar is less affected by secondary alterations and quartz is stable. Based on the study of the behavior of selected alkali metals we can interpret the mechanism of the formation of weathering profiles. The highest degree of the weathering indicates soil profile from the locality Rovné characterized by decreased content of K, Na, and Rb upwards from the parent rock to the A-horizon. The soil profiles from the localities Lipník and Zubří shows a higher proportion of sand fraction and lower WIP (> 50) in comparison to Rovné. Vertical distribution of alkali metals in the soil profile from the locality Štěpánovice indicates that soil profile has been modified by secondary slope movements

Social variation in size at birth and preterm delivery in the Czech Republic and Sweden, 1989-91

1998 ◽  
Vol 12 (1) ◽  
pp. 7-24 ◽  
Author(s):  
Koupilova ◽  
Vagero ◽  
Leon ◽  
Pikhart ◽  
Prikazsky ◽  
...  
Keyword(s):  
Czech Republic ◽  
Preterm Delivery ◽  
The Czech Republic ◽  
Social Variation ◽  
Size At Birth

On Geropsychology in the Czech Republic

GeroPsych ◽  
2012 ◽  
Vol 25 (3) ◽  
pp. 161-166
Author(s):  
Hana Stepankova ◽  
Eva Jarolimova ◽  
Eva Dragomirecka ◽  
Irena Sobotkova ◽  
Lenka Sulova ◽  
...  
Keyword(s):  
Czech Republic ◽  
Clinical Practice ◽  
Old Age ◽  
Cognitive Rehabilitation ◽  
The Czech Republic ◽  
Rehabilitation Research

This work provides an overview of psychology of aging and old age in the Czech Republic. Historical roots as well as recent activities are listed including clinical practice, cognitive rehabilitation, research, and the teaching of geropsychology.

Contemporary Psychology in the Czech Republic

2000 ◽  
Vol 5 (1) ◽  
pp. 62-65 ◽  
Author(s):  
Jiří Hoskovec ◽  
Josef M. Brožek
Keyword(s):  
Czech Republic ◽  
The Czech Republic
Sign in / Sign up

Export Citation Format

Share Document