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Magnetic fabric of loess and paleosols on selected localities in South Moravia
Obersteinová, Tereza ; Kadlec, Jaroslav (advisor) ; Chadima, Martin (referee)
Pleistocene loess-palaeosol sequences provide a unique proxy-record enabling detailed reconstruction of Quaternary palaeoenvironments. Environmental magnetic methods are often used to read the natural archives. The loess-palaeosol sequences exposed in two sections located in southern Moravia and a sequence from central Bohemia were studied in a frame of this Diploma Thesis. Variations of bulk magnetic susceptibility, measured in the sediments, show similar pattern as in the Chinese loess-palaeosol bodies - i.e. palaeosols reveal higher magnetic susceptibility in comparison with loess due to magnetic enhancement. The magnetic enhancement is driven by weathering during pedogenic processes related to the formation of ultra-fine magnetite particles. The magnetite content is controlling the sediment magnetic behavior. The magnetic enhancement rate indicates more intense pedogenic processes in the Moravia in comparison with Bohemia. Magnetic fabric in studied loess, represented by space orientation of anisotropy of magnetic susceptibility ellipsoid, indicates dominating glacial wind palaeocurrents across the southern Moravia blowing from W or SW, respectively. The magnetic fabric in the central Bohemian sequence has revealed a dominant control of running water and re-deposition of the loess material...
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Primary and secondary magnetic fabric as a tool for paleoenvironmental reconstruction
Žatecká, Michaela ; Chadima, Martin (advisor) ; Pruner, Petr (referee)
This diploma thesis deals with the research of primary and secondary magnetic fabric of aeolian loess sediments and paleosols on the cross-section temporary cropping out during the construction work in Prague 6. Magnetic enrichment - and the formation of magnetic nanoparticles in soil horizons - occurs during pedogenesis in warmer interglacials periods. The aim of this work is the interpretation of the paleoenvironment, weathering and pedogenic processes, by measuring the magnetic properties of sediments. Magnetic susceptibility, frequency-dependent magnetic susceptibility, anhysteresis remanent magnetization and natural remanent magnetization are used to detect the increased occurrence of magnetic particles, which indicate these pedogenic processes. The most developed paleosol horizon within the cross-section was the horizon of black soil and subsoil brown soil. Small signs of pedogenesis were revealed in the upper and lower loess part of the section. The magnetic fabric of loess, measured by means of anisotropy of magnetic susceptibility, reflects secondary sedimentary processes. This involves the displacement of clastic particles by flowing water and the redeposition of the material along the slope. The direction of movement of these sediments corresponds to the current geomorphology of the...
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Magnetic fabric of loess and paleosols on selected localities in South Moravia
Obersteinová, Tereza ; Kadlec, Jaroslav (advisor) ; Chadima, Martin (referee)
Pleistocene loess-palaeosol sequences provide a unique proxy-record enabling detailed reconstruction of Quaternary palaeoenvironments. Environmental magnetic methods are often used to read the natural archives. The loess-palaeosol sequences exposed in two sections located in southern Moravia and a sequence from central Bohemia were studied in a frame of this Diploma Thesis. Variations of bulk magnetic susceptibility, measured in the sediments, show similar pattern as in the Chinese loess-palaeosol bodies - i.e. palaeosols reveal higher magnetic susceptibility in comparison with loess due to magnetic enhancement. The magnetic enhancement is driven by weathering during pedogenic processes related to the formation of ultra-fine magnetite particles. The magnetite content is controlling the sediment magnetic behavior. The magnetic enhancement rate indicates more intense pedogenic processes in the Moravia in comparison with Bohemia. Magnetic fabric in studied loess, represented by space orientation of anisotropy of magnetic susceptibility ellipsoid, indicates dominating glacial wind palaeocurrents across the southern Moravia blowing from W or SW, respectively. The magnetic fabric in the central Bohemian sequence has revealed a dominant control of running water and re-deposition of the loess material...
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Contact Centres for Drug Addicts and their Support Activities
Král, Jaromír ; Mašát, Vladimír (referee) ; Chadima, Martin (advisor)
The aim of the thesis "Contact Centres for Drug Addicts and their Support Activities" is to describe a specific way of work with drug addicts except the alcohol drug addicts. Firstly it considers the concept of drugs, drug addiction, while examining an impact on an individual as well as the society. This work describes the functioning of the low threshold contact centres as one of the possible solution of this problem. The philosophy of the centres is to be easy accessible to everyone. The contact centre s purvey to its clients anonymous services free of charge. Service of such centres leads to the reduction of health hazard (transmission of infectious diseases, inflammatory diseases, etc.) and a social stabilization of the client. At the very most it may also leads to the therapy and permanent abstinence of the client. It means this does not solve only the drug addiction, but also decrease the impact of drug addicťs risk behaviours to the society. The research was conducted in the contact centre Sananim. It maps the range of clients in this centre, investigates the degree of their social stabilization, service using and the effectiveness of harm reduction.
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Magnetic fabric and mineralogy of cave deposits in Botovskaya Cave (Eastern Siberia, Russian Federation)
Kadlec, Jaroslav ; Hercman, H. ; Chadima, Martin ; Lisá, Lenka ; Oberhänsli, H. ; Osintsev, A.
The Botovskaya Cave is a typical example of a two-dimensional maze with a total length of explored passages exceeding 60 km, which represents the longest limestone cave system in the Russian Federation. The clastic cave sediments filling the cave passages differ in both mineral and mineral magnetic properties and were deposited under different hydrological conditions. The older portion of the clastic cave fills was derived from overlying sandstones, whereas the properties of younger cave sediments show closer affinity to the soils and weathering products originating on the sandstone plateau above the cave. The cave sediments underwent repeated periods of deposition and erosion during the Tertiary and Pleistocene.
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Valley incision in the Nízké Tatry Mts. (Slovakia) estimated based on paleomagnetic and radiometric cave sediment datings
Kadlec, Jaroslav ; Bella, P. ; Čížková, Kristýna ; Granger, D. E. ; Hercman, H. ; Holúbek, P. ; Chadima, Martin ; Orvošová, M. ; Pruner, Petr ; Schnabl, Petr ; Šlechta, Stanislav
Up to eleven horizontal cave levels occur at different altitudes in Jánska, Demänovská and Mošnická karst valleys in the Nízke Tatry Mts. Most of the caves are filled with allochthonous sediments transported from the area formed mostly by granite. The cave levels were filled with fluvial sediments in dependence on the valleys incision caused by Neogene and Pleistocene uplift of the mountain range. The fluvial sediments are intercalated with, or capped, by flowstone layers in the caves. The paleomagnetic polarities measured both in clastic and chemogenic sediments indicate the age of deposition. Based on obtained polarity data we are able to distinguish cave sediments deposited during the Brunhes, Matuyama and Gauss chrons. The paleomagnetic interpretation was partly verified by U-series datings of flowstones preserved in the sedimentary sections. Except for the horizontal cave levels located in the karst valleys, additional large cave systems were found at extremely high altitudes in the Nízke Tatry Mts. 600–700 m above the lowest horizontal cave level.
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