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Paleomagnetic record of basaltic lava flows on Nelson Island, Antarctica
Haislová, Radka ; Kletetschka, Günther (advisor) ; Pruner, Petr (referee)
Paleomagnetism is geophysical method for determination of former magnetic field orientation on the Earth using measurement of remanent magnetisation of rocks. Combined with radiomagnetic datingk paleomagnetism enables study of time evolution of the magnetic field on the Earth and/or reconstruction of former positions of litospheric plates. This thesis is elaborates on paleomagnetic record of basalt lava flow on the Nelson's Island in Antarctica and summarizes geological data. In the research part of this thesis theory of magnetism is introduced and the paleomagnetism method is emphasized. Additionaly, I provide a short review of magnetic minerals, that can occur in basalt. These mineral can potentialy hold some information about the character of magnetic field of the geological past. Radiometric dating methods are included as atool for determination of absolute age of solidification of ingenous rocks (lava). Specifically, the K-Ar and Ar-Ar dating methods are emphasized. The regional section of this thesis conntains geological overview about the Antarctica and the Nelson's Island with its surroundings.Included is a section about the laboratory devices for measuring vector magnetisation of oriented rock samples (for example rotational and cryogenic magnetometer). The thesis is concluded with its...
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Paleomagnetic study of Paleozoic rocks from SW Mongolia
Joštová, Daniela ; Lexa, Ondrej (advisor) ; Hrouda, František (referee)
English abstract The aim of this thesis is verification of the theory about evolution of the Mongolian orocline in Permo-Triassic by the paleomagnetic analysis of rocks taken from south-west Mongolia and it is the first step to understand the problematics in bigger detail. Basics of magnetism, geomagnetism, paleomagnetism and geology of the studied part of Mongolia are described in first part of this thesis. Second part is dedicated to methodology and my own research with the thermoremanent magnetizations data. Mongolia is situated between three cratons - Siberia, North China and Tarim and it is part of the Central Asian Orogenic Belt (CAOB), which evolution is not well understood and it is still being studied by a lot of researches. Kröner (2010) says, that the area of Mongolia can be divided to 4 tectonic zones (Lake, Trans-Altai, Gobi-Altai and South Gobi), however Badarch et al. (2002) are dividing the area to 44 terranes, which are separated to two parts - North (Caledonian) and South (Variscan) by the Main Mongolian Lineament. Studied part of the Mongolian area lies eastward from north boarder of China and the samples were taken from three parts - Altay, Edrene and Khovd. Sampling techniques and the whole procedure of analysing the measured data is also mentioned. There is also a comparison of the...
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Paleomagnetic record of basaltic lava flows on Nelson Island, Antarctica
Haislová, Radka ; Kletetschka, Günther (advisor) ; Pruner, Petr (referee)
Paleomagnetism is geophysical method for determination of former magnetic field orientation on the Earth using measurement of remanent magnetisation of rocks. Combined with radiomagnetic datingk paleomagnetism enables study of time evolution of the magnetic field on the Earth and/or reconstruction of former positions of litospheric plates. This thesis is elaborates on paleomagnetic record of basalt lava flow on the Nelson's Island in Antarctica and summarizes geological data. In the research part of this thesis theory of magnetism is introduced and the paleomagnetism method is emphasized. Additionaly, I provide a short review of magnetic minerals, that can occur in basalt. These mineral can potentialy hold some information about the character of magnetic field of the geological past. Radiometric dating methods are included as atool for determination of absolute age of solidification of ingenous rocks (lava). Specifically, the K-Ar and Ar-Ar dating methods are emphasized. The regional section of this thesis conntains geological overview about the Antarctica and the Nelson's Island with its surroundings.Included is a section about the laboratory devices for measuring vector magnetisation of oriented rock samples (for example rotational and cryogenic magnetometer). The thesis is concluded with its...
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Paleomagnetism and magnetomineralogy of rocks from the Bohemian Massif and Tethyan Realm
Schnabl, Petr ; Pruner, Petr (advisor) ; Hrouda, František (referee) ; Petrovský, Eduard (referee)
Mgr. Petr Schnabl - Dissertation Paleomagnetism and magnetomineralogy of rocks from the Bohemian Massif and Tethyan Realm Abstract The thesis deals with paleomagnetic and rock magnetic properties of Silurian/Devonian and Jurassic/Cretaceous limestones, Paleogene/Neogene basaltic rocks and altered Silurian basalts. The main goal is to determine the history of the Earths' magnetic field from the Silurian to the present. Two lithostratigraphic formations are defined in the Jičín volcanic field on the basis of volcanology, paleomagnetism and radiometric dating. The Trosky Formation (24.6?/18.3 - 15.7 Ma) is composed of several Strombolian-type volcanoes, while the Kozákov Formation (5.2 - 4.6 Ma) is represented by effusive products with a crater vent of a single giant volcano. One Pliocene (4.3-3.3 Ma) and two Pleistocene phases (2.6 -2.1 Ma and 1.8 - 1.1 Ma) of volcanic activity Magnetostratigraphy is a very important tool for the definition of the J/K boundary. The boundary between the Crassicolaria and Calpionella zones is present within geopolarity zone M19n. The boundary between the ammonite zones Jacobi and Durangites also lies close to this point. Paleomagnetic directions of Silurian and Devonian rocks in the Bohemian Massif are very difficult to interpret and have been studied as a challenging problem...
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Využití magnetické susceptibility ve výzkumu kvartérních sedimentů
Gottvald, Zdeněk
This thesis deals with rock magnetism, paleomagnetism and environmental magnetism. It also gives a complex overview of this methods and presents their practical application and discusses the advantages and disadvantages of using these methods in research. In the first part of the paper the basic theory of magnetism is described. The second section is focused on detailed techniques of magnetic susceptibility measuring using professional laboratory equipment. For analysis were used specimens of quaternary sediments extracted in Moravský Kras. Particulary: the north side of cave Kůlna, cave Výpustek and in valley Křitinský potok. In conclusion the recorded values of magnetic susceptibility are compared with soil deposition. The thesis may be used as a data source for subsequent advanced analysis.
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