From deposition to caldera resurgence: pyroclastic density current dynamics as revealed by magnetic anisotropy of the Teplice rhyolite, Bohemian Massif

• Thesis title in Czech: Od uložení po kalderovou resurgenci: dynamika pyroklastických hustotních proudů zjištěná magnetickou anisotropií z Teplického ryolitu, Český masiv
• Thesis title in English: From deposition to caldera resurgence: pyroclastic density current dynamics as revealed by magnetic anisotropy of the Teplice rhyolite, Bohemian Massif
• Key words: Anisotropie magnetické susceptibility (AMS); Pyroklastický hustotní proud; Spečení; Reomorfismus; Kalderová resurgence; Ryolit
• English key words: Anisotropy of magnetic susceptibility (AMS); Pyroclastic density current; Welding; Rheomorphism; Caldera resurgence; Rhyolite
• Academic year of topic announcement: 2018/2019
• Thesis type: diploma thesis
• Thesis language: angličtina
• Department: Institute of Geology and Paleontology (31-420)
• Supervisor: Mgr. Filip Tomek, Ph.D.
• Author: hidden - assigned by the advisor
• Date of registration: 16.10.2018
• Date of assignment: 17.10.2018
• Date of electronic submission: 14.08.2020
• Date of proceeded defence: 15.09.2020
• Opponents: RNDr. Bedřich Mlčoch

References

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Preliminary scope of work

Těleso teplického ryolitu představuje intra-kalderovou facii napadaných tufů, ignimbritů a lávových dómů altenbersko-teplické kaldery na hranici ČR a Německa v SZ části Českého masívu. Celkem pět extruzivních a intruzivních fází eruptovalo 7 vulkanických jednotek, které jsou výborně odkryté zejména na JV svazích Krušných hor. Nejnovější studie dále propojily české a německé jednotky (Casas-García et al. 2018; Gnojek et al. 2018), což umožní komplexní studium hornin na obou stranách hranice. Cílem práce je výzkum magnetické stavby těchto vulkanitů za účelem interpretace jejího původu. Horké intra-kalderové facie ignimbritů totiž často prochází spečením a reomorfismem (přetavením) a původní toková stavba se tak může kompletně vymazat. Hlavní metody práce zahrnují terénní mapování a anizotropii magnetické susceptibility (AMS). Práce bude dále doplněna o detailní studii horninového magnetismu pomocí termomagnetických a hysterezních křivek a anisotropie remanentní magnetizace (ARM).

Preliminary scope of work in English

The Teplice rhyolite is a representative of intra-caldera facies fall tuffs, ignimbrites and lava flows of the Altenberg-Teplice caldera in the NW portion of the Bohemian Massif (Czech Republic/Germany). In total, five intrusive-extrusive phases erupted 7 volcanic units, that are exposed mainly along south-eastern slopes of the Krušné hory/Erzgebirge Mts. Recent studies linked Czech and German rhyolite facies (Gnojek et al. 2018; Casas-García et al. 2018), which allows complex field study on both sides of the border. Principal aim of the proposed project is to explore the magnetic fabrics (as determined using the anisotropy of magnetic susceptibility method) in order to interpret its origin. The underlying assumption is that the intra-caldera ignimbrite facies often undergo extensive welding or even rheomorphism (remelting) and the original flow fabric may be partially or completely wiped out. The master thesis will be also complemented with detailed rock-magnetic study using the thermomagnetic and hysteresis loops, and the anisotropy of remanent magnetization (ARM).