Blar i forfatter "Jeřábek, Petr"
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Anticlockwise metamorphic pressure–temperature paths and nappe stacking in the Reisa Nappe Complex in the Scandinavian Caledonides, northern Norway: evidence for weakening of lower continental crust before and during continental collision
Faber, Carly; Stunitz, Holger; Gasser, Deta; Jeřábek, Petr; Kraus, Katrin; Corfu, Fernando; Ravna, Erling Krogh; Konopásek, Jiří (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)This study investigates the tectonostratigraphy and metamorphic and tectonic evolution of the Caledonian Reisa Nappe Complex (RNC; from bottom to top: Vaddas, Kåfjord, and Nordmannvik nappes) in northern Troms, Norway. Structural data, phase equilibrium modelling, and U-Pb zircon and titanite geochronology are used to constrain the timing and pressure–temperature (<i>P–T</i>) conditions of deformation ... -
Arc-like magmatism in syn- to post-collisional setting: The Ediacaran Angra Fria Magmatic Complex (NW Namibia) and its cross-Atlantic correlatives in the south Brazilian Florianópolis Batholith
Janousek, Vojtěch; Florisbal, Luana Moreira; Konopásek, Jiří; Jeřábek, Petr; Bitencourt, Maria de Fatima; Gadas, Petr; Erban, Vojtěch; Kopačková-Strnadová, Veronika (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-27)Ediacaran syn-tectonic plutonic rocks (amphibole gabbros, quartz diorites/tonalites to biotite- and muscovite-bearing granites) of the Angra Fria Magmatic Complex (Kaoko Belt, north-western Namibia) belong to two compositionally similar, magnesian, transitional tholeiitic–calc-alkaline suites, the Older (∼625–620 Ma) and the Younger (∼585–575 Ma). Both have counterparts in the broadly contemporaneous ... -
Effect of pressure on the deformation of quartz aggregates in the presence of H2O
Nègre, Lucille; Stunitz, Holger; Raimbourg, Hugues; Lee, Amicia; Précigout, Jacques; Pongrac, Petar; Jeřábek, Petr (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-17)Quartzite samples of high purity with a grain size of ~200 μm have been experimentally deformed by coaxial shortening in a solid medium apparatus at 900 °C and at confining pressures ranging from 0.6 to 2 GPa. Most samples have been shortened by ~30% with 0.1 wt% added H<sub>2</sub>O. The samples deformed dominantly by crystal plasticity (dislocation creep), and there is a systematic decrease of ... -
High-temperature fracturing and subsequent grain-size-sensitive creep in lower crustal gabbros: Evidence for coseismic loading followed by creep during decaying stress in the lower crust
Okudaira, Takamoto; Jeřábek, Petr; Stunitz, Holger; Fusseis, Florian (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)The mechanism of shear zone formation in lower crustal, relatively “dry” rocks is still poorly understood. We have studied the high-temperature deformation of the Hasvik gabbro (northern Norway) which commences by fracturing. The 10–20 μm wide fractures show little displacement. The fine-grained plagioclase and orthopyroxene in the fractures lack a crystallographic preferred orientation (CPO) or ... -
Mechanical properties and recrystallization of quartz in presence of H<inf>2</inf>O: Combination of cracking, subgrain rotation and dissolution-precipitation processes
Pongrac, Petar; Jeřábek, Petr; Stunitz, Holger; Raimbourg, Hugues; Heilbronner, Renee; Racek, Martin; Nègre, Lucille (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-21)Natural quartzite samples, as-is and with 0.1 wt% of added H<sub>2</sub>O, have been deformed up to ∼30% bulk strain in axial shortening experiments with constant strain rate of ∼10<sup>−6</sup> s<sup>−1</sup> at 900 °C and 1 GPa, and in strain rate stepping ∼10<sup>−5</sup> to ∼10<sup>−7</sup> s<sup>−1</sup> at 900 °C and 1–1.5 GPa, in order to investigate the role of H<sub>2</sub>O in deformation ...