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Emplacement dynamics of syn-collapse ring dikes: An example from the Altenberg-Teplice caldera, Bohemian Massif
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SYSNO ASEP 0504671 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Emplacement dynamics of syn-collapse ring dikes: An example from the Altenberg-Teplice caldera, Bohemian Massif Author(s) Tomek, Filip (GLU-S) RID, ORCID, SAI
Žák, J. (CZ)
Svojtka, Martin (GLU-S) SAI, RID, ORCID
Finger, F. (AT)
Weitzinger, M. (AT)Source Title Geological Society of America Bulletin. - : Geological Society of America - ISSN 0016-7606
Roč. 131, 5/6 (2019), s. 997-1016Number of pages 20 s. Publication form Print - P Language eng - English Country US - United States Keywords Bohemian Massif ; Altenberg-Teplice caldera ; caldera collapse Subject RIV DB - Geology ; Mineralogy OECD category Geology Method of publishing Limited access Institutional support GLU-S - RVO:67985831 UT WOS 000466511700015 EID SCOPUS 85066755974 DOI 10.1130/B35019.1 Annotation The late Carboniferous Altenberg-Teplice caldera in the northwestern Bohemian Massif provides an intriguing example of rhyolite eruptions evolving to a trapdoor collapse and coeval ring dike emplacement. Geochemical data suggest that withdrawal of an underlying stratified magma chamber beneath the caldera took place in two steps. Eruptions of the reversely zoned Teplice rhyolite drained the chamber, followed by a trapdoor collapse of the caldera floor and emplacement of voluminous microgranite ring dike system at 312 Ma. The mechanism proposed here is that the subsiding caldera floor increased vertical load on the magma chamber and triggered remobilization of residual, cumulate-like, and otherwise non-eruptible magma mush. The magnetic fabrics (determined using the anisotropy of magnetic susceptibility [AMS]), carried by paramagnetic ferrosilicates and titanomagnetite, indicate that the ring dike magma first flowed upwards via four main feeder domains from which the magma was then distributed laterally. The asymmetric trapdoor collapse generated domains of dilation and contraction along the caldera limit, evidenced by different shapes of fabric ellipsoids and uneven apparent width of the individual ring dike segments. Based on this case example, we develop a general kinematic model for polyphase caldera collapse and ring dike emplacement, invoking a combination of multiple space-making processes: piston and trapdoor collapses together with downsag and faulting of the caldera floor, regional tectonic extension, reactivation of the preexisting structures, and volume changes in the caldera floor due to thermal stresses. Workplace Institute of Geology Contact Jana Popelková, popelkova@gli.cas.cz, Sabina Janíčková, Tel.: 233 087 272 Year of Publishing 2020 Electronic address https://pubs.geoscienceworld.org/gsa/gsabulletin/article/131/5-6/997/566860/Emplacement-dynamics-of-syncollapse-ring-dikes-An
Number of the records: 1