Please use this identifier to cite or link to this item: http://elar.urfu.ru/handle/10995/117946
Title: Zircon microstructures record deformation history of shock- And tectonically-generated pseudotachylites: A case study from the vredefort impact structure, South Africa
Authors: Kovaleva, E.
Huber, M. S.
Habler, G.
Zamyatin, D. A.
Issue Date: 2019
Publisher: Oxford University Press
Citation: Zircon microstructures record deformation history of shock- And tectonically-generated pseudotachylites: A case study from the vredefort impact structure, South Africa / E. Kovaleva, M. S. Huber, G. Habler et al. // Journal of Petrology. — 2019. — Vol. 60. — Iss. 12. — P. 2529-2546.
Abstract: High-strain rate deformation can cause in situ melting of rocks, resulting in the formation of dark, micro- to nanocrystalline pseudotachylite veins. On Earth, pseudotachylite veins form during meteorite impacts, large landslides, and earthquakes. Within the Vredefort impact structure, both impact-generated and (pre-impact) tectonically-generated pseudotachylite veins have been described, but are challenging to distinguish. Here, we demonstrate a genetic distinction between two pseudotachylite veins from Vredefort by studying their petrography, degree of recrystallization and deformation, crosscutting relationships and the deformation microstructures in associated zircon. We conclude that Vein 1 is pre-impact and tectonically-generated, and Vein 2 is impact-generated. In agreement, zircon microstructures in Vein 1 contain planar deformation bands (PDBs), attributed to tectonic deformation, whereas zircon microstructures in Vein 2 reveal microtwin lamellae, indisputable evidence of shock metamorphism. Thus, deformation microstructures in zircon may provide a new criterion for distinguishing the genetic origin of pseudotachylite veins. Zircons that have been removed from their context (i.e., alluvial or detrital zircon, zircon from Lunar breccia) should be interpreted with caution in terms of their deformation history. For example, zircon with PDBs cannot reliably be used as a marker for shock deformation, because this feature has been shown to form in purely tectonic settings. © The Author(s) 2020.
Keywords: PSEUDOTACHYLITE
SHOCK DEFORMATION
VREDEFORT
ZIRCON
DEFORMATION
MICROSTRUCTURE
PETROGRAPHY
PSEUDOTACHYLITE
RECRYSTALLIZATION
SHOCK METAMORPHISM
TECTONIC SETTING
ZIRCON
FREE STATE
SOUTH AFRICA
VREDEFORT DOME
URI: http://elar.urfu.ru/handle/10995/117946
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85090202432
WOS ID: 000596088200010
PURE ID: 13898869
ISSN: 223530
DOI: 10.1093/petrology/egaa017
metadata.dc.description.sponsorship: National Research Foundation, NRF: 106511, 111386, 98443
This research is supported by the National Research Foundation (NRF) [grants number: 98443, 106511, and 111386, received by E.K].
Appears in Collections:Научные публикации ученых УрФУ, проиндексированные в SCOPUS и WoS CC

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