Detrital zircon analysis of metasedimentary rocks of the Staré Mìsto Belt, Sudetes: implications for the provenance and evolution of the eastern margin of the Saxothuringian terrane, NE Bohemian Massif

0560241 - GLÚ 2023 RIV PL eng J - Článek v odborném periodiku
Śliwiński, M. - Jastrzębski, M. - Sláma, Jiří
Detrital zircon analysis of metasedimentary rocks of the Staré Mìsto Belt, Sudetes: implications for the provenance and evolution of the eastern margin of the Saxothuringian terrane, NE Bohemian Massif.
Geological Quarterly. Roč. 66, č. 2 (2022), č. článku 21. ISSN 1641-7291. E-ISSN 2082-5099
Institucionální podpora: RVO:67985831
Klíčová slova: detrital zircon age spectra * provenance * Variscan terranes * Staré Mìsto Belt * Bohemian Massif
Obor OECD: Geology
Impakt faktor: 1, rok: 2022
Způsob publikování: Open access
https://gq.pgi.gov.pl/article/view/33146/pdf

The Staré Mìsto Belt (SMB) in the Central Sudetes forms a Variscan tectonic boundary zone that is located be tween the Saxothuringian and Brunovistulian terranes of the Bohemian Massif. The three thrust-bounded upper, middle and lower lithotectonic units of the SMB are composed of metasedimentary and Late Cambrian metavolcanic rocks. A new LA-ICPMS zircon geochronology supported by zircon typology studies of the mica schists of the up per unit and the migmatitic paragneisses of the middle unit provides new insights into the provenance and evolution of the SMB. Our new data were obtained from metasedimentary rocks and compared to the previously published zircon ages of the SMB metavolcanic rocks. The results indicate that the metasedimentary and bimodal meta volcanic rocks in the separate lithotectonic units of the SMB originally formed Late Cambrian volcano-sedimentary successions. The source areas of the sedimentary basins studied were dominated by Neoproterozoic and Paleoproterozoic crystal line rocks that were presumably located near the West African Craton of Gondwana. A comparison of the detrital age spectra obtained with those previously published from the region indicates a strong association of the en tire SMB with the Saxothuringian terrane of the Bohemian Massif. During partial melting of the metasedimentary rocks of the middle unit of the SMB, Cambrian and older zircon grains were affected by solid-state transformations that caused partial resetting of the U-Pb dates, changes in internal zircon textures and reductions in Th/U ratios.
Trvalý link: https://hdl.handle.net/11104/0334070