Detrital zircon U-Pb geochronology of Pennsylvanian-Permian sandstones from the Turnaicum and Meliaticum (Western Carpathians, Slovakia): provenance and tectonic implications
Abstract
The blueschist-bearing Bôrka Nappe regarded as a part of the Meliaticum Unit s. l. and the Turnaicum Unit in its hanging-wall were thrusted together to the north on the Inner Western Carpathians basement during the orogenic events of the Late Jurassic-Early Cretaceous. A new U-Pb sensitive high-resolution ion microprobe (SHRIMP) magmatic, as well as detrital-zircon ages were used to constrain provenance and paleogeography. The detrital-zircon age spectrum of the studied metasediments contains mainly ages of the Ediacaran-Cryogenian (550-720 Ma) and Tonian-Stenian (0.9-1.1 Ga), which correspond to the Pan-African Belt and Saharan Metacraton. Subordinate Archean ages were likely derived from the Saharan Metacraton of North Gondwana (1.7-2.2 and 2.5-2.7 Ga). The 273 ± 2 Ma zircon age of a metarhyolite, along with the youngest detrital zircon of 265 ± 4 Ma from the associated metasediments, specify the maximum depositional age of the Bučina Fm. from the Bôrka Nappe to the Guadalupian. The rhyolite olistoliths from the Middle/Late Jurassic Meliaticum olistostrome yielded the latest Cambrian/earliest Ordovician (488 ± 6 Ma) and Middle Ordovician (~ 465 Ma) zircon ages. This is consistent with the U-Pb zircon ages from the foot-walling Southern Gemericum basement metavolcanites, which are, therefore, regarded as a potential source. The obtained zircon ages confirm the provenance from the Southern Gemericum basement and its Permian envelope for the Meliaticum-Bôrka Nappe and Turnaicum sedimentary embayment.
- Publication:
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International Journal of Earth Sciences
- Pub Date:
- September 2019
- DOI:
- 10.1007/s00531-019-01733-7
- Bibcode:
- 2019IJEaS.108.1793V
- Keywords:
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- SHRIMP zircon ages;
- Provenance variations;
- Tectonic implication;
- Meliaticum embayment