caa a22 4500 445839600 CHVBK 20180317145339.0 cr unu---uuuuu 170323e20111001xx s 000 0 eng 10.1007/s00015-011-0065-1 doi (NATIONALLICENCE)springer-10.1007/s00015-011-0065-1 Laser ablation U/Pb age patterns of detrital zircons in the Schlieren Flysch (Central Switzerland): new evidence on the detrital sources [Elektronische Daten] [Endrio Bütler, Wilfried Winkler, Marcel Guillong] The palaeogeographic attribution of the Schlieren Flysch and its counterparts in the Gurnigel Nappe is still a matter of debate. These Late Alpine deep-sea trench deposits show a variable tectonic thrust relationship with other nappes inferring either an Ultrahelvetic or South Penninic origin of the elongated trench basin. An improved knowledge of the supplying source terranes of the Schlieren Flysch basin may add to the palaeogeographic ascription. Detrital zircons from seven representative samples have been dated by laser ablation ICP-MS analysis methods. The obtained age patterns are compared with standard provenance analysis methods including modal grain and heavy mineral statistics of the sandstones. The detrital zircons show two major populations of Pan-African (ca. 650-450Ma) and Variscan (ca. 360-320Ma) ages. A low abundance of Devonian detrital zircons separates the two main age populations. The Th/U signature of the zircons implies that igneous rocks of these two orogenic cycles directly, or indirectly (by multicyclic reworking of zircons) have strongly contributed to the clastic input. The earlier described bimodal turbiditic supply to the Schlieren Flysch basin is matched by the geochronologic data. With regard to the other petrographic signatures of the sandstones, it becomes evident that the granitic-rhyolitic source terrane derived (K-feldspar bearing) sandstones show a higher abundance of Pan-African zircons and a higher abundance of tourmaline in the heavy mineral fractions. In contrast, the exclusively plagioclase-bearing sandstones from the tonalitic-andesitic source contain a majority of Variscan zircons and higher contents of apatite. In addition, we observe a third minor population comprising Triassic-Early Jurassic detrital zircons. The correlation of the obtained detrital zircon ages with pre-Cretaceous igneous, metamorphic and geodynamic events, which affected the basement of the northern and southern margins of the Alpine Tethys reveals a major difference by the presence of Triassic magmatic products and volcaniclastics in South Alpine and Austroalpine units. The discovery of the minor Triassic-Early Jurassic population in both sandstone types of the Schlieren Flysch would argue for the derivation of the clastic material from the southern Alpine Tethys or Adriatic-Apulian margin. Swiss Geological Society, 2011 Flysch nationallicence Detrital zircons nationallicence Laser ablation U/Pb ages nationallicence Sandstone petrology nationallicence Provenance nationallicence Palaeogeography nationallicence Bütler Endrio Department of Earth Sciences, Geological Institute, ETH Zentrum, Sonneggstrasse 5, 8092, Zurich, Switzerland aut Winkler Wilfried Department of Earth Sciences, Geological Institute, ETH Zentrum, Sonneggstrasse 5, 8092, Zurich, Switzerland aut Guillong Marcel Department of Earth Sciences, Institute of Geochemistry and Petrology, ETH Zentrum, Clausiusstrasse 25, 8092, Zurich, Switzerland aut Swiss Journal of Geosciences SP Birkhäuser Verlag Basel 104/2(2011-10-01), 225-236 1661-8726 104:2<225 2011 104 15 https://doi.org/10.1007/s00015-011-0065-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00015-011-0065-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bütler Endrio Department of Earth Sciences, Geological Institute, ETH Zentrum, Sonneggstrasse 5, 8092, Zurich, Switzerland aut NATIONALLICENCE 700 1- Winkler Wilfried Department of Earth Sciences, Geological Institute, ETH Zentrum, Sonneggstrasse 5, 8092, Zurich, Switzerland aut NATIONALLICENCE 700 1- Guillong Marcel Department of Earth Sciences, Institute of Geochemistry and Petrology, ETH Zentrum, Clausiusstrasse 25, 8092, Zurich, Switzerland aut NATIONALLICENCE 773 0- Swiss Journal of Geosciences SP Birkhäuser Verlag Basel 104/2(2011-10-01), 225-236 1661-8726 104:2<225 2011 104 15 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 314561838 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer