Detrital zircon ages from a Lower Ordovician quartzite of the İstanbul exotic terrane (NW Turkey): evidence for Amazonian affinity

Abstract

NW Turkey is a mosaic of several continental and oceanic units, that were amalgamated by collisional and strike-slip tectonics. One of the continental units is the _ Istanbul terrane, the Palaeozoic strata of which comprise an Early Ordovician to Early Carboniferous transgressive sedimentary sequence. The basement to the Palaeozoic succession is exposed in the Bolu Massif and is represented by a thick meta-volcanic unit intruded by Late Neoproterozoic (ca. 575 Ma) felsic magma. This meta-igneous basement is considered to be a sliver of the Cadomian magmatic arc. Unconformably overlying Early Ordovician strata start with red fluvial clastics (ca. 3,000 m), overlain by shallow marine quartzites (\250 m). Detrital zircons were separated from an Ordovician quartzite sample located 5 m above the contact with the underlying red fluvial clastics. We have dated a total of 99 zircon grains by U-Pb method using laser ablation-sector field-inductively coupled plasma mass spectrometer (LA-SF-ICP-MS). The ages (97% are [90% concordant) range from 530 to 2550 Ma. The dominance (44 grains) of Neoproterozoic zircon ages (around 540, 570, 600-640 and 700-800 Ma) rules out any link of the _ Istanbul terrane with Baltica. The large amount (40 grains) of Grenvillian and Meso-to Palaeo-proterozoic ages (around 1.0-1.2, 1.3-1.6, 1.7-1.8, and 1.9-2.1 Ga) in the zircon population further rules out a link to Cadomian and Minoan terranes, but is indicative for Amazonian source areas. The new age data suggest the _ Istanbul terrane to be a peri-Gondwanan terrane that was located at the northwestern margin of Gondwana close to Amazonia. This terrane should have travelled a large distance in the Phanerozoic times.

Crustal Evolution of the Northeast Laurentian Margin and the Peri-Gondwanan Microcontinent Ganderia Prior to and During Closure of the Iapetus Ocean: Detrital Zircon U–Pb and Hf Isotope Evidence from Newfoundland

“…7e). It should be noted that, aside from Avalonia, three other terranes having remarkably similar zircon age spectra have closely been linked with Ganderia at its original location: Carolinia, in the present southern continuation of Ganderia along the margin of Laurentia ) and the Istanbul (Ustaömer et al 2011) and Moesia (Balintoni et al 2010) terranes, both at the present southeastern margin of Baltica in Turkey and Romania, respectively.…”

Peri-Gondwanan origin and early geodynamic history of NE Sicily: A zircon tale from the basement of the Peloritani Mountains

“…Stern, 1994;Blasband et al, 2000) and in SE Europe. The latter terranes occur in the Alps (Schaltegger and Gebauer, 1999;Neubauer, 2002;Von Raumer et al, 2002), Carpathians (Kräutner, 1993;Balintoni et al, 2009Balintoni et al, , 2010Balintoni et al, , 2011 and various massifs in Bulgaria, Turkey and Greece (Ustaömer and Rogers, 1999;Keay and Lister, 2002;Carrigan et al, 2006;Zulauf et al, 2007;Meinhold et al, 2010;Ustaömer et al, 2011Ustaömer et al, , 2012.…”

“…Fernández-Suárez et al, 2000;Friedl et al, 2000;Linnemann et al, 2004;Esteban et al, 2011). Sediments with a West African provenance are characterised by a predominance of 3.4-2.8 and 2.2-1.8 Ga zircon, and the absence of Grenvillian-aged zircon (see summaries in Nance et al, 2008;Drost et al, 2011;Ustaömer et al, 2011). In particular, Linnemann et al (2004) pointed out that the presence of a gap of about 900 Ma (~1.7-0.8 Ga) in the igneous activity in the West African section of northern Gondwana is the best 'fingerprint' for material with a West African provenance.…”

“…A peri-Gondwanan origin has also been proposed for some southern and eastern European terranes that are exposed as inliers in the Alps, or along the main mountain chains of Turkey, Greece, Bulgaria and Romania (e.g. Ustaömer and Rogers, 1999;Keay and Lister, 2002;Neubauer, 2002;Von Raumer et al, 2002Carrigan et al, 2006;Balintoni et al, 2009Balintoni et al, , 2010Balintoni et al, , 2011Ustaömer et al, 2011Ustaömer et al, , 2012, but there are fewer constraints on their provenance and related continental affinities.…”

Devonian in Turkey — a review

“…Therefore, the Devonian successions of the Pontides must have been deposited on a terrane located north of the Paleotethys, as recently discussed by Yalçôn et al (2008). Accordingly, Pontides may have been drifted from Gondwana either by the opening of the Rheic Ocean during the Ordovician together with Avalonia or Amazonia (Ustaömer et al 2008 or later in the Silurian by the opening of Paleotethys as a part of one of the Superhun Terranes (Stampfli 2000;Stampfli & Borel 2002;Stampfli & Kozur 2006). Observations, such as that the Ordovician fauna of the Istanbul Zone with Avalonian affinities during the Early Ordovician and a closer affinity to Baltica and Siberia/Laurentia during the Late Ordovician (Kalvoda 2003;Kalvoda et al 2008), that the Devonian ostracod fauna (Dojen et al 2004;Nazik & Gross-Uffenorde 2008) and the brachiopod fauna from the Emsian in the Istanbul Zone ) have both a Peri-Gondwanan and Laurussian affinity support a Peri-Gondwanan (Avalonia and/or Amazonia) origin and the existence of a narrow seaway between these two terranes during the Devonian.…”