Late Proterozoic -Early Palaeozoic rocks of the NW Anatolia-Turkey; a remnant of an active continental margin of the Pan-African oceanic realm


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TUNC I. O., YİĞİTBAŞ E.

World Multidisciplinary Earth Sciences Symposium, Prag, Czech Republic, 5 - 09 September 2016, pp.12

  • Publication Type: Conference Paper / Summary Text
  • City: Prag
  • Country: Czech Republic
  • Page Numbers: pp.12
  • Çanakkale Onsekiz Mart University Affiliated: Yes

Abstract

Late Proterozoic -Early Palaeozoic rocks of the NW Anatolia-Turkey; a remnant of an active continental margin of the Pan-African oceanic realm

İsmail Onur Tunç*, Erdinç Yiğitbaş

 Ardahan University, Faculty of Social Sciences and Humanities, Department of Geography,Ardahan, Turkey

Çanakkale Onsekiz Mart University, Department of Geological Engineering, Çanakkale, Turkey

 

ABSTRACT

In northwest Anatolia, three E–W-trending tectonic units can be distinguished; İstanbul Zone (IZ) in the north, Sakarya Zone (SZ) in the south, and the Armutlu-Ovacık Zone (AOZ) between them which is dominated by strike-slip systems and a tectonic mixture of the IZ and the SZ. The Biga Peninsula (NW Anatolia), which is located in the westernmost part of the SZ, was affected by late Mesozoic-early Tertiary strike-slip tectonics. Metamorphic assemblages crop out as two NE-SW trending belts in the Biga Peninsula, which were described and evaluated by different names, ages, geological and tectonic meanings. Previous studies suggest a suture zone  between these two metamorphic belts,  beneath  a thick Tertiary-Quaternary volcanic and sedimentary cover. This suture was evaluated as Paleo-or Neo-Tethyan. Themetamorphic assemblages in the south of this suture were evaluated as the continuation of the SZ and the northern ones were assigned to the Rhodope and Serbo-Macedonian massifs.The northern metamorphic assemblages are represented by a calc-alkaline metavolcanic  dominated  sequence  at  the  bottom  and  a  metasedimentary  sequence  at  the  top,  which  are tectonically  imbricated  with  metaophiolites  and  eclogitic  rocks  in  various  sizes  from  centimeters  to  meters. Geochoronological  studies  on  the  northern  metamorphic  massifs  yielded  the  following  data:  maximum sedimentation ages of the protoliths of metasedimentary rocks in the range of 559 ±17 to 582 ± 30 Ma; crystallization age of the protolith of metavolcanic rock is of 577 ± 20 Ma, and crystallization age of the protolith of eclogitic rocks is of 565 ± 9Ma. On the other hand, a metamorphic unit called as Torasan formation, which crops out in the southern belt on the Kazdağ antiform, is cut by early Devonian metagranitoids and having 566 ± 7 Ma maximum sedimentation age according to U-Pd zircon dating. In addition to the similar U-Pb zircon ages  and  the  patterns  of  the  concordia  diagrams  of  the  northern  and  the  southern  belt  metamorphic  units, there  is  also  a  very  strong  correlation  between  these  metamorphic  units,  in  terms  of  their  lithological, stratigraphical, structural and metamorphic features. When we consider this correlation and the data together, as a conclusion, the remnants of a late Ediacaran –early Paleozoic active continental margin juxtaposed to the Pan-African oceanic realm in the basement of northwestern Anatolia.

 

Key words:Late Proterozoic-Early Paleozoic;Pan-African;active continental margin;Northwest Anatolia;U-Pb zircon