Tectonic controls on the Karlıova triple junction (Turkey): Implications for tectonic inversion and the initiation of volcanism

• Published in: Tectonophysics 2017-01, Vol.694, p.368-384
• Main Authors: Karaoğlu, Özgür, Selçuk, Azad Sağlam, Gudmundsson, Agust
• Format: Article
• Language: English
• Subjects: Crustal movement; Deformation; Deformation mechanisms; Earth; Eastern Turkish high plateau; Evolution; Extrusion; Fault lines; Fault zones; Faults; Geological faults; Interactions; Inversions; Karlıova Triple Junction; Lithosphere; Seismicity; Strain; Strain rate; Strike-slip faults; Tectonic inversion; Transtesional; Triple junctions; Uplift; Volcanic activity; Volcanism; Volcanoes
• ISSN: 0040-1951; 1879-3266
• DOI: 10.1016/j.tecto.2016.11.018

Few places on Earth are tectonically as active as the Karlıova region of eastern Turkey which comprises a triple junction (KTJ). Triple junctions result in complex kinematic and mechanical interactions within the lithosphere generating tectonic inversions and uplift, extensive seismicity and volcanism. Here we present new data, and summarize existing data, on the tectonic evolution of the KTJ in eastern Turkey over the past 6Ma. In particular, we present a kinematic model for the KTJ and the surrounding area as well as new structural maps. The deformation or strain rate has varied over this 6 million year period. The maximum strain rate occurred between 6Ma and 3Ma, a period that coincides with the initiation of activity in Varto Volcano. We suggest that increased strain rate and the initiation of activity at the Varto Volcano may be tectonically related. Subsequent to its formation, the Varto Volcano was dissected by active faults associated with the Varto Fault Zone, including reverse, normal and strike-slip faults. During the past 3Ma, however, the KTJ area was deformed dominantly through dextral crustal movements associated to right-lateral faults. This deformation resulted in the development of a NE-SW-trending extensional/transtensional regime, together with a complementary NW-SE-trending contractional regime. In the past 6Ma the east end of the KTJ has been subjected to incremental deformation. This deformation has resulted in many episodes of faulting during (i) ongoing shortening phases driven by a regional-scale thrust tectonic regime, and (ii) local-scale transtensional phases caused by westward extrusion. •New data make it possible to reconstruct the tectonic evolution of the Karlıova.•The region has undergone incremental deformation around Karlıova within the past 6Ma.•The NW–SE-striking deformation phase reactivated the faults of the VFZ.•The region has been subjected to inversion tectonics induced by strike-slip and reverse faulting.