Turkish Journal of Earth Sciences (Turkish J. Earth Sci.),B. ROJAY Vol. 21, & 2012, A. KOÇYİĞİT pp. 473–496. Copyright ©TÜBİTAK doi:10.3906/yer-1001-36 First published online 25 January 2011 An Active Composite Pull-apart Basin Within the Central Part of the North Anatolian Fault System: the Merzifon-Suluova Basin, Turkey BORA ROJAY & ALİ KOÇYİĞİT Middle East Technical University, Department of Geological Engineering, Universiteler Mahallesi, Dumplupınar Bulvarı No: 1, TR−06800 Ankara, Turkey (E-mail:
[email protected]) Received 26 January 2010; revised typescript receipt 13 December 2010; accepted 25 January 2010 Abstract: Th e North Anatolian Fault System (NAFS) that separates the Eurasian plate in the north from the Anatolian microplate in the south is an intracontinental transform plate boundary. Its course makes a northward convex arch- shaped pattern by fl exure in its central part between Ladik in the east and Kargı in the west. A number of strike-slip basins of dissimilar type and age occur within the NAFS. One of the spatially large basins is the E–W-trending Merzifon- Suluova basin (MS basin), about 55 km long and 22 km wide, located on the southern inner side of the northerly-convex section of the NAFS. Th e MS basin has two infi lls separated from each other by an angular unconformity. Th e older and folded one is exposed along the fault-controlled margins of the basin, and dominantly consists of a Miocene fl uvio- lacustrine sedimentary sequence. Th e younger, nearly horizontal basin infi ll (neotectonic infi ll) consists mainly of Plio– Quaternary conglomerates and sandstone-mudstone alternations of fan-apron deposits, alluvial fan deposits and recent basin fl oor sediments.