Tectonics of the Sivas Basin: The Neogene Record of the Anatolian Accretion Along the Inner Tauric Suture

Abstract

The Sivas Basin extends over a major crustal structure underlying the contact zone between the Tauride and Pontide belts. The Kirsehir block, a continental crustal element lying between the main belts, introduces a subordinate suture in front of the Pontides-the Inner Tauride suture. The junction of the two main sutures occurs between Hafikand Imranli. Four structural zones have been considered. The northern basement of the basin, which includes both the Kirsehir continental crust and thrust sheets of ophiolite and pelagic sediments, forms an imbricate stack with an Eocene cover. The Eocene cover shows two distinct sequences: marine neritic and continental basalts overlying the Kirsehir basement, and deltaic and basinal deposits lying to the southeast. Southward tectonic stacking of the entire pile has occurred repeatedly since Oligocene time. The Sivas Basin proper is separated from the Kirsehir basement by the Kizilirmak Basin. This new structural unit consists of nearly undeformed, middle Miocene sandstones and conglomerates and a Pliocene lacustrine limestone.The Sivas Basin proper corresponds to a fold-and-thrust belt involving an Oligocene deltaic plain with intervening large-scale evaporitic stages and subsequent lower Miocene shallowmarine deposits. Three distinct tectonic domains are considered-(1) an eastern A domain, characterized by a hinterland of deep imbricate and rare northward thrusts; (2) a transitional B domain, corresponding to a series of lateral thrust branches propagating to the southwest; this domain later was deformed by the (3) C domain, displaying a foreland-dip type of stacking. The Caldag-Tecer-Gurlevik ridge forms a structural entity of topographic highs along the southern margin of the Sivas fold-and-thrust belt. Three Eocene-cored anticlinoria arranged along an E-W relay zone fold a passive-roof composite allochthon including ophiolitic elements together with Upper Cretaceous to Eocene limestone and conglomerate. The sole of this allochthon consists of Oligocene gypsum. The Kangal Basin, a large syncline cored by Pliocene continental deposits, corresponds to the southernmost unit. The boundary with the Caldag-Tercer-Gürlevik ridge is partially concealed by a lower Miocene continental basin, overlain by a N-vergent thrust of a lower Mesozoic limestone of the Taurus platform. If the southeastward propagation of thrusting in the Sivas thrust belt and related northward thrusts at a variety of scales is considered to represent the main thrust over the undeformed Kizilirmak basin, a comparison with modern analog structural features and analog models yields a coherent interpretation of this basin in terms of its forearc-prism evolution. At a larger scale, the Sivas Basin should be considered as a piggyback basin developed along the northward-rotated rear of the Tauride wedge and the synchronous southward thrusting of the Kirsehir-Pontide wedge. At least in early Miocene time, the Inner Tauride and Erzincan sutures corresponded to a single intracontinental thrust zone along which part of t...

3D modeling from outcrop data in a salt tectonic context: Example from the Inceyol minibasin, Sivas Basin, Turkey

“…The Sivas Basin formed from the Paleocene to the Pliocene in a foreland fold-and-thrust belt basin setting is located in the Central Anatolian Plateau, Turkey (Figure 2a) (Kurtman, 1973;Cater et al, 1991;Guezou et al, 1996;Poisson and Guezou, 1996;Gündogan et al, 2005). At the end of the Eocene, a huge accumulation of marine evaporitic deposits occurred in the Sivas Basin.…”

Characteristic features and structural evolution of a post collisional basin: The Sivas Basin, Central Anatolia, Turkey

“…The Sivas Basin has been interpreted as a remnant basin between the Pontides and the Tauride Platform (Kelling et al, 1989;Cater et al, 1991) or as a remnant basin resulting from Inner Tauride Ocean closure (Ş engör and Yılmaz, 1981;Koçyigit, 1990;Gökten, 1993a;Guezou et al, 1996) and/or a collisional relict of the Neo-Tethyan Ocean (Gökten, 1993b;Poisson et al, 1995Poisson et al, , 1996. Alternatively, it has also been interpreted as a postcollisional basin that formed after closure of the northern branch of Neo-Tethys (Yılmaz, 1994(Yılmaz, , 1998.…”

Active tectonics of the Ortaköy fissure-ridge-type travertines: implications for the Quaternary stress state of the neotectonic structures of the Central Anatolia, Turkey

“…The basin is overlain by the Central Anatolian Thrust Zone. Guezou et al (1996) reported that the Sivas Backthrust is a major structure in the basin along a tectonic line extending from Imranli to Gemerek with NE-SW orientation (Figures 10 and 11). Guezou et al (1996) describes the northern region of Sivas backthrust as Kızılırmak basin, by expressing that lower Pliocene age Sivas Backthrust develops from southeast to northwest.…”

“…Guezou et al (1996) reported that the Sivas Backthrust is a major structure in the basin along a tectonic line extending from Imranli to Gemerek with NE-SW orientation (Figures 10 and 11). Guezou et al (1996) describes the northern region of Sivas backthrust as Kızılırmak basin, by expressing that lower Pliocene age Sivas Backthrust develops from southeast to northwest. So the sediments of Kızılırmak basin on which the travertines of Sıcak Çermik, Delikkaya, Sarıkaya, Başıbüyük and Paşafabri-kası are located, have been under the effects of compressional regime in NW-SE direction since lower Pliocene and show unique deformation styles of that regime (Figure 12).…”