See discussions, stats, and author profiles for this publication at: http://www.researchgate.net/publication/233123885 Tectonic Setting and Evolution of the Sivas Basin, Central Anatolia, Turkey ARTICLE in INTERNATIONAL GEOLOGY REVIEW · JULY 2010 Impact Factor: 1.71 · DOI: 10.1080/00206819709465366 CITATIONS READS 53 145 8 AUTHORS, INCLUDING: A. Poisson Haluk Temiz Université Paris-Sud ,Orsay,France Cumhuriyet University 86 PUBLICATIONS 1,252 CITATIONS 25 PUBLICATIONS 296 CITATIONS SEE PROFILE SEE PROFILE Kaan Sevki Kavak Cumhuriyet University 27 PUBLICATIONS 128 CITATIONS SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, Available from: Kaan Sevki Kavak letting you access and read them immediately. Retrieved on: 05 January 2016 International Geology Review, Vol. 38, 1996, p. 838-853. Copyright © 1996 by V. H. Winston & Son, Inc. All rights reserved. Tectonic Setting and Evolution of the Sivas Basin, Central Anatolia, Turkey1 A. POISSON, J. C. GUEZOU, Laboratoire de Geophysique et Geodynamique Interne (Unite CNRS N° 1369), Universite de Paris-Sud, bat. 504, 91405 Orsay Cedex, France A. OZTURK, S. INAN, H. TEMIZ, H. GURSOY, K. S. KAVAK, AND S. OZDEN Department of Geology, Cumhuriyet University, 58140 Sivas, Turkey Abstract The Sivas Basin is one of several Central Anatolian basins. It developed mainly after the closure of the northern branch of Neotethys. Its location between the Kirsehir Massif and the Taurides implies that it should not be confused with the Inner Tauride ocean located south of the Eastern Taurides. The basement of the Sivas Basin consists of ophiolitic nappes and melanges that were thrust toward the margins of the continental blocks present in this area—the Pontide belt to the north and the Anatolide-Tauride platform to the south. The basin was initiated by tectonic subsidence at the end of the Cretaceous, and it can be compared to a foreland basin during Paleocene and early to middle Eocene time. It was emergent during late Eocene and Oligocene time, although it continued to subside. A transgression in some parts of the basin occurred during the Oligocene and early Miocene (maximum flooding). During the Pliocene, it was affected by regional compression directed toward the NNW, which resulted from conver­ gence of the Arabian and Eurasian plates. This basin may have developed as an intracontinental basin within the Tauride platform and probably never had an oceanic basement. As a result of this work, the general paleogeographic organization of Central Anatolia and Northern Tethys during the Mesozoic should to be revised. Introduction to Erzincan to the east and is considered as the suture of the oceanic realm and the line of SINCE LATE CRETACEOUS TIME, the Middle East collision between the southern margin of the has been involved in the formation of the Alpine Eurasian plate (Pontide belt) and the Apulo- belt, resulting from the convergence of the Anatolian block (Anatolide-Tauride platform, Eurasian, African, and Arabian plates. The cor­ Tauride belt) (Fig. 1). Thus, this lineament, responding N-S shortening led to the closure of called "the Central Anatolian thrust belt," rep­ the North Neotethyan ocean, and finally to the resents a fundamental structural boundary in collision between the Eurasian and Arabian Turkey (Tatar, 1982). This global model implies plates with the Anatolian block. The collision the existence of a Northern Neotethyan ocean was accompanied by obduction of the North located south of the Pontide belt. The organiza­ Neotethyan oceanic crust, toward and onto the tion of the southern margin of this oceanic neighboring continental margins. In Central basin also seems clear: the Kirsehir Massif and Anatolia, ophiolitic nappes and colored the Tauride belt, as well as the eastern part of melanges (the "Ankara melange" of Bailey and the Apulo-Anatolian microplate, all represent McCallien, 1950, 1953; Norman, 1984) parts of this southern margin. In the east­ resulted from these events and represent rem­ ernmost part of Anatolia, the Neotethys faces nants of the previous North Neotethyan ocean several continental blocks (Bitlis-Potiirge Mas­ basin. They crop out along a zone that runs E-W sif) and the Arabian plate (Fig. 1). Questions through Turkey: the Izmir-Ankara zone (Brink- regarding Central Anatolia concern: (1) the man, 1966, 1976). That zone can be extended relationship between the Kirsehir Massif and the Tauride belt; (2) the exact emplacement and ]Paper initially presented at the Second International Turk­ age of the Northern Neotethyan suture zone; ish Geology Symposium, Cumhuriyet University, Sivas, and (3) the mode of formation of the Central Turkey; Orhan Tatar, Convenor Editor. 0020-6814/96/214/838-16 $10.00 838 EVOLUTION OF THE SIVAS BASIN 839 FlC. 1. Location of the Sivas Basin in the geodynamic context of the Middle East. Anatolian basins and their general evolution In fact, in many places on both sides of the during Cenozoic and Quaternary time. We shall basin, the oldest beds have been deposited on discuss these questions below, focusing atten­ top of ophiolitic sequences (mainly serpen- tion on the Sivas Basin. tinites and gabbros). Nevertheless, these ophio- lites are allochthonous, and their own basement may be found in the Tauride belt to the south Geologic Setting of the Sivas Basin and in the Kirsehir Massif to the north. All along the northern margin of the Sivas Basin, The Sivas Basin is one of the most important the Kirsehir Massif appears to be present of the Central Anatolian basins (Fig. 1). As a beneath the ophiolites. It crops out just north result of its location, its sedimentary fill of Sivas (Fig. 2) and to the northeast in tectonic (including the products of magmatic activity), windows through the ophiolites (beyond the and its structure, this basin offers a good oppor­ area depicted on the map). Thus the Sivas Basin tunity for study of the Paleogene to Recent appears to be a gutter between Kirsehir and the evolution of an active segment of the Alpine Tauride belt. It does not seem to lie within the belt in the Middle East and for discussion of the Ankara-Erzincan suture zone, as postulated by questions raised above. The western part of the Cater et al. (1991). In fact, this suture must be Sivas Basin is oriented NE-SW (SW of Sivas), located farther to the north of the Kirsehir but the eastern part has an E-W orientation. Massif. The northern limit of the basin (striking E-W) The nature and origin of the Kirsehir Massif corresponds to the Central Anatolian thrust must be reconsidered, as many questions con­ belt. The other margins also have been consid­ cerning this massif have arisen. It is not, how­ ered to be tectonic lineaments (e.g., prolonga­ ever, the purpose of this paper to discuss in tion of the Ecemis corridor). The basement of detail all the available data. We intend here only the basin is reputed to be the oceanic crust of to state precisely what we mean by "Kirsehir the "Inner Tauride suture" of Sengor (1984). Massif" and what other authors mean by "Kir- EVOLUTION OF THE SIVAS BASIN 841 suture zone. The Kirsehir block and the Tauride postulated. Complete revision of the general platform also were intruded by similar plutonic chronology of the basin (by means of bio- rocks. Thus we can say that Kirsehir and the chronology, magnetostratigraphy, isotope chro­ Taurides experienced a quite similar geo- nology, etc.), as well as other subordinate dynamic evolution at the end of the Cretaceous, studies in sedimentology, geochemistry, paleo- and we suggest, as a working hypothesis, that geography, etc., should recognize several struc­ Kirsehir may represent a northern extension of tural units, separated by numerous faults. The the Taurides. Kirsehir and the Taurides may majority of these faults are near-horizontal have been separated by a basin (the ancestor of thrust faults. Consequently, it appears to be the Sivas Basin), the nature and status of which essential to discuss first the general structural remain unknown. line and deformation style that prevailed during basin formation. Our studies have focused on the eastern tip of Geology the basin, on the central area near Sivas, and on Previous works the region along the basin margins. Figures 2 and 3 provide a general map of the central part The first general and detailed report (Yalcin- and two interpretive cross-sections. This map is lar, 1955) and the first important paper (Kurt- simplified from the 138 1:100,000 sheet cur­ man, 1973) concerning the general geology of rently being compiled. the basin have remained the state of knowledge until recently. Later, more specialized papers Previous data. Several unpublished reports were published on the pre-Neogene deposits (MTA, Ankara) preceded the publication of the (Gokcen, 1981; Gokten, 1983, 1986; Gokcen 1:500,000-scale Sivas sheet, which represents a and Kelling, 1985; Gokten and Floyd, 1987; synthesis of the work of Baykal and Erentoz Norman, 1990), the Neogene deposits (Temiz et (1966). Those authors pointed out the exis­ al., 1991), and the entire basin (Aktimur, 1988; tence of NE-SW-trending folds and also Cater et al., 1991; Yilmaz, 1994). The most reported an E-W, southward-verging thrust at important works concerning biostratigraphy the northern margin of the basin (north of are those of Stchepinsky (1939), Yalcinlar Hafik), supposedly of post-Oligocene to pre- (1955, general stratigraphy), Eriinal-Erentoz Miocene age. Arpat (1964) and Artan and Ses- (1956, molluscs), Dizer (1962, foraminifera), tini (1971) reported northward-verging reverse Siimengen et al. (1989, mammals), and De faults and thrusts along the southern margin of Bruijn et al. (1992, mammals). Geological maps the basin. Kurtman (1973) mapped several include the regular l:500,000-scale Sivas sheet important structures between Tecer Dag and (Baykal and Erentoz, 1966) and the new series Hafik, such as the N-verging Tecer thrust and at 1:100,000 scale: F23, F25, F26, and G23 the NW-SE strike-slip faults in the region of (General Directorate for Mineral Research and Karayiin.