The benthic foraminiferal biostratigraphy of Oligo-Miocene aged Muratlı and Petekkaya formations which crop out over wide regions around Akçadağ town, west of Malatya province in Eastern Taurids were revealed in this study. Systematical sampling was carried out in measured stratigraphical sections in four locations in order to perform stratigraphical and paleontological investigations. Benthic foraminifera taken from 182 hard rock samples were defined and three biozones were determined as; SBZ 21-22, belonging to Oligocene (Rupelian -Early Chattian), SBZ 23 (Late Chattian) and SBZ 25 belonging to Lower Miocene in shallow marine deposits in the region. It was stated that the assemblage of planktic foraminifer and nannoplankton which stratigraphically detected within Chattian -Burdigalian units in the succession most probably indicated Aquitanian age. Besides; Oligo-Miocene transition in the region was approved with this study based on biostratigraphical locations of benthic foraminiferal taxa.

In central eastern Anatolia which is located between Eurasia and Africa, the study of basin developments between late Eocene and early Miocene is of great importance for understanding the process of the closure of the Neo-Tethys Ocean and the formation of strike-slip faults and regional uplift. To study these, three basins were selected: the Sivas-Erzincan, Gürün-Akkisla-Divrigi (GAD), and Malatya basins. The study proposes that the opening of the GAD basin played a key role in the formation of the Ecemis fault, which started developing at the end of early Miocene, and in mountain uplift. All these basins are situated on continental blocks and oceanic crust, arranged from north to south as the Sakarya continent, the Izmir-Ankara-Erzincan ocean (Northern Neo-Tethys), the Kirsehir continent, the inner Tauride ocean, the Munzur-Binboga block, the Maden (=Berit) ocean, the Bitlis-Pütürge block, the Çüngüs ocean and the Arabian continent. The findings indicate that late Eocene-early Miocene successions in these basins were not deposited in foreland basins formed in front of the thrust faults associated with the closure of the ocean, as stated in previous studies. Rather, they were deposited in forearc and backarc basins related to the subduction which was effective until the end of early Miocene. The Sivas-Erzincan and Malatya basins, located on the inner Tauride and Maden (=Berit) oceans, were forearc basins, while the GAD basin situated on the Munzur-Binboga block was a backarc basin. These basins have parallel developments up to the end of early Miocene. While marine sediments were deposited in the Malatya and Sivas-Erzincan basins between late Eocene and early Miocene, terrestrial units began to settle in the GAD basin from the late Eocene and the deposition there is continuous until the end of the early Miocene. Collision of the Arabian and the Anatolian plates at the end of early Miocene (16-18 Ma) produced the left-strike slip Ecemis fault zone, which caused the lateral slip of sedimentary units in the Sivas-Erzincan and GAD basins over hundreds of kilometers. This event produced the first westward tectonic escape of the Anatolian plate prior to the north Anatolian fault (NAF) and the east Anatolian fault (EAF). The Gürün region located in the GAD basin was exhumed in late Miocene and this basin was broken. The Gürün region, which remains on the rising part of the Munzur-Binboga block, is not a different basin as stated earlier, but it is a part of the GAD basin, representing the central part of the GAD basin lake, as indicated by the fine grained deposits (limestones and clay) that occur in the Gürün area.

In this study, systematic description of 28 benthic foraminiferal taxa were carried out which had been detected in Oligo-Miocene aged Muratl› and Petekkaya formations cropping out over wide areas around Akçada¤ town, west of Malatya province in Eastern Taurids. Miogypsina globulina which is a cosmopolite species located in Burdigalian aged shallow marine carbonates is described on wide geographical areas ranging from Central America to Indo-Pacific and Mediterranean Tethys. Miogypsina polymorpha on the other hand was reported only from Indo-Pacific in stratigraphical records until today. Considering the association of these species, the assumption of a probable marine connection mentioned between Indo-Pacific and Mediterranean Tethys in Burdigalian period in the region was strongly supported. Also considering the presence of marker planktonic foraminiferal species Globoquadrina dehiscens and Sphenolithus delphix from nannoplanktons which are described in marls between Chattian and Burdigalian units it was determined that these marls most probably indicated Aquitanian age.

No abstract

ÖZBu çalışma ile, Doğu Toroslar'da Malatya ilinin batısındaki Akçadağ ilçesi civarında geniş alanlarda yüzeyleyen Oligo-Miyosen yaşlı Muratlı ve Petekkaya formasyonlarının bentik foraminifer biyostratigrafisi ortaya konulmuştur. Bölgede, stratigrafik ve paleontolojik incelemeler yapmak üzere seçilen dört lokasyondaki ölçülü stratigrafik kesitte sistematik örnek alımı gerçekleştirilmiştir. Toplam 182 adet sert kayaç örneğinden elde edilen bentik foraminiferler tanımlanarak bölgedeki sığ denizel çökellerde Oligosen'e ait SBZ 21-22 (RupeliyenErken Şattiyen), SBZ 23 (Geç Şattiyen) ile Alt Miyosen'e ait SBZ-25 olmak üzere toplam üç biyozon saptanmıştır. İstifte stratigrafik olarak Şattiyen ile Burdigaliyen yaşlı birimler arasındaki marnlarda tespit edilen planktik foraminifer ve nannoplankton topluluğunun olasılıkla Akitaniyen yaşını işaret ettiği belirlenmiştir. Ayrıca bu çalışma ile, bentik foraminifer taksonlarının biyostratigrafik konumlarına dayanarak bölgede Oligo-Miyosen geçişi belgelenmiştir. ABSTRACT The benthic foraminiferal biostratigraphy of Oligo-Miocene aged Muratlı and Petekkaya formations which crop out over wide regions around Akçadağ town, west of Malatya province in Eastern Taurids