Stratigraphic and tectonic features of southwest field of Arapgir (Malatya)

Studied area covers approximately 252 km3 area on the west and southwest part of Arapgir which belongs to Maiatya province, in the studied area from old to young: it is observed the outcrop of Permo-Triassic old Keban Metharnorphites, Lower Miosen of old Alibonca Formation, Lower Miosen-Upper Miosen of old Malatya Volcaniîes, Pleistosen of old Meteristepe formation and Yoncali formation, Quaternary old debris flow and current alluvions. Keban Metharnorphites, which its sole is not studied and forms the base for younger units, is represented calcschist and marble litoiogy. Unit is covered unconformably by Alibonca Formation. Alibonca Formation is formed by medium-thick bedded limestone which is produced from carbonate shelf and clayey limestone precipitated in lagoons related Mioesen sea in which 'limestone is precipitated and mudstone consist of coal bed and marl. Unit, coming unconformably over different bases, was formed since the region was under transgression effect at the time of Akitaniyen-Burdigaliyen. By dividing into 2 sub chapters, Alibonca Formation is examined for the first time in this study, as a member of Suceyin limestone and member of Kmik mari. Lower Miosen-Upper Miosen is formed by Malatya volcanites, basaltic and andesitic compound of agglomerate, tuff-lapiilistone and basaltic, andesitic and dasitic compounded lava flows which cuts all these. Unit covers Alibabonca formation concordantly. This relation concordant and being of with tuff of limestone layers which form Alibonca Formation upper levels show that on the final step of (Late Burdigalien) precipitation of Alibonca Formation, volcanic activities also begins. Unit is covered unconformably by pleistosen old Meteristepe formation. Depending on litologicai features, Maiatya volcanites is examined in this study in different 5 members as rxYanıkiar aglomerate member, Sığırcıuşağı tuff-iapiilistone member, Geyiktepe dacite member, Sarikaya basait member and Saksaktepe andesitc member. The precipitated rare pebble-blocked loose sediments caused by temporary floods, for the first time in this study is defined and named as Meteristepe formation. Planar cross bedded delta precipitated sediments on sandstone-siitstone iitoiogy again for the first time was examined in this study and named as Yoncalı formation. Quaternary old debris flow and current alluvion is the youngest unit on the studied area and covers all the other older units. Studied area which is in the sphere of Alpine Orogeny belt is ratherly aciiv in terms of tectonic. Two important tectonic structures of Turkey which is under the influence of Alphine Orogeny line, some part of Malatya Fault and of Ovacik Fault Zone is inside of studied area. Left-lateral strike slip Malatya Fault, on N 20-25° E direction, also at same characteristics, Ovacik Fault, with its 3 different segments in changing directions between, N 32-70° E pass studied area about 4,5 km width as a zone form. Paraliel-semi parallel to each others from north to south Kızılca Fault, Kuyruksailamaz Fault and Gözeli fault with their line stretched valley morphologies, in due order water resources, in due order hills and with provided offset to units from which they are affected, are rather pronounced. The other important tectonic features of the study area are Yoncalı, Çobandere and Kavuniuk strike-slip fauits and also Arhutdere fault which couldn't be classified due to its unclear outcrop features. All these faults are firstly named and mapped in this study. The small scale strike slip faults, gravity faults and folded bodies situated in the zones of the Ovacik and Malatya fauits indicate the tectonism effecting on the study area. The interpretation of analysis of the fractures and bedding attitudes obtained from the formations indicates that the main compressional stress effects the study area in the direction of N 10-15° W.Key words: Malatya, stratigraphy, tectonic, Alibonca Formation, Malatya Voicanites, Ovacık Fault, Malatya Fault.