İbrahim Türkmen

Sedimentology and evaporite genesis of neogene continental sabkha playa complex, Karakeçili basin, central Anatolia, Turkey

The Karakeçili basin is an intermontane basin located about 60 km SE of Ankara in central Turkey and covers an area of approximately 200 km2. This Neogene basin is bordered by granite and gabbro of the Kirsehir massif to the north-northeast and east, and massive gypsum of the Mezgit Formation (Oligocene) to the west and southwest.Facies associations characterizing a playa complex crop out in this Neogene basin. These facies associations include, from the basin margin to the center, 1-Red massive conglomerate and pebbly mudstone (alluvial fan), 2-Organically rich mudstone, bearing sparse gypsum crystals (marsh), 3-Cross-laminated-bedded gypsarenite (eolian), 4-Brown-gray mudstone bearing gypsum-roses and discoidal and radial gypsum crystals (saline mudflat), and 5-Bedded-laminated gypsum (ephemeral salt lake).Evaporites occur commonly as discoidal crystals, sigmoidal crystals, rosettes, and nodular forms. These were formed displacively within mudstone from calcium sulphate-rich groundwater during the arid conditions. Stratified gypsum represented by macrocrystalline aspects is generally restricted laterally and is precipitated by the evaporation of brine sheets on mudflats.The source of evaporites in the Karakeçili basin is the gypsum of the Oligocene Mezgit Formation.

Alt Pliyosen Çaybağı Formasyonu'nun faunal içeriği ve çökelme ortamları ile ilişkisi, Elazığ doğusu/Türkiye

Caybagi Formasyonu dogu Torid Tektonik Birligi icerisinde yer alir. Birim aluvyal yelpaze, akarsu, delta ve gol ortamlarinda cokelmistir. Aluvyal yelpaze ve orgulu nehir fasiyesleri icerisinde fosil gozlenemezken, az kivrimli nehir, delta-gol cokelleri ostrakod, gastropod ve pelesipod fosilleri icermektedir. Zaman ve mekan boyutunda gecisli olan az kivrimli nehir ve delta-gol fasiyeslerinden olusan Kor Tepe, Cardakdivar Tepe, Hacisam Dere ve Ziyaret Tepe olculu kesitlerinde ostrakodlardan Candona, Ilyocypris, Cyprideis ve Heterocypris cinslerine ait turler ile mollusklardan Valvata, Lymnaea, Tinyyea, Planorbis, Radix, Gyraulus, Hydrobia, Potomida, Unio, Margaritifera, Anadonta ve Leguminaia cinslerine ait turler tanimlanmistir. Ayrica Ziyaret Tepe ve Kor Tepe olculu kesitlerinin farkli seviyelerinde Charophytes fosilleri gozlenmistir. Ostakod ve mollusk turlerinin gosterdikleri ortamsal ozelliklerle sedimantolojik verilerin uyumlu oldugu, Caybagi Formasyonu’nun Erken Pliyosen’de akarsu, delta-gol ortaminda cokeldigi belirlenmistir