Palaeontological study of lacustrine pliocene deposits from the Karapınar – Ayrancı basin, South-Central Turkey

• Κύριος συγγραφέας: Ρεντούμη, Ευαγγελία
• Άλλοι συγγραφείς: Ηλιόπουλος, Γιώργος
• Μορφή: Thesis
• Γλώσσα: English
• Έκδοση: 2022
• Θέματα: Pliocene-Pleistocene; Freshwater; Ostracods; Gastropods; Depositional environment; Karapınar – Ayrancı; Πλειόκαινο-Πλειστόκαινο; Γλυκό νερό; Οστρακώδη; Γαστερόποδα; Περιβάλλοντα απόθεσης; 551.792

The Karapınar-Ayrancı coal deposit is located in the southern part (Karapınar sub-basin) of the Konya Graben (south Central Anatolia). Μicropalaeontological data from the coal-bearing sediments derived from two boreholes (DK-1, DK-2), located in the eastern part of the Karapınar-Ayrancı coal deposit are reported. From core DK-1 (347,15m deep) sixty two sediment samples were obtained whereas from core DK-2 (274m deep) nineteen sediment samples were obtained respectively. The samples were washed with tap water through 0.5 and 0.063 mm mesh sieves, and macro- and microfossils were handpicked under the stereoscope. There was a great difficulty in dissolving the coal samples of DK-1 core. Therefore, another method was implemented that could dissolve the samples that contained coal. Ostracods, gastropods, bivalves, charophyte gyrogonites and fish teeth were collected and determined. Based on the macro- and microfaunal remains the cores were divided into units and a comparison was made between them. In general the dominant ostracod species in both cores were: Candona sp., Zonocypris membranae, Pseudocandona compressa, Pseudocandona sp., Heterocypris salina, Ilyocypris spp. and Cypridopsis sp. Gastropod’s fauna dominant species were Valvata cristata, Gyraulus crista, Hydrobiidae sp., Planorbidae spp., Lymnaeidae spp. Due to the great diversity of gastropod species in the region of South-Central Turkey the determination and classification of the collected specimens required a detailed study on the systematic taxonomy of the studied material. Based on the identified ostracods, gastropods, sedimentological features and the comparison between the two cores we conclude that the study area was a permanent, shallow and enclosed fresh water lake. During two intervals salinity slightly increased. The species Z. membranae and H. salina can tolerate saline conditions (fresh to brackish waters); however, their coexistence with typical freshwater species such as I. bradyi, I. gibba and Cypridopsis sp. indicate freshwater conditions. The absence of certain indicator species in a number of samples and the presence of coal beds along with the presence of gyrogonites, point to (episodic) hypoxia/anoxia events. The geological age of the coal-bearing sequence has been determined as Late Pliocene-Early Pleistocene based on the micropalaeontological data and mainly on the presence of species such as P. cf. compressa and Cypridopsis sp.