University of Patras September 2019 Department of Geology Geosciences and the Environment Laboratory of Palaeontology - Stratigraphy Palaeoenvironmental interpretation of Pleistocene deposits from Magoula (northwestern Peloponnesus, Greece) Konstantina Karanika (R.N: 1029636) Members of the committee: George Iliopoulos (supervisor) Ioannis Koukouvelas Elsa Gliozzi Contents ACKNOWLEDGEMENTS ..................................................................................................................................... 3 ABSTRACT .......................................................................................................................................................... 5 1. INTRODUCTION ......................................................................................................................................... 7 2. GEOLOGICAL SETTING ............................................................................................................................... 8 2.1 Geotectonic evolution of the Corinth-Patras basin ................................................................................ 10 2.2 Pliocene – Quaternary formations of the Corinth-Patras graben .......................................................... 11 2.3 Rio-Antirrio sub-basin ............................................................................................................................ 13 2.3.1 LITHOSTRATIGRAPHY OF RIO-ANTIRRIO SUB-BASIN ....................................................................... 13 2.3.2 TECTONIC, STRATIGRAPHIC AND PALEOGEOGRAPHIC EVOLUTION OF THE RIO-ANTIRRIO SUB- BASIN ....................................................................................................................................................... 15 3. PALAEONTOLOGY ................................................................................................................................... 19 3.1 Ostracods .............................................................................................................................................. 19 3.2 Foraminifera .......................................................................................................................................... 20 4. MATERIAL & METHODS .......................................................................................................................... 22 5.1 Section M ......................................................................................................................................... 27 5.2 Section K ................................................................................................................................................ 28 6. TAXONOMY ............................................................................................................................................. 32 7. RESULTS OF MICROPALAEONTOLOGICAL ANALYSES ............................................................................ 40 7.1 Section M ........................................................................................................................................ 40 7.1.1 RELATIVE ABUNDANCE DIAGRAMS ................................................................................................ 40 7.1.2 STATISTICAL ANALYSIS .................................................................................................................... 41 7.2 Section K .......................................................................................................................................... 44 7.2.1 RELATIVE ABUNDANCE DIAGRAMS ......................................................................................... 44 7.2.2 STATISTICAL ANALYSIS .................................................................................................................... 45 8. DISCUSSION ............................................................................................................................................. 50 8.1 Section M ........................................................................................................................................ 50 8.2 Section K .......................................................................................................................................... 54 8.3 Age of the sections .......................................................................................................................... 60 8.4 Correlation between the sections .................................................................................................. 62 8.5 Correlation with previous studies .................................................................................................. 64 9. CONCLUSIONS ......................................................................................................................................... 66 REFERENCES .................................................................................................................................................... 67 Annex I............................................................................................................................................................. 78 Annex II ........................................................................................................................................................... 82 1 2 ACKNOWLEDGEMENTS I would first like to thank my thesis advisor Prof. George Iliopoulos. The door to his office was always open whenever I ran into a trouble spot or had a question about my research or writing. He consistently allowed this paper to be my own work but steered me in the right the direction whenever he thought I needed it. I would also like to thank the experts who were involved in the validation survey for this research project: Prof. Ioannis Koukouvelas and Prof. Elsa Gliozzi. Without their passionate participation and input, the validation survey could not have been successfully conducted! Moreover, i would like to thank Prof. Nikolaos Kontopoulos for all the knowledge that he gave me during field work and Prof. Avraam Zelilidis for his assistance in understanding the evolution of the basin. Special thanks to my best partners Penelope Papadopoulou and Maria Tsoni for their advices, the conversations we had and Maria Kolendrianou, Eleni Liapi, Irene Pappa and everyone else that helped me during the field work and the sampling and all the great working times in the lab! I will miss you all! Finally, I must express my very profound gratitude to my parents, Andriana & Efthimios, my sister Despoina and to my mate, Eleftherio Georgoula for providing me with unfailing support and continuous encouragement throughout my years of study and through the process of researching and writing this thesis. This accomplishment would not have been possible without them. Thank you. Konstantina Karanika September 2019 3 4 ABSTRACT This work involves the palaeoecological study of Pleistocene deposits from Magoula (northwestern Peloponnesus, Greece), based on the analysis of microfaunal elements. The study area has been chosen not only as a site of significant palaeontological interest where plant fossils, mammal bones and a wide range of different kinds of invertebrate and microfossils occur, but also for its tectonic position at the Rio –Antirio basin. The former basin bridges the Patraikos and Corinth Grabens. Microfaunal analyses were carried out on 267 samples collected every 20-40cm from two natural sections in the area of Magoula. From the first section (section M), which has a total thickness of 31.30 meters, 133 samples were processed, whereas from the second section (section K) with a total thickness of 27.20 meters, 134 samples. Sediment samples were wet sieved with tap water through 500 and 63 μm mesh sieves. Microfossils were sorted from the dried residues and subsequently were studied under the stereoscope. Species were determined based on previous studies of Mediterranean benthic taxa. The collected data were analyzed, relative abundance diagrams were prepared for each species using the software C2. Furthermore, taphonomic indices (Right/Left valve ratio, Sex ratio, Adult/Juvenile ratio and Carapace/Disarticulated Valves ratio) were calculated for most of the abundant species of ostracods. Also, stratigraphic columns were plotted according to collected section log data. Considering both the stratigraphic and the micropalaeontological analysis results, a detailed palaeoenvironmental reconstruction took place. In section M, according to microfaunal analysis, 4 ostracod taxa (Cyprideis torosa (both un-noded and noded morphotypes), Candona neglecta, Ilyocypris gibba, Aurila convexa) were recorded in the studied samples. The most abundant were C. torosa and C. neglecta. Two benthic foraminifera taxa (Ammonia tepida and Haynesina depressula), as well as some charophyte gyrogonites, freshwater gastropod opercula and fragments (Bithynia sp. and Valavata cristata) were identified as well. These data suggest that an initially lagoon system, turned gradually into a lagoonal river mouth environment (barren layers) due to sea level drop, and finally when sea level rose, it became again a lagoonal environment influenced by a river system with strong freshwater influxes. Moreover, the relative abundance diagrams and the taphonomic indices in combination 5 with the stratigraphic column characterize a possible flood event at 24.10-24.30 meters. Thus paleoenvironmental changes occurred due to eustatism.