Aristotle University of Thessaloniki School of Geology Department of Geology
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ARISTOTLE UNIVERSITY OF THESSALONIKI SCHOOL OF GEOLOGY DEPARTMENT OF GEOLOGY GEORGIA KOSTAKI Diploma Geology STRATIGRAPHY AND GEOTECTONIC SETTING OF THE ?KIMMERIDGIAN-TITHONIAN SHALLOW WATER PLATFORM SEDIMENTS ON TOP OF THE AXIOS OPHIOLITES (EASTERN AXIOS SUTURE ZONE, NORTHERN GREECE) MASTER THESIS THESSALONIKI 2013 GEORGIA KOSTAKI Diploma Geology STRATIGRAPHY AND GEOTECTONIC SETTING OF THE ?KIMMERIDGIAN- TITHONIAN SHALLOW WATER PLATFORM SEDIMENTS ON TOP OF THE AXIOS OPHIOLITES (EASTERN AXIOS SUTURE ZONE, NORTHERN GREECE) Submitted to the School of Geology Department of Geology 16/12/2013 Thesis Advisors Committee Professor Adamantios Kilias, Principal Advisor Professor Hans-Jürgen Gawlick, Advisor Committee Lecturer Nicolaos Kantiranis , Advisor Committee Georgia Kostaki, 2013 All rights reserved. STRATIGRAPHY AND GEOTECTONIC SETTING OF THE ?KIMMERIDGIAN- TITHONIAN SHALLOW WATER PLATFORM SEDIMENTS ON TOP OF THE AXIOS OPHIOLITES (EASTERN AXIOS SUTURE ZONE, NORTHERN GREECE) Duplication and distribution of this publication or parts is not permitted for commercial purposes. Whether the whole or part of the material of this thesis is being used for noncommercial, educational or research purposes the source must always be referred and this message should be preserved. Issues concerning the use of this thesis for commercial purposes must be addressed to the writer. The aspects and conclusions that are referred in this thesis declare only the writer and must not be consider as an official stand of the Aristotle University of Thessaloniki. Declaration of authorship „I declare in lieu of oath that this thesis is entirely my own work except where otherwise indicated. The presence of quoted or paraphrased material has been clearly signaled and all sources have been referred. The thesis has not been submitted for a degree at any other institution and has not been published yet.” Preface The present thesis was carried out in the frame of the Program of Postgraduate Studies in Geology and Geoenvironment in the specialization of Structural Geology and Stratigraphy and attempts to contribute an understanding of the tectonic development and geodynamic history of the Hellenides. The Hellenides constitute the southeastern part of the Alpine orogenic belt in Europe (Figure 1). They are traditionally divided into the Internal Hellenides and the External Hellenides. The Internal Hellenides are subdivided into several metamorphic zones, from East to West (Figure 1) (Brunn 1956, Godfriaux 1968, Mercier 1968, Jacobshagen et al. 1978, Jacobshagen 1986, Mountrakis 1986, Kilias 1991, Gawlick et al. 2008, Papanikolaou 2009): Rhodope Massif, Serbomacedonian Massif, Circum- Rhodope Belt, Vardar/Axios Zone and Pelagonian Zone. The Pelagonian Zone is situated between the two ophiolitic belts of Greece the Mirdita/Pindos to the west and the Vardar/Axios to the east. The geotectonic evolution of the Internal Hellenides was influenced by the Eohellenic Phase which took place during Middle to Late Jurassic. The evolution of the Eohellenic Phase is related to intra-oceanic subduction during Middle to early Late Jurassic followed by westward obduction of the Vardar/Axios Ophiolites on top of the Pelagonian Units. There is a variety of published scientific aspects concerning the number and location of the Tethyan Ocean basins, the origin and direction of emplacement of the Tethyan Ophiolites and the timing of ocean basin closure (e.g. Mercier et al. 1975, Mountrakis 1986, Robertson and Shallo 2000, Stampfli and Borel 2002, Brown and Robertson 2004, Gawlick et al. 2008, Schmid et al. 2008, Kilias et al. 2010, Missoni and Gawlick 2011). One group of authors (e.g. Smith and Spray 1984, Channell and Kozur 1997, Stampfli and Kozur 2006, Robertson et al. 2012) propose that the Vardar/Axios Ocean should represent an independent ocean between Pelagonian continent to the west and the wider Rhodope Massif to the east, which existed during most of the Mesozoic era. However, another group of authors (Schmid et al. 2008, Gawlick et al. 2008, Bortolotti et al. 2012) considers Vardar/Axios Ocean a as part of the Neotethys Ocean floor, which was obducted on top of Pelagonian continent in westward direction in Middle to early Late Jurassic time. The aspect of this work is based on is the following: In Triassic to Early Cretaceous times the Hellenides formed together with the Albanides, Dinarides, Western Carpathians, Northern Calcareous Alps and other regions a continuous NNE- SSW trending belt facing the north-western margin of the Neotethys Ocean and undergoing the same history. Formation of oceanic crust since Late Anisian, onset of inneroceanic thrusting in late Early Jurassic, ophiolite obduction in Middle-Late Jurassic, followed by the formation of shallow-water platforms, extensional collapse due to tectonic thickening and mountain uplift before the Jurassic/Cretaceous boundary (Kilias et al. 2010), and infilling of the foreland basins with erosional products of this orogeny in the Early Cretaceous (Missoni and Gawlick 2011). In the frame of the present thesis, field observations, biostratigraphic and microfacies analysis were carried out in an area, which is located 15 km north-west of Thessaloniki in Northern Greece and provides an excellent opportunity to investigate the Late Jurassic to Early Cretaceous geodynamic history of Vardar/Axios Zone. Microfacies studies were based on thin section of samples which were taken from carbonate rocks near the villages Neochorouda, Oreokastro and Kampanis. This research focuses mostly on the mass-flow deposits, which were found near the village Neochorouda, that are important for the reconstruction and the timing of the obduction processes of the Vardar/Axios Ophiolites. The analysis of the different components in the mass-flow deposits can be used as a tool to reconstruct an eroded carbonate platform sealing the emplacement of the ophiolites. The first chapter describes the general geology and provides a geological overview of the area. The second chapter is an introduction to the microfacies concept and carbonate classification. In the third chapter, each formation is separately described using also previous studies. Then the results of the biostratigraphic, microfacies and structural analysis are presented. At the end a correlation of the results of this work with others is made and the biostratigraphic, microfacies and structural data are combined towards an evolutionary scenario for the obduction processes of Vardar/Axios Ophiolites. Acknowledgements I would like to express the deepest appreciation to my supervisor Prof. Adamantios Kilias for his kind help during field work, his valuable comments and advice during research time and also for the long discussions we held on this work and other interesting subjects of geology. This study comes as a sequence of work that took place at Leoben University through the European Community Action Scheme for the Mobility of University Students program. I am indebted to my supervisor Prof. Hans-Jürgen Gawlick who gave me the great chance to go to Leoben and work on this project. I am most grateful for his valuable help in all aspects of my study. My sincere gratitude to the third member of the Thesis advisor committee Nikolaos Kantiranis for his support. I wish to thank Dr. Felix Schlagintweit for the fossil determination that was a significant part of this work. I would like to offer my special thanks to Dr. Effimia Thomaidou for her invaluable guidance during the course of my studies at the School of Geology of Aristotle University of Thessaloniki. For the allowance to use of the laboratory facilities, the Department of Applied Geosciences and Geophysics, Chair of Petroleum Geology at the University of Leoben is gratefully acknowledged. I own my deepest gratitude to Dr. Sigrid Missoni for her help and assistance during the laboratory work. I also would like to thank Katerina Kostaki and Dr. Georgios Sagriotis for helping me with the text editing and the Phd candidate Anastasios Plougarlis who was a valuable help with all computer problems. Finally, I am sincerely grateful to my friends Bernd Dahlinger, Eleni Sapountzi and Michalis Vlachos for accompanying me during field work. TABLE OF CONTENTS CHAPTER 1. Introduction and Geological Overview 1 CHAPTER 2. Methodology 9 2.1 Microfacies, Facies Zones and Standard Microfacies Types 10 2.2 Classification 11 CHAPTER 3. Geological Setting 13 3.1 Gneiss and Micaschist Unit 13 3.2 Melissochori Formation 14 3.3 Aspri Vrisi-Chortiatis Unit 15 3.4 Volcanosedimentary series 16 3.5 Triassic limestones 18 3.6 Ophiolite Complex 18 3.7 Neochorouda Unit 21 CHAPTER 4. Microfacies and Facies Interpretation - Results 22 4.1 Melissochori Formation 23 4.2 Aspri Vrisi-Chortiatis Unit 27 4.3 Triassic limestone 28 4.4 Neochorouda Unit 35 4.4.1 Reconstruction of the Jurassic to Early Cretaceous tectonic evolution 57 CHAPTER 5. Discussion and Conclusions 63 Abstract 65 Περίληψη 66 References 67 CHAPTER 1. Introduction and Geological Overview Vardar/Axios Zone The Vardar/Axios Zone is located parallel to the Hellenides-Dinarides chain in Northern Greece, FYROM and Serbia (Figure 1). The Vardar/Axios Zone was named after the Vardar/Axios River which is the longest river in FYROM and also a major river of Greece. Kossmat (1924) was the first who described the Vardar/Axios Zone as a 30 to 70 km wide NNW-SSE trending belt between the Serbomacedonian Massif to the east and Pelagonian Zone to the west, in Northern Greece. Southwards it extends in to the Thermaic Golf and Aegean Sea and then bends to Anatolia with a possible SW-NE trending. The Greek part of the Vardar/Axios Zone has been subdivided by Mercier (1968) into three subzones according to their palaeogeographic, lithological and facial characteristics. The western part of the Vardar/Axios Zone is the Almopia Subzone, characterized by ophiolites and deep sea sediments, as well as gneiss and schists. The Almopia Subzone to the east is in tectonic contact with the Paikon Subzone. The most characteristic rocks of the Paikon Subzone are Triassic marbles intercalated with schists and phyllites, overlain by volcanoclastic and carbonate rocks of Jurassic to Early Cretaceous age, as well as ophiolites.