Paleolimnology of Lake Iznik (NW Turkey) during the past ~ 31 ka cal BP Dissertation zur Erlangung des Doktorgrades (Dr. rer. nat.) der Mathematisch-Naturwissenschaftlichen Fakultät der Rheinischen Friedrich-Wilhelms-Universität Bonn vorgelegt von Patricia Angelika Roeser aus Wiesbaden Bonn, 2013 Angefertigt mit Genehmigung der Mathematisch-Naturwissenschaftlichen Fakultät der Rheinischen Friedrich-Wilhelms-Universität Bonn 1. Gutachter: Prof. Dr. Thomas Litt / Rheinische Friedrich- Wilhelms- Universität Bonn 2. Gutachter: Prof Dr. Kurt Friese / Martin-Luther-Universität Halle-Wittenberg Prüfungsdatum der Promotion: 26.03.2014 Erscheinungsjahr: 2014 i Index List of Figures .......................................................................................................................... v List of Tables ........................................................................................................................... ix Abbreviations .......................................................................................................................... xi PART I – STATE OF THE ART AND METHODS 1.) Introduction ................................................................................................................... 1 1.1) Objectives .................................................................................................................... 2 1.1.1) Project frame ........................................................................................................ 4 1.2) Thesis Outline .............................................................................................................. 4 2.) Iznik basin and the Marmara region........................................................................... 7 2.1) Geological settings ...................................................................................................... 7 2.1.1) North Anatolian Fault ........................................................................................... 8 2.2) Geomorphology and Iznik past lake levels ................................................................ 10 2.2.1) Timing for a Iznik-Marmara connection ............................................................ 11 2.3) Regional climate ........................................................................................................ 12 2.4) Basin hydrology ......................................................................................................... 14 2.5) Lake Iznik limnology ................................................................................................. 15 2.5.1) Hydrochemistry and lake mixing ....................................................................... 15 2.5.2) Sediments and deposition processes .................................................................. 17 3.) Materials and methods................................................................................................ 21 3.1) Field work and core recovery .................................................................................... 21 3.2) Core documentation and storage ............................................................................... 21 3.3) Composite profile ...................................................................................................... 22 3.4) Sampling Strategy ...................................................................................................... 24 3.5) Overview on analytical methods ............................................................................... 26 3.6) Physical properties ..................................................................................................... 26 3.6.1) Water content and dry bulk density .................................................................... 26 3.6.2) Magnetic susceptibility ...................................................................................... 27 3.6.3) Grain size ............................................................................................................ 27 3.6.3.1) Sampling and analysis ................................................................................ 27 3.6.3.2) Pre-treatment procedures ............................................................................ 28 3.6.3.3) Control group ............................................................................................. 29 3.7) Loss on ignition ......................................................................................................... 30 3.8) Mineralogy ................................................................................................................. 31 ii 3.8.1) Bulk sediment ..................................................................................................... 31 3.8.2) Clay fraction ....................................................................................................... 31 3.9) Geochemistry ............................................................................................................. 32 3.9.1) Major and trace elements ................................................................................... 32 3.9.2) Organic and inorganic carbon, nitrogen and sulfur ............................................ 33 3.9.3) Stable isotopes .................................................................................................... 34 3.10) Chronology ................................................................................................................ 35 PART II - RESULTS AND DISCUSSION 4.) Lithology, Physical Properties and Stratigraphy ..................................................... 37 4.1) Magnetic Susceptibility and Sedimentary Units ....................................................... 37 4.1.1) Unit I .................................................................................................................. 37 4.1.2) Unit II ................................................................................................................. 38 4.1.3) Unit III ................................................................................................................ 40 4.1.4) Unit IV ................................................................................................................ 41 4.1.5) Unit V ................................................................................................................. 41 4.2) Tephra Layers ............................................................................................................ 42 4.3) Water content and dry bulk density ........................................................................... 43 5.) Chronology ................................................................................................................... 45 5.1) Samples and dating results ........................................................................................ 45 5.1.1) Reservoir effect and hardwater effect ................................................................ 46 5.2) Age-depth model ....................................................................................................... 49 5.2.1) Considerations on datings rejected for age depth model .................................... 51 5.3) Mass accumulation rates ............................................................................................ 53 6.) Sediment geochemical and mineralogical evolution: a compositional approach .. 55 6.1) Introduction ............................................................................................................... 55 6.2) Nature of compositional data and brief history ......................................................... 55 6.3) Bulk Geochemistry .................................................................................................... 56 6.3.1) CoDa Analysis .................................................................................................... 56 6.3.1.1) Major elements – Itrax core scanner .......................................................... 56 6.3.1.2) Major elements and trace elements ............................................................ 58 6.3.2) Stratigraphic changes ......................................................................................... 62 6.4) Bulk Mineralogy ........................................................................................................ 65 6.4.1) CoDa analysis ..................................................................................................... 65 6.4.2) Stratigraphic changes ......................................................................................... 68 6.4.3) Clay size fraction ................................................................................................ 68 6.4.4) Other minerals .................................................................................................... 71 6.5) Discussion – Detrital deposition ................................................................................ 72 iii 6.5.1) Major cations - sources and sinks ...................................................................... 72 6.5.2) Constraints on the use of conventional alteration indexes ................................. 74 6.5.3) Alternative indexes and weathering evolution ................................................... 75 7.) Grain size composition and its implications for the paleo-record .......................... 79 7.1) Introduction ..............................................................................................................