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Lakustrine Sedimente Als Archive Des Spätquartären Umweltwandels in Der Amery-Oase, Ostantarktis

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Lakustrine Sedimente Als Archive Des Spätquartären Umweltwandels in Der Amery-Oase, Ostantarktis Alfred-Wegener-Institut für Polar- und Meeresforschung Sektion Periglazialforschung MARCOPOLI-Forschungsprogramm Arbeitspaket POL 6 ’Klimavariabilität seit dem Pliozän’ Lakustrine Sedimente als Archive des spätquartären Umweltwandels in der Amery-Oase, Ostantarktis Dissertation zur Erlangung des akademischen Grades Doktor der Naturwissenschaften (Dr. rer. nat.) in der Wissenschaftsdisziplin Geologie eingereicht an der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam von Nadja Hultzsch geboren am 25.01.1974 in Wiesbaden Potsdam, im März 2006 Inhaltsverzeichnis Dank Zusammenfassung Summary Abkürzungsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis 1 Einleitung.......................................................................................................................................... 1 2 Theoretischer Hintergrund ............................................................................................................... 6 2.1 Antarktis ................................................................................................................................. 6 2.2 Antarktische Oasen................................................................................................................ 8 2.3 Antarktische Seen .................................................................................................................. 8 3 Untersuchungsgebiet Amery-Oase................................................................................................ 10 3.1 Entdeckungs- und Erforschungsgeschichte......................................................................... 10 3.2 Geographische Lage............................................................................................................ 10 3.3 Klima .................................................................................................................................... 11 3.4 Geologischer Aufbau............................................................................................................ 12 3.5 Seen der Amery-Oase ......................................................................................................... 14 3.5.1 Beaver-See......................................................................................................................14 3.5.2 Radok-See.......................................................................................................................14 3.5.3 Terrasovoje-See .............................................................................................................. 14 4 Material und Methoden................................................................................................................... 15 4.1 Bathymetrie und Hydrologie................................................................................................. 17 4.2 Seesedimentuntersuchungen .............................................................................................. 17 4.2.1 Sedimentkerngewinnung ................................................................................................. 17 4.2.2 Kernbeschreibung, Beprobung, Aufbereitung ................................................................. 17 4.2.3 Korngrößenanalyse ......................................................................................................... 18 4.2.4 Gesamtmineralogie.......................................................................................................... 18 4.2.5 Mineralogie der Tonfraktion ............................................................................................. 19 4.2.6 Anorganische Geochemie ............................................................................................... 20 4.2.7 Biogeochemie (C, N, S) ................................................................................................... 20 13 4.2.8 Isotopengeochemie (δ Corg)............................................................................................ 21 4.2.9 Diatomeenanalyse ........................................................................................................... 21 4.2.10 Rock-Eval-Pyrolyse ......................................................................................................... 21 4.2.11 Dünnschliffpräparation und -analyse ............................................................................... 22 4.2.12 EDXRF-Geoscanner........................................................................................................ 22 5 Altersmodell und Sedimentationsraten .......................................................................................... 23 6 Ergebnisse ..................................................................................................................................... 26 6.1 Bathymetrie und Hydrologie................................................................................................. 26 6.1.1 Bathymetrie und Hydrologie, Beaver-See ....................................................................... 26 6.1.2 Bathymetrie und Hydrologie, Radok-See ........................................................................ 28 6.1.3 Bathymetrie und Hydrologie, Terrasovoje-See................................................................ 29 6.1.4 Vergleich der bathymetrischen und hydrologischen Charakteristika............................... 30 6.2 Sedimentuntersuchungen .................................................................................................... 32 6.2.1 Sedimentkernbeschreibung ............................................................................................. 32 6.2.1.1 Vergleich der makroskopischen Sedimentkernmerkmale....................................... 35 6.2.2 Korngrößenverteilung ...................................................................................................... 35 6.2.2.1 Vergleich der Korngrößenverteilungen in den Sedimentkernen............................. 37 6.2.3 Gesamtmineralogie.......................................................................................................... 38 6.2.3.1 Gesamtmineralogie, Beaver-See-Sedimente ......................................................... 38 6.2.3.2 Gesamtmineralogie, Radok-See-Sedimente .......................................................... 39 6.2.3.3 Gesamtmineralogie, Terrasovoje-See-Sedimente.................................................. 41 6.2.3.4 Vergleich der mineralogischen Zusammensetzung der Sedimentkerne ................ 42 6.2.4 Mineralogie der Tonfraktion ............................................................................................. 43 6.2.4.1 Mineralogie der Tonfraktion, Beaver-See-Sedimente............................................. 43 6.2.4.2 Mineralogie der Tonfraktion, Radok-See-Sedimente.............................................. 44 6.2.4.3 Mineralogie der Tonfraktion, Terrasovoje-See-Sedimente ..................................... 46 6.2.4.4 Vergleich der tonmineralogischen Zusammensetzung der Sedimentkerne ........... 47 6.2.5 Anorganische Geochemie ............................................................................................... 48 6.2.6 Biogene Sedimente im Terrasovoje-See......................................................................... 56 13 6.2.6.1 Biogeochemie (C, N, S), Isotopengeochemie (δ Corg), Diatomeen ....................... 56 6.2.6.2 Rock-Eval-Pyrolyse................................................................................................. 58 6.2.6.3 Mikrofazielle Dünnschliffanalyse............................................................................. 58 6.2.6.4 EDXRF-Geoscanner ............................................................................................... 65 7 Diskussion und Interpretation......................................................................................................... 68 7.1 Genese und Bathymetrie der Seen...................................................................................... 68 7.2 Hydrologie ............................................................................................................................ 68 7.3 Detritische Sedimentherkunft............................................................................................... 70 7.3.1 Detritische Sedimentherkunft, Beaver-See-Sedimente................................................... 72 7.3.2 Detritische Sedimentherkunft, Radok-See-Sedimente.................................................... 73 7.3.3 Detritische Sedimentherkunft, Terrasovoje-See-Sedimente ........................................... 74 7.3.4 Zusammenfassung detritische Sedimentherkunft ........................................................... 76 7.4 Sedimentfazies und Ablagerungsmilieu............................................................................... 77 7.4.1 Sedimentfazies und Ablagerungsmilieu, Beaver-See-Sedimente................................... 78 7.4.2 Sedimentfazies und Ablagerungsmilieu, Radok-See-Sedimente.................................... 79 7.4.3 Sedimentfazies und Ablagerungsmilieu, Terrasovoje-See-Sedimente ........................... 80 7.4.4 Zusammenfassung Sedimentfazies und Ablagerungsmilieu........................................... 81 7.5 Postglaziale biogene Sedimentation im Terrasovoje-See ................................................... 83 7.5.1 Bioproduktivität ................................................................................................................83
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