Themenauswahl der Arbeitsgruppe Prof. Pross für Diplom- und Master-Arbeiten

Did the last interglacial start with a climate fluctuation similar to that of the Younger Dryas event at the beginning of the present Holocene interglacial?

Projektbeschreibung: Der Übergang vom letzten Glazial zum heutigen Holozän-Interglazial wurde in der nördlichen Hemisphäre durch die abrupte Klimafluktuation der Jüngeren Dryas geprägt. Als auslösender Mechanismus für dieses Event wird ein plötzliches Ergießen des Süßwasser-Stausees Lake Agassiz in den Nordatlantik und somit die Abschwächung der thermohalinen Zirkulation diskutiert (Clark et al. 2001, Science; Broecker 2006, Science). Eine Klimaschwankung mit ähnlichem Auslösermechanismus wird für den Beginn des letzten Interglazials vermutet (Sánchez Goñi et al. 1999, Earth and Planetary Science Letters). Zur Klärung dieser Frage sind u.a. palynologische Analysen an einem bereits vorhandenen Bohrkern aus SW-Deutschland geeignet.

Arbeitsbereiche: Palynologie, Vegetationsdynamik, Quartärökologie, Paläoklimatologie

Ansprechpartner: Dr. Ulrich Müller, Prof. Jörg Pross

Man-made or climatic change? Deforestation phases in the prehistoric and historic Holocene record of Tenaghi Philippon, Greece

Projektbeschreibung: Der Raum rund um das östliche Mittelmeer erfuhr eine außergewöhnlich tiefe historische Prägung. Ägyptische, griechische und römische Kulturen führten zu einer erheblichen Umgestaltung der Landschaft. Gleichzeitig wurden diese Kulturen von einer ganzen Reihe natürlicher Klimaschwankungen (Trockenphasen, "Noahs Flut") getroffen. Hochauflösende pollenanalytische Untersuchungen am Kern von Tenaghi Philippon (NE-Griechenland) ermöglichen eine Evaluation antiker Texte sowie des Ablaufs der Kultur- und Siedlungsgeschichte aus geowissenschaftlicher Sicht.

Arbeitsbereiche: Palynologie, Vegetationsdynamik, Quartärökologie, Paläoklimatologie

Ansprechpartner: Dipl.-Geol. Ulrich Kotthoff, Dr. Ulrich Müller, Prof. Jörg Pross

Systematic prospection of sedimentary archives related to former explosive volcanism on the Schwäbische Alb, SW Germany

Projektbeschreibung: Im mittleren Miozän wurde die Schwäbische Alb durch hoch explosiven Vulkanismus erschüttert. Damals angelegte Vulkanschlote dienen teilweise bis heute als Sedimentfallen und beinhalten somit ein natürliches Archiv der Ökosystem- und Klimadynamik in SW-Deutschland. Systematische Sondierungen im Rahmen intensiver Geländearbeit sowie deren dokumentarische Auswertung sind gefragt zur Darstellung und stratigraphischen Interpretation der oberflächennahen Sedimentffüllung ausgewählter Vulkanschlote.

Arbeitsbereiche: Sedimentologie, Quartärgeologie, Angewandte Geologie

Ansprechpartner: Dr. Ulrich Müller, Prof. Jörg Pross

Terrestrial environmental dynamics during the mid-Cretaceous greenhouse world: signals across the Niveau Leenhardt black shale (early Albian, ca. 111 ma)

Project description: This project aims at deciphering terrestrial ecosystem dynamics during the mid-Cretaceous greenhouse world based on the analysis of pollen and spores in marine sediments. The generated terrestrial data will be compared to marine proxy data such as those from stable isotopes (O, C), benthic foraminifera and calcareous nannoplankton in order to develop a model for terrestrial-marine coupling during formation of the Niveau Leenhardt black shale in the Vocontian Basin, SE France. Particular emphasis will be on the identification of potential changes in terrestrial vegetation and/or changes in the hydrological cycle during the formation of the Niveau Leenhardt black shale. Samples are already available.

Research fields: palynology, geochemistry, land/sea correlation

Contact: Prof. Jörg Pross

The Carnian (Late Triassic) carbonate platform drowning event

Project description: The Late Carnian marks a widespread crisis in carbonate deposition (i.e., a so-called carbonate platform drowning event) that has been linked to rapid changes in paleoclimate towards particularly humid conditions. The mechanisms behind this humid pulse and its effects have remained largely unclear.
Intercalated marine shales and siltstones of the Raibler Formation provide possibilities for palynological (pollen and spores) studies, establishing links between changes on the continents and oceans. Fieldwork could be undertaken in the Austrian Alps.

Research fields: palynology, sedimentology, geochemistry, land/sea correlation

Contact: Dr. Bas van de Schootbrugge, Prof. Jörg Pross

The Rhaetian (Late Triassic) evolution of the coral-dinoflagellate symbiosis

Project description: The Late Triassic Rhaetian stage marked the rapid radiation of modern scleractinian ("stony") corals, who became for the first time dominant reef-builders along the margins of Pangea. The paleoecological parameters responsible for this major evolutionary event have remained largely unclear. One theory proposes that scleractinian corals acquired symbiotic dinoflagellate algae, allowing them to calcify more rapidly and hence to take up the best positions on reefs, where they were competing with sponges. Geochemical and paleontological studies of pristinely preserved fossil material from e.g. Turkey will provide insights into the exact relationship between corals and dinoflagellates during the Late Triassic as a function of changes in nutrient status of shallow marine waters, temperature and salinity.

Research fields: palynology, sedimentology, geochemistry, paleoceanography

Contact: Dr. Bas van de Schootbrugge

Biocalcification crisis at the Triassic-Jurassic boundary

Project description: The Triassic-Jurassic boundary witnessed a dramatic extinction in a range of biocalcifying organisms, including bivalves, ammonites, corals, coccolithophorids, and benthic foraminifera. All these groups show either much reduced size, changes in primary mineralogy from aragonite to calcite (or agglutinating in the case of foraminifera), and/or strongly reduced diversity. One proposed cause for these changes in biocalcification is the expulsion of large amounts of CO2 from flood basalt volcanism. Here, you will be investigating the role of pCO2 changes in this biocalcification crisis by studying sedimentological and geochemical phenomena from sections in the Southern Alps in Italy and Carpathian Mountains in Slowakia.

Research fields: geochemistry, sedimentology

Contact: Dr. Bas van de Schootbrugge

"Business as usual" after the Toarcian (Early Jurassic) Oceanic Anoxic Event (T-OAE)?

Project description: The T-OAE represents a brief Early Jurassic episode characterized by widespread deposition of organic-carbon rich black shales and a decrease in carbonate burial rates that have been linked with a dramatic global rise in pCO2. As such the study of Toarcian black shales could provide clues for the impact of future global warming. Whereas much attention has been paid to the onset of this event and its possible causes, relatively little is known about mechanisms that led to a return to "business as usual". A working hypothesis that can be tested with multi-proxy studies is that the globally increased burial of organic carbon led to a decrease in pCO2 during the later part of the Toarcian and possibly Aalenian, causing substantially cooler climate conditions. Our group uses palynomorphs (pollen, spores, phytoplankton) to track changes in vegetation on land and in the oceans and makes use of skeletal carbonates (e.g belemnites, oysters) to derive geochemical proxy records for temperature and salinity. The former tool allows land/sea correlations to be constructed, thereby shedding light on leads and lags between terrestrial and marine ecosystems.

Research fields: palynology, isotope geochemistry, land/sea correlation

Contact: Dr. Bas van de Schootbrugge, Prof. Jörg Pross

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