I am interested in the life cycle of sedimentary carbonates – from precipitation (abiotic, biologically induced and biologically controlled) through deposition to early diagenesis. Initially, my group was working with deep lacustrine settings, now we do make excursions into the shallows or on land. Depending on the environment, depositional processes leave a characteristic imprint on carbonate chemistry. We start with carbonate mineralogy and chemistry and are working our way through to reconstruct environmental changes. Unravelling the primary and/or secondary nature of the isotopic (d18O, d13C) and elemental (Mg/Ca, Sr/Ca) signal of different carbonate components is a fascinating challange which involves geochemical and petrographical approach often combined with ecological and (micro)facies analyses.
Lake Van carbonates
Sedimentary record of Lake Van, the world’s largest soda lake, spans the last 600 ka and documents climatic and tectonic evolution of the region. Available data clearly show the transition from a freshwater to alkaline lake at ca. 450 ka and a strong influence of glacial/interglacial cycles ever since. Set in the robust climatic context, lake Van carbonates and microfossil assemblages (ostracods, gastropods and bivalves) are an excellent material for testing the strengths and limitations of carbonate-based hydrological proxies.
Application of land snails’ shells for environmental reconstruction
Land snails’ shells constitute a valuable source of environmental information, especially in arid regions where other carbonate material are scarce. The oxygen isotope signal of the shell is related to temperature and a source and amount of moisture, while the carbon isotope signal reflects the dietary control. My team analyses shells from arid environments (warm – Morocco, and cold – Siberia) and archeological sites in Belize and Italy. We are interested not only in environmental reconstructions but also aim at improving cleaning and sampling procedures. Shells from archeological sites were likely part of a diet and we try (in a set of systematic experiments) assess the influence of thermal processing (e.g.: boiling) on the shell isotopic composition.
Paleolakes in Morocco
African Humid Period (AFH, ca. 14 to 5 ka BP) is an excellent example of precessional forcing on lower latitudes. Much is already know about the Termination of AFH, considerably less about its onset. Similarly, possible older humid periods remain unexplored. We are studying paleo-lacustrine and –palustrine sequences from Morocco (NW Africa), combining geomorphological, sedimentological, geochemical and ecological proxies with 14C and U/Th dating. Out project aims not only at compelling documentation of hydrological changes at a regional scale but also represents an integrated approach to better understand palustrine depositional environment.