MARINE CARBONATE ARCHIVES:
CONTROLS ON CARBONATE PRECIPITATION AND PATHWAYS OF DIAGENETIC ALTERATION

Context
Carbonates are arguably the most important rock type for reconstructing Earth system evolution with respect to the physical and chemical evolution of the oceans, as well as changes in atmospheric composition and global climate. The evolution of the climatic and physico-chemical parameters on Earth's continents and in the oceans throughout the Phanerozoic can be inferred by analysing marine and continental carbonate archive proxies including the geochemistry, fabrics, and mineralogy of these deposits. All carbonates are subject to variable degrees of post-depositional/post-mortem alteration, often commencing at a very early stage and continuing into the deep burial and anchimetamorphic domain.

Diagenesis, i.e. the overprint of environmental and metabolic signatures, represents the single most significant obstacle in deep-time carbonate archive research. Moreover, the interpretation of individual proxy data sets from carbonate archives requires a detailed understanding on the distribution behaviour of elements and isotopes during the formation of biogenic, abiogenic and organomineralic calcium carbonate.

In Phase II of the CHARON research project, we move from calibration of our tools to application using a wide range of experimental and natural carbonate materials. Among others, examples of our research include corals and their earliest diagenesis, the early diagenetic microbe-sediment interaction in shallow marine cores, patterns in the crystallography and material properties of diagenetically altered biogenic carbonates as well as limestone-to-dolostone transition zones. Similar to Phase I, a wide range of traditional and non-traditional geochemical proxies are applied to test the resilience to diagenetic overprint for various carbonate mineral archives.

For questions please contact   adrian.immenhauser@rub.de




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