Understanding geological time: An innovative fusion of diagenetic and cyclostratigraphic concepts to reconstruct sediment composition, deposition rate, and geological time spans

• Applicant: Dr. Theresa Nohl
• Subject Area: Geology
• Term: from 2022 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 498286524

Rhythmically alternating carbonate lithologies have been subject of intense discussion in terms of their origin. They are often used as a record of astronomically forced climate change, even though it has been shown that diagenesis can enhance or disguise the environmental signal, or even introduce rhythmicity. The aims of the project are to scrutinise how diagenesis affects original astronomically forced sedimentary cycles, to evaluate which depositional environments and ages are especially affected, and to evaluate how time is distributed within an astronomically forced lithological cycle. To achieve this, two new methods from diagenesis (based on the geochemistry, "vector length methode") and cyclostratigraphy (statistical method, "alpha method") will be applied to different records from IODP cores and outcrop records from different water depths, latitudes and ages with existing interpretations on diagenesis or cyclostratigraphy. Further, a database with data on rhythmically alternating carbonate lithologies will be established and used to archieve the projects objectives. This combination of diagenesis and cyclostratigraphy is unprecedented and holds the potential to test the boundaries of both methods, and to improve the reconstruction of sediment composition, deposition rate and, as a consequence, geological time.

• DFG Programme: WBP Position