Project Details
Projekt
Evolution of half-precession cycles in the equatorial Atlantic during the last 3.5 Myr
Applicant
Dr. Arne Ulfers
Subject Area
Geology
Term
since 2022
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 507262650
The effect of orbital cycles on climate and on sedimentary systems has been the subject of extensive research in recent decades. In this project, we analyze half-precession (HP) cycles, which, with a period of 12-9 ka, are the missing link between Milanković cycles (periods of 405-19 kyr) and (sub)millennial cycles (periods shorter than ~6 kyr). The HP signal is suggested to be transmitted from its equatorial origin to mid/high latitudes via several mechanisms. In this context, both the eastern equatorial Atlantic and the African continent as the source region of the HP signal are an important part of our understanding of HP cycles.A high-resolution, multi-element XRF dataset from ODP Sites 662 and 663 will provide the basis for the proposed investigations. They are located in the equatorial Atlantic in an area influenced by African continental climate and cover the last 3.5 Ma. Previously published terrigenous input data do not have the optimal resolution for analyses of high-frequency cycles, but still reveal distinct appearance of HP.The new XRF dataset will enable characterization of the HP signal not only in the Pleistocene, but also across the 'Mid-Pleistocene Transition' (around 1 Ma) into the late Pliocene. Thereby, questions will be addressed concerning (i) the connectivity of the HP signal to the 'classical' Milanković cycles (mainly to eccentricity) in the different epochs, (ii) the origin of the HP signal in the equatorial Atlantic and on the African continent, (iii) and the HP is placed into a spatial context through the analysis of additional ICDP and IODP datasets.
DFG Programme
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