- Home
- Ursula Röhl
- Recent Research Projects (PI)
- DFG SP IODP
DFG SP IODP
Benthic Reference Curve
New high-resolution compilation of benthic stable isotope data spanning 34 to 75 Ma – for both Atlantic and Pacific Ocean (RO 1113/8) (jointly with T. Westerhold) 2017 - 2019
We plan to assemble the next generation of a deep-sea benthic isotope compilation spanning the Late Cretaceous to Eocene (34-75 Ma) for both Atlantic and Pacific Ocean. The compilation will utilize ocean-drilling material at unprecedented resolution (<10kyr). Current benthic stable carbon and oxygen isotope compilations for this period do not resolve Milancovitch cyclicity and lack an astronomically tuned age model. This hampers to get the detailed information needed to study the true climate variability of the warm latest Cretaceous to Eocene global climate. With the recovery of new high-quality, multiple-hole cored sedimentary successions from the Atlantic (ODP Leg 171B, 207, 208, IODP Exp. 342) and the Pacific (ODP Leg 198 and 199, IODP Exp. 320/321) suitable material has been recovered to generate high-resolution (<10kyr) benthic stable isotope records. In this project we intend to synthesis available records as well as generate new benthic stable isotope data on species from the genus Cibicidoides and Nuttallides only to fill gaps not yet covered or increase the resolution of records in the 34-75 Ma interval. Based on earlier projects we will update, modify and then establish a fully integrated and consistent astronomically calibrated age model for the Atlantic and Pacific compilation. The envisaged new benthic stable isotope reference record on a synchronized astronomical time scale will provide completely new insight to the Eocene to late Cretaceous climate dynamics. We will be able to compare Atlantic and Pacific paleoceanographic changes and characteristics at unprecedented detail in a relatively warm interval of Earth’s history. One important aspect of this study will be to gain new insight to the instability of the climate system moving from greenhouse to icehouse climate state in the Late Eocene.
Cyclostratigraphy Eocene
We plan to complete the cyclostratigraphic framework based on the identification of the stable long eccentricity cycle (405 kyr) for the entire Eocene time (55 to 34 Ma) for both the Atlantic and Pacific Ocean by integrating high-resolution XRF core scanning and paleomagnetic data with stable isotope records.This project will synthesize a huge dataset to establish a fully integrated and astronomically calibrated bio-, chemo-, and magnetostratigraphy for the entire Eocene for the two major ocean basins, the Atlantic and Pacific. An accurate and precise age model for both oceans will be the key to substantially improve our understanding of the Eocene greenhouse climate variability and termination. Our results could substantially contribute to understand the frequency of Eocene hyperthermal events, investigate their relation to orbital forcing, as well as their relation to processes of greenhouse climate evolution. Our multi-proxy approach will allow deep insight into the processes and evolution of the global carbon cycle dynamics and its role in climate development during the Eocene. Finally, the high-resolution geochemical stratigraphic framework would serve as the backbone of the next generation of a deep-sea benthic isotope record for the entire Cenozoic.
Wilkes Land Paleogene
(Ro 1113/6) 2011-2013
The plan was to establish an integrated and cyclically calibrated bio-, chemo-, and magnetostratigraphy for the Paleogene records recovered during IODP Expedition 318 (Eocene intervals, Lower Oligocene to lower Upper Oligocene) to also further improve, test, and intercalibrate bio- and magnetostratigraphic datums for the Wilkes Land Antarctic margin. Prerequisite was the detailed analysis of Hole IODP 318-U1356A, and in a second step, the correlation to data from ODP Leg 189 (Sites 1168, 1171 and 1172) and Leg 199 (Site 1218) (XRF core scanning, physical properties, and stratigraphy) for the early Eocene through early Late Oligocene (magnetic polarity chrons C7An to C24n). The revised composite records were used to examine to what degree the records from the Wilkes Land Antarctic margin can be linked to and/or used to validate and extend the astronomical calibration of the geological timescale of the Oligocene (magnetic polarity chrons C7An to C12r). The stable carbon isotope ratio on the organic matter (d13Corg) was analyzed - in combination with the concentration of the total amount of organic carbon (TOC), both critical data for identifying and characterizing hyperthermal layers in the Eocene. Further the characteristics of these hyperthermals in early Eocene sediments are explored and evaluate their possible relationship to orbital cycles in the Wilkes Land Antarctic margin sediments. In addition contributions to a detailed reconstruction of the nature and distribution of ice-rafted debris (IRD) in earliest Oligocene sediment cores by applying X-ray CT analysis were provided.
The Eocene/Oligocene Transition
perspective’ (Ro 1113/5) (incl. Postdoc position T. Westerhold), 2011-2014
Synthesis of Paleogene stratigraphy
‘Synthesis of Paleogene depth transects in the Pacific and Atlantic Oceans - high-resolution stratigraphy for deciphering new aspects of early Paleogene Paleoceanography’ (Ro 1113/3) (incl. Postdoc position T. Westerhold), 2004 - 2006