A5048303274- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Hydrocarbon exploration and reservoir analysis
- Geomagnetism and Paleomagnetism Studies
- Geological and Geophysical Studies
- Geological Studies and Exploration
- Cryospheric studies and observations
- Geological formations and processes
- Paleontology and Stratigraphy of Fossils
- Isotope Analysis in Ecology
- Polar Research and Ecology
- Geological Modeling and Analysis
- Geological and Geochemical Analysis
- Underwater Acoustics Research
- Seismic Imaging and Inversion Techniques
- Marine and environmental studies
- Astro and Planetary Science
- Atmospheric and Environmental Gas Dynamics
- Winter Sports Injuries and Performance
- Magnetic and Electromagnetic Effects
- Analytical Chemistry and Sensors
- X-ray Diffraction in Crystallography
- Geochemistry and Elemental Analysis
- Geophysical and Geoelectrical Methods
- Hydraulic Fracturing and Reservoir Analysis
University of Bremen
2016-2025
Leibniz Centre for Tropical Marine Research
2021-2022
United States Office of Personnel Management
2021
Sam Houston State University
2021
International Ocean Discovery Program
2021
University of Plymouth
2021
Geological Survey of Western Australia
2021
Tongji University
2021
Discovery Place
2021
Texas A&M University
2021
Much of our understanding Earth's past climate comes from the measurement oxygen and carbon isotope variations in deep-sea benthic foraminifera. Yet, long intervals existing records lack temporal resolution age control needed to thoroughly categorize states Cenozoic era study their dynamics. Here, we present a new, highly resolved, astronomically dated, continuous composite foraminifer developed laboratories. Four states-Hothouse, Warmhouse, Coolhouse, Icehouse-are identified on basis...
Nitrenes are a highly reactive, yet fundamental, compound class. They possess monovalent nitrogen atom and usually short life span, typically in the nanosecond range. Here, we report on synthesis of stable nitrene by photolysis arylazide M
Abstract. To fully understand the global climate dynamics of warm early Eocene with its reoccurring hyperthermal events, an accurate high-fidelity age model is required. The Ypresian stage (56–47.8 Ma) covers a key interval within as it ranges from warmest marine temperatures in to long-term cooling trends middle Eocene. Despite recent development detailed isotope records spanning portions stage, establish complete astronomically calibrated for are still missing. Here we present new...
Abstract. Vivianite, Fe3(PO4)2 · 8 H2O, is a ferrous iron phosphate mineral which forms in waterlogged soils and sediments. The phosphorus (P) bound its crystal lattice considered to be immobilised because vivianite stable under anoxic, reducing, sedimentary conditions. Thus, formation can make major contribution P retention during early diagenesis. Much remains unknown about sediments, technical challenges have rendered direct identification quantification difficult. To identify assess...
Research Article| September 01, 1997 Arctic Ocean evidence for late Quaternary initiation of northern Eurasian ice sheets Robert F. Spielhagen; Spielhagen 1GEOMAR Center Marine Geosciences, 24148 Kiel, Germany Search other works by this author on: GSW Google Scholar Georges Bonani; Bonani 2Institute Particle Physics, ETH Hönggerberg, 8093 Zürich, Switzerland Anton Eisenhauer; Eisenhauer 3Geochemical Institute, Göttingen University, 37077 Göttingen, Martin Frank; Frank 4Heidelberg Academy...
Palaeomagnetic investigations of two sediment cores recovered from RV Polarstern near the eastern slope Yermak Plateau (sites PS 1533 and 2212) reveal convincing evidence for four polarity events Earth's magnetic field during last 170 Ka. A comprehensive rock study sediments proved that fine-grained magnetite is principal carrier remanent magnetization. No changes in magneto-mineralogy across transitions investigated were found. Calcareous nannofossil biostratigraphy, AMS-14C (accelerated...
The Heidelberg Basin (Germany) hosts a quasi-continuous sedimentary sequence of primarily fluvial sediments with pedogenetic overprints and lacustrine intercalations. This unconsolidated succession has been shown to record consistent magnetic polarity stratigraphy the Quaternary late Neogene. Previous work reported that sulphides high-coercive minerals are carriers remanent magnetization. Here, we provide results an extended mineral study aims disentangle complex mineralogy. In addition,...
Abstract. To explore cause and consequences of past climate change, very accurate age models such as those provided by the astronomical timescale (ATS) are needed. Beyond 40 million years accuracy ATS critically depends on correctness orbital radioisotopic dating techniques. Discrepancies in sedimentary successions lack suitable records spanning middle Eocene have prevented development a continuous astronomically calibrated geological for entire Cenozoic Era. We now solve this problem...
Today's paleomagnetic and magnetic proxy studies involve processing of large sample collections while simultaneously demanding high quality data reproducibility. Here we describe a fully automated interface based on commercial horizontal pass-through "2G" DC-SQUID magnetometer. This system is operational at the universities Bremen (Germany) Utrecht (Netherlands) since 1998 2006, respectively, currently being built NGU Trondheim (Norway). The magnetometers are equipped with "in-line"...
Variations in the atmospheric production rate of cosmogenic 10Be lead to global changes depositional fluxes. This may serve as a powerful tool for synchronizing various paleoclimate archives. For robust synchronization, however, it is essential understand pathways from its upper atmosphere deposition sediments and ice. While deposited ice within one two years after production, marine less direct, complicating use synchronization. To address this issue, we investigate response authigenic...
The carbonate-free abyss of the North Pacific defies most paleoceanographic proxy methods and hence remains a "blank spot" in ocean climate history. Paleomagnetic rock magnetic, geochemical, sedimentological were combined to date analyze seven middle late Pleistocene northwest sediment cores from water depths 5100 5700 m. Besides largely coherent tephra layers, striking features these records are nearly magnetite-free zones corresponding glacial marine isotope stages (MISs) 22, 12, 10, 8, 6,...
One of Earth’s most fundamental climate shifts, the greenhouse-icehouse transition 34 million years ago, initiated Antarctic ice sheet buildup, influencing global until today. However, extent during Early Oligocene Glacial Maximum (~33.7 to 33.2 ago) that immediately followed this transition—a critical knowledge gap for assessing feedbacks between permanently glaciated areas and early Cenozoic reorganization—is uncertain. In work, we present shallow-marine drilling data constraining earliest...
The Antarctic Zone has long been suspected to play a crucial role in the glacial-interglacial changes atmospheric concentration of CO2. However, global climate many possible influences on Antarctic  conditions, with potential for interactions between ice, winds and circulation that, turn, influence biogeochemistry carbon budget surface. In sediment core from polar Zone, we analyzed diatom-bound nitrogen isotopes reconstruct surface nitrate concentration, which reflects balance...
Abstract Subglacial lakes are widespread beneath the Antarctic Ice Sheet but their control on ice-sheet dynamics and ability to harbour life remain poorly characterized. Here we present evidence for a palaeo-subglacial lake continental shelf. A distinct sediment facies recovered from bedrock basin in Pine Island Bay indicates deposition within low-energy environment. Diffusive-advection modelling demonstrates that low chloride concentrations pore water of corresponding sediments can only be...
Precise knowledge about the extent of West Antarctic Ice Sheet (WAIS) at Last Glacial Maximum (LGM; c. 26.5–19 cal. ka BP) is important in order to 1) improve paleo-ice sheet reconstructions, 2) provide a robust empirical framework for calibrating models, and 3) locate potential shelf refugia benthos during last glacial period. However, reliable reconstructions are still lacking many WAIS sectors, particularly key areas on outer continental shelf, where LGM-ice assumed have terminated. In...