The Sedimentary Geochemistry group was founded in November 2020, and is led by Prof. Dr. Philip Pogge von Strandmann.
Its main goal is to use sedimentary rocks (carbonates, clays, shales) to reconstruct the Earth’s past marine chemistry and biogeochemical cycles, in particular through periods of rapid climate change. To do this, we not only analyse sediments, but also modern analogues, such as rivers and soils. We further conduct laboratory experiments, in order to recreate observed processes in the geological record under controlled conditions.
The group also examines the artificial acceleration of natural biogeochemical cycles, in order to remove CO2 from the atmosphere more rapidly.
Sediments tell you something about the conditions they were deposited under. In particular, subtle changes in their chemistry can give information on chemical changes in seawater from millions or billions of years ago.
We therefore analyse sediments from time periods of rapid climate change, to determine how the Earth’s climate system responds. In particular, we are interested in chemical weathering of the continents. This is the Earth’s primary natural mechanism for removing carbon dioxide from the atmosphere, following which it is transported to the oceans and sequestered as carbonate or organic carbon.
The response of weathering to changes in climate (e.g. temperatures increase, so weathering increases, removes more carbon from the atmosphere, allowing the climate to cool) may be fundamental to maintaining a habitable planet, but we currently know relatively little about the precise processes, or the timescales they operate on.
The primary tools we currently use are lithium (Li), magnesium (Mg) and calcium (Ca) isotopes. All are tracers of different aspects of chemical weathering processes, as well as the cycling of elements in the oceans.
In terms of analyses, we use an Agilent 7700 ICP-MS and a Metrohm Ion Chromatograph to determine elemental concentrations. Isotopes (mainly Li, Mg, Ca) are measured on a Thermo Neptune Plus.Our laboratory includes a preparation and experimental lab, and metal-free isotope clean labs are currently under construction (completion due mid-2022).
In Memory Of:
Prof. Dr. Alfred Kröner (1939-2019):