In our laboratory, the stable isotopes of the light elements carbon (C), nitrogen (N), oxygen (O) and hydrogen (H) in continental geoarchives such as lake sediments and speleothems as well as in precipitation and surface water are measured. Stable isotopes are non-radioactive nuclides of an element with the same number of protons and different numbers of neutrons and thus different atomic masses. This results in different physical properties that can lead to a shift in the isotope ratios in a …

Tephra, the Greek word for ash, is used to describe any material that is ejected by a volcano into the atmosphere (pyroclasts). Tephra includes dense blocks and bombs (> 64 mm), and lighter materials such as scoria, pumice and ash (< 2 mm). As one moves away from a volcano, the tephra deposits become finer grained (smaller particles) and thinner. This is because small airborne particles hover longer and stay within the atmosphere for a greater distance from the volcano. These particles of ash …

In the Organic Surface Geochemistry Lab (OSGLab) of the Geomorphology section, the smallest of molecules and isotopes open a door to the past. In the OSGLab we conduct research on regional differences of the causes and effects of past climate change and variations in biochemical cycles. In some projects, we can determine the "traces" of climate change down to a decade, in other projects biogeochemical processes are traced over millions of years.
In the laboratory, changes in the carbon …