Recent  

We describe the design and performance of a new noble gas mass laboratory dedicated for the development and application to cosmogenic nuclides at the University of Cologne (Germany). At the core of the laboratory are a state-of-the-art high mass resolution multicollector Helix MCPlus (Thermo-Fisher) noble gas mass spectrometer and a novel custom-designed automated extraction line; including a laser-powered extraction furnace. Performance was tested with intercomparison (CREU-1) material.

When using trapped-charge dating methods to determine the time of deposition of a sediment, it is of great importance to know whether the signal containing the age information, has been completely erased before burial or if a residual signal is inherited. We examined the residual doses of the quartz ESR signals of young fluvial sediments from the lower Rhine terraces with known luminescence ages. We found varying but large residuals indicating an incomplete bleaching of the quartz ESR signals.

We use X-ray scanning to improve the quality of geologic ages derived from measuring the products of cosmic rays in the mineral magnetite. We show that the presence of other minerals can lead to wrong age estimates. By detecting those minerals with X-rays and analyzing only pure magnetite, this problem can be avoided. We also measure the rate at which helium from cosmic rays is produced in magnetite, which can be used for similar studies in the future.

Cooling ages date the time at which minerals cross a certain isotherm on the way up to Earth's surface. Such ages can be measured from bedrock material as well as from river sand. If spatial variations of bedrock ages are known in a river catchment, the spatial distribution of erosion can be inferred from the distribution of the ages measured from the river sand grains. Here we develop a new tool to help such analyses, with particular emphasis on quantifying uncertainties due to sample size.

Fission tracks are generated in minerals due to spontaneous fission of U-238. The initial track length decreases with time due to recrystallization. The age of a track can be calculated by counting the number per volume of the shorter tracks and include the decay constant. However, the theoretical order of track length versus time is disrupted by uncertainties. We have shown how the order can be reestablished. It is then possible to determine the age of tectonic events such as uplift or burial.

We apply new rock luminescence techniques to a well-constrained scenario of the Beinn Alligin rock avalanche, NW Scotland. We measure accurate erosion rates consistent with independently-derived rates and reveal a transient state of erosion over the last ~4,000 years in the wet, temperate climate of NW Scotland. This study shows that the new luminescence erosion-meter has huge potential for inferring erosion rates on sub-millennial scales, which is currently impossible with existing techniques.

A conventional isochron is a straight line fit to two sets of isotopic ratios, D / d and P / d, where P is the radioactive parent, D is the radiogenic daughter and d is a second isotope of the daughter element. The slope of this line is proportional to the age of the system. An inverse isochron is linear fit through d / D and P / D. The horizontal intercept of this line is inversely proportional to the age. The latter approach is preferred when d < D, which is the case in Re–Os and K–Ca geochronology.

Our contribution enhances the infrared-radiofluorescence dating technique, used to determine the last sunlight exposure of potassium feldspars in a range of about 600 to 600.000 years backwards. We recorded radiofluorescence images of fine sands and processed them with tailored open-source software to obtain ages from single grains. Finally, we tested our new method successfully on two natural sediment samples. Studies in Earth science will benefit from improved age accuracy and new insights.