Sedimentkerne

Sedimentkerne, or sediment cores, are cylindrical samples of deposited sediment collected from lakes, rivers, oceans, and wetlands to study past environments. They are obtained with coring devices such as gravity corers, piston corers, vibrocorers, or drilling rigs. The cores preserve a continuous vertical record of sediment deposition: younger material sits atop older layers, and the total length can range from a few centimeters to several meters depending on the site and method.

The content of a core reveals temporal changes in climate, hydrology, biology, and geomorphology. Analyses commonly include grain size and mineralogy, organic content, and geochemical measurements; pollen, spores, and microfossils such as diatoms or foraminifera provide ecological and oceanographic signals. Chronologies are built with radiocarbon dating, lead-210, event stratigraphy, varve counting in lakes, and other dating methods, enabling age models for the record. Proxy data such as stable isotopes, trace elements, and molecular indicators are used to infer temperature, precipitation, productivity, salinity, and redox conditions.

Limitations and challenges include disturbance by bioturbation, compaction, gas buildup, and post-depositional alteration, which can blur fine-scale features or modify chemistry. Handling and laboratory processing require careful contamination control. Despite these limitations, sediment cores are central to paleoclimatology, paleoceanography, geology, and archaeology, providing long-term archives of environmental change and human-landscape interactions.