Sediment Cores - Probing Earth's History
The largest environmental archive of all is the seabed. Dead organisms are constantly deposited there. The remains of living organisms in limestone promise clues about the environmental conditions during their lifetime. Furthermore, many layers also contain particles of mineral material such as clay, sand and stones that were carried into the sea by rivers, winds and glaciers.
The detailed sampling of these organic and mineral remains of past times in sediment cores provides researchers with important information about the climate that once prevailed on our planet, ocean currents, the mass balance and the interaction between sediment and seawater, as well as the development of magmatic systems.
Increasingly, sediment cores are also being used in the research fields of raw materials and natural hazards. For example, they are used to study mineral resources in hydrothermal systems and the stability of continental slopes. Sediment cores can also provide precise information about prominent events, such as rapid sea-level fluctuations or volcanic eruptions.
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A gravity corer is deployed from a research vessel. Equipped with weights of several tonnes, it penetrates the seabed and is brought back on board together with the sediment trapped in the tube and then sampled. Photo: Elgar Esser
The sediment cores obtained with gravity corers are cut into several pieces on board the research vessel and packed airtight for further transport. Photo: Jan Steffen/GEOMAR
While still on board or in the laboratory on shore at the latest, the one-metre-long core segments are divided lengthwise. One half is used for research work, the other one serves as an archive and is stored in the core repository. Photo: Jan Steffen/GEOMAR
From the "working halves" of the sediment core, the researchers can take samples for detailed geochemical analyses, for age determination or for the extraction of microfossils. Photo: GEOMAR
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