Fossil water

Fossil water is water in deep soil layers, which since very long periods of time had no more contact with the Earth's atmosphere or surface waters, its age can be determined by radiocarbon or other isotope studies.

Even deeper water layers of lakes (eg Lake Tanganyika ) can be described as fossil water when the temperature stratification of the lake is so strong that the seasonal mixing does not reach all water layers. The deepest layers are thereby permanently cut off from the atmosphere.

Fossil water permits (eg gas contents quantitatively and qualitatively ) to draw conclusions about its origin time due to its composition.

Occurrence

Europe

In Central Europe there are, for example, in Germany's north and its south under the Hegau occurrence fossil water.

Africa

In Africa, the fossil water reserves have not formed as in Central Europe from meltwater of the last ice age, but they consist of groundwater in rock crevices and layers of soil, which has accumulated in climate periods from prehistoric times, such as during the last Pluvial.

The groundwater lakes under the Sahara or the Kalahari, for example, also made from fossil water.

Risks

Although Fossil water is not part of the natural atmospheric water cycle, but is promoted now with modern technology (pumps, earth-boring ), while not renew the tens of thousands of years old inventories ( can ); go for the Nubian Sandstone Aquifer optimistic forecasts with unchanged exploitation of a maximum useful life of even 200 years from.

In China, fossil water reserves are now being exploited on a large scale; this leads to predicted subsidence of its underground water level of up to 1.5 meters per year.