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In geology

With compaction designating geology , solidification and reduction in volume of sediment by the pressure of the overlying ( " hang forming ") rock layers .

In medium to deep sedimentary basins , it can make up a few millimeters per year. The density increases accordingly - e.g. B. in the tertiary underground of the Pannonian and Vienna basins by about 0.01 to 0.02 g / cm² per million years . As a result, for example, the density of the mixture of sand , clay and gravel deposited in the Miocene has increased over the course of 15 million years from originally 1.5 to 2 g / cm³ to about 2.2 g / cm³, with simultaneous pressing out of pore water and cementing of the Aggregates due to solution water (see chemical weathering and cementation (geology) ). The compaction is strongly dependent on the grain size or the grain size distribution of the sediment. Fine-grained sediments such as clays and silts can be more compacted than sandstones or carbonate sands (differential compaction). The chemical composition of the sediment and the early diagnosis also influence the degree of compaction.

In cosmology

In cosmology , compaction means the compression of cosmic dust and gas clouds, for example in the formation of stars and solar systems .

In other sciences, too, the term can appear in a general sense; see also compactification .


  • Lexicon of Geosciences. 3rd volume Instr to Nor. 486 p., Spektrum Akademischer Verlag Heidelberg & Berlin 2001, ISBN 3-8274-0422-3 .