Lens (geology)

from Wikipedia, the free encyclopedia
Lenticular layering at the transition to the wave layering. The yellowish sandstone lenses between the gray siltstone layers are clearly pronounced. This is a special case, the so-called hummocky cross stratification , which is caused by the action of storm waves on the sea floor. Carboniferous (?) The Fife Peninsula, Scotland.

As lens lenticular are mineral deposits of different sizes, respectively. Lentils belong to the irregularly shaped occurrences. The name is derived from the typical lens shape.

Ore lenses often arise during the formation of pegmatic-pneumatolytic deposits. Oil and gas deposits can also be lens-shaped. In Kleinenbremen, the Wohlverwahrter and the Schermbeck ore lens were mined in the Wohlverwahrt iron ore mine.

This term is also used in sedimentology . It describes lenticular accumulations of coarse sediment (mostly sand or sandstone), which are enclosed by a fine-grained sediment (mostly clay or mudstone). If the proportion of coarser sediment in the deposit area increases, the so-called flaser stratification develops from the lens , with irregularly shaped and branching, thin layers of fine-grained sediment in a coarse sediment. The intermediate form is known as wave layering. Lenticular, wave and flasher stratification are characteristic of sediments that were deposited under the influence of flowing water, i.e. by rivers or in areas of the sea with ground-contacting currents. Therefore, lens and flasher stratification usually occurs along with sedimentary structures such as oblique stratification .

See also

literature

  • Collective of authors: Basic geological knowledge . Ed .: Horst Roschlau, Hans-Joachim Haberkorn. 2nd Edition. German publishing house for basic industry, Leipzig 1977, p. 199 .
  • G. Leithold et al .: Taschenbuch Bergbau . Civil engineering. Ed .: Chamber of Technology, Association of Mining. tape III . German publishing house for basic industry, Leipzig 1962, p. 489 .
  • Christiane Martin, Manfred Eiblmaier (Ed.): Lexicon of Geosciences . 6 volumes (2000–2002). Spectrum, Akad. Verl., Heidelberg [a. a.].

Web links