Lens (geology)

Exposed white chalk next to a road.
Lens shown next to a road.

In geology, a lens or lentil is a body of ore or rock that is thick in the middle and thin at the edges, resembling a convex lens in cross-section.[1]

To thin out in all directions is to "lens out", also known as "lensing". The adjectives "lenticular" and "lentiform" are used to describe lens-like formations. Lenticle is a synonym for lentil, but may also refer to a fragment of rock that is lens-shaped. "Lenticule" is used for small lentil.[2]

A lentil may also refer a minor unit in a formation of rock, similar to a member but not generally spread out over a large geographical area. In this usage, the lentil thins out towards its edges.[3]

Lenticular bedding is a special form of rock interbedded mudrock and cross-laminated rippled sandstone. The lenses or ripples in lenticular beds are discontinuous in all directions.[2]

  1. ^ Bates, Robert L.; Jackson, Julia A. (1984). Dictionary of Geological Terms. New York: Anchor Press. p. 293. ISBN 978-0385181013.
  2. ^ a b Neuendorf, Klaus K. E.; Jackson, Julia A. (2005). Glossary of Geology. Alexandria, Va.: American Geological Institute. p. 368. ISBN 978-0922152766.
  3. ^ Koeberl, Christian; Martinez-Ruiz, Francisca (2013). Impact Markers in the Stratigraphic Record. Berlin: Springer Berlin. p. 45. ISBN 978-3642624575.