Offlap

Onlap

Onlap

Geological phenomenon of younger rock extending progressively further across erosion in older rocks

Onlap or overlap is the geological phenomenon of successively wedge-shaped younger rock strata extending progressively further across an erosion surface cut in older rocks. It is generally associated with a marine transgression. It is a more general term than overstep, in which the younger beds overlap onto successively older beds.[1] The opposite is offlap, in which each younger rock bed pinches out short of the full extent of the underlying older bed, typically due to a marine regression.[2]

References

  1. [1]
    Jackson, Julia A., ed. (1997). "onlap". Glossary of geology (Fourth ed.). Alexandria, Virginia: American Geological Institute. ISBN 0922152349.
  2. [2]
    Jackson 1997, "offlap".


Stub icon

This article about stratigraphy is a stub. You can help Wikipedia by expanding it.
Share this article:

This article uses material from the Wikipedia article Offlap, and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.