Conglomerate (geology)

Conglomerate
Sedimentary rock
Boulder of conglomerate with cobble-sized clasts. Rock hammer for scale.
Carmelo Formation (conglomerate) at Point Lobos
Nagdong Formation at Sangju

Conglomerate (/kənˈɡlɒmərɪt/) is a clastic sedimentary rock that is composed of a substantial fraction of rounded to subangular gravel-size clasts. A conglomerate typically contains a matrix of finer-grained sediments, such as sand, silt, or clay, which fills the interstices between the clasts. The clasts and matrix are typically cemented by calcium carbonate, iron oxide, silica, or hardened clay.

Conglomerates form by the consolidation and lithification of gravel. They can be found in sedimentary rock sequences of all ages but probably make up less than 1 percent by weight of all sedimentary rocks. In terms of origin and depositional mechanisms, they are closely related to sandstones and exhibit many of the same types of sedimentary structures, e.g., tabular and trough cross-bedding and graded bedding.[1][2][3]

Fanglomerates are poorly sorted, matrix-rich conglomerates that originated as debris flows on alluvial fans and likely contain the largest accumulations of gravel in the geologic record.[4]

  1. ^ Boggs, S. (2006) Principles of Sedimentology and Stratigraphy., 2nd ed. Prentice Hall, New York. 662 pp. ISBN 0-13-154728-3
  2. ^ Friedman, G.M. (2003) Classification of sediments and sedimentary rocks. In Gerard V. Middleton, ed., pp. 127-135, Encyclopedia of Sediments & Sedimentary Rocks, Encyclopedia of Earth Science Series. Kluwer Academic Publishers, Boston, Massachusetts. 821 pp. ISBN 978-1-4020-0872-6
  3. ^ Neuendorf, K.K.E., J.P. Mehl Jr., and J.A. Jackson, eds. (2005) Glossary of Geology (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. ISBN 0-922152-76-4
  4. ^ Leeder, Mike (2011). Sedimentology and sedimentary basins : from turbulence to tectonics (2nd ed.). Chichester, West Sussex, UK: Wiley-Blackwell. p. 290. ISBN 9781405177832.

From Wikipedia, the free encyclopedia · View on Wikipedia

Developed by Nelliwinne