Diamicton

Diamicton (also diamict) (from Greek δια (dia-): through and μεικτός (meiktós): mixed) is a terrigenous sediment (a sediment resulting from dry-land erosion) that is unsorted to poorly sorted and contains particles ranging in size from clay to boulders, suspended in an unconsolidated matrix of mud or sand. Today, the word has strong connotations to glaciation but can be used in a variety of geological settings.[1][2][3]

The term was proposed by Flint and others[4] as a purely descriptive term, devoid of any reference to a specific origin or depositional environment. Although the term is most commonly applied to unsorted glacial deposits (i.e., glacial till), other processes that create diamictons are solifluction, landslides, debris flows, and turbiditic olistostromes.[2][3]

The term can generally be applied to types of siliciclastic sediments and sedimentary rocks, and acts as a root name for sediments that are poorly sorted and contain a wide clast size range. Sediments given this root often transverse the boundary of siliciclastic rudaceous, arenaceous and argillaceous sediments. Diamicton is the unconsolidated equivalent of diamictite.,[2][3] otherwise known as lithified diamicton.

The British Geological Survey (BGS), based in the UK, defines diamicton to comprise over 50% pre-existing siliceous rock clasts, but otherwise having undefined composition.[5]

  1. ^ Jackson, J.A., J. Mehl, and K. Neuendorf (2005) Glossary of Geology American Geological Institute, Alexandria, Virginia. 800 pp. ISBN 0-922152-76-4
  2. ^ a b c Bennett, M.R., and N.F. Glasser (2009) Glacial Geology: Ice Sheets and Landforms, 2nd Ed. John Wiley & Sons, Ltd., New York, New York. 400 pp. ISBN 978-0470516911
  3. ^ a b c Tucker, M.E. (2003) Sedimentary Rocks in the Field John Wiley & Sons, Ltd., New York, New York. 244 pp. ISBN 978-0470851234
  4. ^ Flint, R.F., J.E. Sanders, and J. Rodgers (1960) Diamictite, a substitute term for symmictite Geological Society of America Bulletin. 71(12):1809–1810.
  5. ^ "BGS Rock Classification Scheme - Details forDiamicton - A type of siliciclastic sediment and sedimentary rock. Sediments that are poorly sorted and contain a wide range of clast sizes can be given this root name. The strict descriptive definition relates to range of particle size and not to relative abundance of any or all size classes. These sediment types therefore traverse the boundary of siliciclastic rudaceous, arenaceous and argillaceous sediments. This is the unconsolidated equivalent of diamictite. British Geological Survey Research Report RR/99/03, section 2 and figs. 2, 3 and 5.| British Geological Survey (BGS)". webapps.bgs.ac.uk. Retrieved 2024-03-24.