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Fluvial Clast

  • Living reference work entry
  • First Online:
Encyclopedia of Planetary Landforms

  • 117 Accesses

Definition

A pebble to boulder-size stone transported by flowing water, usually by a river or a stream.

Synonyms

Bed load; Fluvial gravel

Morphometry

Grain size is most commonly classified according to the Wentworth scale (Wentworth 1922) as follows: >256 mm, boulder; 64–256 mm, cobble; and 2–64 mm, pebble. Particles below 2 mm belong to sand, silt, or clay.

Shape is another important morphological aspect of fluvial clasts. A large variety of so-called shape indices have been proposed to describe the overall three-dimensional shape of particles (Blott and Pye 2008*); all these indices are derived from the measurements of the three linear dimensions: the length (a), breadth (b), and thickness (c) of the particles. The most widespread shape indices are the axis ratios b/a and c/b, proposed by Zingg (1935). Beyond length measurements, recent studies show that the number of static equilibria is a natural and clear indicator of the overall clast shape (Domokos et al. 2010). Another...

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References

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Authors and Affiliations

  1. Department of Mechanics, Materials and Structures, Budapest University of Technology and Economics, Budapest, Hungary

    Tímea Szabó

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  1. Tímea Szabó
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Correspondence to Tímea Szabó .

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Szabó, T. (2014). Fluvial Clast. In: Encyclopedia of Planetary Landforms. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-9213-9_421-1

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  • DOI: https://doi.org/10.1007/978-1-4614-9213-9_421-1

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  • Online ISBN: 978-1-4614-9213-9

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