Pebble

Pebble

A pebble is a clast of rock with a particle size of 4 to 64 millimeters based on the Krumbein phi scale of sedimentology. It is generally described to be larger than gravel and smaller than cobble. A rock made predominantly of pebbles is termed a conglomerate. Pebble tools are among the earliest known man-made artifacts, dating from the Palaeolithic period of human history.

A beach composed chiefly of surface pebbles is commonly termed a shingle beach, which has armoring characteristics with respect to wave erosion; moreover, this type of beach has unusual ecological niches that may provide habitat for a number of rare and endangered species.

Pebbles can come in a variety of different colors and textures, and can often have streaks of quartz and different colored sedimentary rock. Pebbles are mostly smooth, but dependent of how frequent they come in contact with the sea, can have marks of contact with other pebbles. Pebbles left above the high water mark, may have the growth of organisms such as lichen on them, signifying the lack of contact with sea water.

Pebbles can also be found inland where ancient seas used to be cover the land, when seas retreat the rocks become landlocked. Pebbles can also form in rivers, and travel into estuaries where the smoothing continues in the sea.

Gallery

ee also

* Gravel


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Синонимы:

См. также в других словарях:

  • Pebble — Peb ble, n. [AS. papolst[=a]n; cf. L. papula pimple, mote. See {Stone}.] 1. A small roundish stone or bowlder; especially, a stone worn and rounded by the action of water; a pebblestone. The pebbles on the hungry beach. Shak. [1913 Webster] As… …   The Collaborative International Dictionary of English

  • Pebble — bezeichnet eine Insel, siehe Pebble Island mehrerer Townships, siehe Pebble Township Siehe auch: Pebbles Diese Seite ist eine Begriffsklärung zur Unterscheidung mehrer …   Deutsch Wikipedia

  • pebble — [peb′əl] n. [ME pobble < OE papol (stan), popol (stan), pebble (stone), prob. of echoic orig.] 1. a) a small stone worn smooth and round, as by the action of water b) Geol. such a stone, smaller than a cobblestone, with a maximum diameter of… …   English World dictionary

  • pebble — ► NOUN 1) a small stone made smooth and round by the action of water or sand. 2) (before another noun ) informal with very thick lenses: pebble glasses. DERIVATIVES pebbly adjective. ORIGIN Old English …   English terms dictionary

  • Pebble — Peb ble, v. t. [imp. & p. p. {Pebbled}; p. pr. & vb. n. {Pebbling}.] To grain (leather) so as to produce a surface covered with small rounded prominences. [1913 Webster] …   The Collaborative International Dictionary of English

  • pebble — late 13c., from O.E. papolstan pebblestone, of unknown origin …   Etymology dictionary

  • pebble — n. 1 a small smooth stone worn by the action of water. 2 a a type of colourless transparent rock crystal used for spectacles. b a lens of this. c (attrib.) colloq. (of a spectacle lens) very thick and convex. 3 an agate or other gem, esp. when… …   Useful english dictionary

  • pebble — /ˈpɛbəl / (say pebuhl) noun 1. a small, rounded stone, especially one worn by the action of water. 2. pebbled leather, or its granulated surface. 3. a transparent, colourless rock crystal used for the lenses of spectacles. 4. a lens made of it. 5 …   Australian-English dictionary

  • pebble — noun a small stone made smooth and round by the action of water or sand. adjective informal (of a spectacle lens) very thick and convex. Derivatives pebbled adjective pebbly adjective Origin OE, recorded as the first element of papel stān pebble… …   English new terms dictionary

  • pebble — UK [ˈpeb(ə)l] / US noun [countable] Word forms pebble : singular pebble plural pebbles a small stone, especially one that has been made smooth by water …   English dictionary


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