breccia


breccia
/brech"ee euh, bresh"-/, n. Petrol.
rock composed of angular fragments of older rocks melded together.
[1765-75; < It < Gmc; cf. OHG brecha breaking]

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Coarse sedimentary rock consisting of angular or nearly angular fragments larger than 0.

08 in. (2 mm). Breccia commonly results from processes such as landslides or geologic faulting, in which rocks are fractured. It can also be of igneous explosive origin (e.g., a volcanic breccia).

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rock
 lithified sedimentary rock consisting of angular or subangular fragments larger than 2 millimetres (0.08 inch). It differs from a conglomerate, which consists of rounded clasts.

      A brief treatment of breccias follows. For full treatment, see sedimentary rock: Conglomerates and breccias (sedimentary rock).

      There are three categories of breccia: sedimentary, pyroclastic or igneous, and cataclastic. The constituent fragments may be of one lithology such as a rock fractured in position, or of many lithologies suggesting accumulation from preexisting rocks. Void spaces between these clasts may be filled with a cementing material of carbonate, silica, or silt.

      In one class of breccia, clast material, breccia formation, and cement are all closely related in time. Typically these occur because of a volume change of sedimentary material and the subsequent redeposition of the same material to fill voids. Several examples are (1) volume loss during dolomitization, causing self-brecciation; (2) selective solution such as limestone formations, resulting in the collapse of weakened structures; and (3) mudcracks forming because of a loss of water and cemented by mud in the next wet cycle. All of these examples result in clasts of one lithology.

      A second class of breccia has clasts that are not related to their cement and do not form in place. Examples of such include (1) submarine landslides in regions of active faulting; (2) subaerial landslides, talus, and mudflows common in certain regions; and (3) limestone pebble breccias that result from wave action and downward movement on flanks of reefs yielding clasts of coral and limestone. These examples are characterized by lateral transport with gravity as the driving force and clasts that may be mixtures of several rock types.

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Universalium. 2010.

Look at other dictionaries:

  • Breccia — (pronEng|ˈbrɛtʃiə, ˈbrɛʃiə, it. breach) is a rock composed of angular fragments of several minerals or rocks in a matrix, that is a cementing material, that may be similar or different in composition to the fragments. A breccia may have a variety …   Wikipedia

  • Breccia — Brec cia, n. [It., breach, pebble, fragments of stone, fr. F. br[ e]che; of German origin. See {Breach}.] (Geol.) A rock composed of angular fragments either of the same mineral or of different minerals, etc., united by a cement, and commonly… …   The Collaborative International Dictionary of English

  • Breccia — ist der Familienname folgender Personen: Alberto Breccia (1919–1993), uruguayischer Comiczeichner und autor Enrique Breccia (* 1945), argentinischer Comiczeichner Paolo Breccia (* 1941), italienischer Regisseur Siehe auch: Brekzie, eine Form von… …   Deutsch Wikipedia

  • breccia (1) — {{hw}}{{breccia (1)}{{/hw}}s. f.  (pl. ce ) Apertura fatta in un opera di fortificazione mediante tiro di artiglieria o lavoro di mina, per penetrarvi a viva forza | Essere, rimanere sulla –b, (fig.) continuare a svolgere con successo la propria… …   Enciclopedia di italiano

  • breccia — rock of angular pieces, 1774, from It. breccia, marble of angular pieces, from a Germanic source akin to O.H.G. brecha a breaking, from P.Gmc. *brekan, from PIE *bhreg to break (see FRACTION (Cf. fraction)) …   Etymology dictionary

  • breccia — [brech′ē ə, bresh′ē ə] n. [It, fragments of stone < Fr brèche: see BRASH2] rock consisting of sharp cornered bits of fragmented rock, cemented together by sand, clay, or lime …   English World dictionary

  • breccia — 1bréc·cia s.f. CO 1a. varco aperto con cannonate, mine o sim. in una cinta muraria o altra opera difensiva per penetrarvi con truppe di assalto: aprire una breccia, la breccia di Porta Pia | anche fig.: il centravanti ha aperto una breccia nella… …   Dizionario italiano

  • breccia —    1. Angular fragments of rock, commonly, but not inevitably, cemented by finer grained materials including silica, iron minerals, and calcite to form a new rock. Many fault planes are marked by zones of broken rock, either loose or re cemented …   Lexicon of Cave and Karst Terminology

  • breccia — n. & v. n. a rock of angular stones etc. cemented by finer material. v.tr. form into breccia. Derivatives: brecciate v.tr. brecciation n. Etymology: It., = gravel, f. Gmc, rel. to BREAK(1) …   Useful english dictionary

  • breccia — noun Etymology: Italian Date: 1774 a rock composed of sharp fragments embedded in a fine grained matrix (as sand or clay) …   New Collegiate Dictionary


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