Cataclastic

Cataclastic

Cataclastic rocks contain angular fragments formed by cataclasis. Cataclasis is a deformation of the rock caused by fracture and rotation of aggregates or mineral grains.

The term cataclastic refers to the structure produced in a rock by the actions of severe mechanical stresses that occur during metamorphism. Characteristic features of cataclastic metamorphism include the bending, breaking, and granulation of minerals.

Cataclastic structures, also called mortar structures, or "porphyroclastic," are granites and gneisses that are produced by dynamic metamorphism of crystalline rock, and are characterized by mica-free aggregates of small finely-crushed grains of quartz or feldspar that fill the interstices between larger individual relicts and thus resemble stones set in mortar.

Porphyroclastic refers to the metamorphic texture characterized by large strained metacrysts within a finely recrystallized matrix of neoblasts that are free of strain.

ee also

*pyroclastic


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  • cataclastic — CATACLÁSTIC, Ă, cataclastici, ce, adj. (Despre minerale, roci etc.) Care este zdrobit sub acţiunea forţelor tectonice; (despre procese geologice) care provoacă o cataclază. – Din fr. cataclastique. Trimis de valeriu, 13.09.2007. Sursa: DEX 98 … …   Dicționar Român

  • cataclastic — [kat΄əklas′tik] adj. 〚< Gr kataklastos, broken down < kataklan, to snap off: see CATA & CLASTIC〛 designating or of a rock, esp. a metamorphic rock, that was formed, bent, broken, etc. by extreme mechanical pressure * * * …   Universalium

  • cataclastic — [kat΄əklas′tik] adj. [< Gr kataklastos, broken down < kataklan, to snap off: see CATA & CLASTIC] designating or of a rock, esp. a metamorphic rock, that was formed, bent, broken, etc. by extreme mechanical pressure …   English World dictionary

  • cataclastic — | ̷ ̷ ̷ ̷|klastik adjective Etymology: probably modification of Norwegian kataklastisk, from Gk. kataklastos broken down (from kataklan) + Norwegian isk ish 1. : of, relating to, or caused by cataclasis a pronounced cataclastic texture 2. :… …   Useful english dictionary

  • cataclastic — adjective describing a type of metamorphic rock that has undergone shearing and granulation by high mechanical stress …   Wiktionary

  • cataclàstic — ca|ta|clàs|tic Mot Pla Adjectiu variable …   Diccionari Català-Català

  • cataclastic — cata·clas·tic …   English syllables

  • cataclasis — cataclastic /kat euh klas tik/, adj. /kat euh klay sis, keuh tak leuh sis/, n. Petrol. a process of deformation or metamorphism in which the grains of a rock are fractured and rotated. [ < Gk katáklasis refraction, equiv. to katakla , s. of… …   Universalium

  • Deformation mechanism — In structural geology, metallurgy and materials science, deformation mechanisms refer to the various mechanisms at the grain scale that are responsible for accommodating large plastic strains in rocks, metals and other materials. Contents 1… …   Wikipedia

  • Mylonite — An amphibolitic mylonite showing a number of (rotated) porphyroclasts: a clear red garnet left in the picture while smaller white feldspar porphyroclasts can be found all over. Location: the tectonic contact between th …   Wikipedia

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