microbreccian.
/ˌmʌɪkrə(ʊ)ˈbrɛtʃ(ɪ)ə/, U.S. /ˈˌmaɪkroʊˈˌbrɛ(t)ʃ(i)ə/ Geology.
Breccia containing relatively small particles of mineral or rock.
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the world > the earth > structure of the earth > constituent materials > rock > composite rock > [noun] > breccia > specific
bone breccia1829
fault breccia1891
ferricrete1902
microbreccia1926
suevite1936
1926 G. W. Tyrrell Princ. Petrol. (1978) xvii. 281 Cataclasis may act on fine-grained rock bodies as a whole, producing crush-breccias; or upon individual minerals (in coarse-grained rocks), forming micro-breccias, flaser rocks, and mylonites.
1935 Amer. Jrnl. Sci. 229 476 Grubenmann and Niggli have proposed the name ‘cataclasite’ for those microbreccias which do not show fluxion structure.
1963 D. W. Humphries & E. E. Humphries tr. H. Termier & G. Termier Erosion & Sedimentation xiii. 294 The true reefs contain several facies:..breccias and microbreccias formed of fragments of calcareous organisms; oyster limestones; [etc.].
1973 Nature 23 Mar. 252/2 A feldspathic microbreccia from the Descartes region of the lunar highlands contains an unusual assemblage of pyroxene fragments.
1988 Nature 27 Oct. 813/1 Cross-cutting karstic channels..are filled by microbreccia and fine sediments.
This entry has been updated (OED Third Edition, December 2001; most recently modified version published online March 2022).
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n.1926