schistosityn.
Geology.
The direction or line of cleavage in a rock of crystalline formation.
ΘΚΠ
the world > the earth > structure of the earth > constituent materials > rock > texture or colour > [noun] > texture > laminated or fissile > cleavage or plane
sline1811
cleavage1816
cleavage-plane1831
rift1841
schistosity1885
strain-slip cleavage1886
1885 Nature 8 Oct. 558/2 The Arnaboll (Hebridean gneiss) can be traced..from spots where it retains its original strike and petrological characters, to others where it acquires the normal strike and mineralogical features of the ordinary Sutherland schists. The old planes of schistosity become obliterated, and new ones are developed.
1888 J. J. H. Teall Brit. Petrogr. 446 Schistosity,..denotes the fissility of the crystalline schists.
1901 J. Horne in Nature 19 Sept. 513/2 Before the planes of schistosity were developed in these Dalradian schists.
1908 Mineral. Mag. 15 145 To the imperfect substitution of dissolved kaolin by mica and secondary quartz and resultant gravitation under the pressure of superincumbent masses may, in like manner, be attributed schistosity in Zinnwald greisen.
1919 Amer. Jrnl. Sci. 197 203 Geinitz called attention to the delicate ruffling of the surface of schistosity of many slates, which may represent an analogous phenomenon of friction.
1951 Jrnl. Geol. (Chicago) 59 68 The ice..forms along joints, planes of schistosity, or any other available fractures.
1977 A. Hallam Planet Earth 175/3 Deformation and the development of schistosity may result in the complete obliteration of primary planar features such as sedimentary bedding.
This entry has not yet been fully updated (first published 1910; most recently modified version published online June 2019).
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n.1885