orthophyren.
/ˈɔːθə(ʊ)fʌɪə/, U.S. /ˈɔrθoʊˌfaɪ(ə)r/ Geology. Now rare.
A porphyritic rock containing phenocrysts chiefly of orthoclase in a feldspathic groundmass.
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the world > the earth > structure of the earth > constituent materials > rock > igneous rock > [noun] > porphyrite rock > subdivision
melaphyre1824
orthophyre1869
granophyre1882
vitrophyre1882
granite-porphyry1885
1869 Amer. Naturalist 3 442 To the lower division, viz.: (2) the Mispeck division, belong, in the lower subdivision, conglomerates and diorites, Cordaite, fine-grained slate and orthophyre.
1895 A. Harker Petrol. viii. 102 The most usual type of orthoclase-porphyry (orthophyre of Rosenbusch) is exemplified by dykes and sills in the Carboniferous of Thuringia.
1930 B. N. Peach & J. Horne Chapters Geol. Scotl. iv. 108 Examples of dykes of orthophyre occur on Sgonnan Mòr.
1954 C. E. Tilley et al. Harker's Petrol. (ed. 8) ix. 109 A few orthophyres are found among the tertiary intrusions of the west of Scotland.
2000 Jrnl. Geodynamics 29 143 The veinlet-like glass in the xenoliths does not extend beyond the xenoliths and the host rock (aegrinite-augite orthophyre).
This entry has been updated (OED Third Edition, September 2004; most recently modified version published online March 2022).
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n.1869