migmatite Petrol.
(ˈmɪgmətaɪt)
[ad. Sw. migmatit (J. J. Sederholm 1907, in Bull. Comm. Géol. Finlande V. xxiii. 88), f. Gr. µίγµα (see prec.): see -ite1.]
A rock composed of a metamorphic host rock with streaks or veins of a granitic rock.
| 1907 J. J. Sederholm in Bull. Comm. Géol. Finlande V. xxiii. 110 For the gneisses here in question, characteristic of which are two elements of different genetic value,..the author proposes the name of migmatites. 1942 Proc. Geol. Assoc. LIII. 77 Pseudodioritic migmatite is a field-term used to name a group of fairly homogeneous foliated hornblende-rich rocks having a dioritic aspect. 1965 G. J. Williams Econ. Geol. N.Z. xiii. 203/2 The monazites and xenotine [read xenotime] in migmatites of the Charleston-Fox River area, do not seem to have produced a red colour in the adjoining felspars. 1974 Encycl. Brit. Micropædia VI. 880/1 Many migmatites probably represent the partial fusion of the metamorphic host during extreme metamorphism. |
Hence migˈmatic, migmaˈtitic adjs., composed of migmatite.
| 1926 Mineral. Abstr. III. 84 Three types of pegmatites are distinguished: I, normal pegmatites; II, contact-pegmatites..; and III, migmatic pegmatites. 1942 Proc. Geol. Assoc. LIII. 67 The region around Bettyhill on the north coast of Sutherland furnishes a splendid display of migmatitic rocks produced by the injection of granitic and pegmatitic material into the different lithological types found in the Moine series. 1968 K. R. Mehnert Migmatites i. 5 It is inappropriate to burden petrographic investigations of metamorphic or migmatic rocks from the beginning with the question about the possible parent rock. 1969 Bennison & Wright Geol. Hist. Brit. Isles iii. 53 The Moinian rocks are generally metasediments showing little metamorphic segregation, although in the central migmatitic core..they are gneissose. |