| 释义 |
eucrite, n.|ˈjuːkraɪt|
Also 9 eukrite.
[ad. G. Eukrit, ad. Gr. εὔκριτος easily discerned, f. κρίνειν to separate, distinguish.]
1. Petrogr. A gabbro or olivine-gabbro in which the feldspar is anorthite or bytownite and the pyroxene is typically augite.
1866P. H. Lawrence tr. von Cotta's Rocks ii. i. 148 Eukrite, a crystalline-granular compound of anorthite and augite, occasionally with some olivine, hornblende, and epidote. 1888J. J. H. Teall Brit. Petrogr. vii. 134 Von Lasaulx describes a rock occurring at Rostrevor, County Down, as a eucrite. 1908A. Harker Geol. Small Isles viii. 97 The eucrites are crystalline rocks of medium to rather coarse grain. 1969Bennison & Wright Geol. Hist. Brit. Isles xv. 345 Gabbro-eucrite masses were intruded at the margins of the caldera.
2. Astron. Any of a group of achondritic meteorites principally composed of anorthite and pigeonite.
1881L. Fletcher Guide Coll. Meteorites (Brit. Mus.) 17 Perhaps for those aerolites which contain little or no nickel-iron the division into Howardites, Eukrites, Chladnites, Chassignites, Shalkites, and Carbonaceous is the most convenient. 1916Mineral. Mag. XVIII. 36 The angrites, nakhlites, howardites, eucrites, and sherghottites..are richer in lime..than chondritic stones generally. 1971Sci. Amer. Oct. 55/1 One small group (some 25 in all) of stony meteorites, the eucrites, does show chemical and mineralogical analogies with some of the lunar crystalline rocks. 1975Nature 20 Nov. 220/2 The mineralogical, textural and compositional characteristics of the eucrite meteorites suggest that they are the products of igneous processes. 1987Geochimica et Cosmochim. Acta LI. 2543/1 One can speculate that the higher average enrichment in eucrites, relative to chondrites, reflects differences in weathering behaviour of those two broad classes of meteorites. |