| 释义 |
ultramafic, a. (and n.) Petrol.|ʌltrəˈmæfɪk|
[f. ultra- 3 + mafic a.]
Of an igneous rock: composed chiefly of mafic minerals. Also as n.
1933R. A. Daly Igneous Rocks & Depths of the Earth ii. 31 The more important groups [of igneous rocks] are the granite clan.., the ultramafic clans, and the ‘feldspathoidal’ clans. Ibid. xxii. 565 Each of the ultramafic and ultrabasic species..treated in this chapter has its own unsolved problems. 1948Bull. Oregon State Dept. Geol. & Mineral. XXXIX. 8 The ultramafics include bodies of dunite, pyroxenite, and gabbro which have been extensively altered to hornblendite and serpentine. 1965G. J. Williams Econ. Geol. N.Z. x. 143/1 The useful non-metallic minerals are more abundant in those ultramafics which have been subjected either to metamorphic or metasomatic changes. 1967P. J. Wyllie Ultramafic & Related Rocks 1/1 Ultramafic monomineralic rocks composed of the following mafic minerals would certainly be ultrabasic..forsterite..fayalite..hornblende..biotite. 1971I. G. Gass et al. Understanding Earth i. 23/1 Only in the ultramafic rocks..does Al2O3 fall to significantly lower values than those quoted. |