| 释义 |
plumasite Petrogr.|ˈpluːməsaɪt|
[f. the name of Plumas Co., California, where it was first found + -ite1.]
A coarse-grained, under-saturated, dike-rock consisting essentially of crystals of corundum in an oligoclase matrix.
1903A. C. Lawson in Bull. Dept. Geol. Univ. Calif. III. 228 This particular type of rock magma does not appear to have been as yet recognized among the known occurrences of rocks, and it is, therefore, proposed to name it, for convenience in reference, Plumasite, from Plumas county to which it occurs. 1949F. H. Hatch et al. Petrol. Ign. Rocks (ed. 10) iii. iii. 262 Dioritic rocks of unusual composition include plumasite. 1972Jrnl. Geol. Soc. India XIII. 198 Investigations in the present case have proved that plumasite is a result of the local enrichment of alumina in the magma due to the reaction of the acid magma of the Peninsular gneissic period with the older magnesian country. |