| 释义 |
orbicule Petrol.|ˈɔːbɪkjuːl|
[back-formation from orbicular a.; cf. L. orbiculus (see orbicle).]
A spheroidal inclusion, esp. one composed of a number of concentric layers.
1931A. Johannsen Descr. Petrogr. Igneous Rocks I. ii. 17 In many glassy rocks there are found certain more or less spherical bodies varying in size from pellets visible only under the microscope..to huge spheres ten feet or more in diameter. These rounded bodies are called spherulites when the constituents are arranged radially..and orbicules when these constituents are in concentric shells. 1956L. E. Spock Guide to Study of Rocks iii. 26 A few igneous rocks contain orbicules. These are close spherical concentrations of amphibole arranged radially or of biotite in concentric-tangential pattern. 1970[see orbicular a. 6]. |