Microprobe mineralogy of plagioclase, clinopyroxene and amphibole as records of cooling rate in the Shirotori—Hiketa dike swarm, northeastern Shikoku, Japan |
| |
| Authors: | Osamu Ujike |
| |
| Institution: | Shikoku Office, Geological Survey of Japan, 10-6, Bacho-1, Tokamatsu, Kagawa 760, Japan |
| |
| Abstract: | A compositional gap between hypersolidus plagioclase and subsolidus plagioclase, most of which must have formed by devitrification, decreases in An % with decreasing cooling rate, probably reflecting a melt composition derived by in situ differentiation. Augitic pyroxenes, crystallized from a quickly cooling magma, tend to contain more Al, Ti, Na(+K) and Fe3+, and less Si and Mn. Compositional breaks between hypersolidus and subsolidus amphiboles with respect to the components of edenite and titanoamphibole, decrease in width with decreasing cooling rate. Subcalcic hornblende seems to grow from differentiated magmas in the course of moderate to rapid cooling. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
