摘要
在两个斜方辉石样品中观察到G.P.区亚稳相。内蒙古暗色辉长岩古铜辉石成分是En_(77)Fs_(18·6)Wo_(4·4),其高分辨象显示了密集的单层G.P.区;玄武岩中变辉长岩包体古铜辉石成分是En_(72·2)Fs_(25·7)Wo_(2·1),具双层G.P.区。该包体与具多层G.P.区的月岩橄长岩相似,后期冷却极快。在地体火成岩体结晶和冷却过程中易出现单层G.P.区,而岩体的大小,冷却的快慢可能影响G.P.区的密度。对N-14样品不同放大倍数的高分辨象G.P.区线密度和面密度的统计值同样具代表性。文中设想了G.P.区出溶的假二元系相图。
The Guinier-Preston zones in two bronzites have been investigated: one is sample M-108 collected from a melagabbro intrusion, and the other N-14 separated from a gabbro xenolith in basalt.Electron micrograph of sample M-108 shows a higher number of G.P. zones per area being one unit-cell thick, while in sample N-14 the G.P. zones are two unit-cell thick.The line density and area density have been counted.Sample N-14 is similar to lunar sample 76535 with a rapid cooling history at low temperature and a complex thermal history.A possible pseudo-binary phase diagram of the pyroxene subsolidus is proposed.
出处
《矿物学报》
CAS
CSCD
北大核心
1989年第2期104-111,193,共8页
Acta Mineralogica Sinica
关键词
辉石
古铜辉石
样品
G.P区
G. P. zone
orthopyroxene
gabbro
xenolith
