Liquidus phase relationships on the join anorthiteforsterite-quartz at 20 kbar with applications to basalt petrogenesis and igneous sapphirine
Liquidus phase relationships on the join anorthiteforsterite-quartz at 20 kbar with applications to basalt petrogenesis and igneous sapphirine
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20 kbar 下钙长石镁橄榄石-石英连接处的液相线相关系及其在玄武岩成因和火成蓝宝石中的应用
DOI：
10.1007/bf01167290
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发表时间：
1990
影响因子：
3.5
通讯作者：
D. C. Presnall
中科院分区：
文献类型：
--
作者：
Teh;D. C. Presnall
在 20 kbar 下对钙长石-镁橄榄石-石英连接处确定的液相线相关系显示了石英 (q)、镁橄榄石 (fo)、顽火辉石 (en)、尖晶石 (sp)、钙长石 (an)、蓝宝石 (sa) 和刚玉 (cor) 的主相场。增加压力会导致 (1) thefoandan 主相场收缩，(2) theen、q 和 corfields 膨胀，(3) thefo-边界线远离 Q 顶点，(4) theen-q 边界线也远离 Q 顶点，但移动量较小，(5) 在 10 到 20 kbar 之间的压力下出现主相场 forsato。 20 kbar 下的七个液相线穿透点的位置如下：晶相液体成分 (wt %)温度(°C)sp+sa+corAn81Fo17Q21575fo+en+spAn52Fo39Q91540en+sp+saAn59Fo31Q101490sa+an+corA n70Fo15Q151430an+q+corAn66Fo7Q271410sa+an+enAn62Fo18Q201400an+en+qAn59Fo15Q261380It结论是：（1）thefo-边界线随着压力而远离石英顶点，这证实了许多其他研究，表明橄榄岩源岩产生的熔体中二氧化硅含量随着压力的增加而减少； (2)尽管斜长石在高于约10kbar的压力下在橄榄岩烃源岩中不是稳定相，但它可以在至少高达20kbar的压力下从镁铁质岩浆中结晶； (3) 蓝宝石是在高压下从镁铁质岩浆中结晶出来的，对于基于微量元素考虑的岩石成因模型的构建可能很重要。
Liquidus phase relationships determined on the join anorthite-forsterite-quartz at 20 kbar show primary phase fields for quartz (q), forsterite (fo), enstatite (en), spinel (sp), anorthite (an), sapphirine (sa), and corundum (cor). Increasing pressure causes (1) thefoandanprimary phase fields to contract, (2) theen, q, andcorfields to expand, (3) thefo-enboundary line to move away from the Q apex, (4) theen-qboundary line to move also away from the Q apex but by a smaller amount, and (5) a primary phase field forsato appear at a pressure between 10 and 20 kbar. Seven liquidus piercing points at 20 kbar have been located as follows:Crystalline phasesLiquid composition (wt %)Temperature (°C)sp+sa+corAn81Fo17Q21575fo+en+spAn52Fo39Q91540en+sp+saAn59Fo31Q101490sa+an+corAn70Fo15Q151430an+q+corAn66Fo7Q271410sa+an+enAn62Fo18Q201400an+en+qAn59Fo15Q261380It is concluded that (1) the shift of thefo-enboundary line away from the quartz apex with pressure confirms many other studies showing that melts generated from peridotite source rocks decrease in silica content as pressure increases; (2) even though plagioclase is not a stable phase in peridotite source rocks at pressures above about 10 kbar, it can crystallize from mafic magmas at pressures at least up to 20 kbar; (3) sapphirine crystallizes from mafic magmas at high pressures and may be important in the construction of petrogenetic models based on trace element considerations.