摘要
黄山东镁铁-超镁铁杂岩体中的橄榄石为主要造岩矿物,其化学成分与寄主岩(?)有关,具有一定的变化范围:角闪辉长岩相中为透铁橄榄石(Fo:64—73);超镁铁岩相中为贵橄榄石(Fo:81—85);在化学成分中,TiO_2,Al_2O_3和CaO;FcO,MnO和CoO;MgO和NiO各自呈正相关,而组与组之间却表现为负相关或相关性不明显。由此得出:杂岩体的侵入序次为角闪辉长岩相在先,超镁铁岩相在后;杂岩体的原始岩浆为玄武岩浆,在其侵位过程中曾发生过金属硫化物的深部熔离作用并由富MgO到富FeO演化;岩浆开始结晶的温度为1783℃,该温度同时也代表了母岩浆温度的下限。
Olivines which are one of the main rock-forming minerals in Huangshandong mafic-ultramafic complex are mostly (?)esh and exist in ultramafic rock facies and hornblende-gabbro facies, Their chemical composition varies with the type of their adventive rocks. In hornblende-gabbro facies, they are hyalosiderites and Fo is 64-73; in ultramafic rock facies, they are chrysolites and Fo is 81-85.
In olivines, TiO_2, Al_2O_3 and CaO; FeO, MnO and CoO MgO and NiO are in close positive correlations, but the upper three groups are in negative correlations or unclear corre lations between g(?)ps.
According to chemical composition of olivines, the following conclus ions are obtained:
1) intrusive phase of the complex is one that hornblende-gabbro facies is former and ultramafic rock facies is later.
2) Parental magma of the complex is basaltic. A deep—seated liquation of metal sulphide happened during the time intruded. It evoluted from rich MgO to rich FeO.
3) The temperature magma crystallized is about 1 783℃, which also represented the under temperature of parental magma.
出处
《矿物岩石》
CAS
CSCD
1991年第3期40-47,共8页
Mineralogy and Petrology
关键词
超镁铁岩
镁铁岩
橄榄石
化学成分
Huangshandong, mafic—ultramafic complex, olivine, chemical composition, petrologic significance
