The petrology of the Mont Saint Hilaire complex, southern Quebec: An alkaline gabbro-peralkaline syenite association
The petrology of the Mont Saint Hilaire complex, southern Quebec: An alkaline gabbro-peralkaline syenite association
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魁北克南部圣伊莱尔山综合体的岩石学：碱性辉长岩-过碱性正长岩组合
DOI：
10.1016/0024-4937(86)90016-2
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发表时间：
1986
期刊：
影响因子：
3.5
通讯作者：
J. Gittins
中科院分区：
文献类型：
--
作者：
K. Currie;G. Eby;J. Gittins
圣希莱尔山杂岩包括一套较老的(133 Ma)由钛辉石、钾长石、斜长石和含钛磁铁矿组成的层状堆积体，以及两套较年轻的(122 Ma)套，其中一套是由霞石-橄榄闪长岩到二长岩的厚环岩墙，另一套是与各种角砾岩有关的管状或漏斗状的霞石-方钠长岩正长岩和斑岩。微量元素数据表明，较老的岩套来自石榴石来源。只有少量可能的液体成分被保存在这个套间中。霞石和橄榄石系列遵循从辉长岩到二长岩的分馏过程，包括辉石、磁铁矿、磷灰石和斜长石的分馏。现场和微量元素数据表明，演化的液体与地壳深处的盐水混合产生了强烈的霞石标准过碱性岩浆。卤水富钠、富氯，其他常量和微量元素贫乏，初始锶比高。该杂岩的定位和侵位时间的延长似乎是由于热异常从裸露板块底部向上迁移所致。
The Mont Saint Hilaire complex consists of an older (133 Ma) suite of layered cumulates of titanaugite, kaersutite, plagioclase and titaniferous magnetite, and two younger (122 Ma) suites, one a thick ring dyke of nepheline-olivine diorite to monzonite, and the other a pipe or funnel-like mass of peralkaline nepheline-sodalite syenite and porphyry associated with a variety of breccias. Trace element data suggest derivation of the older suite from a garnet-bearing source. Only minor amounts of possible liquid compositions are preserved in this suite. The nepheline and olivine-bearing suite followed a course of fractionation from gabbroic to monzonitic compositions involving fractionation of pyroxene, magnetite, apatite and plagioclase. Field and trace element data suggest mixing of the evolved liquid with a saline brine at crustal depths produced the strongly nepheline-normative peralkaline magma. Rich in Na and Cl, the brine was poor in other major and trace elements, and had a high initial Sr ratio. The localization and extended time of emplacement of the complex appear to be due to upward migration of a thermal anomaly from the base of a lithosperic plate.