Monazite-(Ce)–huttonite solid solutions in granulite-facies metabasites from the Ivrea-Verbano Zone, Italy
Monazite-(Ce)–huttonite solid solutions in granulite-facies metabasites from the Ivrea-Verbano Zone, Italy
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DOI：
10.1180/minmag.1999.063.4.11
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发表时间：
1999-08
影响因子：
2.7
通讯作者：
H. Förster;D. Harlov
中科院分区：
文献类型：
--
作者：
H. Förster;D. Harlov
摘要在意大利Ivrea-Verbano带瓦尔Strona di奥梅尼亚地区麻粒岩相变基性岩与变岩的薄层中发现了变质成因和交代成因的独居石族矿物复合群。除了独居石-（铈），这是不常见的穷人在Th，可能是由磷灰石的不一致溶解形成，这些人口包括独居石-胡吞岩系列的成员。后一种矿物质含有13至30.1摩尔%的ThSiO 4 [= huttonitic monazite-（Ce）]，全世界只有六个其他的矿点。我们认为，在麻粒岩相变质过程中，变质岩中原生独居石-（Ce）的分解使Th和REE活化，然后被高级变质流体搬运到变质基性岩层中，形成独居石-胡吞岩系列的富Th矿物。
Abstract Composite populations of monazite-group minerals of both metamorphic and metasomatic origin have been discovered in thin layers of granulite-facies metabasites interlayered with metapelites, located in the Val Strona di Omegna region of the Ivrea-Verbano Zone, Italy. In addition to monazite-(Ce), which is uncommonly poor in Th and is probably formed by incongruent dissolution of apatite, these populations include members of the monazite-huttonite series. The latter minerals contain between 13 and 30.1 mol.% ThSiO4 [= huttonitic monazite-(Ce)], and are known from only half a dozen other occurrences worldwide. We propose that breakdown of primary monazite-(Ce) in the metapelites during granulite-facies metamorphism mobilized Th and the REEs, which were then transported by high-grade metamorphic fluids into the metabasite layers to form the Th-rich minerals of the monazite-huttonite series.