Contrasting sapphirine parageneses from Wilson Lake, Labrador and their tectonic implications
Contrasting sapphirine parageneses from Wilson Lake, Labrador and their tectonic implications
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拉布拉多威尔逊湖的蓝宝石共生岩对比及其构造意义
DOI：
10.1111/j.1525-1314.1988.tb00443.x
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发表时间：
1988
影响因子：
3.4
通讯作者：
J. Gittins
中科院分区：
文献类型：
--
作者：
K. Currie;J. Gittins
威尔逊湖地区分布的泥质麻粒岩组合为紫苏辉石+紫苏辉石+硅线石+石英。地质年代学和地质压力测量表明，它是在温度接近900°C和压力超过10千巴的早元古代岩石中形成的。一套镁铁质到超镁铁质侵入体周围的脉状交代岩，在大约1700 Ma前的变质作用高峰期附近侵位，含有镁铁榴石，但这些组合是在温度接近750°C和压力为4.5 kbar时形成的。这两种类型的组合出现在角闪岩级（黑云母-硅线石）混合岩的遗迹。
P-T测定表明，伴随着镁铁质侵入和水化作用的20公里的快速等温抬升。变质历史和构造背景表明，大陆碰撞期间逆冲推覆使深部陆壳暴露，随后发生基本等温减压。
Regionally distributed pelitic granulites in the Wilson Lake region contain the assemblage sapphirine + hypersthene + sillimanite + quartz. Geochronology and geobarometry suggest it developed in early Proterozoic rocks at temperatures approaching 900°C and pressures above 10 kbar. Vein-like metasomatized rocks around a suite of mafic to ultramafic intrusions, emplaced near the peak of metamorphism about 1700 Ma ago, contain sapphirine, but these assemblages developed at temperatures near 750°C and pressures of 4.5 kbar. Both types of assemblage occur as relics in amphibolite-grade (biotite–sillimanite) migmatites.
P–T determinations indicate rapid isothermal uplift of 20 km accompanied by mafic intrusion and hydration. The metamorphic history and tectonic setting suggest exposure of deep continental crust by thrusting during continental collision, followed by essentially isothermal decompression.