New petrographic, geochemical, and Sm-Nd isotopic data provide constraints on the petrogenesis of ca. 2400 Ma gabbronorite, picrodolerite and dolerite mafic sills and dikes in the Liinakhamari and Sorvaranger areas, Kola–Norwegian terrane, Northern Fennoscandia. The sills are differentiated. Their chilled margins are composed of porphyritic picrodolerite with olivine (Fo_92-81) and clinopyroxene (Mg# = 85–80) phenocrysts enclosed by quenched groundmass with intergrows of fan-shaped branched plagioclase grains and clinopyroxenes. The bottom of the sills are usually composed of cumulative olivine gabbronorite upsection followed by olivine gabbro, gabbro, and quartz-bearing dolerites. Picrodolerite and dolerite dikes are close to chilled margins and evolved quartz-bearing dolerites from the upper parts of picrodolerite sills, correspondingly, in terms of mineral and chemical composition. The distribution of trace elements in sills sections is caused by fractionation crystallization of picrodolerite magma with a leading role of gravity settling of olivine phenocrysts. Variations of neodymium isotopic composition in the cumulative gabbronorites in the lower (ε_Nd from –0.25 to +0.82) and dolerites in the upper (ε_Nd from –0.85 to –2.4) parts of the sills are probably related with an addition of crustal contaminant into the magma after phenocrysts crystallization. Doleritic dikes have more radiogenic neodymium isotopic composition (ε_Nd = –0.10) in comparison with dolerites of sills that suggests lower degrees of crustal contamination in dikes. Evaluation of conditions of phenocrysts crystallization using mineral thermobarometers and modelling of crystallization using alphaMELTS indicate that the main stage of the evolution of ca. 2400 Ma mafic melts was probably related with high degrees of fractional crystallization and crustal contamination of high-Mg (MgO ~ 18 wt %) primary melt in the upper crust at P =1–4 kbar. Ca. 2400 Ma mafic intrusions in the Kola–Norwegian terrane are similar with coeval mafic dikes in Troms area in the Northern Fennoscandia, basaltic komatiites of Vetreny Belt and doleritic dikes of Kostomuksha area in the Karelian Craton in terms of petrographic, geochemical and Sm-Nd isotopic characteristics. It suggests that studied mafic sills and dikes in the Kola–Norwegian terrane could be considered as a component of ca. 2400 Ma large igneous province in the Fennoscandia.

中文翻译：

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2.4北部芬诺斯坎迪亚的Ga黑手党堤防和岩石：岩石学和地壳演化

新的岩石学，地球化学和Sm-Nd同位素数据提供了对成岩作用的限制。2400年，北芬诺斯坎迪亚的科拉-挪威地带，利纳卡马里和索瓦朗厄尔地区，辉长岩，辉绿岩和白云母镁铁基石和堤坝2400 Ma。窗台有所区别。它们的冷缘是由斑状的黄铁矿和橄榄石构成的（Fo _92-81）和斜环茂金属（Mg＃= 85–80）被淬火的地面物质包围着，扇状分支斜长石晶粒与斜环茂金属的混合物。窗台的底部通常由累积的橄榄石辉长岩上部组成，然后是橄榄石辉长岩，辉长岩和含石英的白云石。在矿物和化学成分方面，黄云母和白云母堤防接近于冷边缘，并且从黄云母基石的上部演化出了含石英的白云母。基岩剖面中痕量元素的分布是由次橄榄岩岩浆的分级结晶引起的，其中橄榄石现象的重力沉降起主要作用。在下部的累积gabbronorites钕同位素组成的变化（ε_钕从-0.25到0.82）和粒玄岩在上部（ε_钕从-0.85至-2.4）的门槛的各部分可能与加法地壳污染物进入后斑晶结晶岩浆有关。Doleritic堤防有更多的放射性钕同位素组成（ε_钕在与该显示较低程度的地壳污染的堤防槛粒玄岩比较= -0.10）。使用矿物热压计评估触晶结晶条件，并使用alphaMELTS进行结晶建模，表明ca演化的主要阶段。2400 Ma镁铁质熔体可能与P上地壳中高Mg（MgO〜18 wt％）初熔体的高分步结晶度和地壳污染有关= 1–4 kbar。钙 在岩石学，地球化学和Sm-Nd同位素方面，在科拉–挪威地体中的2400个Ma黑镁质岩侵入体与北部Fennoscandia的Troms地区的中世纪黑铁质岩脉，Vetreny Belt的玄武岩科马蒂岩和Karelian Craton的Kostomuksha地区的白云岩岩体相似特征。这表明在科拉-挪威地体中研究的铁镁质基岩和堤坝可被认为是ca的组成部分。芬诺斯坎迪亚2400马氏大火成岩省。