Neodymium isotopic study of rare earth element sources and mobility in hydrothermal Fe oxide (Fe-P-REE) systems
Neodymium isotopic study of rare earth element sources and mobility in hydrothermal Fe oxide (Fe-P-REE) systems
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DOI：
10.1016/s0016-7037(99)00325-7
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发表时间：
2000-03-01
影响因子：
5
通讯作者：
Johnson, DA
中科院分区：
文献类型：
--
作者：
Gleason, JD;Marikos, MA;Johnson, DA
对北美四个地区富含稀土元素 (REE) 的、与火成岩相关的热液铁氧化物 (Fe-P-REE) 系统进行了钕同位素组成分析，以限制这些系统中的稀土元素来源和流动性。 Nd 同位素结果证明，尽管年龄（元古代到第三纪）、构造环境（俯冲与板内）和岩浆类型（镁铁质与长英质）存在很大差异，但火成岩来源的 REE 浓度存在共同模式。在密苏里州东南部的中元古代圣弗朗索瓦山脉地体中，ε(Nd) 为 Fe-P-REE（磷灰石、独居石、磷钇矿）矿床的范围为 +3.5 至 +-5.1，类似于同年龄的相关长英质至中型火成岩（ε(Nd) = +2.6 至 +6.2）在内华达州西部的侏罗纪中期洪堡镁铁质杂岩中，Fe-P-REE（磷灰石）矿化的ε(Nd) 变化范围为 +1.1 至 +2.4，类似于相关的镁铁质火成岩岩石（-1.0 至 +3.5）。在内华达州中部附近的科尔特斯山脉，中侏罗世长英质火山岩和深成岩（ε(Nd) = -2.0 至 -4.4）与具有类似ε(Nd)（-1.7 至 -2.4）的 Fe-P-REE（磷灰石-独居石）矿化有关。在墨西哥杜兰戈的梅尔卡多山 (Cerro de Mercado)，在第三纪流纹岩赋存的氧化铁矿床中分析的所有组合都具有相同的同位素组成，ε(Nd) = -2.5。这些数据与同时代的火成岩围岩是所有四个地区稀土元素的主要来源一致，但与其他来源的稀土元素的显着贡献不一致。对这些热液系统的起源及其伴随的稀土元素流动性的解释必须考虑非专门的火成岩来源和不同的构造环境。版权所有 (C) 2000 Elsevier Science Lt.
Dare earth element (REE)-enriched, igneous-related hydrothermal Fe-oxide hosted (Fe-P-REE) systems from four areas in North America have been analyzed for their neodymium isotopic composition to constrain REE sources and mobility in these systems. The Nd isotopic results evidence a common pattern of REE concentration from igneous sources despite large differences in age (Proterozoic to Tertiary), tectonic setting (subduction vs, intraplate), and magmatic style (mafic vs. felsic).In the Middle Proterozoic St. Francois Mountains terrane of southeastern Missouri, epsilon(Nd) for Fe-P-REE (apatite, monazite, xenotime) deposits ranges from +3.5 to +-5.1, similar to associated felsic to intermediate igneous rocks of the same age (epsilon(Nd) = +2.6 to +6.2) At the mid-Jurassic Humboldt mafic complex in western Nevada, epsilon(Nd) for Fe-P-REE (apatite) mineralization varies between + 1.1 and +2.4, similar to associated mafic igneous rocks (-1.0 to +3.5). In the nearby Cortez Mountains in central Nevada, mid-jurassic felsic volcanic and plutonic rocks (epsilon(Nd) = -2.0 to -4.4) are associated with Fe-P-REE (apatite-monazite) mineralization having similar epsilon(Nd) (-1.7 to -2.4). At Cerro de Mercado, Durango, Mexico,all assemblages analyzed in this Tertiary rhyolite-hosted Fe oxide deposit have identical isotopic compositions with epsilon(Nd) = -2.5. These data are consistent with coeval igneous host rocks being the primary source of REE in all four regions, and are inconsistent with a significant contribution of REE from other sources. Interpretations of the origin of these hydrothermal systems and their concomitant REE mobility must account for nonspecialized igneous sources and varied tectonic settings. Copyright (C) 2000 Elsevier Science Lt.