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江苏省海州式磷矿岩石地球化学特征及成矿背景
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作者 李双喜 宋玉明 +2 位作者 王肖 洪连明 王超 《地质与勘探》 CAS CSCD 北大核心 2022年第6期1196-1208,共13页
本文对苏北地区锦屏组磷矿石及地层样品进行了岩相学及地球化学分析,研究了磷矿初始沉积环境和源区特征。磷矿类微量元素富集Ba、Pb、U、Sr,贫Th、Ta、Nb、Ti;REE配分曲线为LREE富集型,Ce负异常,表明成矿环境为陆缘海,且成矿过程受深海... 本文对苏北地区锦屏组磷矿石及地层样品进行了岩相学及地球化学分析,研究了磷矿初始沉积环境和源区特征。磷矿类微量元素富集Ba、Pb、U、Sr,贫Th、Ta、Nb、Ti;REE配分曲线为LREE富集型,Ce负异常,表明成矿环境为陆缘海,且成矿过程受深海热水沉积和生物作用影响。Sr、Nd同位素初始值判断磷灰岩物质来源为年轻的地壳物质。绿片岩类微量元素富集Rb、Th、K,贫Th、U、Ta、Nb、Sr、Ti;REE配分曲线为LREE富集型,判断其原岩为陆源碎屑岩。(混合)片麻岩类微量元素富集Pb、Th、K,亏损Ba、Ta、Nb、Sr、Ti;REE配分曲线为LREE富集型,具地幔源区特征。 展开更多
关键词 “海州式”磷矿 苏北磷矿 沉积变质磷矿 磷矿地球化学
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Studying distribution of rare earth elements by classifiers,Se-Chahun iron ore,Central Iran
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作者 Mohammadali Sarparandeh Ardeshir Hezarkhani 《Acta Geochimica》 EI CAS CSCD 2017年第2期232-239,共8页
The increased production and price of rare earth elements(REEs) are indicative of their importance and of growing global attention. More accurate and practical exploration procedures are needed for REEs, and for other... The increased production and price of rare earth elements(REEs) are indicative of their importance and of growing global attention. More accurate and practical exploration procedures are needed for REEs, and for other geochemical resources. One such procedure is a multivariate approach. In this study, five classifiers, including multilayer perceptron(MLP), Bayesian, k-Nearest Neighbors(KNN), Parzen, and support vector machine(SVM),were applied in supervised pattern classification of bulk geochemical samples based on REEs, P, and Fe in the Kiruna type magnetite-apatite deposit of Se-Chahun,Central Iran. This deposit is composed of four rock types:(1) High anomaly(phosphorus iron ore),(2) Low anomaly(metasomatized tuff),(3) Low anomaly(iron ore), and(4)Background(iron ore and others). The proposed methods help to predict the proper classes for new samples from the study area without the need for costly and time-consuming additional studies. In addition, this paper provides a performance comparison of the five models. Results show that all five classifiers have appropriate and acceptable performance. Therefore, pattern classification can be used for evaluation of REE distribution. However, MLP and KNN classifiers show the same results and have the highest CCRs in comparison to Bayesian, Parzen, and SVM classifiers. MLP is more generalizable than KNN and seems to be an applicable approach for classification and predictionof the classes. We hope the predictability of the proposed methods will encourage geochemists to expand the use of numerical models in future work. 展开更多
关键词 Geochemical exploration of REEs Supervised pattern classification Geochemistry of Se-Chahun ~Central Iran
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