| 白云鄂博稀土超大型矿床的成矿时代及其主要地质热事件 |
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| 引用本文：任英忱,张英臣,张宗清.1994.白云鄂博稀土超大型矿床的成矿时代及其主要地质热事件[J].地球学报,15(z1):95-101. |
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| 摘要点击次数: 2014 |
| 全文下载次数: 103 |
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| 中文摘要:于白云鄂博矿床的主、东矿体及附近地区采集用于测定同位素年龄样品，通过镜下含稀土矿物的矿石结构构造的研究，选取了相同世代的独居石=氟碳铈矿、钠闪石等单矿物进行Th-Pb、Sm-Nd 和 40Ar/39Ar 同位素分析。其结果表明：独居石-氟碳铈矿7个点构成一条较好的Sm-Nd等时线，等时年龄 t=1313±41（2σ）Ma，143Nd/144Nd(INd)=0.210919±13(2σ),εNd（t）=-0.5±0.3(2σ).1313Ma 应为白云鄂博矿床的稀土成矿时代。主矿北和都拉哈拉的独居石分别测定了 |
| 中文关键词:矿床 Sm-Nd Th-Pb 40Ar/39Ar 年龄 白云鄂博 |
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| Study on heat events of ore-forming bayan obo deposit |
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| Abstract:There are four ore-forming heat events in Bayan Obo deposit.(1)Proterozofic period;(2)Late Proterozoic period;(3) Caledonian period;(4) Hercynian period;these events are determinated with radioisotope methods of whole-rock and minerals.The Middle Proterozoic age is basd on the following data:the data of seven samles of early monazite and bastnaesite from main orebody from a Sm-Nd isochron line with isochron age of 1312.5±41.24Ma and initial 143Nd/144Ar ration(INd) of 0.51092±13(2σ),corresponding to εNd（t）=0.49±0.26.The heat plateau 40Ar/39Ar age of one sample of early alkali amphibole from Dulahala carbonatite dyke is 1288±11.9Ma.The late Proterozoic heat event is determinated by Rb-Sr whole-rock isochron age and 40Ar/39Ar heat plateau age .The age of Rb-Sr whole-rock isochron of black slate is 749.6±62.11 Ma and 685.9±24.12Ma.The 40Ar/39Ar heat plateau ages of three alkali amphiboles are 818±5Ma、720±20Ma and 719±2Ma. The Caledonian age is determinated by Th-Pb isochron age of internal minerals and Sm-Nd isochron age of REEminerals. The Th-Pb internal isochron ages of monazites and bastnaesites are 550±400Ma and the Sm-Nd isochron age of REE minerals are 402±18Ma、424±91Ma,with the initial 143Nd/144Nd ratio of 0.51125、0.51128,corresponding to εNd（t）=-16.9,εNd（t）=-15.9.40Ar/39Ar plateau age of late alkali amphibole is 380.4 ±2.1Ma,indicating also Caledonian heat event. The Herynian age is determinated by the K-Ar and Rb-Sr method of minerals and whole-rock. The REE mineralization of Bayan Obo ore deposite have two ore-foming stages.The first was Middle Proterozoic.The second was Caledonian period. |
| keywords:deposit Sm-Nd Th-Pb 40Ar/39Ar isochron age Bayan Obo |
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