| 韩娟.江西黄蜂岭铀矿床花岗岩时代、成因:锆石
U-Pb 年龄和Hf 同位素证据[J].地质与勘探,2011,47(2):284-293 |
| 江西黄蜂岭铀矿床花岗岩时代、成因:锆石
U-Pb 年龄和Hf 同位素证据 |
| Age and Genesis of the Granite in the Huangfengling Uranium Deposit,Jiangxi Province: Evidence from Zircon U-Pb Dating and Hf Isotopes |
| 投稿时间：2010-09-08 修订日期：2010-10-15 |
| DOI： |
| 中文关键词: 黄峰岭铀矿黑云母花岗岩锆石U-Pb 定年Hf 同位素 |
| 英文关键词: Huangfengling uranium deposit, biotite granite, U-Pb dating, Hf isotope |
| 基金项目:中国地质大调查“我国重要矿产和区域成矿规律研究冶项目(1212010633903)资助。 |
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| 中文摘要: |
| [摘要]黄峰岭铀矿隶属我国著名的鹿井铀矿田,其铀矿产与区内高铀含量的中粗粒似斑状黑云
母花岗岩有着密切的时空、成因联系。本文对矿区出露的肉红色中粗粒似斑状黑云母花岗岩体进行了
锆石SHRIMP U-Pb 同位素定年,获得锆石的结晶年龄为235郾4 依1郾1 Ma,说明该岩体的侵位时代为印
支期。该印支期的岩体被后期燕山期细粒黑云母花岗岩(全岩Rb-Sr 年龄为155郾2 Ma)侵入,铀矿的两
期成矿时代分别为白垩纪的103 ~87 Ma(沥青铀矿U-Pb 年龄) 和古近纪的48 Ma(沥青铀矿U-Pb 年
龄)。印支期年龄锆石的着Hf(t)值为-4郾7 ~ -13郾5,Hf 两阶段模式年龄为2118 ~ 1564 Ma。这些岩浆锆
石低的着Hf(t)(-4郾7 ~ -13郾5)值说明这些岩石主要来自地壳岩石的部分熔融,着Hf(t) 变化范围较大,说
明源区同位素的不均一。印支期年龄锆石的Hf 同位素两阶段模式年龄(2郾1 ~ 1郾6 Ga) 和中元古-古元
古代继承锆石的存在说明该花岗岩的源区可能为古老的地壳物质。古元古代继承锆石中正的着Hf(t)值
(+10郾8)的存在,暗示形成这些古老继承锆石的初始物质中有幔源物质的加入。这些新资料为探讨黄
峰岭铀矿的形成演化提供了重要的年代学和Hf 同位素地球化学依据。 |
| 英文摘要: |
| Abstract:Granite intrusion is spatially and temporally associated with the uranium mineralization in the Huangfengling uranium deposit located in the
well-known Lujing uranium orefield郾To constrain the age of the biotite granite pluton related to uranium mineralization, U-Pb dating of zircon was con鄄
ducted, resulting in age (235郾4 依1郾1 Ma) which confirms that this biotite granite emplacement occurred during the Indo-Chinese period郾Hafnium iso鄄
tope data from laser-ablation multicollector ICPMS analysis of zircon show that the Indo-Chinese biotite granite has negative and variable 着Hf(t) values
(-4郾7 to -13郾5) and age of the Palaeo-Mesoproterozoic (1郾6 to 2郾1 Ga) as a Hafnium two-stage depleted-mantle model郾The values of 着Hf(t) are in鄄
terpreted to reflect derivation from an isotopically heterogeneous crust source郾Inherited zircon cores yield Caledonian and Palaeo-Mesoproterozoic ages,
indicating the effect of Caledonian郾The positive 着Hf(t) value 10郾8 of the Paleoproterozoic inherited zircons suggest that the mantle materials could be in鄄
volved in the magmatic sources when the inherited zircons were formed郾Considering Palaeo-Mesoproterozoic inherited zircon cores and Palaeo-Mesoprot鄄
erozoic Hafnium depleted-mantle model ages, the source region for these magmas may be tentatively correlated with Palaeo-Mesoproterozoic material of
the South China Block郾Further work is necessary to demonstrate this suggestion郾 |
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