Precise and accurate Lu–Hf isotope analysis of columbite-group minerals by MC-ICP-MS,Journal of Analytical Atomic Spectrometry

当前位置： X-MOL 学术 › J. Anal. At. Spectrom. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Precise and accurate Lu–Hf isotope analysis of columbite-group minerals by MC-ICP-MS
Journal of Analytical Atomic Spectrometry ( IF 3.1 ) Pub Date : 2021-06-10 , DOI: 10.1039/d1ja00125f
Zhi-Min Tang _{1,

2,

3,

4,

5} , Xu-Dong Che _{1,

2,

3,

4,

5} , Yue-Heng Yang _{5,

6,

7,

8,

9} , Fu-Yuan Wu _{5,

6,

7,

8,

9} , Ru-Cheng Wang _{1,

2,

3,

4,

5} , Jin-Hui Yang _{5,

6,

7,

8,

9} , Axel Gerdes _{10,

11,

12,

13} , Ze-Ying Zhu _{5,

14,

15,

16} , Feng Liu _{1,

2,

3,

4,

5} , Chang Zhang _{5,

6,

7,

8,

9}

Affiliation

State Key Laboratory for Mineral Deposits Research
School of Earth Sciences and Engineering
Nanjing University
Nanjing
China
State Key Laboratory of Lithospheric Evolution
Institute of Geology and Geophysics
Chinese Academy of Sciences
Beijing
Institut für Geowissenschaften
Goethe Universität Frankfurt
D-60438 Frankfurt am Main
Germany
Tianjin Center of Geological Survey
CGS
Tianjin

Due to their relatively high Hf contents (i.e., several hundreds to thousands of ppm), columbite-group minerals (CGMs) are suitable for Lu–Hf isotope analysis, which can provide new insights into the source of such minerals in combination with the U–Pb age of rare-metal deposits. However, few studies have reported Lu–Hf isotope data for CGMs. Tantalum is a major element in CGMs (12–48 wt% Ta₂O₅) and has a significant effect on measurements of Hf isotopes using MC-ICP-MS. This effect was first evaluated in this study by analysis of mixed Hf–Ta standard solutions with different Ta/Hf ratios and LA-MC-ICP-MS analysis of various CGMs. This analytical artifact reflects serious tailing of the large ¹⁸¹Ta signal onto the ¹⁸⁰Hf and ¹⁷⁹Hf masses during analysis. Therefore, in order to obtain accurate Hf isotope data for CGMs by MC-ICP-MS, we present an improved chemical separation procedure for Hf from Ta, and also a novel analytical protocol for LA-MC-ICP-MS analysis of CGMs. Accurate in situ ¹⁷⁶Hf/¹⁷⁷Hf ratios for CGMs can be obtained by normalization to ¹⁷⁸Hf/¹⁷⁷Hf = 1.4672, rather than ¹⁷⁹Hf/¹⁷⁷Hf = 0.7325, using the exponential law. This approach was validated by solution and laser ablation MC-ICP-MS analysis of four CGM samples from China and Africa. The Lu–Hf isotopic composition of CGMs provides a new geochemical tracer for rare-metal deposits.

更新日期：2021-07-02

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11