Platinum-group element geochemistry of mafic rocks from the Dongchuan area,southwestern China | |
Siqi Yang; Hong Zhong; Weiguang Zhu; Wenjun Hu; Zhongjie Bai | |
2017 | |
Source Publication | Acta Geochimica
![]() |
Volume | 36Issue:1Pages:52-65 |
Abstract | Mafic intrusions and dykes are well preserved in the Yinmin and Lanniping districts, located within the western margin of the Yangtze Block, SW China. Although these mafic rocks from the two areas formed during different periods, they share similar ranges of PGE concentration. Most of the Yinmin gabbroic dykes contain relatively high PGE concentrations (PGEs = 13.9-87.0 ppb) and low S contents (0.003 %-0.020 %),higher than the maximum PGE concentrations of mafic magmas melting from the mantle. Two exceptional Yinmin samples are characterized by relatively low PGE (PGEs = 0.31-0.37 ppb) and high S (0.114 %-0.257 %) contents. In contrast, most samples from the Lanniping gabbroic intrusion have low PGE concentrations (PGEs = 0.12-1.02 ppb) and high S contents (0.130 %-0.360 %),except that the three samples exhibit relatively high PGE (PGEs = 16.3-34.8 ppb) and low S concentrations (0.014 %-0.070 %). All the Yinmin and Lanniping samples are characterized by the enrichment of PPGE relative to IPGE in the primitive-mantle normalized diagrams, and the high-PGE samples exhibit obvious Ru anomalies. This study suggests that during the ascent of the parental magma, removal of Os-Ir-Ru alloys and/or chro-mite/spinel leads to high Pd/Ir ratios and Ru anomalies for the Yinmin high-PGE samples and relatively lower Pd/Ir ratios and Ru anomalies for the Lanniping low-PGE samples. We propose that the magmas parental to the Yinmin gabbroic dykes are initially S-unsaturated,and subsequently, minor evolved magma reached sulfur saturation and led to sulfide segregation. Although the Lanniping parental magmas are originally not saturated in S, the high Cu/Pd ratios (3.8 * 10~4 to 3.2 * 10~6)for most of the Lanniping samples indicate the S-saturated state and sulfide segregation. A calculation shows that the PGE-poor magmas might have experienced 0.01 %-0.1 % sulfide segregation in the magma chamber. Therefore, our study provides a possible opportunity to discover PGE-enriched sulfide mineralization somewhere near or within the Lanniping mafic intrusion. |
Keyword | Mafic Intrusions And Dykes Platinum-group Element Sulfide Saturation Dongchuan Area |
Indexed By | EI |
Language | 英语 |
Document Type | 期刊论文 |
Identifier | http://ir.gyig.ac.cn/handle/42920512-1/7774 |
Collection | 矿床地球化学国家重点实验室 |
Affiliation | 1.State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China 2.University of Chinese Academy of Sciences, Beijing 100049, China |
First Author Affilication | 中国科学院地球化学研究所 |
Corresponding Author Affilication | 中国科学院地球化学研究所 |
Recommended Citation GB/T 7714 | Siqi Yang;Hong Zhong;Weiguang Zhu;Wenjun Hu;Zhongjie Bai. Platinum-group element geochemistry of mafic rocks from the Dongchuan area,southwestern China[J]. Acta Geochimica,2017,36(1):52-65. |
APA | Siqi Yang;Hong Zhong;Weiguang Zhu;Wenjun Hu;Zhongjie Bai.(2017).Platinum-group element geochemistry of mafic rocks from the Dongchuan area,southwestern China.Acta Geochimica,36(1),52-65. |
MLA | Siqi Yang;Hong Zhong;Weiguang Zhu;Wenjun Hu;Zhongjie Bai."Platinum-group element geochemistry of mafic rocks from the Dongchuan area,southwestern China".Acta Geochimica 36.1(2017):52-65. |
Files in This Item: | Download All | |||||
File Name/Size | DocType | Version | Access | License | ||
Platinum-group eleme(1705KB) | 期刊论文 | 作者接受稿 | 开放获取 | CC BY-NC-SA | View Download |
Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.
Edit Comment