Application of Electron Probe Microanalyzer to Study the Textures and Compositions of Alteration Coronas of Monazite from the Longhuashan Granite, Northern Guangdong Province

BACKGROUND Monazite is a common uranium-bearing accessory mineral in granite-related uranium deposits in South China. The Longhuashan pluton is an important U-bearing granite in the Zhuguangshan batholith, Northern Guangdong. Distinct alteration coronas of monazite were observed in the pluton. Howev...

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Main Authors: ZHANG Long, CHEN Zhenyu, WANG Fangyue, ZHOU Taofa
Format: Article
Language:English
Published: Science Press, PR China 2022-03-01
Series:Yankuang ceshi
Subjects:
Online Access:http://www.ykcs.ac.cn/en/article/doi/10.15898/j.cnki.11-2131/td.202109070118
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author ZHANG Long
CHEN Zhenyu
WANG Fangyue
ZHOU Taofa
author_facet ZHANG Long
CHEN Zhenyu
WANG Fangyue
ZHOU Taofa
author_sort ZHANG Long
collection DOAJ
description BACKGROUND Monazite is a common uranium-bearing accessory mineral in granite-related uranium deposits in South China. The Longhuashan pluton is an important U-bearing granite in the Zhuguangshan batholith, Northern Guangdong. Distinct alteration coronas of monazite were observed in the pluton. However, textures and compositions of alteration coronas of monazite and their implications for uranium mineralization are still poorly understood. OBJECTIVES To investigate the detailed textural and compositional evolution of monazite in granites during alteration, and to provide insights into uranium mobilization and enrichment in granite-related uranium deposits. METHODS Textures and chemical compositions of alteration coronas of monazite were investigated using electron probe microanalyzer (EPMA). RESULTS Alteration coronas of monazite in the Longhuashan granite consisted of newly formed apatite, allanite, epidote, and Th-rich phases. The monazite alteration coronas area was a concentric zone composed of monazite, apatite (including thorium-rich minerals), and monazite-epidote from the inside to the outside. Mass balance calculations showed that during the alteration of monazite, light rare earth (LREE), Y, Th, and U elements were remobilized and migrated, and the fluid brought in elements such as Ca, Fe, Al, and F to form alteration coronas composed of apatite, epidote, and thorium-rich minerals. The EPMA mapping showed that monazite alteration led to the remobilization of uranium, but the uranium was mainly enriched in the altered coronas. In this pluton, 3.7% U was located in monazite, and more than 80% U was hosted by uraninite. CONCLUSIONS Monazite only contributes limited uranium to regional uranium mineralization, and uraninite is the most important host for uranium in the Longhuashan granite.
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spelling doaj.art-04b4ecf823834bef86bb3bab99b0de7f2023-01-13T05:42:00ZengScience Press, PR ChinaYankuang ceshi0254-53572022-03-0141217418410.15898/j.cnki.11-2131/td.202109070118yk202109070118Application of Electron Probe Microanalyzer to Study the Textures and Compositions of Alteration Coronas of Monazite from the Longhuashan Granite, Northern Guangdong ProvinceZHANG Long0CHEN Zhenyu1WANG Fangyue2ZHOU Taofa3Ore Deposit and Exploration Center, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, ChinaKey Laboratory of Metallogeny and Mineral Assessment, Ministry of Natural Resources; Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, ChinaOre Deposit and Exploration Center, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, ChinaOre Deposit and Exploration Center, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, ChinaBACKGROUND Monazite is a common uranium-bearing accessory mineral in granite-related uranium deposits in South China. The Longhuashan pluton is an important U-bearing granite in the Zhuguangshan batholith, Northern Guangdong. Distinct alteration coronas of monazite were observed in the pluton. However, textures and compositions of alteration coronas of monazite and their implications for uranium mineralization are still poorly understood. OBJECTIVES To investigate the detailed textural and compositional evolution of monazite in granites during alteration, and to provide insights into uranium mobilization and enrichment in granite-related uranium deposits. METHODS Textures and chemical compositions of alteration coronas of monazite were investigated using electron probe microanalyzer (EPMA). RESULTS Alteration coronas of monazite in the Longhuashan granite consisted of newly formed apatite, allanite, epidote, and Th-rich phases. The monazite alteration coronas area was a concentric zone composed of monazite, apatite (including thorium-rich minerals), and monazite-epidote from the inside to the outside. Mass balance calculations showed that during the alteration of monazite, light rare earth (LREE), Y, Th, and U elements were remobilized and migrated, and the fluid brought in elements such as Ca, Fe, Al, and F to form alteration coronas composed of apatite, epidote, and thorium-rich minerals. The EPMA mapping showed that monazite alteration led to the remobilization of uranium, but the uranium was mainly enriched in the altered coronas. In this pluton, 3.7% U was located in monazite, and more than 80% U was hosted by uraninite. CONCLUSIONS Monazite only contributes limited uranium to regional uranium mineralization, and uraninite is the most important host for uranium in the Longhuashan granite.http://www.ykcs.ac.cn/en/article/doi/10.15898/j.cnki.11-2131/td.202109070118monazitealteration coronaselectron probe microanalyzerlonghuashan granitenorthern guangdong
spellingShingle ZHANG Long
CHEN Zhenyu
WANG Fangyue
ZHOU Taofa
Application of Electron Probe Microanalyzer to Study the Textures and Compositions of Alteration Coronas of Monazite from the Longhuashan Granite, Northern Guangdong Province
Yankuang ceshi
monazite
alteration coronas
electron probe microanalyzer
longhuashan granite
northern guangdong
title Application of Electron Probe Microanalyzer to Study the Textures and Compositions of Alteration Coronas of Monazite from the Longhuashan Granite, Northern Guangdong Province
title_full Application of Electron Probe Microanalyzer to Study the Textures and Compositions of Alteration Coronas of Monazite from the Longhuashan Granite, Northern Guangdong Province
title_fullStr Application of Electron Probe Microanalyzer to Study the Textures and Compositions of Alteration Coronas of Monazite from the Longhuashan Granite, Northern Guangdong Province
title_full_unstemmed Application of Electron Probe Microanalyzer to Study the Textures and Compositions of Alteration Coronas of Monazite from the Longhuashan Granite, Northern Guangdong Province
title_short Application of Electron Probe Microanalyzer to Study the Textures and Compositions of Alteration Coronas of Monazite from the Longhuashan Granite, Northern Guangdong Province
title_sort application of electron probe microanalyzer to study the textures and compositions of alteration coronas of monazite from the longhuashan granite northern guangdong province
topic monazite
alteration coronas
electron probe microanalyzer
longhuashan granite
northern guangdong
url http://www.ykcs.ac.cn/en/article/doi/10.15898/j.cnki.11-2131/td.202109070118
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