Origin of the Fangmayu Chromite Deposit, Miyun, Beijing: Constraints from Electron Microprobe Analyses of Cr-Spinel
Stratiform chromite deposits in China have long been considered to form by fractional crystallization of mafic magma. However, some researchers recently proposed that some chromite deposits are also hosted in ophiolite. In this study, Cr-spinels of the dunites, wehrlites and clinopyroxenites from th...
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| Format: | Article |
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Science Press, PR China
2015-09-01
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| Series: | Yankuang ceshi |
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| Online Access: | http://www.ykcs.ac.cn/en/article/doi/10.15898/j.cnki.11-2131/td.2015.05.017 |
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| author | LI Li-xing ZHU Ming-yu FANG Tong-ming LI Hou-min |
| author_facet | LI Li-xing ZHU Ming-yu FANG Tong-ming LI Hou-min |
| author_sort | LI Li-xing |
| collection | DOAJ |
| description | Stratiform chromite deposits in China have long been considered to form by fractional crystallization of mafic magma. However, some researchers recently proposed that some chromite deposits are also hosted in ophiolite. In this study, Cr-spinels of the dunites, wehrlites and clinopyroxenites from the Fangmayu chromite deposit in Beijing are analyzed by EPMA. Results show that Cr-spinels of dunites and wehrlites at the early stage of magma differentiation are rich in Cr with an average Cr2O3 content of 43.32%. At the late stage of magma differentiation, the crystallization of clinopyroxenites consumed large amounts of Cr3+ and elevated the oxygen fugacity, leading to the Cr-rich magnetite and Al-rich spinel with average Cr2O3 contents of 10.32% and 15.77%, respectively. By comparing with the chemical composition of different types of Cr-spinels from the world, the suggestion is that Fangmayu chromite deposit was a magmatic deposit hosted in Alaskan-type intrusion, and was not related to ophiolite. The constraints on the genesis and metallogenic specialization provide evidence for mineral prospecting of Cr, Cu-Ni and PGE deposits hosted in mafic-ultramafic intrusions. |
| first_indexed | 2024-04-10T16:28:16Z |
| format | Article |
| id | doaj.art-a8e691e463e849b1bb14578c9ae08acc |
| institution | Directory Open Access Journal |
| issn | 0254-5357 |
| language | English |
| last_indexed | 2024-04-10T16:28:16Z |
| publishDate | 2015-09-01 |
| publisher | Science Press, PR China |
| record_format | Article |
| series | Yankuang ceshi |
| spelling | doaj.art-a8e691e463e849b1bb14578c9ae08acc2023-02-09T01:42:34ZengScience Press, PR ChinaYankuang ceshi0254-53572015-09-0134560060810.15898/j.cnki.11-2131/td.2015.05.017ykcs-34-5-600Origin of the Fangmayu Chromite Deposit, Miyun, Beijing: Constraints from Electron Microprobe Analyses of Cr-SpinelLI Li-xing0ZHU Ming-yu1FANG Tong-ming2LI Hou-min3Key Laboratory of Metallogeny and Mineral Assessment, Ministry of Land and Resources, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, ChinaKey Laboratory of Metallogeny and Mineral Assessment, Ministry of Land and Resources, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, ChinaBeijing Institute of Geological Survey, Beijing 100195, ChinaKey Laboratory of Metallogeny and Mineral Assessment, Ministry of Land and Resources, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, ChinaStratiform chromite deposits in China have long been considered to form by fractional crystallization of mafic magma. However, some researchers recently proposed that some chromite deposits are also hosted in ophiolite. In this study, Cr-spinels of the dunites, wehrlites and clinopyroxenites from the Fangmayu chromite deposit in Beijing are analyzed by EPMA. Results show that Cr-spinels of dunites and wehrlites at the early stage of magma differentiation are rich in Cr with an average Cr2O3 content of 43.32%. At the late stage of magma differentiation, the crystallization of clinopyroxenites consumed large amounts of Cr3+ and elevated the oxygen fugacity, leading to the Cr-rich magnetite and Al-rich spinel with average Cr2O3 contents of 10.32% and 15.77%, respectively. By comparing with the chemical composition of different types of Cr-spinels from the world, the suggestion is that Fangmayu chromite deposit was a magmatic deposit hosted in Alaskan-type intrusion, and was not related to ophiolite. The constraints on the genesis and metallogenic specialization provide evidence for mineral prospecting of Cr, Cu-Ni and PGE deposits hosted in mafic-ultramafic intrusions.http://www.ykcs.ac.cn/en/article/doi/10.15898/j.cnki.11-2131/td.2015.05.017fangmayuchromite depositcr-spinelultramafic rocksalaskan-type intrusionelectron microprobe |
| spellingShingle | LI Li-xing ZHU Ming-yu FANG Tong-ming LI Hou-min Origin of the Fangmayu Chromite Deposit, Miyun, Beijing: Constraints from Electron Microprobe Analyses of Cr-Spinel Yankuang ceshi fangmayu chromite deposit cr-spinel ultramafic rocks alaskan-type intrusion electron microprobe |
| title | Origin of the Fangmayu Chromite Deposit, Miyun, Beijing: Constraints from Electron Microprobe Analyses of Cr-Spinel |
| title_full | Origin of the Fangmayu Chromite Deposit, Miyun, Beijing: Constraints from Electron Microprobe Analyses of Cr-Spinel |
| title_fullStr | Origin of the Fangmayu Chromite Deposit, Miyun, Beijing: Constraints from Electron Microprobe Analyses of Cr-Spinel |
| title_full_unstemmed | Origin of the Fangmayu Chromite Deposit, Miyun, Beijing: Constraints from Electron Microprobe Analyses of Cr-Spinel |
| title_short | Origin of the Fangmayu Chromite Deposit, Miyun, Beijing: Constraints from Electron Microprobe Analyses of Cr-Spinel |
| title_sort | origin of the fangmayu chromite deposit miyun beijing constraints from electron microprobe analyses of cr spinel |
| topic | fangmayu chromite deposit cr-spinel ultramafic rocks alaskan-type intrusion electron microprobe |
| url | http://www.ykcs.ac.cn/en/article/doi/10.15898/j.cnki.11-2131/td.2015.05.017 |
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