The Yinachang Fe-Cu-Au-U-REE deposit and its relationship with intermediate to mafic intrusions, SW China: implications for ore genesis and geodynamic setting

Zhu, Ligang, Liu, Jiajun, Bagas, Leon, Carranza, Emmanuel John M., Zhai, Degao, Meng, Guangzhi, Wang, Jianping, Wang, Yinhong, Zhang, Fangfang, and Liu, Zhenjiang (2019) The Yinachang Fe-Cu-Au-U-REE deposit and its relationship with intermediate to mafic intrusions, SW China: implications for ore genesis and geodynamic setting. Ore Geology Reviews, 104. pp. 190-207.

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Abstract

The Yinachang Fe-Cu-Au-U-REE deposit is located in the Kangdian region at the southwestern margin of the Yangtze Block. This contribution presents petrological, geochronological, whole rock geochemical, and Rare Earth Elements (REE) geochemistry of zircons of gabbro and diorite dykes associated with the Yinachang Fe-Cu-Au-U-REE deposit, aiming to constrain the age of the mineralisation and help refine our understanding of the tectonic setting of the region. Zircons from diorite have a Palaeoproterozoic U-Pb age of 2014 +/- 30 Ma, and zircons from the gabbro could not be dated because they are metamict, having a high concentration of uranium. The ca. 2014 Ma age of the zircons in the diorite indicates that the southwestern part of the Yangtze Block is partly synchronous with the Columbia Supercontinent. Geochemically, the diorite and gabbro are enriched in large-ion lithophile elements (LILEs) such as Rb and U, and depleted in high-field-strength elements (HFSEs) such as Nb, P, Ti, Ba, and Sr. The diorite is enriched in light REEs (LREEs) and has a slight to negligible Eu anomaly, which are characteristic of ocean-island basalts containing mantle-derived high potassic calc-alkaline rocks. In contrast, the gabbro is weakly enriched in LREES and has a slightly negative Eu anomaly similar to those of potassic calc-alkaline enriched mid-ocean-ridge basalt. The average combined REE content of zircons from the gabbro is 19401 ppm and is significantly higher than that of the zircons from the diorite averaging 1020 ppm. This indicates that the gabbro is closely related with the REE mineralisation at the deposit. The geochemistry of the diorite indicates that it formed at the continental margin of a volcanic-arc. It also indicates that the magmatic rocks in the region have a possible mantle plume origin contaminated by crustal material and located at a transitional zone between a rift and an ocean-continent tectonic setting.

Item ID: 57737
Item Type: Article (Research - C1)
ISSN: 1872-7360
Keywords: Columbia supercontinent, Yangtze block, Kangdian region, Yinachang deposit, LA-ICP-MS zircon U-Pb dating, Zircon trace element analysis
Copyright Information: © 2018 Elsevier B.V. All rights reserved.
Funders: Major Basic Research Program of People's Republic of China (MBRP), China Scholarship Council (CSC), Fundamental Research Funds for the Central Universities (FRFCU), China University of Geosciences (CUG), State Administration of Foreign Experts Affairs, China (SAFEAC)
Projects and Grants: MBRP 2014CB440903, CSC 201706400056, FRFCU/CUG grant no. 2652017266, SAFEAC grant no. B07011, CUG MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources
Date Deposited: 27 Mar 2019 07:38
FoR Codes: 04 EARTH SCIENCES > 0403 Geology > 040307 Ore Deposit Petrology @ 34%
04 EARTH SCIENCES > 0403 Geology > 040304 Igneous and Metamorphic Petrology @ 33%
04 EARTH SCIENCES > 0403 Geology > 040306 Mineralogy and Crystallography @ 33%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970104 Expanding Knowledge in the Earth Sciences @ 100%
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