40Ar-39Ar dating of lamprophyre dykes in the Baimazhai nickel deposit, Yunnan Province, China, and its geological significance |
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| Authors: | LI Bo HUANG Zhilong GUAN Tao DING Wei |
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| Institution: | [1]Land and Mineral Resource Engineering College of Kunming University of Science and Technology, Kunming 650093, China [2]The Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China |
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| Abstract: | The Baimazhai nickel deposit, Yunnan Province, China, is located in the southern part of the Sanjiang (Tri-river) alkali-rich intrusive rock belt (Sanjiang ARIR). In this paper was conducted 40Ar-39Ar dating of two phlogopites in lamprophyres which are, as dikes, widely distributed in the orefield, and two plateau ages were acquired, i.e., 32.46±0.62 Ma and 32.01±0.60 Ma, respectively (averaging 32.23±0.60 Ma). The ages are obviously younger than those of the ore-hosted complex and mineralization of the Baimazhai nickel deposit. In combination with the characteristics, it is indicated that lamprophyres in the orefield and those in the Sanjiang ARIR are similar in tectonic setting, mineral assemblage and geochemistry. It is considered that lamprophyres in the orefield are the important component of the Sanjiang ARIR, and the lamprophyres and ore-hosted complex in the orefield represent the products of two times of different magmatic activity from different mantle sources. On the other hand, the age of lamprophyres in the orefield is older than that of the strike-slip shearing of the Ailaoshan-Honghe fault belt, suggesting that the strike-slip shearing of the Ailaoshan-Honghe fault belt is not the factor leading to magmatic activity of lamprophyres in the orefield, while it is more possible that magmatic activity of the Sanjiang ARIR promoted strike-slip shearing of the fault belt. |
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| Keywords: | lamprophyre 40Ar-39Ar dating geological significance Baimazhai nickel deposit Yunnan Province |
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