Sulfur isotope and trace element compositions of pyrite determined by NanoSIMS and LA-ICP-MS: new constraints on the gen
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ARTICLE
Sulfur isotope and trace element compositions of pyrite determined by NanoSIMS and LA-ICP-MS: new constraints on the genesis of the Shuiyindong Carlin-like gold deposit in SW China Jin-xiang Li 1,2 & Rui-zhong Hu 1,2 & Cheng-hai Zhao 1 & Jing-jing Zhu 1 & Yong Huang 1,2 & Wei Gao 1,2 & Jin-wei Li 1,2 & Yu-zhou Zhuo 1,2 Received: 28 September 2018 / Accepted: 1 October 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019
Abstract The Shuiyindong Carlin-like gold deposit, the largest one of this type in China, is located in the Late Paleozoic–Early Mesozoic Youjiang basin. The pyrites in the studied ore bodies (No. I to V) can be divided into four main types plus several sub-types: (1) Aspoor pyrites include Py1 (Py1a and Py1b), Py2, and Py3; and (2) As-rich pyrite Py4 (Py4a and Py4b). In situ LA-ICP-MS analyses show that the As-rich pyrite also contains higher Au, Cu, Sb, and Tl than the other pyrite types. In situ NanoSIMS analyses show the δ34S variation of Py1 (48.1~67.5‰), Py2 (2.4~7.6‰), Py3 (9.2~14.2‰), and Py4 (− 3.0~6.6‰), with the average values of 58.1‰, 5.1‰, 11.4‰, and 3.1‰, respectively. The large δ34S variations of As-poor pyrites may reflect a sedimentary source. However, the narrow ranges of δ34S values for the As-rich pyrite (Py4) may not reflect a sedimentary but a magmatic or metamorphic origin. A metamorphic sulfur source of Py4 is favored due to paucity of coeval magmatism in the region and decreasing variations of δ34S values from Py1 to Py4. Integrated transmission electron microscope (TEM) and NanoSIMS element mapping show that the distribution and concentration of Au are discordant with As and Cu at the submicron scale, also implied by the occurrence of some of Au as nanosubmicron particles in Py4. Overall, our new data indicate that the ore fluids were not only enriched in Au but also in As, Cu, and S. Taking an alternative of fluid oxidation probably resulting in the decreasing δ34S values of Py4, our result of I to Vorebodies indicates the mixing between the underlying metamorphic fluid and meteoric water. Integrated variations in δ34S and As-Au-Cu correlations across individual pyrite grains infer the physicochemical changes of aqueous and/or aqueous-carbonic fluids along migration paths. Keywords Shuiyindong Carlin-like gold deposit . Pyrite . NanoSIMS and LA-ICP-MS analyses . Sulfur isotopes . Trace element compositions
Introduction
Editorial handling: S.-Y. Jiang Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00126-019-00929-w) contains supplementary material, which is available to authorized users. * Rui-zhong Hu [email protected] 1
State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
2
College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
As a significant type of gold deposits worldwide, Carlin-like gold deposit (CLGD) is best known in northern Nevada, the USA, and southwest
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