WU Tao1,2, HUANG Zhi-long1*, XIANG Zhen-zhong1,2, YE Lin1, SUI Zhi-heng3, HU Yu-si1,2, YAN Zai-fei1
(1. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China;
2. University of Chinese Academy of Sciences, Beijing 100049, China;
3. 405 Geological Prospecting Party, Bureau of Geology and Mineral Exploration and Development of Hunan Province, Jishou 416099, China)
Abstract: The Danaopo Pb-Zn deposit, located in the central part of the Western Hubei-Western Hunan-Eastern Guizhou metallogenic province, is a newly discovered super-large deposit in the Huayuan orefield. Although previous studies have obtained a lot of understandings on Pb-Zn deposits in the Huayuan region, the genetic types of Pb-Zn deposits in this area have been debated for a long time. In this paper, we have selected pyrites from ores at different elevations of the Danaopo deposit for the LA-ICP-MS in-situ point test and element mapping analysis, in order to reveal the occurrence states of various trace elements in pyrites and to provide new constraints for the genesis of the deposit. The analytical results show that these pyrites contain a few types and low contents of trace elements, indicating that they were formed in a relatively low-temperature environment. Comparatively, these pyrites are relatively rich in Co, Ni, As, Mn, Cu, Pb, and Zn. Especially, Co, Ni, As, Sb, and Ge occurred mainly in the pyrite lattice in the form of isomorphism. Most of the Zn and Pb occurred as sphalerite micro-inclusions and galena micro-/nano-particles in the pyrites, whereas the Cd, Mn, and Cu, Ag occurred as isomorphous substitution in the lattices of sphalerite and galena, respectively. In addition, the Co/Ni (mean=1.0), Zn/Ni (mean=42.0), and Cu/Ni (mean=3.5) ratios suggest that these pyrites are hydrothermal ones. Generally, features of trace elements in pyrites from the Danaopo deposit are similar to those of typical MVT type Pb-Zn deposits as pyrite samples are mostly plotted into the projection field of MVT type deposit on the diagram of Co-Ni contents. Hence, combined with the geological and geochemical characteristics of the deposit as well as the trace elements of pyrites, we have suggested that the Danaopo deposit belongs to the MVT type Pb-Zn deposit.
Keywords: The Danaopo Pb-Zn deposit; pyrite; in situ trace elements; MVT type deposit; LA-ICP-MS
ACTA MINERALOGICA SINICA Vol. 40, No.4, 2020, page 430-440
