The trace (dispersed) elements in pyrite from the Fule Pb-Zn deposit, Yunnan Province, China, and its genetic information: A LA-ICPMS study
Li, ZL and Ye, L and Hu, YS and Wei, C and Huang, ZL and Nian, HL and Cai, JJ and Danyushevsky, L, The trace (dispersed) elements in pyrite from the Fule Pb-Zn deposit, Yunnan Province, China, and its genetic information: A LA-ICPMS study, Acta Petrologica Sinica, 35, (11) pp. 3370-3384. ISSN 1000-0569 (2019) [Refereed Article]
The Sichuan-Yunnan-Guizhou Pb-Zn mineralization province (SYGMP) is an important part of the large-scale low-temperature metallogenic domain in Southwest China. There is always controversy on whether the Pb-Zn deposits in the SYGMP belong to a MVT-type. Additionally, these deposits are mainly characterized by enrichment in dispersed elements (especially Ge) which is chiefly hosted in sphalerite. Owing to the lack of study on trace elements in pyrite, in this paper, we analyzed the characteristics of trace (including dispersed) elements in pyrite from the Fule Pb-Zn deposit by LA-ICPMS, showing that the pyrite is one of carrier minerals of Ge except the sphalerite. Three samples were collected from Fule and Fusheng ore blocks, which represent ore bodies in level 1350, 1410 and 1536 meters, respectively, i.e. from deep to shallow. The results show that the pyrites are characterized by enrichment of Cu, As, Co and Ni, and local high contents of Pb (Sb) and Zn are identified as micro-inclusions like galena and sphalerite. The dispersed elements in pyrite are typically recognized by enrichment of Se and Ge, together with minor Tl and Te. Most of the dispersed elements occur as isomorphous substitution in the pyrite, except Cd and In which principally hosted in Zn-bearing micro-inclusions (sphalerite) as isomorphous substitution too. The strongly positive correlations between Ge and Cu in the pyrite indicate the replacement mechanism is Cu2++Ge2+↔2Fe2+. The enrichment of dispersed elements in pyrite is closely related to the enrichment of ore-forming elements, especially Cu. With the development of the mineralization (ore-bodies from deep to shallow), the Se/Te ratios, dispersed and ore-forming elements are concentrated gradually. Most of the Co/Ni ratios are less than 1.00, suggesting pyrites have experienced a sedimentary-reworked process. In the scattergrams of the Co-Ni and dispersed elements Se-Tl, pyrites from the Fule deposit were plotted within the field of typical MVT deposit, and are different from that of pyrites in the SEDEX, VMS and skarn deposits. Combining the evidence of the geological features, the Fule deposit is similar to MVT deposit, it is suggested the Fule Pb-Zn deposit belong to a MVT-type deposit.