Consistent crystal orientation of core and rim pyrites indicates an epitaxial growth of rim in Carlin-type gold deposits  

作　　者：Jingdan Xiao Zhuojun Xie Yong Xia Phillip Gopon Qinping Tan 

机构地区：[1]State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China [2]Department of Applied Geology and Geophysics,University of Leoben,Peter Tunner Strasse,8770 Leoben,Styria,Austria

出　　处：《Geoscience Frontiers》2025年第1期223-234,共12页地学前缘(英文版)

基　　金：supported by grants from the National Natural Science Foundation of China(42073044);National Key R&D Program of China(2023YFC2906801);Geological Exploration Fund of Guizhou Province(No.2024-2;520000214TLCOG7DGTNRG);Youth Innovation Promotion Association,Chinese Academy of Sciences(2022402);Science and Technology Foundation of Guizhou Province(Qiankehepingtairencai-CXTD[2021]007);West Light Foundation of the Chinese Academy of Sciences(xbzg-zdsys-202108).

摘　　要：The gold-bearing arsenian pyrite in Carlin-type gold deposits typically grows around the gold/arsenic-poor pyrite core,forming core-rim textured pyrite.However,the causes of rim pyrite precipitation around the early-formed core pyrite and the growth mechanisms of the rim pyrite remain unclear.Here,we combined scanning electron microscopy,electron probe micro-analysis,and nanoscale secondary ion mass spectrometry to investigate the textural and chemical characteristics of core-rim textured pyrite from the giant Shuiyindong and Lannigou gold deposits.Furthermore,we used electron backscattered diffraction and transmission electron microscopy to characterize their crystallographic structure.The results indicated that core-rim textured pyrite is the dominant pyrite type in the ore.This type of pyrite is characterized by the sharp core-rim interfaces,euhedral-subhedral morphology,and oscillating zoning.The gold/arsenic-rich rim and gold/arsenic-poor core formed during the main-ore and pre-ore stages,respectively.Crystallographically,the rim showed that a crystallographic orientation is similar to that of the core along the(010)crystal facet,indicating that the core pyrite serves as a template for the epitaxial growth of rim pyrite.Textural and chemical features indicate that the epitaxy occurs in the process of direct precipitation of main-ore pyrite over the pre-ore pyrite.As Carlin ore fluids dissolve the iron-bearing carbonates,iron concentrations in the fluids increase,thereby creating a supersaturation environment suitable for the nucleation of main-ore pyrite.Because the minimal lattice misfit would minimize the surface free energy and the(010)facet of pyrite has a lower surface energy than other facets,the nucleated pyrite would readily grow along the(010)facet of preexisting pyrite via epitaxy.Our findings highlight that the widespread preexisting pyrite facilitates late-stage pyrite precipitation.For Carlin-type gold deposits,the pre-ore pyrite is essential owing to its promoting the precipitation of gold-bear

关 键 词：Core-rim textured pyrite Epitaxial growth Carlin-type gold deposits SHUIYINDONG Lannigou 

分 类 号：P61[天文地球—矿床学]